2024/06/26 更新

写真a

オクイ マナブ
奥井 学
OKUI Manabu
所属
理工学部 准教授
外部リンク

学位

  • 博士(工学) ( 中央大学 )

  • 修士(工学) ( 東京工業大学 )

学歴

  • 2018年3月
     

    中央大学   理工学研究科   精密工学専攻   博士後期   修了

  • 2014年3月
     

    東京工業大学   機械制御システム専攻   博士前期   修了

  • 2012年3月
     

    東京工業大学   工学部   制御システム工学科   卒業

経歴

  • 2024年4月 - 現在

    中央大学理工学部   准教授

  • 2023年4月 - 2024年3月

    株式会社IHI   技術開発本部

  • 2019年4月 - 2023年3月

    中央大学   理工学部   助教

  • 2018年4月 - 2019年3月

    中央大学   研究開発機構   助教

  • 2016年1月 - 2018年3月

    中央大学   研究開発機構   研究員

  • 2014年4月 - 2015年12月

    日産自動車株式会社

  • 2012年9月 - 2012年12月

    The Centre for Rapid and Sustainable Product Development   Intern

▼全件表示

研究キーワード

  • 制御

  • ロボティクス

  • アクチュエータ

  • 空気圧

研究分野

  • 情報通信 / 機械力学、メカトロニクス

  • ライフサイエンス / リハビリテーション科学

論文

  • Construction of Motion Mode Switching System by Machine Learning for Peristaltic Mixing Conveyor Based on Intestinal Movement

    Iori Terayama, Sana Oshino, Rie Nishihama, Manabu Okui, Ryosuke Adachi, Taro Nakamura

    IEEE Access   12   25980 - 25992   2024年

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Institute of Electrical and Electronics Engineers (IEEE)  

    The high frequency of rocket launches requires low-cost solid rocket fuel. Currently, the fuel manufacturing process faces increased launch costs caused by the risk of ignition from rotary mixers and increased equipment and labor costs from batch processes in which mixing and conveying are separated. Therefore, this paper proposes and verifies an automatic switching system between mixing and conveying modes for a peristaltic mixing conveyor that enables safe and continuous mixing and conveying of solid fuel. In a previous study, peristaltic mixing conveyor with low shear force was developed and successfully produced solid fuel. However, there was room for improvement for more efficient fuel production because the device was controlled by pre-determined driving pattern. The actual intestine generates movement autonomously by enteric nerves. Therefore, the development of a sensing function that imitates the enteric nervous system and generates movement patterns based on the acquired data is expected to improve manufacturing efficiency. In this study, the sensor data of a mixed solid fuel simulant packaged in a bag were acquired, and the degree of mixing (unmixed and mixed completely) was discriminated using supervised learning (the k-nearest neighbor method). Furthermore, a system was constructed to continue the mixing mode when unmixing and automatically switch the motion to the conveying mode when the mixing was complete. The experiment showed that the motion mode automatically switched to the conveying mode at almost the same time as the labeled training data, and mixing and conveying of the simulated material was successfully performed.

    DOI: 10.1109/ACCESS.2024.3366457

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  • Validation of a lower limb exoskeleton assist device focusing on viscous properties: verification of assist effectiveness by measuring muscle activity

    Yusuke Shimoda, Tomotaka Sugino, Manabu Okui, Rie Nishihama, Taro Nakamura

    ROBOMECH Journal   10 ( 1 )   2023年12月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Springer Science and Business Media LLC  

    Abstract

    Because exoskeletal assistive devices are worn directly by a person, enhancing cooperation is important. However, existing assistive devices have problems in terms of their cooperation with human behaviors. This is because existing assistive devices are driven by estimating the wearer’s movement intention based on predetermined movement time and device angle information. Although these methods are expected to work as expected, in practice, it is difficult to achieve the expected behavior. Therefore, an assistance method is required to reduce such misalignment with time and misalignment between the device and wearer. Therefore, this study focused on the viscoelastic properties that generate force in response to movement and are expected to enhance coordination. In a previous study, the authors confirmed the effects of viscoelastic properties or an assistive device with variable stiffness. However, viscous characteristics during movement have not been considered. In this study, we aimed to improve the coordination by focusing on the viscous characteristics. The viscous torque outputs in response to the angular velocity are expected to be driven in response to actual human motion. In this study, the viscous torque was calculated as the product of the command viscosity coefficient and the joint angular velocity and was applied to a lower-limb exoskeleton-type assist device equipped with a magneto-viscous fluid brake and a planetary gear mechanism. In addition, a viscous command that changes the torque according to speed (proposed method), a time command that changes the output value according to the passage of time, and an angle command that changes the command value according to the angle information of the device were applied to the assist device, and surface EMG measurements and command signals were compared. The target movement was a seated movement, and the left and right vastus medialis and semimembranosus muscles were measured. More than half of the subjects showed a decrease in myopotential for five subjects for all three command methods, confirming the effectiveness of the viscous command.

    DOI: 10.1186/s40648-023-00262-y

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    その他リンク: https://link.springer.com/article/10.1186/s40648-023-00262-y/fulltext.html

  • Development of a Bimanual Wearable Force Feedback Device with Pneumatic Artificial Muscles, MR Fluid Brakes, and Sensibility Evaluation Based on Pushing Motion

    Ryunosuke Sawahashi, Jonah Komatsu, Rie Nishihama, Manabu Okui, Taro Nakamura

    Journal of Robotics and Mechatronics   35 ( 1 )   180 - 193   2023年2月

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Fuji Technology Press Ltd.  

    In a virtual reality (VR) space, wearing a head-mounted display can help with the visualization of objects; however, users cannot experience realistic tactile sensations. Recently, several force feedback devices have been developed, including wearable devices that use straight-fiber-type pneumatic muscles and magnetorheological fluids. This allows the devices to render elastic, frictional, and viscous forces during spatially unrestricted movement. Nevertheless, a problem remains in that previous devices could handle many bilateral upper limb movement tasks. Therefore, this study aims to develop a device that can handle movements that interact with both arms. Based on experiments concerning the pushing motion in a VR space, the influence of the pseudo force sense was determined to not be small. In addition, we confirmed that the force sensation presented by this system was more realistic when the robot was operated with both arms than when operated with the right arm.

    DOI: 10.20965/jrm.2023.p0180

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  • Development of Shoulder Mechanism for a Wearable Upper Limb Force-Feedback Device with Pneumatic Artificial Muscles and MR Brakes

    J. Komatsu, R. Sawahashi, T. Masuda, M. Okui, T. Nakamura

    2023 IEEE/SICE International Symposium on System Integration, SII 2023   2023年1月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    We have been developing a wearable force-feedback device using pneumatic artificial muscles and magnetorheological fluid brakes. In a previous study, we confirmed that this device can present the stiffness of a virtual object. However, based on the results of a questionnaire administered during the experiment, we considered that the subjects' awareness of the device's weight suppressed the reality of the VR experience. Therefore, we redesigned the device to reduce the physical burden on the user. From simulation results, we confirmed that this redesign reduced the shoulder joint torque required for flexion and increased the workspace of the force-feedback device. In addition, the torque transmission characteristics of the link mechanism involved in horizontal shoulder motion was tested. We also measured the vertical load applied to the user's hand during horizontal shoulder motion. The results show that the device transmits torque close to the target value in the horizontal flexing direction but does not reach the target value in the horizontal extending direction. We also confirmed that the vertical load during horizontal motion could be reduced by redesigning the device.

    DOI: 10.1109/SII55687.2023.10039212

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  • Discrimination of Powder Particle Size and Input Amounts for the Estimation of Mixing Using a Peristaltic Mixing Conveyor Imitating an Intestinal Tube

    Iori Terayama, Sana Oshino, Rie Nishihama, Manabu Okui, Taro Nakamura

    2023 IEEE/SICE International Symposium on System Integration, SII 2023   2023年1月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Continuous mixing and conveying technology for solid-liquid mixtures and highly viscous fluids are required during food and medicine manufacturing. To realize this, we developed a peristaltic mixing and conveying device that mimics the motion of intestines. The device uses air pressure to inflate a rubber tube or other materials to mix and convey the contents. We are working on estimating the state of the contents using pressure and flow sensors and acceleration sensors mounted on the device. In this study, for powder discrimination, a multi-class determination was conducted for powders with different particle sizes and input amounts using the three types of sensor data. We used principal component analysis of time series data for each sensor and decision trees and support vector machine (SVM) as judges. The results indicate that the correct response rate was 97.0% when the three types of sensors were used. Accelerometers have more information than pressure or flow sensors, and using accelerometers increased the percentage of correct responses.

    DOI: 10.1109/SII55687.2023.10039173

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  • Prolonging rubber fatigue life using hysteresis of strain-induced crystallization of natural rubber

    Manabu Okui, Akihiro Kojima, Itsuki Hisamichi, Shotaro Kuriyama, Tomohisa Kojima, Tomoaki Tsuji, Taro Nakamura

    Polymer Testing   117   107800 - 107800   2023年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier BV  

    Recently, soft robots have attracted considerable attention; however, they often undergo large deformations. Thus, their lifespans are critical issues. Therefore, this study proposes a novel method for extending the lives of rubber materials. We extend the fatigue life of rubber materials by focusing on the hysteresis of the straininduced crystallization characteristics of rubber. Strain-induced crystallization is a phenomenon wherein rubber molecules exhibit crystal structures by elongation. These crystal structures are generated by elongation and disappear with relaxation. However, hysteresis occurs in both the generation and disappearance processes. Therefore, if the rubber is not completely relaxed, the disappearance of the crystal layers is slowed by hysteresis, and the formation of cracks is hindered. Herein, we select two types of rubbers: those exhibiting strain-induced crystallization characteristics (natural rubber (NR)) and those that do not (styrene-butadiene rubber (SBR)). First, wide-angle X-ray diffraction is used to confirm the formation of crystal layers under stretching for both types of rubbers. Fatigue life test is conducted using rectangular test pieces made of NR and SBR by repeated tensile tests. Subsequently, a fatigue life test is conducted for a straight-fiber-type pneumatic artificial muscle prepared by NR and SBR. The results reveal that the fatigue life is approximately 100 times longer than normal, thereby confirming the effects of prolonging the fatigue life using the hysteresis of strain-induced crystallization.

    DOI: 10.1016/j.polymertesting.2022.107800

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  • Evaluation of Support Device for Manual Handling of Gas Cylinders

    Kiyotaka Oba, Manabu Okui, Rie Nishihama, Taro Nakamura

    Lecture Notes in Networks and Systems   530 LNNS   550 - 559   2023年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPRINGER INTERNATIONAL PUBLISHING AG  

    In this study, a support device for liquefied petroleum (LP) gas cylinder delivery was developed and evaluated using questionnaires. This study contributes to developing a method for reducing the burden of gas cylinder delivery. LP gas cylinders are manually transported, and the physical burden on delivery personnel is high. Existing methods to minimize this burden include cart transportation. In the delivery environment, narrow spaces and steps exist, increasing the difficulty of cart transportation. Therefore, we propose a support device as a new method for reducing this burden. The support device was designed based on a survey of the LP gas cylinder delivery environment and a method for holding cylinders. The support device enhanced walking and was less physically demanding. The subjective evaluation showed that it exhibits the characteristics of the main method used for holding cylinders while improving the shortcomings. This device significantly reduces the load on the upper body during delivery.

    DOI: 10.1007/978-3-031-15226-9_50

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    その他リンク: https://dblp.uni-trier.de/db/conf/clawar/clawar2022.html#ObaON022

  • Grasping Characteristics of Flexible Propulsion Unit Using Braid Mechanism for Lunar Exploration Robot

    Chikage Fujikawa, Ryosuke Tokoi, Wataru Toyama, Manabu Okui, Tsuji Tomoaki, Taro Nakamura, Takashi Kubota

    Lecture Notes in Networks and Systems   530 LNNS   33 - 41   2023年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:SPRINGER INTERNATIONAL PUBLISHING AG  

    In this study, the authors model and conduct experiment on the braid propulsion unit of an excavation robot for lunar exploration. In existing studies, it is difficult for robots to create sufficiently big holes and achieve deep excavations. Therefore, in this study, we developed a lunar earthworm-type excavation robot "LEAVO," which attempts to excavate boreholes for environmental sensors and collect samples in particular layers. LEAVO has already succeeded in a vertical excavation of more than 938 mm and we have verified its usefulness in the first target mission. However, the existing propulsion unit of LEAVO cannot sufficiently bend and grip curved or uneven walls. In this research, we proposed a novel propulsion unit using braid to achieve curving excavation for the second target mission, modeled the gripping force of the proposed mechanism, and measured the gripping force of the prototype using the mechanism. The experiment demonstrated the validity of the modeling and the usefulness of the proposed mechanism.

    DOI: 10.1007/978-3-031-15226-9_6

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    その他リンク: https://dblp.uni-trier.de/db/conf/clawar/clawar2022.html#FujikawaTTOT0K22

  • Components and Basic Evaluation of Earthworm-Type Ice-Drilling Robot for Exploration Under Arctic-Sea-Ice

    Yuka Takeda, Ryosuke Tokoi, Chikage Fujikawa, Manabu Okui, Hiroshi Yoshida, Taro Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2023年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    In recent years, the sea ice in the Arctic Ocean has been decreasing due to climate change caused by greenhouse gases. Therefore, the phenomena under the sea ice must be investigated. The existing method of autonomous underwater vehicle (AUV) exploration is limited by its narrow communication and acoustic triangulation range. Therefore, digging a hole through the ice sheet is proposed to secure a communication relay system under the ice sheet. The objective of this study is to develop a robot using peristaltic motion as a system for drilling holes in sea ice. In the previous study, we determined the required specifications for the sea ice drilling robot. In this study, the excavation unit and the propulsion unit of the sea ice drilling robot are developed according to this specification. The basic characteristics of each mechanism were evaluated, and the digging performance of the excavation unit and the gripping performance of the propulsion unit were confirmed.

    DOI: 10.1109/IECON51785.2023.10311873

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  • Presentation of Underwater Sensation by Drag in Knee Motion with a Lower Limb Exoskeleton Using MR Fluid Brakes

    Ryunosuke Sawahashi, Taiki Masuda, Taiga Shimizu, Rie Nishihama, Manabu Okui, Taro Nakamura

    IEEE International Symposium on Industrial Electronics   2023-June   2023年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    In recent years, force feedback devices have been developed to improve the reality of VR experiences. However, a majority of force feedback devices target the upper limbs. Force feedback to the lower limbs will enable a VR experience that cannot be achieved by force feedback to the upper limbs alone. In this study, an exoskeletal lower limb force-feedback device was developed to improve the sense of reality in a Virtual Reality (VR) space. This device has Magnetorheological (MR) fluid brakes placed at the joints and can present frictional and viscous force through torque control. We designed a drag model that simplifies the force generated in reality as the force presented when the knee is operated in water. Then, the sensation of motion when the knee is flexed and extended in water was evaluated from the viewpoints of reality and drag force. The experimental results showed that the force presentation using the MR fluid brake proportional to the velocity gave a sense of reality of approximately 50%.

    DOI: 10.1109/ISIE51358.2023.10227941

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  • Proposal of a Method for Measuring Inside Diameter of Tubes Using a Drive Unit of a Robot for Inspection of Small Tubes

    Hiroto Nagashima, Fumio Ito, Taro Nakamura, Kousuke Uchiyama, Manabu Okui

    IEEE International Symposium on Industrial Electronics   2023-June   1 - 7   2023年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    Sewerage systems are indispensable infrastructures; thus, it is important to monitor their condition through periodic inspections. The wall thickness of pipes is particularly important during inspection. However, measuring the wall thickness of pipes in long, narrow, and complicated shapes using existing technologies is difficult. Therefore, this study aims to establish a method for measuring and estimating the inside diameter of pipes that can be used for long-distance, complex buried pipes. In a previous study, a pneumatically driven robot was developed for long-distance pipe inspection. We proposed a method to estimate the pipe inner diameter from the information obtained from the driving unit of this robot. In this method, a geometry model of the pneumatic drive unit was developed, and the model was used to estimate the pipe's inner diameter from the supply pressure and flow rate to the unit. Experimental results show that the developed model can estimate the inside diameter within an error range of less than 5%. This method can be used to estimate the inside diameters of long, narrow, and complicated pipes, and it can help prevent accidents, such as liquefaction and gas leakage caused by pipe failure.

    DOI: 10.1109/ISIE51358.2023.10228060

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    その他リンク: https://dblp.uni-trier.de/db/conf/isie/isie2023.html#NagashimaINUO23

  • Experimental evaluation of the white cane device with force-feedback function using air jets

    H. Oshima, R. Sawahashi, M. Okui, R. Nishihama, T. Nakamura

    2023 IEEE/SICE International Symposium on System Integration, SII 2023   2023年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    It is estimated that 250 million visually impaired people reside worldwide, and this number is expected to increase. Even though Braille blocks and guide dogs are used to guide the visually impaired, availability of installation location and cost are some of the major issues in implementing the same. Therefore, there is a need for a device for personal guidance that does not limit the location of use. Therefore, this study focuses on force-sensing presentation using the reaction force of air jets. The proposed white cane-type force-sensing device consists of a white cane, an air pressure source, solenoid valves, and a nozzle is attached to the white cane to inject compressed air. The reaction force obtained at the time of jetting generates a moment in the hand of the user, presenting force perception. Here, as a part of an initial study of the device, the effectiveness of the directional presentation, an obstacle avoidance experiment using an ultrasonic sensor, and a demonstration experiment of guidance were conducted.

    DOI: 10.1109/SII55687.2023.10039470

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  • Proposal for a Lifting Support Device for LP Gas Delivery Operations

    Kiyotaka Oba, Ryunosuke Sawahashi, Manabu Okui, Rie Nishihama, Taro Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2023年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    We present the development of a wearable body support device for LP gas delivery work and evaluation of the device by wearers. This study proposes a method for reducing the physical burden involved in delivering LP gas cylinders, as LP gas cylinders are transported manually. Delivery personnel must navigate stairs and narrow spaces, which make it difficult to use existing methods for reducing physical burden, such as carts. We aim to develop a device that can be used for LP gas delivery. In a previous study, we conducted a field survey. We found that the burden on delivery workers was due not only to carrying the cylinder, but also to lifting. Based on the field survey, this paper describes the development of a lifting support device that reduces the physical burden and facilitates smooth delivery. The subjective evaluations confirmed that the proposed device reduced the physical burden while providing the same ease of lifting as do conventional grasping methods. The device is designed to support lifting during delivery work and greatly supports lifting movements during delivery work.

    DOI: 10.1109/IECON51785.2023.10312418

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  • Development of an Evaluation Simulator for Gastrointestinal Stents by Applying a Peristaltic Pump: Prototype fabrication of evaluation simulators and characteristic tests

    Shogo Uzawa, Takeru Hashiguchi, Manabu Okui, Taro Nakamura

    2023 IEEE International Conference on Robotics and Biomimetics, ROBIO 2023   1 - 6   2023年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    This study proposes an evaluation simulator for gastrointestinal stents that reproduces the three-dimensional (3D) behavior of the intestine. One of the symptoms of colorectal cancer is intestinal obstruction. When an intestinal obstruction occurs, the contents of the intestinal tract become blocked, which has various adverse effects on the body. Treatment of intestinal obstruction is generally conservative, but surgery is performed when improvement is not expected. Currently, there are two methods of evaluating the performance of gastrointestinal stents: durability and movement tests. In the durability test, a compression test is repeatedly performed to evaluate the durability of the gastrointestinal stent. In the movement test, the stent is compressed continuously like a wave, and the displacement of the gastrointestinal stent with respect to the number of repetitions is measured. These two types of evaluation tests are used to evaluate the function of the gastrointestinal stent. However, there is no unified standard for evaluation tests of gastrointestinal stents, and each manufacturer conducts their own performance tests. In addition, current evaluation test methods differ from the actual intestine at multiple points. Therefore, an evaluation test method that can reproduce the environment of the intestinal tract with high accuracy is needed. Therefore, the authors focused on a peristaltic pump that mimics a living body. We propose an evaluation simulator for gastrointestinal stents that can reproduce 3D behavior similar to actual intestinal peristalsis, based on the driving principle of a unit-connected peristaltic pump. This paper first establishes the concept behind the development of an evaluation simulator for gastrointestinal stents, and then describes the developed evaluation simulator. Finally, we conducted experiments to measure the contraction pattern and internal pressure during contraction of the evaluation simulator and evaluated this simulator by comparing it with the actual peristalsis of the intestinal tract. The experimental results confirmed that it is possible to reproduce behavior similar to the actual intestinal tract movement.

    DOI: 10.1109/ROBIO58561.2023.10354781

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    その他リンク: https://dblp.uni-trier.de/db/conf/robio/robio2023.html#UzawaHON23

  • Control of single-stroke movement of a drum-playing robot by reinforcement learning using a realistic artificial muscle-driven robot

    Manabu Okui, Shiori Nakamura, Seigo Kimura, Ryuji Suzuki, Rie Nishihama, Taro Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2022-October   2022年10月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Artificial muscles are advantageous owing to dynamic stiffness; however, the drawback of this is their poor controllability. Here, a reinforcement learning-based control system is proposed and exemplified on a realistic artificial muscle-driven robot. The proposed system suppresses the modeling error, and allows to generate dynamic motion patterns that utilize the body structure and variable stiffness characteristics. As an example application, we consider drum playing. We propose a reinforcement learning-based realistic drum-playing robot. We propose a reinforcement learning-based strategy for this realistic robot and confirm its effectiveness through simulations and experiments.

    DOI: 10.1109/IECON49645.2022.9968757

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  • 空気噴出を利用した力覚装置による身体誘導 査読

    澤橋 龍之介, 保井 拓巳, 奥井 学, 西濵 里英, 中村 太郎

    日本バーチャルリアリティ学会論文誌   27 ( 3 )   264 - 273   2022年9月

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    記述言語:日本語   出版者・発行元:特定非営利活動法人 日本バーチャルリアリティ学会  

    DOI: 10.18974/tvrsj.27.3_264

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  • Development of Variable Viscoelastic Joint Module Performance Evaluation and Proposal of Application Examples

    Tetsuhito Fujita, Yusuke Shimoda, Katsuki Machida, Manabu Okui, Rie Nishihama, Taro Nakamura

    Actuators   11 ( 3 )   2022年3月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:MDPI  

    With the diversification of robots, modularization of robots has been attracting attention. In our previous study, we developed a robot that mimics the principle of human joint drive using a straight-fiber-type pneumatic rubber artificial muscle ("artificial muscle") and a magnetorheological fluid brake ("MR brake"). The variable viscoelastic joints have been modularized. Therefore, this paper evaluates the basic characteristics of the developed Joint Module, characterizes the variable viscoelastic joint, and compares it with existing modules. As basic characteristics, we confirmed that the Joint Module has a variable viscoelastic element by experimentally verifying the joint angle, stiffness, viscosity, and tracking performance of the generated torque to the command value. As a characteristic evaluation, we verified the change in motion and response to external disturbances due to differences in driving methods through simulations and experiments and proved the strength of the variable viscoelastic joint against external disturbances, which is a characteristic of variable viscoelastic joints. Based on the results of the basic characterization and the characterization of the variable viscoelastic drive joint, we discussed what kind of device the Joint Module is suitable to be applied to and clarified the position of the variable viscoelastic joint as an actuator system.

    DOI: 10.3390/act11030089

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  • Deveropmrnt of Anisotropic Short-Fiber Oriented Rubber and its Application To Elongation Actuators

    H. Kunisada, K. Fujitani, F. Ito, M. Okui, T. Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2022-October   2022年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    In this paper, we describe the development of short-fiber oriented rubber and its application to elongation-type actuators. Short-fiber oriented rubber, i.e., rubber containing oriented short fibers with lengths of 3 mm, has anisotropy in the direction of fiber orientation. In a previous study, it was shown that short fiber-reinforced artificial muscles made of short-fiber oriented rubber can achieve up to 17% shrinkage. However, in that study, characteristics other than the amount of shrinkage were not measured, the basic characteristics of the developed artificial muscle were unclear, and the shrinkage ratio was smaller than that for existing straight-fiber-type artificial muscle. In the present study, we developed a new method for fabricating short-fiber oriented rubber and measured the tensile characteristics in the direction of fiber orientation and vertical to the orientation direction. Moreover, we developed an elongation-type artificial muscle from the rubber sheet and measured its elongation characteristics. Test results indicated that the fabricated rubber sheet had anisotropy. They also indicated that the anisotropy increased with the fiber concentration and that the fiber restraint acted not only in the orientation direction but also in the vertical direction. Furthermore, the developed elongation-type artificial muscle was three times more anisotropic in the ratio of axial changes to diametral changes. On the basis of these results, we expect to develop an automated production method for soft actuators.

    DOI: 10.1109/IECON49645.2022.9969096

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  • Excavation Experiment of Earth Worm Type Seabed Exploration Robot in Actual Sea Area

    Manabu Okui, Ryosuke Tokoi, Wataru Toyama, Kazuki Tsumura, Keita Isaka, Tomoki Watanabe, Taro Nakamura, Hiroshi Yoshida

    Lecture Notes in Networks and Systems   324 LNNS   337 - 347   2022年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Springer  

    The results of an excavation experiment in an actual sea area using the earth worm type seabed exploration robot are reported in this paper. The robot tested in the experiments is SEAVO II, which has been developed by the authors. Seawater-resistant processing was applied to the SEAVO II, and field experiments were conducted on the coast of Izu Oshima island. Four types of experiments were conducted: vertical excavation in sand, gravel, and water, and horizontal excavation in sand. In the vertical excavation on sand, the SEAVO II successfully excavated 490 mm, which is the same level as that of the previous studies. However, although the excavation was difficult and the excavating distance was limited to 100 mm or less for the other three conditions, the issues in each environment could be clarified.

    DOI: 10.1007/978-3-030-86294-7_30

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  • Proposal of a decentralized peristaltic movement generation based on actual intestines and verification by content transfer experiment

    D. Matsui, S. Oshino, I. Terayama, R. Nishihama, M. Okui, T. Nakamura

    2022 IEEE/SICE International Symposium on System Integration, SII 2022   65 - 70   2022年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    The intestines are an autonomous decentralized system with a neural network independent of the brain. Until now, some devices could reproduce the movement of the intestines, but autonomously switching the movement pattern as the biological intestine was impossible. In this study, we proposed a method for generating an autonomous peristaltic movement of a peristaltic continuous mixing conveyor that mimics the intestines. Peristaltic movements contribute to the transport of intestinal contents. With the proposed method, peristaltic movement is generated when the intestinal contents are detected by a unit with a unitized device. The proposed method was installed in a peristaltic continuous mixing conveyor and experimentally verified. The peristaltic movement was generated when there was content, and the content was successfully transported.

    DOI: 10.1109/SII52469.2022.9708865

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  • 海底探査用掘削ロボットにおける水平掘削の検討

    床井 亮祐, 外山 渡, 津村 一輝, 渡邊 友貴, 奥井 学, 中村 太郎, 吉田 弘

    ロボティクス・メカトロニクス講演会講演概要集   324 LNNS   329 - 336   2022年

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    記述言語:英語   出版者・発行元:一般社団法人 日本機械学会  

    DOI: 10.1007/978-3-030-86294-7_29

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  • Development of Peristaltic Transfer System to Transport Feces in Space: Proposal of Driving Method Using Pressure Difference in Peristaltic Pump

    Shogo Uzawa, Hiroya Kumamoto, Chiaki Yamazaki, Manabu Okui, Taro Nakamura

    IEEE Access   10   128399 - 128407   2022年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Institute of Electrical and Electronics Engineers (IEEE)  

    We propose a transport system combining peristaltic motion and a negative pressure as a new method of transporting and collecting feces for space toilets. In recent years, for the development of space exploration, the need for a regenerative Environmental Control and Life Support System (ECLSS) to perform manned space exploration for long periods without resource supply has emerged. Currently, human feces is disposed of, but if it can be reused like urine, the performance of the ECLSS can be significantly improved. Existing space toilets do not reuse of feces, and the transfer of feces presents a technical problem. There is no technology that can reliably transport highly viscous solid-liquid mixtures on an intermittent basis. If such technologies are developed, they will be useful for transporting not only feces in space but also chemicals on the ground. Therefore, the authors propose a peristaltic system based on the intestinal tracts of living organisms for the transport of feces in space. Each unit of the system can be actively closed and opened by air pressure. The units are operated in turn to transport feces. The proposed driving method utilizes the pressure difference between the units of a peristaltic pump to increase the transfer rate. A prototype system consisting of three units was developed, and a simulated feces transfer experiment was conducted to validate the proposed method. In the experiment, we compared the conventional peristaltic driving method and the proposed peristaltic driving method, and the results indicated that the proposed method can carry more than twice the amount of simulated feces. Thus, the proposed method is suitable for the transfer of feces in space and can be used to transfer highly viscous solid-liquid mixed fluids under intermittent supply and with little water consumption.

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  • Assist Effectiveness Study based on Viscosity: Comparison of Assumed Command Signal and Actual Command Signal

    Y. Shimoda, T. Fujita, K. MacHida, M. Okui, R. Nishihama, T. Nakamura

    RO-MAN 2022 - 31st IEEE International Conference on Robot and Human Interactive Communication: Social, Asocial, and Antisocial Robots   686 - 692   2022年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    In wearable assist devices, the assumed and actual command timings are different. This discrepancy cause problems, such as a decrease in the assist effect. In this study, we focus on viscosity, which is a characteristic of human muscles, and propose viscosity assistance to solve the problems. This method outputs the torque based on the predetermined viscosity coefficient and the actual angular velocity if the torque and angular velocity of the human joints are in opposite directions. The possibility of viscosity assist is demonstrated by analyzing the seated movement, and an assist device using a magnetorheological fluid brake is developed. The assist device is driven using three command inputs: time-based, joint angle-based, and constant viscosity coefficient command inputs. Under conditions based on time and angle, the actual output deviates from the assumed value when the motion is different from the expected motion. In terms of the viscosity command, when only the constant command is used throughout the entire motion section, some subjects showed almost identical results to those expected. Even if a deviation from this assumption is indicated, the degree of agreement can be improved by switching several types of viscosity coefficients during motion.

    DOI: 10.1109/RO-MAN53752.2022.9900630

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  • Ice-drilling and Gripping Experiments in Actual Conditions for Developing Earthworm-type Ice-drilling Robot for Extensive Under-sea-ice Surveys

    Ryosuke Tokoi, Chikage Fujikawa, Wataru Toyama, Manabu Okui, Hiroshi Yoshida, Taro Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2022-October   2022年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    There is an urgent requirement to solve the problem of global warming. The sea ice beneath the Arctic Ocean strongly affects the global climate. However, it has not been fully explored. The range of Autonomous Underwater Vehicles (AUV) used for under-ice exploration is limited owing to their short communication range. To solve this problem, we propose a communication relay system that uses a sea ice drilling robot. We conducted excavation and gripping experiments on actual sea ice to study the parameters and control methods required to design a sea ice drilling robot. The required specifications of excavation and propulsion units were obtained from the experimental results, and a recovery method was developed to address drilling failure.

    DOI: 10.1109/IECON49645.2022.9968618

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  • Mixing Determination for Solid Rocket Fuel Production by Peristaltic Mixing Pump Using Packing Method

    Sana Oshino, Iori Terayama, Rie Nishihama, Manabu Okui, Taro Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2022-October   2022年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    For space rockets, a rotating mixer is used to produce solid fuel. However, mixing with the rotary mixer is subject to high shear forces that limit the equipment drive. In a previous study, the authors developed a new production method using a pneumatically driven peristaltic mixing pump that simulates the intestine and a sensing system with pressure and flow rate sensors. Solid rocket fuel was successfully produced by a small pump unit. In this study, mixing experiments of solid propellant consisting of several types of powders, including metal powder and highly viscous fluids were conducted using a pump unit with a volume size eight times larger than that used in the previous study. In this experiment, mixing was performed with the materials packed in a plastic bag to increase efficiency. This reduces the contact area between the rubber tube and the contents of the device. Because only part of the mixing process is reflected in the behavior of the device, it is difficult to see differences in the sensor values, and it is unknown whether existing methods can be applied. The results of the experiment showed that the existing sensing system could be used to confirm the differences in characteristics due to the mixing process based on the time series data of air pressure and flow rate. By using Gaussian mixture model, which is a type of clustering, the mixing state was roughly binary discrimination from the acquired sensor values. This suggests that it is possible to estimate the mixing degree in large pumps using existing systems.

    DOI: 10.1109/IECON49645.2022.9968625

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  • Proposal of posture guidance method using air jetting with table tennis racket type device

    Rin Suzuki, Ryunosuke Sawahashi, Rie Nishihama, Manabu Okui, Taro Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2022-October   2022年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    Because information transmission by force is a vector quantity with magnitude and direction, it can directly affect humans. However, most existing force feedback devices are stationary, and their movement is restricted. On the other hand, wearable force-feedback devices induce a strange feeling, as they must support the reaction force of the presented force at the body fixing part. Therefore, in this paper, we propose a posture guidance method using force feedback provided by air jets. Specifically, for table tennis movement guidance, we developed a prototype with two degrees of freedom using a table tennis racket. We also conducted a hand posture guidance experiment and confirmed that the proposed method can guide the wrist posture without disturbing the wearer's movement.

    DOI: 10.1109/IECON49645.2022.9968815

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  • Development of Semi-active Force Feedback Shoes with MR Brake Rendering a Falling Sensation and Descent Acceleration Measurement

    Ryunosuke Sawahashi, Toshinari Tanaka, Taiki Masuda, Manabu Okui, Rie Nishihama, Taro Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2022-October   2022年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    Recently, force feedback devices have been developed to improve the virtual reality (VR) experiences. However, most conventional force feedback devices target the upper limbs. In addition to achieving force feedback to the upper limbs, realizing force feedback to the lower limbs will make it possible to realize an experience in the VR space, which would not be achieved by force feedback to the upper limbs alone. The authors have elucidated the perceptual characteristics of the human dropping sensation to present force feedback to the lower limbs. In this study, we develop a pair of wearable force feedback shoes that can realize the falling sensation in the VR space. The proposed device meets the required specifications for descent height and acceleration to render the falling sensation. Furthermore, we confirm the usefulness of the theoretical equation by measuring the basic characteristics of the developed device.

    DOI: 10.1109/IECON49645.2022.9968554

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  • Prototype of an exoskeletal lower limb force-feedback device for moving extensively in VR space

    Taiki Masuda, Ryunosuke Sawahashi, Jonah Komatsu, Manabu Okui, Rie Nishihama, Taro Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2022-October   2022年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    In recent years, force feedback devices have been developed to improve the reality of virtual reality (VR) experiences. However, most of the general force feedback devices target the upper limbs. By realizing force feedback to the lower limbs, it is possible to realize an experience in VR space that cannot be achieved by force feedback to the upper limbs alone. Therefore, in this study, we developed a lower limb force feedback device based on a physical model of the human lower limb. The output torque of the developed device that met the target torque by the experiment was confirmed. The device was then experimented with to determine if it could reproduce an impact force similar to that of a soccer pass as an initial study. The results suggested that even a low torque of 10 Nm could reproduce a soccer pass.

    DOI: 10.1109/IECON49645.2022.9968915

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  • Dropping sensation for development of lower limb force feedback device

    T. Masuda, T. Tanaka, R. Sawahashi, M. Okui, R. Nishihama, T. Nakamura

    2021 30th IEEE International Conference on Robot and Human Interactive Communication, RO-MAN 2021   398 - 405   2021年8月

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    掲載種別:研究論文(国際会議プロシーディングス)  

    In this study, we evaluate the dropping sensation for the development of a wearable lower limb force feedback device that can render both dropping and walking sensations. The developed device can render the dropping sensation at a smaller height than in reality by decelerating and stopping descent during the rendering of the drop image. Considering the user will be walking with the device, a smaller device height leads to better safety. The purpose of this study is to clarify the required specifications of the height of the vertical range of motion of the platform part, and the feasibility of the concept of rendering the dropping sensation. For this purpose, the dropping sensation for the difference in human acceleration time and human deceleration acceleration was evaluated. The results showed that the rendering of the dropping sensation required more than 0.41 s of descent at an acceleration of approximately 1377 mm/s2. Moreover, the dropping sensation and sense of reality were not impaired, even when the platform part of the foot was decelerated. This result indicates that the device can be made smaller.

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  • Propulsion unit control method for visualization of grasping state of earthworm-type lunar excavation robot

    R. Tokoi, W. Toyama, T. Watanabe, K. Tsumura, M. Okui, H. Sawada, T. Kubota, T. Nakamura

    IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM   2021-July   675 - 681   2021年7月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Investigation of the lunar subsurface environment is expected to lead to the elucidation of the origin of stars and the discovery of new resources. However, there are still many unknowns in this regard. In a previous study, we developed a drilling robot for lunar exploration and succeeded in drilling vertically up to 938 mm. However, control methods for the robot have not been studied in detail so far, and the grasping state of the propulsion unit during drilling has not been observed. In the study described in this paper, threshold coordination method for the current of the propulsion unit's motors is introduced to achieve effective hole grasping and propulsion. Subsequently, gripping force and penetrating force characteristics of the propulsion unit are tested to understand the grasping state of the propulsion unit during drilling based on the current value and the angle information of the motor. Finally, in-pipe propulsion and excavation experiments were conducted. From the experimental results, we concluded that the proposed control method can be used to grasp the hole with changing hole diameter and monitor the grasping state of the propulsion unit in the hole.

    DOI: 10.1109/AIM46487.2021.9517536

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  • 腸を規範とした蠕動運動型混合搬送装置における分散型センシングシステムの構築―加速度センサによる内部状態計測―

    押野 紗菜, 若松 康太, 松井 大育, 足立 遼, 熊本 寛也, 大島 煕恭, 西濵 里英, 奥井 学, 中村 太郎

    ロボティクス・メカトロニクス講演会講演概要集   2021-July   86 - 92   2021年7月

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    DOI: 10.1109/AIM46487.2021.9517474

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  • Development of a Wearable Four-Degrees-of-Freedom Force Feedback Device with a Clutch Mechanism Using Artificial Muscle Contraction

    Ryunosuke Sawahashi, Yuki Onozuka, Toshinari Tanaka, Manabu Okui, Taro Nakamura

    Proceedings of the IEEE International Conference on Industrial Technology   2021-March   47 - 54   2021年3月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    In a virtual reality (VR) space, wearing a head-mounted display can help with the visualization of objects although users cannot experience realistic tactile sensations. Recently, several force feedback devices have been developed, including wearable devices that use straight-fiber-type pneumatic muscles and magnetorheological fluids. This allows the devices to render elastic, frictional, and viscous forces during spatially unrestricted movement. However, during friction and viscosity rendering, the elasticity of the artificial muscle is influenced by the elastic element of the muscle, preventing proper presentation of the force. Therefore, this study proposed a clutch mechanism to switch the force presentation of elastic elements by the contraction of artificial muscles. The mechanism was incorporated into a wearable four-degrees-of-freedom force feedback device, and its elastic, frictional, and viscous force feedback performances were quantitatively assessed via fundamental property experiments. Furthermore, a VR space was constructed to present the operator with force perceptions of virtual elastic, frictional, and viscous objects within that space, and the system's performance was qualitatively assessed. The results confirmed a reduction in the effect of elastic elements and an improvement in the presentation performance. Additionally, the use of this device in the VR space was confirmed to improve the realism of virtual objects in terms of friction and viscosity.

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  • Development of an exoskeleton-type assist suit utilizing variable stiffness control devices based on human joint characteristics 査読

    Seigo Kimura, Ryuji Suzuki, Katsuki Machida, Masashi Kashima, Manabu Okui, Rie Nishihama, Taro Nakamura

    Actuators   10 ( 1 )   1 - 20   2021年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:MDPI  

    In this paper, the prototype of the assistive suit for lower limbs was developed. The prototype was based on an assist method with joint stiffness and antagonized angle control. The assist method comprises a system consisting of a pneumatic artificial muscle and a pull spring, which changes the joint stiffness and the antagonized angle to correspond to the movement phase and aims at coordinated motion assistance with the wearer. First, the characteristics of the developed prototype were tested. It was confirmed that the measured value of the prototype followed the target value in the relationship between torque and angle. In addition, there was hysteresis in the measured value, but it did not affect the assist. Next, the evaluation of standing-up and gait assist by measuring electromyography (EMG) of the knee extensor muscle was conducted using the prototype. In all subjects, a decrease in EMG due to the assist was confirmed. In one subject, the maximum decrease rate at the peak of the EMG was about 50% for standing-up motion and about 75% for gait motion. From the results of these assist evaluations, the effectiveness of the assist method based on the joint stiffness and antagonistic angle control using the prototype was confirmed.

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  • Development of a Compact Pneumatic Valve Using Rotational Motion for a Pneumatically Driven Mobile Robot with Periodic Motion in a Pipe

    Hiroto Sato, Kousuke Uchiyama, Yuki Mano, Fumio Ito, Shunichi Kurumaya, Manabu Okui, Yasuyuki Yamada, Taro Nakamura

    IEEE Access   9   165271 - 165285   2021年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    This paper describes the development of a compact pneumatic valve that can obtain a high flow rate in a periodically pneumatically driven pipe-moving robot. Plumbing facilities around the world have fallen into disrepair in recent years. Pneumatically driven mobile robots are widely used as an inspection method due to the small inner diameter and complicated shape of the pipes. Various types of robots have been studied, such as earthworm, inchworm, and spiral tube robots. However, these robots are driven by existing pneumatic valve technologies, such as needle-type and solenoid valves, which limit the use of small mobile robots. Small pneumatic valves have a low flow rate, and the entire system is complicated because multiple air pressures are controlled by multiple electrical systems. Thus, focusing on the structure and periodic motion of the ball valve, we developed a pneumatic valve that can periodically apply pressure to multiple pneumatic actuators using only rotational motion with one degree of freedom. We also applied this pneumatic valve to a wave propagation robot and discussed the theoretical running speed of the robot with this valve.

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  • Prolonging the Fatigue Life of Soft Rubber Actuators by Inhibiting Crack Extension Using the Hysteresis of Strain-Induced Crystallization of Natural Rubber

    Manabu Okui, Akihiro Kojima, Itsuki Hisamichi, Shotaro Kuriyama, Tomohisa Kojima, Tomoaki Tsuji, Taro Nakamura

    SSRN Electronic Journal   2021年

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Elsevier BV  

    DOI: 10.2139/ssrn.3996748

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  • Development of Front-Actuation-Type Excavating Unit for Lunar Excavating Exploration Robot “LEAVO”

    Tomoki WATANABE, Ami FUJIWARA, Naoaki TADAMI, Keita ISAKA, Megan BARTHELEMY, Manabu OKUI, Hirotaka SAWADA, Takashi KUBOTA, Taro NAKAMURA

    TRANSACTIONS OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES, AEROSPACE TECHNOLOGY JAPAN   19 ( 2 )   211 - 216   2021年

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    掲載種別:研究論文(学術雑誌)   出版者・発行元:Japan Society for Aeronautical and Space Sciences  

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  • In-Pipe Inspection Robot Capable of Actively Exerting Propulsive and Tractive Forces with Linear Antagonistic Mechanism

    F. Ito, K. Takaya, M. Kamata, M. Okui, Y. Yamada, T. Nakamura

    IEEE Access   9   131245 - 131259   2021年

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    掲載種別:研究論文(学術雑誌)  

    In this study, the authors comprehensively evaluated the traveling performance of a flexible pipe inspection robot (PI-RO) that can actively output both propulsion and traction forces. Household pipes must be frequently inspected for cracks and corrosion to ensure continuous provision of water and gas. As these pipes are essential for our everyday life, it is difficult to suspend their usage for long periods; hence, inspection should be conducted for short durations. In addition, inspecting entire pipelines using existing methods is challenging because the pipes are constructed over long distances and have complex structures. Therefore, we developed a flexible robot that can actively output propulsion and traction forces to inspect long-distance complex pipelines, such as household pipelines. Herein, we describe the flexible structural design of a PI-RO that inspects thin one-inch pipes (inner diameter of approximately 28 mm) typically present in household piping. We also evaluated the characteristics of each PI-RO unit. Finally, we confirmed that the PI-RO is not significantly affected by the traveling environment, such as long distances and complex small-diameter pipes, by conducting traveling experiments on small pipes (inner diameter 28 mm) and long-distance (up to approximately 11.7 m) complex pipes composed of horizontal, vertical, and 90° bend pipes.

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  • Generalization Capability of Mixture Estimation Model for Peristaltic Continuous Mixing Conveyor

    Sana Oshino, Rie Nishihama, Kota Wakamatsu, Katsuma Inoue, Daisuke Matsui, Manabu Okui, Kohei Nakajima, Yasuo Kuniyoshi, Taro Nakamura

    IEEE Access   9   138866 - 138875   2021年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    We propose herein a method for estimating the mixing state of the contents of a peristaltic continuous mixing conveyor simulating the intestine, developed for mixing and conveying powders and liquids. This study serves to improve a previously proposed method for estimating the mixing state using a logistic regression model with the pressure and flow rate sensors installed in the device as inputs. Moreover, the estimation accuracy of the proposed method is better than that of the previous method. The generalizability of the proposed method is evaluated for four conditions in which the feeding order of the contents, powder, and liquid are changed. The feeding order is as follows: powder first, liquid first, and powder and liquid alternately. As a result, a highly accurate estimation of mixing is achieved under the condition wherein the powder component is in the unit adjacent to the lid, but not under the condition wherein the liquid component is fed first. It is speculated that this is because the movement of the powder component inside the device is more easily reflected by the pressure and flow rate sensors installed in the device than in the liquid component.

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  • Development of Soft Pneumatic Actuators Using High-Strain Elastic Materials with Stress Anisotropy of Short Fibers 査読

    A. Kojima, M. Okui, T. Nakamura

    in Proceeding of the First International Electronic Conference on Actuator Technology   ( 1048150 )   2020年12月

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  • Path restriction and speed regulation via force feedback-type welding teaching device using magnetorheological brakes 査読

    Manabu Okui, Soichiro Sugibayashi, Ryuji Suzuki, Taro Nakamura

    Smart Materials and Structures   29 ( 10 )   2020年10月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    Welding is one of the forms of nonautomated, heavy labor used in the shipbuilding industry. In the shipbuilding process, the hull is first welded by an industrial automatic welding machine, then irregular welded part correction and welding in narrow places that machines cannot reach are performed by welding workers. Welding operators are required to weld indeterminate objects in narrow working spaces. In addition, it is difficult to perform high-quality welding because the ability to accurately trace a welding line at a constant speed requires a long training period. In this research, a welding training device that assists trainees in skill acquisition was developed. The proposed device, which comprises two magnetorheological (MR) brakes, renders a welding path and restricts welding speed. The MR brakes have a response speed comparable to that of powder brakes, have a high output-to-weight ratio, and are also considered to be suitable for use in welding training devices. A prototype and control strategy were developed, and the performance of the device in actual welding work was evaluated. Results shows that path rendering strategy is possible to present routes with an accuracy of 1 mm or better and speed control strategy can regulate the speed required for welding.

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  • Influence of vertical acceleration for inducing sensation of dropping by lower limb force feedback device 査読

    T. Tanaka, Y. Onozuka, M. Okui, R. Nishihama, T. Nakamura

    29th IEEE International Conference on Robot and Human Interactive Communication, RO-MAN 2020   392 - 397   2020年8月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Many haptic devices are currently being developed for human upper limbs. There are various types of force feedback devices for upper limbs, such as desktop and wearable type. However, the lower limbs absorb most of the force when standing or walking. Therefore, to render the sensation of force to the lower limbs, a device worn like a shoe to enable users to walk and have a wide range of movement and a device that provides a dropping sensation have been developed. However, both wide-area movement and a dropping sensation could not be combined in one device. Therefore, the authors propose the concept of a lower limb force feedback device that allows the user to wear it like a shoe and provides the sensation of dropping while enabling wide-area movement. In addition, as the first stage of device development, the authors evaluated the human sensation of dropping. Consequently, it was found that a relatively high sensation of dropping can be provided to a human even with an acceleration smaller than the gravitational acceleration in real space. Thus, the lower limb force feedback device to be developed in the future will allow the user to experience the sensation of dropping by using an acceleration smaller than the gravitational acceleration in real space.

    DOI: 10.1109/RO-MAN47096.2020.9223476

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  • M. Okui, R. Enjo, D. Inoue, Y. Yamada, T. Nakamura 査読

    Development of a Negative-Pressure Driven Soft Linear Actuator for Fixation Part of Wearable, Assistive Devies

    in Proceedings of 23nd International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines (CLAWAR2020)   23 - 30   2020年8月

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  • Effect of penetration force on drilling efficiency for seabed drilling robot 査読

    W. Toyama, K. Isaka, K. Tsumura, T. Watanabe, M. Okui, H. Yoshida, T. Nakamura

    IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM   2020-July   1908 - 1913   2020年7月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Seabed mineral resources have been discovered on the bottom of the ocean; to utilize them, samples must be obtained and analyzed. In this study, a seafloor robotic explorer that can excavate and sample seafloor soil is developed. In a previous study, we developed a drilling robot that could excavate 650 mm into the ground while being underwater. And, we discovered that the excavation robot rotation speed, penetration force, and characteristics of the target ground affected the excavation resistance. In this paper, the effect of penetration force on excavation efficiency is verified experimentally using both dry and underwater silica sand ground with different ground characteristics. Results of the experiment indicated that the most efficient excavation was performed at 15 N in dry silica sand ground. In underwater silica sand ground, the excavation efficiency improved as the penetration force increased, and the most efficient excavation was achieved when the penetration force was 10 N. Hence, we concluded that controlling the excavation parameters, which are penetration force and rotational speed, enables an efficient excavation according to ground characteristics.

    DOI: 10.1109/AIM43001.2020.9158934

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  • Wearable air-jet force feedback device without exoskeletal structure and its application to elastic ball rendering 査読

    M. Okui, T. Masuda, T. Tamura, Y. Onozuka, T. Nakamura

    IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM   2020-July   276 - 281   2020年7月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Various haptic devices for application to virtual reality have been developed. Most of them have to be stationary on a desk, thus users cannot move around. To overcome this shortcoming, exoskeletal haptic devices have been developed. However, they also have shortcomings such as discomfort caused by the reaction force of the presented haptic force in another part of the body. In addition, the limited range of motion caused by exoskeleton structure is also a problem. Therefore, in this research, we propose a wearable device without an exoskeletal structure that uses airjet to provide force feedback. In this study, ω-jet, a prototype for the finger joints, was developed, and its basic characteristics were evaluated. Moreover, the prototype was evaluated based on its performance in an elastic ball presentation experiment. The results confirmed that the proposed device was capable of rendering virtual balls of different sizes and stiffness.

    DOI: 10.1109/AIM43001.2020.9158981

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  • Proposal for pipeline-shape measurement method based on highly accurate pipeline length measurement by IMU sensor using peristaltic motion characteristics 査読

    Hiroto Sato, Yuki Mano, Fumio Ito, Takumi Yasui, Manabu Okui, Rie Nishihama, Taro Nakamura

    IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM   2020-July   874 - 881   2020年7月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    In order to prevent accidents caused by the aging of sewer pipes, it is necessary to identify the state of the pipe as well as the damage position. A pipeline diagram is required to specify the location of the damage, but pipeline diagrams are often lost. Therefore, it is necessary to measure the pipeline shape and create a pipeline diagram. We developed a robot for sewage pipe inspection that mimics the movement method of earthworms. In this paper, we propose a method for estimating the pipe shape from an inertial measurement unit (IMU) sensor mounted on the developed robot with peristaltic motion. The pipe shape is realized by a combination of distance measurement using acceleration and changes in angular velocity, and bending pipe discrimination using changes in the attitude angle of the sensor. To solve the problem in which a cumulative error occurs when the acceleration is second-order integrated in the distance measurement, the cumulative error was corrected in consideration of the periodicity of the progression and stops during the peristaltic motion; this is a unique movement method of this robot. In bending pipe discrimination, a bending pipe and a straight pipe were distinguished based on changes in the angular velocity, and the angle of the bending pipe was judged from the attitude angle of the sensor. The developed robot with an IMU was crawl on a pipe composed of multiple bending pipe and inclined pipe for pipe rise, and the pipe shape was estimated using the proposed method. In the experiments, it was possible to measure the length of the pipeline with an error of 1.42 % relative to the actual length, and it was possible to express the approximate shape of the pipeline.

    DOI: 10.1109/AIM43001.2020.9158972

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  • Variable viscoelastic joint module with built-in pneumatic power source 査読

    Katsuki Machida, Seigo Kimura, Ryuji Suzuki, Kazuya Yokoyama, Manabu Okui, Taro Nakamura

    IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM   2020-July   1048 - 1055   2020年7月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    A variable viscoelastic joint was developed that mimics the principle of human joint drive and uses a pneumatic artificial muscle with an antagonistic arrangement and a magnetic viscous fluid brake. Herein, the versatility of this joint was improved via modularization. The variable viscoelastic joint module is the world's first pneumatic drive module with an internal power source and variable viscoelastic characteristics.

    DOI: 10.1109/AIM43001.2020.9158861

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  • Mixing State Estimation of Peristaltic Continuous Mixing Conveyor with Distributed Sensing System Based on Soft Intestine Motion 査読

    K. Wakamatsu, K. Inoue, D. Hagiwara, H. Adachi, D. Matsui, S. Kurumaya, R. Nishihama, M. Okui, K. Nakajima, Y. Kuniyoshi, T. Nakamura

    2020 3rd IEEE International Conference on Soft Robotics, RoboSoft 2020   208 - 214   2020年5月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    A peristaltic continuous mixing conveyor that focuses on the mechanism of the intestine has been developed as a technology for the mixing and transport of a solid-liquid mixture and high viscosity fluids. The developed peristaltic continuous mixing conveyor succeeded in the mixing and transport of such mixtures in a previous study. A simple cyclic pattern is currently used as the movement pattern of the system, and the control method can be further improved. In this study, we aim to realize an intelligent mixing and generation of a conveyor pattern based on intestinal movement. The mixing state of content during activation was estimated through machine learning. The results from the time-series measurement data show that an internal mixing state in three units of the peristaltic continuous mixing conveyor was estimated.

    DOI: 10.1109/RoboSoft48309.2020.9116058

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  • Development of a locomotion robot using deformable dielectric elastomer actuator without pre-stretch 査読

    H. Kumamoto, T. Hayashi, Y. Yonehara, M. Okui, T. Nakamura

    Proceedings of SPIE - The International Society for Optical Engineering   11375 ( 1137509 )   2020年4月

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    掲載種別:研究論文(国際会議プロシーディングス)  

    This study proposes the development of a locomotion robot using a deformable dielectric elastomer for actuation without pre-stretch. Electroactive polymers (EAPs) that are driven by electrical stimulation have recently garnered attention. Among EAPs, dielectric elastomer actuators (DEAs) are focused herein. DEAs have a structure wherein a dielectric is sandwiched between elastic electrodes. The performance of the DEA depends on the relative permittivity, Young's modulus, and the applicable voltage of the dielectric material. DEAs are usually used with pre-stretching, because of the material properties of the dielectric, which requires a large stress in the initial stage of extension, and the increase in the displacement of DEAs with the application of pre-stretch. However, because rigid frames are generally used for prestretching, there are few DEA applications that utilize their flexibility. Therefore, we focused on slide-ring materials (SRMs) as new dielectric materials. SRMs are polymer materials in which the cross-linking points move freely, and having excellent properties as dielectrics for DEA applications. Thus, pre-stretching is not required, and applications utilizing the flexibility of DEAs is possible. In previous research, a bending unit that did not require pre-stretching was manufactured by attaching non-stretchable tape to one side of the DEA using an SRM as the dielectric material. In addition, a locomotion robot with a bending unit was developed, and it was confirmed that the robot achieved locomotion because of a phase difference between the units. However, the basic characteristics of the bending unit and locomotion robot were not discussed. Therefore, in this research, we measured the frequency characteristics of the bending unit alone and demonstrated the locomotion of the robot.

    DOI: 10.1117/12.2558422

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  • Noninflatable Pneumatic Artificial Muscle Requiring Low Space and Consumption Flow Rate 査読

    M. Okui, F. Ito, A. Kojima, T. Nakamura

    Proceedings of the 2020 IEEE/SICE International Symposium on System Integration, SII 2020   495 - 499   2020年1月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Actuators known as pneumatic artificial muscles are superior for practical use because they do not require maintenance, are inexpensive, and can be assembled with a drive unit and an energy generation unit independently. However, because these actuators expand greatly in the radial direction when pressurized, one problem is that they occupy a large amount of space and consume a significant amount of flow. In this study, we propose a space-saving, constant-axis fiber-reinforced artificial muscle that does not expand and also takes advantage of the benefits of pneumatic artificial muscles. Hence, this paper reports on the driving principle of the proposed noninflatable pneumatic artificial muscle and the basic characteristics are then confirmed using a prototype.

    DOI: 10.1109/SII46433.2020.9026201

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  • Clay Drilling Performance of Seabed Robotic Explorer Using Peristaltic Motion 査読

    K. Isaka, K. Tsumura, T. Watanabe, W. Toyama, M. Okui, H. Yoshida, T. Nakamura

    Proceedings of the 2020 IEEE/SICE International Symposium on System Integration, SII 2020   1340 - 1347   2020年1月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Mineral resources have been discovered on the bottom of the ocean; to utilize them, seabed soil samples must be obtained and analyzed. This study aimed to develop a seafloor robotic explorer that can excavate and gather samples of the seafloor soil. In our previous study, we developed a drilling robot named SEAVO II that could excavate 430 mm into the sand ground underwater. However, in the present study, the target to be excavated was the rare earth mud layer. Therefore, we examined the drilling properties specific to the underwater clay ground. In addition, a drilling experiment in the clay ground was conducted using SEAVO II. The results showed that SEAVO II could successfully dri11430 mm into the clay ground underwater.

    DOI: 10.1109/SII46433.2020.9026231

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  • Fundamental characteristics for rendering elasticity of a force feedback method using elastic spring and magneto-rheological fluid clutch 査読

    M. Ooba, Y. Onozuka, M. Okui, T. Nakamura

    Proceedings of the 2020 IEEE/SICE International Symposium on System Integration, SII 2020   1150 - 1155   2020年1月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Force feedback devices are attracting attention as a way to apply virtual and augmented reality to entertainment, sports, and rehabilitation. We previously developed a force feedback device using pneumatic artificial muscle and a magneto-rheological fluid clutch. However, problems occurred, such as an increase in the weight of the device and complications in the control system. To solve these problems, a new force feedback method using an elastic spring and a magneto-rheological fluid clutch was therefore proposed. In addition, the force feedback characteristics of the force feedback method were modeled. A 1-degree-of-freedom force feedback device using the new force feedback method was also developed. The model characteristics of the force feedback for rendering the elasticity using the device were confirmed experimentally.

    DOI: 10.1109/SII46433.2020.9025927

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  • Proposal for 3D-printed pneumatic artificial muscles -Effect of leaf spring stiffness on contraction amount and contraction force- 査読

    F. Ito, A. Kojima, M. Okui, T. Nakamura

    Proceedings of the 2020 IEEE/SICE International Symposium on System Integration, SII 2020   1163 - 1167   2020年1月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    In this paper, we describe the performance of a pneumatic artificial muscle integrally molded by a 3D printer that can mold materials with different stiffnesses.In the recent years, soft and hard materials can be integrally molded as the performances of 3D printers improve. For this reason, attention has been focused on the integral molding of actuators by using 3D printers. In this study, an artificial muscle is integrally molded by a state-of-the-art 3D printer, and the amount of contraction and contraction force generated are experimentally measured. In particular, the integrally molded artificial muscle formulated in this study is a pleated artificial muscle that does not require high material stretching performance. When the stiffness of the leaf spring material constituting the 3D printable artificial muscle is changed in a stepwise manner, the generated contraction amount and force were measured. From these measurement results, the usefulness of this actuator was confirmed by comparing the generated force with that of a pneumatic piston with the same inner diameter.

    DOI: 10.1109/SII46433.2020.9026165

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  • Dielectric elastomer actuator that can be deformed without pre-stretching and its application to flexible wave-generating device 査読

    T. Hayashi, H. Kumamoto, M. Okui, Y. Yonehara, H. Takeuchi, T. Nakamura

    Proceedings of the 2020 IEEE/SICE International Symposium on System Integration, SII 2020   1218 - 1223   2020年1月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    We attempt to generate traveling waves by applying a dielectric elastomer actuator (DEA) with a sliding ring material (SRM). A normal DEA using silicon or acrylic rubber requires pre-stretching with a rigid frame to obtain a large displacement, owing to the material properties of the dielectric, which require a large stress to be applied at the initial stage of the extension. A DEA using an SRM does not need to be restricted by a rigid frame and can be expected to generate large displacements and complex motions while maintaining its flexibility. In this paper, we report the development of a traveling wave generator as an initial study. Through experiments, the developed DEA was confirmed to function as an actuator without pre-stretching. In the future, in addition to determining the optimum phase difference, frequency band, and shape of the constrained parts to increase the speed, we plan to develop a mobile robot utilizing a DEA traveling wave with a mechanism that would allow the units to overlap.

    DOI: 10.1109/SII46433.2020.9026285

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  • Soil Discharging Mechanism Utilizing Water Jetting to Improve Excavation Depth for Seabed Drilling Explorer 査読

    Keita Isaka, Kazuki Tsumura, Tomoki Watanabe, Wataru Toyama, Manabu Okui, Hiroshi Yoshida, Taro Nakamura

    IEEE Access   8   28560 - 28570   2020年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    Seabed mineral resources have been found on the bottom of the ocean, and to utilize them, samples must be taken and analyzed. This study develops a seafloor robotic explorer that can excavate and sample seafloor soil. In a previous study, we developed a drilling robot that could excavate 430 mm into the ground while underwater. However, excavation deeper than 430 mm was not possible because the discharging outlet became buried, making it difficult to discharge the drilled soil. In this paper, we develop a discharging mechanism utilizing water jetting to improve the excavation depth to 650 mm and potentially deeper.

    DOI: 10.1109/ACCESS.2020.2972572

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  • 周期的空気圧印加により駆動する管内移動ロボットのための小型回転型バルブ機構

    眞野雄貴, 佐藤広都, 伊藤文臣, 奥井学, 山田泰之, 中村太郎

    日本ロボット学会誌   38 ( 10 )   965 - 974   2020年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本ロボット学会  

    DOI: 10.7210/jrsj.38.965

    DOI: 10.20965/jrm.2023.p0633_references_DOI_GrMm5ygjFtfynoUzZ62TOKgGCeZ

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  • Development of a negative-pressure-driven soft linear actuator for fixation part of wearable assistive devices

    Manabu Okui, Ryuto Enjo, Daisuke Inoue, Yasuyuki Yamada, Taro Nakamura

    Robots in Human Life- Proceedings of the 23rd International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2020   23 - 30   2020年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    In the study, we propose a negative-pressure-driven soft linear actuator for the fixation part of an exoskeleton. In the study, a concept of the fixation part that is easy to wear with reliable force transmission is first proposed. Subsequently, a negative-pressure-driven soft linear actuator for the proposed fixation method is introduced and prototyped. Finally, basic characteristic experiments are conducted with a prototype. The results indicate that decreases in the pressure increase the actuator's contraction force and maximum contraction. It exhibits a large hysteresis that is approximately 50% at maximum contraction force. Increases in the width increase the contraction force. Increases in the height increase the force and rate of contraction.

    DOI: 10.13180/clawar.2020.24-26.08.30

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  • Proposal of motion judgment algorithm based on joint angle of variable elastic assist suit with high back drivability 査読

    Seigo Kimura, Ryuji Suzuki, Katsuki Machida, Rie Nishihama, Manabu Okui, Taro Nakamura

    Journal of Robotics and Mechatronics   32 ( 5 )   863 - 875   2020年

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:FUJI TECHNOLOGY PRESS LTD  

    In recent years, the burden per worker has increased due to a decrease in the working population. Wearable assist suits have been developed as one of the methods for solving the problem. To extend the assist suit to practical situations, it is necessary to provide a motion judgment interface for judging the motion of a wearer. Therefore, in our study, a motion judgment algorithm is proposed for assist suits, based on variable viscoelasticity. The proposed algorithm judges sitting, standing-up, stance, sitting-down, and gait using only the joint angle information of the suit and verification is performed using human joint angles obtained by motion capture. Thus, the motion judgment rate is 90% or more for sitting, standing-up, stance, and sitting-down, and 80% or more for gait, confirming the usefulness of motion judgment. Additionally, based on these results, further verification is performed on an actual machine. As a result, in a series of motions starting from the sitting to the standing-up, the stance, and the gait, the motion judgement is successful five times from the sitting to the standing-up, the stance, and once in gait. In a series of motions from sitting to standing-up, the stance, and sitting-down, the motion judgment is successful five times during sitting; five times during sitting, stance, and sitting-down; and three times during standing-up. In this way, it is confirmed that the proposed method can judge the motion only by angle information, although there is a problem in a success rate depending on the motion.

    DOI: 10.20965/jrm.2020.p0863

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  • FEM Analysis of 3D Printable Pleated Pneumatic Artificial muscle 査読

    S. Kuriyama, I. Hisamichi, F. Ito, A. Kojima, M. Okui, T. Kojima, T. Nakamura, T. Tsuji

    Proceedings of the 10th TSME International Conference on Mechanical Engineering   1 ( 1 )   149 - 155   2019年12月

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  • Assistive method that controls joint stiffness and antagonized angle based on human joint stiffness characteristics and its application to an exoskeleton 査読

    Seigo Kimura, Ryuji Suzuki, Masashi Kashima, Manabu Okui, Rie Nishihama, Taro Nakamura

    2019 19th International Conference on Advanced Robotics, ICAR 2019   553 - 559   2019年12月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    In this paper, we propose an assistance method that controls joint stiffness and the antagonized angle using variable elastic elements. The proposed system changes the stiffness and angle so that they correspond to the phase of movement and performs movement assistance in cooperation with the wearer. To achieve structural variability in the configuration of stiffness and the antagonized angle, we propose a joint structure in which the artificial muscle and tension spring are antagonistically arranged. While performing a movement, motion analysis was conducted to investigate the change in joint stiffness and antagonized angle. We confirmed that the proposed joint and human joint have the same tendency while in motion.

    DOI: 10.1109/ICAR46387.2019.8981664

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  • Evaluation experiment of squat motion with variable viscoelastic assistive suit “Airsist I”

    Ryuji Suzuki, Manabu Okui, Shingo Iikawa, Yasuyuki Yamada, Taro Nakamura

    IFAC-PapersOnLine   52 ( 22 )   73 - 77   2019年10月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)  

    Copyright © 2019. The Authors. Published by Elsevier Ltd. All rights reserved. In this study, an experiment is conducted to evaluate a squat motion while using the wearable variable viscoelastic assistive suit “Airsist I,” and the assistive effect of the suit is confirmed. Wearable assistive suits help in reducing the burden on laborers. Airsist I was developed in a previous study, based on the characteristics of variable viscoelasticity. In addition, a variable viscoelastic control strategy was proposed. However, an evaluation has not been performed to confirm the assistive effect of Airsist I. Therefore, this study reports on the confirmation of the assistive effect of the variable viscoelastic suit Airsist I.

    DOI: 10.1016/j.ifacol.2019.11.050

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  • Path rendering and velocity restriction with welding-assisting device composed of magnetorheological brakes 査読

    M. Okui, R. Suzuki, S. Morita, T. Nakamura

    IFAC-PapersOnLine   52 ( 22 )   108 - 111   2019年10月

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    掲載種別:研究論文(国際会議プロシーディングス)  

    Copyright © 2019. The Authors. Published by Elsevier Ltd. All rights reserved. In the shipbuilding industry, welding is one of the forms of nonautomated heavy labor, and the welding operator is required to weld indeterminate objects in a narrow working space. Therefore, it is difficult to use large equipment, such as industrial robots. In addition, it is not easy to perform high-quality welding, because tracing a welding line accurately at a constant speed requires a long training period. In this research, the aim was to develop a welding assist device that can be applied to a welding environment. The proposed device fixes to the welding surface by magnetic force and assists semiautomatic welding with a magnetorheological (MR) brake. MR brakes have a sufficient response speed compared with powder brakes, have a large output weight ratio, and are considered to be suitable for welding assistance. In this work, a strategy for control of path rendering and speed restriction by MR brakes is proposed. Its effectiveness was confirmed by experiments with a prototype.

    DOI: 10.1016/j.ifacol.2019.11.057

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  • Rendering friction and viscosity using a wearable 4 degrees of freedom force feedback device with magnetorheological fluid clutches and pneumatic artificial muscles 査読

    Yuki Onozuka, Minoru Oba, Manabu Okui, Taro Nakamura

    IECON Proceedings (Industrial Electronics Conference)   2019-October   705 - 710   2019年10月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Using a head-mounted display, users can immerse themselves in virtual reality space and users can via the visual recognition of virtual objects. However, users do not experience the same haptic perception when they interact with these objects, that they do with actual objects. Force feedback devices can render haptic perception. They are classified into desktop and wearable types. A wearable 1 degree of freedom force feedback device using magnetorheological fluid brake, magnetorheological clutches, and pneumatic artificial muscles has been previously developed and it was confirmed that the device can render elasticity, friction, and viscosity. In addition, a wearable 4 degrees of freedom force feedback device using magnetorheological fluid clutches and pneumatic artificial muscles that can render elasticity was also previously developed. However, it was not established that the device could render friction, and viscosity using magnetorheological fluid clutches and pneumatic artificial muscles. In this report, it is confirmed that such a device can render friction and viscosity using magnetorheological fluid clutches and pneumatic artificial muscles without the need for magnetorheological fluid brake.

    DOI: 10.1109/IECON.2019.8927514

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  • Straight-fiber-type artificial muscle deformation under pressurization 査読

    Akihiro Kojima, Manabu Okui, Itsuki Hisamichi, Tomoaki Tsuji, Taro Nakamura

    IEEE Robotics and Automation Letters   4 ( 3 )   2595 - 2598   2019年7月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:Institute of Electrical and Electronics Engineers (IEEE)  

    Currently, researchers are actively conducting studies and experiments on soft robots due to their increasing abilities to cooperate with humans. Particular attention is being paid to pneumatic artificial muscles because of their flexibility and relatively light weight as actuators. Among the multiple types of pneumatic artificial muscles, the straight-fiber-type has a structure, which is typically configured in a cylindrical rubber tube reinforced by fibers in the axial direction. The application of an internal pressure expands the tube in the radial direction, while it contracts in the axial direction. In this study, the deformation of such tubes was theoretically analyzed. First, the differential equation for the cylinder profile was derived, and the solution then obtained in the closed form, when the rubber is relatively soft enough compared to the fiber. Finally, for a large enough inner pressure, the profile of the reinforced rubber cylinder was derived from the incomplete elliptic integral. Moreover, the spring constant, the contraction ratio, and the maximum stress were obtained regarding the cylinder length. The spring constant linearly increased with the initial length of the cylinder. The contraction ratio also increased with the initial cylinder length up to 54.3%. The maximum stress was found to be related to the elastic modulus of the rubber but not to the inner pressure; when the cylinder length was three to five times larger than the initial diameter of the cylinder, the rubber exhibited small a maximum stress and large contraction ratio.

    DOI: 10.1109/LRA.2019.2902016

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  • Research of human-robot handshakes under variable stiffness conditions 査読

    Kejia Dai, Yage Liu, Manabu Okui, Rie Nishihama, Taro Nakamura

    2019 4th IEEE International Conference on Advanced Robotics and Mechatronics, ICARM 2019   744 - 749   2019年7月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    In this study, we made the assumption that the feeling of a firm handshake is related to the stiffness of the elbow joint and we performed handshake experiments under variable stiffness conditions to verify the assumption. EMG signals were recorded to be used as an evaluation. Then human-robot handshake experiments were performed utilizing a handshake manipulator proposed in the previous research. The joint of the manipulator was driven by antagonized artificial muscles, which are considered to be soft actuators designed to mimic the movement of real human muscles. The muscle activations of the subject were compared when the subject shook hand with the experimenter and the manipulator. And it has been demonstrated that even though the subject was not aware of the experiment conditions, the muscle activations are higher in the firm handshake condition in both human-human handshake and human robot handshake experiments, which indicated that firmness of handshakes are related to the stiffness of the joint and the EMG signals can used as an evaluation method.

    DOI: 10.1109/ICARM.2019.8833897

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  • Delta-type four-DOF force-feedback device composed of pneumatic artificial muscles and magnetorheological clutch and its application to lid opening 査読

    Manabu Okui, Masatoshi Kobayashi, Yasuyuki Yamada, Taro Nakamura

    Smart Materials and Structures   28 ( 6 )   2019年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    Force-feedback devices, along with virtual reality, are being studied for applications related to entertainment and rehabilitation. These devices generally comprise either direct drive motors or motors with reduction gear. However, suitable force feedback with high stiffness requires high-power and very large motors with reduction gears. Although rigidity can be increased with reduction gears, they reduce back-drivability and limit the motion freedom of the device. To address these problems, we developed a force-feedback device actuated with a magnetorheological clutch and pneumatic artificial muscles. The device can smoothly vary its stiffness and viscosity, and provides good back-drivability. In this paper, we report the development and testing of a prototype with one rotational and three translational degrees of freedom. We evaluated the effectiveness of force feedback per degree of freedom, and the prototype being used to resemble lid opening.

    DOI: 10.1088/1361-665X/ab192a

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  • Variable viscoelasticity handshake manipulator for physical human-robot interaction using artificial muscle and MR brake 査読

    Kejia Dai, Yage Liu, Manabu Okui, Yasuyuki Yamada, Taro Nakamura

    Smart Materials and Structures   28 ( 6 )   2019年5月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IOP PUBLISHING LTD  

    In this study, a handshake manipulator with variable viscoelastic joints was proposed. The variable viscoelastic joint system comprised of antagonized artificial muscles and a magneto-rheological fluid brake. This joint system resembles the characteristic of real human joint. The objective of this study is to evaluate the proposed manipulator's effectiveness in the research of human-robot physical interaction and to verify that by adjusting the viscosity and stiffness of the joint it is possible to create handshakes with different feelings. In this research two sets of experiments were conducted; the first set of experiments was to conducted on the manipulator alone in order to test the performance of the manipulator. And the second set of experiments was the subjective evaluation of the manipulator when subjects shook hand with the manipulator under variable viscosity and stiffness conditions. The results of these experiments indicated that the manipulator was suitable for doing research on human-robot handshake, and the variable viscosity and stiffness of the elbow joint did create distinctive feelings to the subjects.

    DOI: 10.1088/1361-665X/ab0d9b

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  • Deformation Measurement of Dielectric Elastomer using Slide Ring Material on a 2-D Plane 査読

    T. Hayashi, M. Okui, Y. Yonehara, T. Nakamura

    Proceedings of the 2019 IEEE/SICE International Symposium on System Integration, SII 2019   712 - 717   2019年4月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Dielectric elastomer actuator (DEA) is a soft actuator with low manufacturing cost and high energy efficiency; it expands when an electric field is applied. The structure of DEA comprises a dielectric material interlayered with elastic electrodes similar to a sandwich. The performance of DEA is determined by the material of the dielectric layer, which is generally silicon or acrylic rubber. This study focused on investigating the characteristics and various applications of slide ring material (SRM) as a dielectric. SRM is more suitable for use as a dielectric of DEA as compared to silicone and acrylic rubbers in terms of the dielectric constant and hysteresis loss. Several measurement methods of existing DEAs measure only uniaxial deformation. However, the actual DEA strain distribution is not completely uniform. In addition, obtaining the two-dimensional (2D) strain distribution leads to a better understanding of the lifetime and performance of DEA as DEA deforms in 2D practical applications. Therefore, this study measured the strain on the DEA, while changing the load, applied voltage, and number of layers, using the image correlation method, which is a 2D planar measurement method. This measurement confirmed the two-dimensionally spreading strain distribution. The relationship between the stress, strain, and number of DEA layers was also obtained.

    DOI: 10.1109/SII.2019.8700353

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  • VariabVariable viscoelasticity handshake manipulator for physical human-robot interaction using artificial muscle and MR brakele viscoelasticity handshake manipulator for physical human-robot interaction using artificial muscle and MR brake 査読

    KEJIA DAI, Yage Liu, Manabu Okui, Yasuyuki Yamada, Taro Nakamura

    Smart Materials and Structures   2019年3月

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  • Measurement of strain distribution of dielectric elastomer actuator with plural pairs of electrodes via the image correlation method 査読

    T. Hayashi, M. Okui, Y. Yonehara, T. Nakamura

    Proceedings of SPIE - The International Society for Optical Engineering   10966   2019年3月

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    掲載種別:研究論文(国際会議プロシーディングス)  

    A dielectric elastomer actuator (DEA) is a soft actuator with low manufacturing cost and high energy efficiency. The structure of a DEA consists of a dielectric material interlayered with elastic electrodes, and DEA expands when an electric field is applied. The degree of freedom of movement of the DEA can be increased by devising the electrode arrangement in DEA. The performance of DEA is determined by permittivity, Young's modulus, and applicable electric field. Material properties including hysteresis loss are also important when a DEA is used as a sensor or high precision actuator. Generally, silicon and acrylic rubbers are used as the dielectric layer. This study focused on the use of a slidering material (SRM) as a more suitable dielectric for DEA than silicone and acrylic rubbers in terms of its dielectric constant and hysteresis loss. In a previous study, a DEA was developed using SRM as a dielectric, and the image correlation method (ICM) was applied to measure the strain distributions in a two-dimensional plane and the basic characteristics of DEA with one pair of electrodes. Here, the strain distribution was measured when the electrodes of the DEA were segmented into several pairs as the next step in the investigation of its basic characteristics. Patterns of electrode arrangements and the amount of DEA prestretching were changed, and strain distribution was measured using ICM.

    DOI: 10.1117/12.2514194

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  • 天然ゴムの伸張結晶化を用いた軸方向繊維強化型空気圧人工筋肉の長寿命化

    小島 明寛, 奥井 学, 久道 樹, 只見 侃朗, 辻 知章, 中村 太郎

    日本フルードパワーシステム学会論文集   50 ( 2 )   46 - 52   2019年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本フルードパワーシステム学会  

    <p>Pneumatic rubber artificial muscle is attracting attention as an actuator having high cooperativeness with human because of its feature of being flexible and lightweight. The authors have developed Straight fiber type pneumatic artificial muscle (SF-ARM), which is a high power, highly displaced pneumatic rubber artificial muscle. Although SF-ARM has excellent contraction characteristics, it has a problem of short fatigue life. Therefore, in this study, focusing on strain-induced crystallization of natural rubber, the fatigue life of SF-ARM has been extended. First, strain-induced crystallization of natural rubber were confirmed by wide angle X-ray diffraction. Next, analysis of strain concentration in the vicinity of the crack was performed by the finite element method. Finally, a fatigue life test of SF-ARM was carried out to confirm the effect of prolonging the fatigue life by using strain-induced crystallization.</p>

    DOI: 10.5739/jfps.50.46

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  • Strain-induced crystallization to prolong the lifetime of pneumatic artificial muscles

    A. Kojima, M. Okui, I. Hisamichi, N. Tadami, T. Tsuji, T. Nakamura

    Proceedings of SPIE - The International Society for Optical Engineering   10965   2019年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    Various types of soft actuators have been developed for application in wearable movement-assist devices or soft robots. The authors have developed a straight-fiber-reinforced pneumatic rubber artificial muscle (SF-ARM). The SFARM is composed of rubber that is reinforced with fibers aligned only in the axial direction. When air pressure is applied to the SF-ARM, the reinforced fibers limit the rubber expansion to the radial direction so that the muscle contracts in the axial direction. The SF-ARM contracts by 38% at maximum, and this contraction rate exceeds the contraction rate of the McKibben artificial muscle. However, the SF-ARM is not well-suited for practical use because the strain on the SF-ARM while it is actuated is large which can cause fatigue failure of the rubber. This study focuses on suppressing the growth of cracks using strain-induced crystallization of the natural rubber, to prolong the lifetime of the SF-ARM. Natural rubbers form a crystalline layer in the direction perpendicular to the direction of stretching. This crystal layer effectively suppresses the growth of cracks in the SF-ARM when under strain. Deliberately developing a crystal layer should extend the lifetime of the SF-ARM. First, this study confirmed the formation of a crystal layer under extension of natural rubber (NR) and styrene butadiene rubber (SBR) using wide-angle X-ray diffraction measurements. Next, the strain concentration near the crack was analyzed using finite element method simulations. Finally, fatigue-life tests were conducted with SF-ARMs made of NR and SBR.

    DOI: 10.1117/12.2513246

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  • Proposal of air compressing device using walking vibration energy regeneration for pneumatic driven assistive device 査読

    Manabu Okui, Yasuyuki Yamada, Taro Nakamura

    Robotics Transforming the Future - Proceedings of the 21st International Conference on Climbing and Walking Robots and the Support Technologies for Mobile Machines, CLAWAR 2018   ( 012 )   36 - 43   2019年

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    掲載種別:研究論文(国際会議プロシーディングス)  

    Pneumatically driven wearable assistive devices for walking have been developed recently. These devices can achieve flexible assistance without control; however, they require large and heavy air compressors for activation. In this study, a pneumatically driven source using vibration energy regeneration from walking was developed. The aim was to activate the cylinder using vibrations due to walking and compressed air. A mass element, which is connected to a human body via a spring and a cylinder, vibrates along with the human gait cycle. Next, a prototype was developed and tested. In walking experiments, stored pressure was measured at several gait cycles and masses for comparison. Results indicate that the gait cycle period and masses affect the stored pressure; the highest pressure recorded was 0.08 MPa.

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  • 生物規範型ソフトロボット

    奥井学, 中村太郎

    機械の研究   71 ( 12 )   925‐934 - 934   2019年

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    記述言語:日本語   出版者・発行元:東京 : 養賢堂  

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  • クエン酸と炭酸水素ナトリウムの化学反応を利用した空気圧源

    奥井学, 中村太郎

    フルードパワーシステム   50 ( 2 )   78‐81   2019年

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    記述言語:日本語  

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  • Hollow Pneumatic Artificial Muscles with Air Cylinder: Improvement for compatibility of high durability and high efficiency 査読

    Yasuyuki Yamada, Akihiro Kojima, Yutaro Higashi, Manabu Okui, Taro Nakamura

    Proceedings of the IEEE RAS and EMBS International Conference on Biomedical Robotics and Biomechatronics   2018-August   865 - 870   2018年10月

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    掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Pneumatic soft actuators has been developed to improved characteristics, such as operating flexibility, low weight, and high output etc. However, the application range of these artificial muscles has been limited by their fragility, the size of pneumatic source and the system size required to control the position and force. Therefore, this research proposes hollow artificial muscles with air cylinder that is high durability and driven with less air. Furthermore, this actuator control both stiffness and displacement independently as single mechanical element.

    DOI: 10.1109/BIOROB.2018.8487219

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  • Socks type actuator that provides exercise for ankle and toes from the medical point of view 査読

    Hayato Sasanuma, Hideyuki Tsukagoshi, Manabu Okui

    IEEE/ASME International Conference on Advanced Intelligent Mechatronics, AIM   2018-July   1228 - 1233   2018年8月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    This paper presents a socks type wearable soft actuator driven by pneumatics: Motion Socks, aimed to provide exercise for both ankle and toes automatically and safely. The goal of this project is to prevent the symptom of DVT (Deep Vein Thrombosis) which tends to arise for the elderlies lying on the bed for a long time. To improve the blood circulation effectively, two design methods are proposed. One is the desirable design of soft pneumatic actuators to provide exercise, which enables the force vector to act on the instep of the foot perpendicularly in order to reduce the load on the foot. The other is a limiter as the safety function to prevent undesirably large force from acting on ankle and toes, which is composed of magnets and hinges to detect the load, and a tube type valve to exhaust. The validity of the proposed methods is verified through the experiment, which shows the developed Motions Socks could effectively improve the blood flow.

    DOI: 10.1109/AIM.2018.8452682

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  • Prolonging the lifetime of straight-fiber-type pneumatic rubber artificial muscle by shape consideration and material development 査読

    Akihiro Kojima, Manabu Okui, Yasuyuki Yamada, Taro Nakamura

    2018 IEEE International Conference on Soft Robotics, RoboSoft 2018   188 - 195   2018年7月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    © 2018 IEEE. A pneumatic artificial muscle is an air pressure-activated rubber actuator. It is lightweight and high in power density compared to motorized actuators and fluid-powered cylinders. In addition, it shows high compatibility with the human body because it has good flexibility. The authors have developed a straight-fiber-type pneumatic artificial muscle (SF-ARM) with high output and contraction amounts compared to those of the widely used McKibben-type artificial muscle. Although the fatigue life of the McKibben type has been examined, similar studies have not yet been performed for SF-ARM. In this study, the extension of the lifetime of SF-ARM, development of high-deformation rubber material, and examination of the SF-ARM aspect ratio were performed. First, from deformation analysis by the finite element method, the target elongation value of the rubber material was determined and a suitable material was developed. Next, the fatigue life and contraction characteristics were measured by reducing the strain of the rubber material by changing the aspect ratio. The results showed a relationship between the lifetime and the shape of the artificial muscle. We demonstrate that the relationship between the lifetime and contraction force and ratio, according to the application, can be selected by manipulating the shape and the size of the SF-ARM.

    DOI: 10.1109/ROBOSOFT.2018.8404918

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  • Novel feedforward controller for straight-fiber-type artificial muscle based on an experimental identification model 査読

    Ryuji Suzuki, Manabu Okui, Shingo Iikawa, Yasuyuki Yamada, Taro Nakamura

    2018 IEEE International Conference on Soft Robotics, RoboSoft 2018   31 - 38   2018年7月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    © 2018 IEEE. This paper reports on an improvement to a feedforward controller for a straight-fiber-type artificial muscle that can control the amount of contraction, stiffness, and contraction force by use of an experimental identification model. This straight-fiber-type artificial muscle has a higher contraction force and a higher contraction rate than a McKibben artificial muscle. In a previous study, we developed a feedforward controller for a straight-fiber-type artificial muscle based on a mechanical model. However, this controller could not accurately control the stiffness or the contraction force. A feedback controller was necessary to compensate for the lack of feedforward control accuracy, which increased the system complexity. In addition, the calculations of the previous controller were so complex that the microcontroller could not keep up with the sequential calculations. This is not practical when the controller is used in devices such as an assist suit. In this paper, to solve these problems, we propose a novel feedforward controller based on an experimental identification model whose calculations are simpler than the previous ones. An experimental identification model enables the feedforward controller to improve the accuracy by identifying the parameters used in the model. Also, we compare the accuracy of the proposed controller with the previous one.

    DOI: 10.1109/ROBOSOFT.2018.8404893

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  • Proposal of Welding Assisting Device Using Magneto Rheological Brake

    M. Okui, R. Suzuki, Y. Yamada, T. Nakamura

    16th International Conference on Electrorheological Fluids and Magnetorheological Suspensions, I-1-1   2018年7月

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  • Proposal of A Variable Viscoelastic Control Strategy for an Assistive Suit with MR Brakes and Straight-Fiber-Type Artificial Muscles

    R. Suzuki, M. Okui, S. Iikawa, Y. Yamada, T. Nakamura

    16th International Conference on Electrorheological Fluids and Magnetorheological Suspensions, G-2-6   2018年7月

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  • Development of a Wearable 4-DOF Force Feedback Device for Upper-Limb Using MR Clutches and Pneumatic Artificial Muscles

    Y. Onozuka, R. Suzuki, M. Okui, Y. Yamada, T. Nakamura

    16th International Conference on Electrorheological Fluids and Magnetorheological Suspensions, G-2-2   2018年7月

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  • Delta Type 4 DOF Force Feedback Device Composed of Pneumatic Artificial Muscles and MR Clutches and Its Application to Lid Opening Operation

    M. Okui, M. Kobayashi, Y. Yamada, T. Nakamura

    16th International Conference on Electrorheological Fluids and Magnetorheological Suspensions, P-2   2018年7月

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  • Hybrid pneumatic source based on evaluation of air compression methods for portability 査読

    Manabu Okui, Yuki Nagura, Yasuyuki Yamada, Taro Nakamura

    IEEE Robotics and Automation Letters   3 ( 2 )   819 - 826   2018年4月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC  

    This letter proposes a novel hybrid pneumatic power source for the development of a portable pneumatic source. The hybrid pneumatic source achieves a lightweight system by combining two pneumatic sources: one that can generate high pressure/small suppliable flow and one that can generate small pressure/large suppliable flow. In this study, first, the mobility of various pneumatic sources is evaluated by experiments. The evaluation methods involve a small battery-driven compressor, tank, phase change of material, and chemical reaction. From the results, it is clarified that there is no best method because each method has advantages and disadvantages. Then, a hybrid pneumatic source utilizing the result is proposed. Finally, a prototype that has phase change of CO2 and dimethyl ether as a pneumatic source is developed, and the effectiveness of the proposed method is confirmed by experiments.

    DOI: 10.1109/LRA.2018.2792145

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  • Fundamental characteristic of novel actuation system with variable viscoelastic joints and magneto-rheological clutches for human assistance 査読

    Manabu Okui, Shingo Iikawa, Yasuyuki Yamada, Taro Nakamura

    Journal of Intelligent Material Systems and Structures   29 ( 1 )   82 - 90   2018年1月

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    記述言語:英語   掲載種別:研究論文(学術雑誌)   出版者・発行元:SAGE Publications Ltd  

    In this study, a variable viscoelastic joint system with a clutch for human assistance was proposed. The variable viscoelastic joint system comprised antagonized artificial muscles and magneto-rheological fluid brake. This system enabled the human assisting device, such as exoskeletons, to retain structural softness when compared with the existing devices driven by motor and reduction gear, which could only achieve superficial softness. In addition, a clutch system that provided high back-drivability to the wearer by structurally separating the device from the wearer was proposed. As an initial step in designing the human assisting device, a prototype with the proposed variable viscoelastic joint system for knee assistance is developed. Also, its control method was developed. Furthermore, experiments were conducted to confirm the influence of the proposed viscoelastic joint system and control method on the wearer.

    DOI: 10.1177/1045389X17705216

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  • 圧縮空気生成手法の携帯性評価に基づくハイブリッド型携帯空気圧源の開発 査読

    奥井学, 名倉裕貴, 山田泰之, 中村太郎

    日本ロボット学会誌   36 ( 3 )   233‐241(J‐STAGE) - 241   2018年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本ロボット学会  

    DOI: 10.7210/jrsj.36.233

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  • 軸方向繊維強化型空気圧式ゴム人工筋肉の長寿命高効率化のための形状検討 査読

    山田泰之, 小島明寛, 奥井学, 中村太郎

    計測自動制御学会論文集   54 ( 6 )   557‐563(J‐STAGE) - 563   2018年

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    記述言語:日本語   出版者・発行元:公益社団法人 計測自動制御学会  

    DOI: 10.9746/sicetr.54.557

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  • 軸方向繊維強化型空気圧ゴム人工筋肉の長寿命化のための材料とアスペクト比の検討 査読

    小島明寛, 奥井学, 山田泰之, 中村太郎

    日本機械学会論文集(Web)   84 ( 857 )   ROMBUNNO.17‐00299(J‐STAGE) - 17-00299   2018年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    DOI: 10.1299/transjsme.17-00299

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  • 可変粘弾性関節を有するアシストスーツの開発 -粘弾性が人の動作に与える影響と粘弾性制御則の提案-

    飯川伸吾, 奥井学, 鈴木隆二, 山田泰之, 中村太郎

    日本ロボット学会誌   36 ( 8 )   567 - 575   2018年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本ロボット学会  

    <p>Recently, assisting human motion with a wearable robot is studied widely. These assisting systems are proposed from various points of view. Our study has proposed an assisting system that the torque, angle, and the viscoelasticity of the joint are variable because the human muscle has the characteristic of variable viscoelasticity. This system consists of antagonized muscle that the stiffness is variable and magneto-rheological fluid brake that the viscosity is variable. Therefore, the system enables the wearable assistive device such as exoskeletons to be structurally soft and to provide the wearer with a high back-drivability. We have proposed the assisting method by changing the viscoelasticity of the device joint according to the viscoelasticity of wearer's muscle. But suitable viscoelasticity of the joint for the assistive motion is not well known. In this paper, an experiment is conducted to examine how the viscoelasticity of the joint affects to human motion when assisting. Also, based on the results from the experiments, we propose the control method for the joint viscoelasticity of the device that responds to the assistive motion and confirm the effects with the experiments. </p>

    DOI: 10.7210/jrsj.36.567

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  • Novel feedforward controller for straight-fiber-type artificial muscle based on an experimental identification model. 査読

    Ryuji Suzuki, Manabu Okui, Shingo Iikawa, Yasuyuki Yamada, Taro Nakamura

    IEEE International Conference on Soft Robotics, RoboSoft 2018, Livorno, Italy, April 24-28, 2018   2018 ( RoboSoft )   31 - 38   2018年

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    出版者・発行元:IEEE  

    DOI: 10.1109/ROBOSOFT.2018.8404893

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  • 内圧を受ける軸方向繊維強化ゴム円筒の変形特性

    辻知章, 小島明寛, 奥井学, 久道樹, 中村太郎

    日本機械学会論文集(Web)   84 ( 868 )   18 - 00351-18-00351   2018年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本機械学会  

    &lt;p&gt;The cylindrical rubber is axially reinforced by the fiber and closed by the rigid ends. When the inner pressure is applied to this fiber reinforced rubber cylinder, the diameter expands and the length shrinks. Such the cylinder can be used as the soft actuator, that is, the artificial muscle. In this paper, this problem is analyzed theoretically. Firstly, the differential equation, which is satisfied the cylinder&#039;s profile, is derived. Secondary, the solution is obtained as the closed form, when the rubber is soft enough compared to the fiber. Finally, it is found that the profile of the rubber cylinder is given by the incomplete elliptic integral, when the inner pressure is large enough. Moreover, the spring constant, the contraction ratio and the maximum stress are obtained with respect to the length of the cylinder. The spring constant is linearly increasing with the inclement of the initial length of the cylinder. The contraction ratio is increasing with the inclement of the initial length of the cylinder and converged to 54.3%. The maximum stress is related to the elastic modulus of the rubber and is not related to the inner pressure. When the length of the cylinder is through three to five times larger than the initial diameter of the cylinder, the rubber has the small maximum stress and the large contraction ratio.&lt;/p&gt;

    DOI: 10.1299/transjsme.18-00351

    DOI: 10.1299/transjsme.21-00290_references_DOI_9BBAHHSD7Dm6U1R0heJSGo5sD4X

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  • Hollow Pneumatic Artificial Muscles with Air Cylinder : Improvement for compatibility of high durability and high efficiency

    Yasuyuki Yamada, Akihiro Kojima, Yutaro Higashi, Manabu Okui, Taro Nakamura

    2018 7TH IEEE INTERNATIONAL CONFERENCE ON BIOMEDICAL ROBOTICS AND BIOMECHATRONICS (BIOROB2018)   865 - 870   2018年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    Pneumatic soft actuators has been developed to improved characteristics, such as operating flexibility, low weight, and high output etc. However, the application range of these artificial muscles has been limited by their fragility, the size of pneumatic source and the system size required to control the position and force. Therefore, this research proposes hollow artificial muscles with air cylinder that is high durability and driven with less air. Furthermore, this actuator control both stiffness and displacement independently as single mechanical element.

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  • Proposal of a fixation method for wearable assistive systems using jamming transition and the expansion of an elastic bag 査読

    Manabu Okui, Kazuya Sekido, Shingo Iikawa, Yasuyuki Yamda, Taro Nakamura

    International Conference on Control, Automation and Systems   2017-October   1466 - 1468   2017年12月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE Computer Society  

    A body fixing method for wearable assistive devices was proposed that utilized jamming transition and the expansion of an elastic bag. The proposed fixing part comprised a jamming layer, a rubber bag, and other components. The jamming layer deformed due to the application of pressure to an elastic bag. Then, it hardened due to negative pressure. In this research, we described the configuration and movement of the proposed method and conducted a sensory evaluation using a prototype.

    DOI: 10.23919/ICCAS.2017.8204222

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  • A pneumatic power source using a sodium bicarbonate and citric acid reaction with pressure booster for use in mobile devices 査読

    Manabu Okui, Yuki Nagura, Shingo Iikawa, Yasuyuki Yamada, Taro Nakamura

    IEEE International Conference on Intelligent Robots and Systems   2017-September   1040 - 1045   2017年12月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Institute of Electrical and Electronics Engineers Inc.  

    A range of pneumatically-driven devices have been developed. However, these require a large air compressor, making them heavy, bulky, and therefore inappropriate for use in portable devices. In this study, we proposed and tested a portable pneumatic power source using the chemical reaction between sodium bicarbonate and citric acid. The carbon dioxide generated in the reaction was used as a pneumatic power source. The chemicals used are inexpensive, nontoxic, and readily available. From the result of basic experiment demonstrated in this paper, we conclude that the method can provide enough high pressure (more than 1 MPa) for activating pneumatic actuators and the chemical reaction is safe since it is endothermic reaction. We also demonstrated a novel system that provides continuous mixing of the reagents, using a pressure booster. The system keeps a pressure inside of a tank moderate, and tank can become light weight because it doesn't need to endure high pressure.

    DOI: 10.1109/IROS.2017.8202272

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  • Variable viscoelastic joint system and its application to exoskeleton 査読

    Manabu Okui, Shingo Iikawa, Yasuyuki Yamada, Taro Nakamura

    IEEE International Conference on Intelligent Robots and Systems   2017-September   3897 - 3902   2017年12月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Institute of Electrical and Electronics Engineers Inc.  

    In this study, a variable viscoelastic joint system comprising antagonized artificial muscles and magneto-rheological fluid brakes is proposed. This system enables human assisting devices such as robotic exoskeletons to retain structural softness when compared with the existing devices driven by motors and reduction gears, which can only achieve superficial softness. The authors had proposed the system and showed its effectiveness via experiments using a prototype with one degree of freedom in their previous works. In this study, as the next step in designing the human assisting device, a lower body assistive prototype 'Airsist' is introduced. In addition, a control method that can cooperate with the wearer without the need for an additional operation is proposed.

    DOI: 10.1109/IROS.2017.8206242

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  • Shape consideration for prolonging the lifetime of the Straight-fiber-type pneumatic artificial muscle

    Akihiro KOJIMA, Manabu OKUI, Yasuyuki YAMADA, Taro NAKAMURA

    Proc. of The 11th International Convention on Rehabilitation Engineering and Assistive Technology(i-CREATe2017), KOBE, JAPAN, PT5-3   2017年8月

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  • Semi-endoskeleton-type waist assist AB-wear suit equipped with compressive force reduction mechanism 査読

    Hiroki Inose, Shun Mohri, Hirokazu Arakawa, Manabu Okui, Katsuya Koide, Yasuyuki Yamada, Isao Kikutani, Taro Nakamura

    Proceedings - IEEE International Conference on Robotics and Automation   6014 - 6019   2017年7月

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:Institute of Electrical and Electronics Engineers Inc.  

    In recent years in Japan, over half of all workers suffered from lower back pain. This has become a social problem that needs to be addressed. To reduce its occurrence, we developed a flexible, high-output waist assist suit called 'AB-Wear' in a previous study. The AB-Wear suit can assist human motion and reduce muscular fatigue of the waist. However, the assistive forces of the device generate compressive forces on the backbone, which have adverse effects on the body. Hence, in this study, we propose an exoskeleton-type AB-Wear equipped with a compressive force reduction mechanism, called 'semi-endoskeleton-type AB-Wear'. This device has a reduction mechanism similar to a flexible flat spring behind the upper body. Because of this structure, this device can generate an effective assistive force. First, we explain the difference between the semi-endoskeleton-type AB-Wear and the previous device. Then, we model the semi-endoskeleton-type AB-Wear because the model is used for its operation. Moreover, its effectiveness is confirmed using musculoskeletal simulation. Finally it is evaluated by measuring surface electromyography (EMG) on a subject's body to confirm its effectiveness with a real body. The EMGs of the wearer with and without the suit are compared. The usefulness of the AB-Wear is confirmed by simulation and experiment.

    DOI: 10.1109/ICRA.2017.7989711

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  • Evaluaion of Air Compressing Methods for Development of a Portable Pneumatic Power Source 査読

    M. Okui, Y.Nagura, S.Iikawa, Y.Yamada, T. Nakamura

    Proc. of the 10th JFPS International Symposium on Fluid Power   2017 ( 2B14 )   2P1-D02   2017年

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    記述言語:日本語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:一般社団法人 日本機械学会  

    DOI: 10.1299/jsmermd.2017.2p1-d02

    DOI: 10.20965/jrm.2018.p0752_references_DOI_9NQpVoc1kai9cqGTk8y6cAuNg3d

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  • Proposal of a Fixation Method for Wearable Assistive Systems Using Jamming Transition and the Expansion of an Elastic Bag

    Manabu Okui, Kazuya Sekido, Shingo Iikawa, Yasuyuki Yamda, Taro Nakamura

    2017 17TH INTERNATIONAL CONFERENCE ON CONTROL, AUTOMATION AND SYSTEMS (ICCAS)   1466 - 1468   2017年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    A body fixing method for wearable assistive devices was proposed that utilized jamming transition and the expansion of an elastic bag. The proposed fixing part comprised a jamming layer, a rubber bag, and other components. The jamming layer deformed due to the application of pressure to an elastic bag. Then, it hardened due to negative pressure. In this research, we described the configuration and movement of the proposed method and conducted a sensory evaluation using a prototype.

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  • 炭酸水素ナトリウムとクエン酸の化学反応を用いた小型増圧ポンプを有する携帯型空気圧源の提案 査読

    奥井学, 名倉裕貴, 飯川伸吾, 山田泰之, 中村太郎

    日本フルードパワーシステム学会論文集   48 ( 3 )   17‐23 - 23   2017年

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    記述言語:日本語   出版者・発行元:一般社団法人 日本フルードパワーシステム学会  

    DOI: 10.5739/jfps.48.17

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  • The verification of permissible resistant torque considering back-drivability to develop a wearable assist suit 査読

    Shingo Iikawa, Manabu Okui, Yasuyuki Yamada, Taro Nakamura

    2016 14th International Conference on Control, Automation, Robotics and Vision, ICARCV 2016   1 - 6   2016年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    In this paper, permissible resistant torque considering back-drivability is verified to develop a wearable assist suit (WAS). The WAS has a clutch and a variable viscoelasticity joint. In this paper, permissible resistant torque is defined as torque that is acceptable in daily use. As first stage of the WAS development, the paper discusses the relationship between the resistant torque to the knee and the degree of discomfort experienced by the wearer as evaluated through a survey questionnaire experiment. In addition, the influence of the resistant torque on a muscle of the knee extension is considered and confirmed by measuring surface electromyography (surface-EMG).

    DOI: 10.1109/ICARCV.2016.7838709

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  • 1st prototype of a variable viscoelastic joint system with a clutch composed of pneumtic air muscle and magneto rheological brake 査読

    Auth Manabu Okui, Shingo Iikawa, Yasuyuki Yamada, Taro Nakamura

    2016 14th International Conference on Control, Automation, Robotics and Vision, ICARCV 2016   1 - 6   2016年

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    記述言語:英語   掲載種別:研究論文(国際会議プロシーディングス)   出版者・発行元:IEEE  

    In this study, a variable viscoelastic joint system with a clutch for a human assistance was proposed. The variable viscoelastic joint system comprised antagonized artificial muscles and magneto-rheological fluid brake (MR-brake). This system enabled the human assisting device such as exoskeletons to retain structural softness when compared with the existing devices driven by motor and reduction gear, which could only achieve superficial softness. In addition, a clutch system that provided high back-drivability to the wearer by structurally separating the device from the wearer was proposed. As an initial step in designing the human assisting device, a prototype with the proposed variable viscoelastic joint system for knee assistance is developed. Also, its control method were developed. Furthermore, experiments were conducted to confirm the influence of the proposed viscoelastic joint system on the wearer and the effectiveness of the clutch system.

    DOI: 10.1109/ICARCV.2016.7838562

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  • Development of a Walking Integrative Rehabilitation Device 査読

    M. Okui, D. Freitas, H.A. Almeida, P.J. Bártolo

    5th National Congress of Biomechanics   689 - 694   2013年

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    掲載種別:研究論文(国際会議プロシーディングス)  

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書籍等出版物

  • オーグメンテッド・ヒューマン Augmented Human―AIと人体科学の融合による人機一体、究極のIFが創る未来

    暦本 純一( 担当: 分担執筆 範囲: 第2編 第1章 第2節 第2項「軸方向繊維強化型人工筋肉」,第1章 第5節「人工筋肉アーム」)

    エヌ・ティー・エス  2018年1月  ( ISBN:486043515X

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    総ページ数:400  

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受賞

  • Towers Supporter's Group賞

    2020年11月  

    奥井学, 渡邊友貴, 外山渡, 井坂惠太, 津村一輝, 中村 太郎, 澤田弘崇, 久保田孝

  • SI2019優秀講演賞

    2019年12月   第20回計測自動制御学会システムインテグレーション部門講演会  

  • CLAWAR Association Best Technical Paper Award

    2019年8月  

  • 瀧野秀雄学術奨励賞

    2018年   中央大学  

    奥井学

  • 平成29年度学術論文賞

    2018年   日本フルードパワーシステム学会  

    奥井学

  • The Best Student Paper Award (The 10th JFPS International Symposium on Fluid Power)

    2017年10月  

    奥井学

  • SI2016優秀講演賞(第17回SICEシステムインテグレーション部門講演会)

    2016年   計測自動制御学会  

    奥井学

  • ROBOMEC表彰(日本機械学会,ロボティクス・メカトロニクス講演会2012)

    2014年   日本機械学会ロボメカ部門  

    奥井学

  • テクノルネサンス 村田製作所賞最優秀賞

    2014年   日本経済新聞  

    奥井学

  • 平成24年春季講演会最優秀講演賞

    2012年   日本フルードパワーシステム学会  

    奥井学

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共同研究・競争的資金等の研究課題

  • VR/AR空間における広域な移動と重力感覚の提示が可能な全身型力覚提示スーツ

    研究課題/領域番号:19H01127  2019年4月 - 2024年3月

    日本学術振興会  科研費基盤研究(A)(一般)  基盤研究(A)  中央大学

    中村 太郎, 奥井 学, 西濱 里英

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    担当区分:研究分担者 

    配分額:44070000円 ( 直接経費:33900000円 、 間接経費:10170000円 )

    本研究では、広域な移動が可能で,水中や泥濘の上の歩行感覚,また落下感覚といった多様な感覚を提示可能な装着型下肢力覚提示装置の開発を目指している.本装置は外骨格部分と足底部分に分かれており,靴のように装着することで自由に歩き回ることができる.現在は、足底部に落下装置を搭載することを鑑みた重力感覚の提示プロセスについて検討している.
    落下感覚の提示には,実際に台を降下させることで高い現実感を与えることが可能だが,安全性や高所からの落下を考えた場合,可能な限り小さな範囲の高低変化で落下感覚を提示する必要がある.そこで,降下台が現実より小さな加速度で降下し,その後台を停止させた後,映像の落下終了と合うように再度降下・停止することを考えた.昨年度までには,装置足底の落下部分の設計に必要な落下初期の加速度について,必要となる加速度の大きさを明らかにした.しかし,降下台の実現のためには降下途中に装置を減速させる必要があるが,この減速が落下感覚に及ぼす影響が明らかになっていない.そこで今年度は装置の減速が落下感覚に与える影響について調査した.
    結果から,減速をしたいくつかの条件のなかで,落下感覚と現実感覚の双方において,加速大&減速小の条件の中央値が最も高かった.したがって,開発する下肢力覚提示装置にも加速大(-1000 mm/s2)&減速小(500 mm/s2)を取り入れる.
    今後は,落下による重力感覚提示のコンセプトの着地部分についての評価を行う.また,下肢力覚提示装置の足底部分の開発を行う.

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  • 反力指示が不要な装着型力覚インターフェースの開発と運動教示への適用

    研究課題/領域番号:20K14700  2020年4月 - 2023年3月

    日本学術振興会  科研費若手研究  若手研究  中央大学

    奥井 学

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    配分額:4160000円 ( 直接経費:3200000円 、 間接経費:960000円 )

    力覚による情報伝達は,視覚・聴覚・触角と異なり大きさと向きを持つベクトル量であるため,映像や音,振動による伝達と比べてより効果的なサイバー空間から実空間への情報伝達インターフェースの実現が期待できる.しかし,据え置き型装置では使用者は移動ができない,外骨格型装置は人の関節可動域に制限がかかるといった課題がある.そこで空気噴出を用いた装着型の力覚提示装置を提案している.
    本年度は,並進3自由度に力覚を提示可能な試作機を製作した.試作機に用いたノズルの基礎特性を計測し,最大で1N程度の力の提示を確認した.またノズルへの印加圧力と発生力の関係を明らかにした.ノズルから発生する力をヒトは感知できるか確かめるために試作機を用いた主観評価実験を行った.その結果,すべての被験者において力の発生方向を検知できることを確認した.試作機を手に取り付け,力覚による位置誘導実験を行い,提案デバイスが誘導に応用可能であることを確認した.

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  • 可変粘弾性機構を用いた装着型力覚提示デバイスの開発と知能化空間への応用

    研究課題/領域番号:26709006  2014年4月 - 2019年3月

    日本学術振興会  科学研究費助成事業  若手研究(A)  中央大学

    中村 太郎, 奥井 学

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    配分額:22620000円 ( 直接経費:17400000円 、 間接経費:5220000円 )

    現在VR/AR空間ではHMDによる視覚的情報の提示が多く用いられている.しかしながらスポーツやリハビリ等の分野における能動的な動作のアプローチに対して,よりリアリティのある環境を実現するためには「力覚」の提示が必要不可欠である.
    本研究では,申請者が開発している人工筋肉と機能性流体デバイスで構成された可変粘弾性機構を用いることで、腕部に対して 軽量でありながら機構的に高機能・高出力な力覚を提示できる全く新しい「装着型力覚提示デバイス」を開発する。
    開発された上肢4自由度の装着型力覚提示装置をHMDによる3DのVR空間に適用させた結果、複数の被験者に対して有用な結果を得ることができた。

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  • 外部刺激により調整可能な突発性脊椎側弯症のためのインプラントデバイスの開発

    研究課題/領域番号:15K13859  2015年4月 - 2018年3月

    日本学術振興会  科学研究費助成事業  挑戦的萌芽研究  中央大学

    中村 太郎, 風間 裕人, 川上 紀明, 奥井 学

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    配分額:3770000円 ( 直接経費:2900000円 、 間接経費:870000円 )

    本研究では、脊椎側弯症のインプラントデバイスの前段階として、脊柱部の側弯を外部から矯正するためのコルセットを開発する。
    基本的に従来のコルセットは基本的に24時間装着することが望ましいが、従来のコルセットは固いプラスティック製のコルセットを腰部から胸部にかけて捩じりながら締め上げることで矯正しており、患者にとっては窮屈で長時間の使用に不向きであった。また外見も目立ってしまい、装具として好ましい形態とはいいがたい。
    そこで本プロジェクトでは、メッシュ素材や人工筋肉等のデバイスを多用することで下着感覚での矯正が可能となるような装具を目指す。

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  • 関節剛性の制御により音色を変化できる人工筋肉駆動打楽器演奏ロボットの開発補助事業

    公益財団法人JKA  研究補助 若手研究(2022年度) 

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  • 爆発的に速い集積型燃焼人工筋肉の具現化

    JST  ACT-X リアル空間を強靭にするハードウェアの未来(2021~2023年度) 

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知的財産権

  • 力覚提示装置及び力覚提示方法

    中村 太郎

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    出願番号:特願2019-191264  出願日:2019年10月18日

    公開番号:特開2021-068041  公開日:2021年4月30日

    出願人(機関):学校法人中央大学

  • アシスト装置の制御方法及びアシスト装置

    中村 太郎,山田 泰之,飯川 伸吾,鈴木 隆二

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    出願番号:特願2018-011931  出願日:2018年1月26日

    公開番号:特開2019-126668  公開日:2019年8月1日

    出願人(機関):学校法人中央大学

  • マッサージ装置

    山田 泰之,中村 太郎

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    出願番号:特願2017-246480  出願日:2017年12月22日

    公開番号:特開2019-111082  公開日:2019年7月11日

    出願人(機関):学校法人中央大学

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    出願番号:特願2017-173545  出願日:2017年9月8日

    公開番号:特開2019-049308  公開日:2019年3月28日

    登録番号:特許第7015515号  登録日:2022年1月16日 

    出願人(機関):学校法人中央大学

  • 流体圧アクチュエータ駆動システム

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    出願番号:特願2017-081673  出願日:2017年4月17日

    公開番号:特開2017-215036  公開日:2017年12月7日

    登録番号:特許第6875730号  登録日:2021年4月27日 

    出願人(機関):学校法人中央大学

  • 装着具の装着方法及び装着具

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    出願番号:特願2017-051685  出願日:2017年3月16日

    公開番号:特開2018-153358  公開日:2018年10月4日

    出願人(機関):学校法人中央大学

  • アクチュエータ

    中村 太郎, 山田 泰之, 奥井 学

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    出願番号:特願2017-051679  出願日:2017年3月16日

    公開番号:特開2018-155298  公開日:2018年10月4日

    登録番号:特許第6873468号  登録日:2021年4月23日 

    出願人(機関):学校法人中央大学

  • 流体装置

    中村 太郎, 山田 泰之, 奥井 学

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    出願番号:特願2016-215450  出願日:2016年11月2日

    公開番号:特開2018-071740  公開日:2018年5月10日

    登録番号:特許第6854504号  登録日:2021年3月18日 

    出願人(機関):学校法人中央大学

  • 揺動体

    中村 太郎, 山田 泰之, 奥井 学, 風間 祐人, 佐藤 良昭

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    出願番号:特願2016-200304  出願日:2016年10月11日

    公開番号:特開2018-061613  公開日:2018年4月19日

    登録番号:特許第6781457号  登録日:2020年10月20日 

    出願人(機関):学校法人中央大学

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    中村 太郎, 山田 泰之, 奥井 学, 森 彪生

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    出願番号:特願2016-126474  出願日:2016年6月27日

    公開番号:特開2018-003855  公開日:2018年1月11日

    登録番号:特許第6757027号  登録日:2020年9月1日 

    出願人(機関):学校法人中央大学

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