Koki NAKAGAWA – 道木研究室


研究テーマ / Research topic

布状アクチュエータの用いたアシストスーツの実現/Realization of Assistive Suits with Fabric Actuators


Japanese ver. English ver.




































STEP1 布状アクチュエータ設計の自由度向上<完了>




STEP2 所望の変形を実現する布状アクチュエータの設計<検討中>





STEP3 アシストスーツの作成<検討中>






English ver—————————-


Research Background


Soft Actuator

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Soft actuators are actuators that function by deforming a lightweight, flexible material. For example, the “McKibben artificial muscle” as shown below. This is a soft actuator that has the property of contracting when air pressure is applied.


Gait training device using pneumatic rubber artificial muscles[1]

Due to its light weight and flexibility, they have been widely studied mainly in the field of wearable devices.

The image on the left shows Bridgestone’s gait training device using  pneumatic rubber artificial muscles. The soft actuator used in the device expands and contracts by adding and subtracting pressure from the air in the rubber tube, assisting the bending and stretching of the legs.


Fabric Actuator

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A new soft actuator, “fabric actuator” has been developed by placing pneumatically contracting McKibben artificial muscles on both sides of a fabric made of woven flat rubber, as shown in the left figure[2]. Most of the existing soft actuators have only one degree of freedom(DOF) of deformation, such as contraction or bending, but this fabric actuator can perform a high DOF of deformation, such as forward bending, side bending, and rotation as shown in the video below. It can also be molded into a cylindrical shape, allowing a wide range of three-dimensional movements with a single device.

This is expected to lead to the realization of assistive suits that can assist not only in single movements but also in highly flexible movements.


However, in previous studies, the possibility of using fabric actuators for assistive suits has not yet been investigated.

Therefore, the purpose of this research is to “realize an assistive suit using fabric actuator.



Research content


Problem of Creating an Assist Suit

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When using fabric actuators for assistive suits, there is a problem with the fabric actuators in the previous study alone, as shown in the figure above. In order to change the range of motion of the fabric actuator, it is necessary to change the pattern of the artificial muscles and the fabric. In order to change the range of motion of the fabric actuator, we need to change the artificial muscle placement patterns and fabric.


Therefore, it is necessary to examine the artificial muscle placement and fabric  to achieve the appropriate deformation for each body part.



3 Steps to Achieve Goal

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Based on the above issues, this research is proceeding in the following steps.


STEP1 Improve DOF of Fabric Actuator Design :Completed

In the existing fabric actuator, the artificial muscles are fixed through the flat rubber of the fabric. However, as it is, there are limitations such as the fixed position of the artificial muscle depends on the fabric and the placement patterns are limited, and only the fabric that can pass the artificial muscle can be moved. The purpose of this STEP 1 is to eliminate these limitations and make a wider variety of artificial muscle placement patterns and fabrics available for assistive suits.



STEP2 Design Fabric Actuator to Achieve Desired Deformations :Working

After the selection of various artificial muscle placement patterns and fabrics in STEP 1, we will search for artificial muscle placement patterns and fabrics that can realize the movement of body parts in small sizes.



STEP3 Create Assist Suits :Working

We will create an adult-sized assistive suit based on our knowledge of artificial muscle placement and fabrics explored in STEP 2 and consider whether the desired movement can be achieved.








[1]Rentec Jornal「Vol.141 空気圧式ゴム人工筋肉を使った歩行トレーニング装置」journal.orixrentec.jp/2018/02/post-57.html

[2]Y. Funabora. Flexible fabric actuator realizing 3d movements like human body surface for wearable devices. IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), pp. 6992–6997, 2018.