Improvement of McKibben Artificial Muscle with Long Stroke Motion and Its Application

Abstract

The actuators required for a wearable system need to be flexible so as not to injure the body. The purpose of this study is to develop a flexible and lightweight actuator which can be safe enough to be attached to the human body. In the previous study, a new type of McKibben artificial muscle that had a long stroke of more than 80 % of its original length was proposed and tested. However, the damages on the tube of the actuator were found. They are caused by a large friction between the slide stage and the tube. Therefore, the life time of the actuator becomes shorter. In this paper, the improved McKibben actuator which consists of a McKibben artificial muscle on the market (FESTO Co. Ltd.), steel balls as a cylinder head and two pairs of slide stages is proposed and tested. The slide stage has steel balls set on the inner bore of the stage to decrease the friction. The steel ball in the McKibben actuator is held by two pairs of slide stages from both sides of the ball. As a result, the minimum driving pressure of the improved actuator decreases about 68 % compared with that of the previous one. The actuator can realize both pushing and pulling motion even if it has flexibility. By using these properties of the actuator, the various rehabilitation devices were proposed and tested.

Thermally actuated hydrogel bead based braided artificial muscle

“…McKibben muscles are a popular type of artificial muscle due to their similarity in performance to biological muscles as well as their high actuation force per mass [11][12][13]. These systems use an inflatable bladder that operates against an external braid such that pressurisation of the bladder causes a contraction in braid length.…”

Development of Compact Flexible Displacement Sensors Using Ultrasonic Sensor for Wearable Actuators

“…In the system, many wearable actuators such as a rubber artificial muscle have been used [5][6][7]. The systems using the wearable actuators had been sold in Japanese market.…”

“…The target of this study is to develop a low-cost and compact flexible displacement sensor for a wearable actuator. In the previous study, the indirect displacement measurement using an inner diameter sensor of rubber artificial muscle had been proposed and tested [7][8][9]. To decrease the measuring error, the direct measurement is useful.…”

Development and Analysis of Flexible Thin Actuator with a Built-in Fluid Pressure Source

“…In order to solve this problem, that is, to improve a quality of life (QOL) for the elderly and the disabled and to decrease the budget for nursing care, a simple rehabilitation device to keep their physical ability might be one of solutions. The actuator used in such a rehabilitation device requires lightweight, softness, small size and larger generated force that can support human body [2,3]. Therefore, many researchers are studying wearable actuators such as a McKibben artificial muscle [4,5].…”