Development of a Rubber Artificial Muscle with Inner Diameter Sensor and Its Control

Abstract

Due to the ageing and the decreasing birth rate in Japanese society, an important problem of providing nursing care for the elderly has occurred. Therefore, it is strongly desired to develop a wearable actuator to use in nursing care or rehabilitation. The purpose of this study is to develop a high-power flexible actuator which can be used in supporting a bathing. We proposed and tested a rubber artificial muscle with the inner diameter sensor which consisted of two photo reflectors. This inner diameter sensor can be expected to estimate the axial-direction displacement of the rubber artificial muscle. The position control was carried out using the actuator with the built-in inner diameter sensor and the quasi-servo valve. As a result, the axial-direction displacement of the actuator could be estimated well by the tested inner diameter sensor, and a good position control performance was obtained even when a load mass of 29.4N existed. As an application of the tested actuator, the large-scale bending actuator was also proposed and tested. As a result, its maximum bending angle is about 90 degrees. The bending angle of the actuator could be also estimated well using the tested inner diameter sensor.