Model Based Axial Displacement Measurement of Rubber Artificial Muscle Using Inner Diameter Sensor

Abstract

The purpose of this study is to develop a soft actuator which can be used as nursing care task in a bathing. In our previous study, a rubber artificial muscle with the inner diameter sensor was proposed and tested. The inner diameter sensor consists of two electric circuit boards with two photo reflectors. The sensor is inserted into the tube of the artificial muscle. It could be also obtained an empirical relation between the inner diameter and the axial directional displacement of the muscle with a strong correlation. By using the sensor and the empirical equation, the feedback position control of the muscle in the water could be also realized. In this paper, the model based axial displacement measurement of the muscle is described in order to estimate the condition of the muscle such as the inner diameter exactly. As a result, the design parameters of the muscle were obtained.