IPMC Linear Actuator with Re-Doping Capability and its Application to Biped Walking Robot

Abstract

We are developing an artificial muscle linear actuator using ionic polymer-metal composite (IPMC) which is an electro-active polymer (EAP) that bends in response to electric stimuli and the goal of our study is applying the actuator to robotic applications especially to a biped walking robot. In this paper, we will describe the structure of the actuator and an empirical model of the actuator, and whose parameters are identified from input-output data. Based on the empirical model, basic experiments and position control of the linear actuator are demonstrated. We consider walking control of a small-sized biped walking robot and investigate changes of the characteristics of the actuator for walking by ionic re-doping chemically. In the application we assume that the developed actuators are connected both in series and in parallel to a joint of the walking robot so that the actuators supply enough torque to the robot and that they are stretched and compressed enough. It is shown throughout simulations that the biped walking robot with the actuators can walk on a level ground with a period synchronized with a period of input signal, and that walking patterns are changed by ionic re-doping.