Hybrid-Type Position and Force Control of Robot Manipulator Using Artificial Rubber Muscle

Abstract

An artificial rubber muscle has attracted much attention because of its light weight and mechanical flexibility. Thus, it is anticipated that it may be applied to a robot which can operate gently against or with humans. However, there are only few reports on multi-d.o.f. manipulators using this actuator. In this study, a hybrid-type position and force control is carried out by using a 2 d.o.f. manipulator comprising this manipulator, and its fundamental control performance is investigated. This actuator has a nonlinear characteristic in terms of structure and air compressibility, which makes accurate position control difficult. To cope with such a problem, a position controller using a two d.o.f. PID controller is realized by adding a feedforward compensator. As a result, a satisfactory position-tracking control performance can be obtained. Also, hybrid-type control of force control and tracking speed can be accomplished with sufficient accuracy.