The Effect of the Muscular Parameters in the Motion Control of Two-joint Robot Arm with Muscular Arrangement

Abstract

A conventional robot arm has the joint coordinate system constructed with an equal number of actuators to the number of its joints, whereas a two-joint link mechanism reported for human extremities has the muscle coordinate system constructed with the three pairs of antagonistic muscles consisting of one antagonistic pair of bi-articular muscles and two antagonistic pairs of mono-articular muscles. We have reported that motion control through the coordination of bi-articular and mono-articular muscles has been confirmed using electromyography and verified using a robot arm equipped with bi-articular actuators. This study describes the motion control of humanlike two-joint robot arm based on the muscle coordinate system to dissolve the contact task problem. The mechanical properties of endpoint operated with the muscle coordinate system consisting of three pairs of antagonistic actuators including the bi-articular actuators, were comparatively examined theoretically and experimentally in terms of robotics, and simple robotic experiments were designed to show how the humanlike two-joint robot arm with muscle coordinate system could dissolve the contact task.The results obtained here demonstrate the moment arms and elastic coefficient of the bi-articular actuators and the mono-articular actuators at the first joints contributes to control the elastic ellipse and the trajectory exerted at the endpoint, and the two-joint robot arm provided with these mechanical properties on the muscle coordinate system could dissolve the contact task.