Control of a Manipulator with Bi-Articular Muscles (Simultaneous Control of Trajectory and Stiffness Ellipse Using Saturation Functions)

Abstract

In a control method of a manipulator, it is important that an end effector can softly touch a subject. In order to realize a control for flexibility of a hand, a control with an artificial muscle actuator has been executed. However, the artificial muscle actuators are known to have a problem in controllability because they have nonlinear viscoelastic properties. This study shows simultaneous control of manipulator posture and joint stiffness using the artificial muscle actuators. It is realized by using a simple feedback control system. We also deal with the method to obtain the ellipse that indicates the stiffness characteristic of the end effector. Moreover, the control method is used for leg control of a walking robot. The control performance of the proposed method is verified by simulation.