Digital adaptive control of space robot manipulator having input constraints

This paper deals with a digital adaptive control for a manipulator mounted on a space robot. Most control methods are based on the supposition that all physical parameters of the space robot are known. However, if the end-effector catches an unknown object, the physical parameters of the robot are changed. Furthermore, joint actuators of a manipulator generally have input constraints. Even though the end-effector does not catch any objects, if the inputs of the actuators become saturated, the control performance gets worse. In this paper, we propose a digital adaptive control method for a manipulator having input constraints. Experimental results from a Space Manipulator Robot Testbed demonstrate the effectiveness of the proposed method.