Redundant manipulator control with autonomous consideration algorithm of torque saturation

Abstract

As each joint actuator of a robot manipulator has a limit value of torque, the motion control system should consider the torque saturation. Since the redundant robot manipulator has plural attitudes for a position of its end-effector. Jacobian matrix of redundant robot manipulator can select the optimal one considering its motion energy. Using the optimal Jacobian matrix, the motion control system can fairly consider the torque saturation in steady state. When the motion control system carries out fast motion and quick disturbance suppression, high joint torque is required in the transient state. However, the high torque cannot often be produced by torque limitation. In order to consider the torque saturation in the steady and transient states, this paper proposes a new redundant motion control system, which uses both the autonomous consideration algorithm on torque saturation and the optimal Jacobian matrix on motion energy. The proposed Jacobian matrix minimizes the motion energy of joint space in steady state. The autonomous consideration algorithm on torque saturation adjusts the acceleration torque in joint space, and compensates the saturation effect in Cartesian space. In the simulation results, on condition of having a large payload torque and a fast motion reference, the proposed redundant manipulator control well realizes the quick robot motion robustly and smoothly.