Motion and Vibration Control for Robot Arm with Elastic Joint. Application of Disturbance Observer Including Elastic Vibration.

Abstract

Recently, high speed and high precision have become very important qualities in industrial robots. High speed, however, leads to lower precision because of inertial force, interference from the axes and vibration. In particular, a large robot has low natural frequency because of its flexible joint, thus vibration control is an important problem. In this paper, in the case of the robot arm with an elastic joint, the disturbance observer which includes the elastic vibration of the robot arm and the calculated torque method are applied. First, the control rule of this disturbance observer is derived. Next, the efficiency of this disturbance observer is analyzed by the simulation of the one-link robot arm linked to a flexible joint. Lastly, this method is applied to an actual industrial robot manipulator, and high accuracy has been confirmed.