Compliance measurement for the Mitsubishi PA-10 robot

In this study, we measure the compliance characteristics of the 7-degree-of-freedom (DOF) vertical multiarticulated Mitsubishi PA-10 robot. To determine the compliance characteristics of the robot, numerical values of joint compliance are identified by a partial simultaneous measurement method using a force/torque sensor and a 3-D measurement system. The identified compliance is derived from an extended 10-DOF link model that comprises three additional virtual joints and seven actual joints. The virtual joints, which can be handled in the same manner as the actual joints, can be used for more accurate identification. The modeling error derived from link flexibility may be compensated by introducing the extended link model with additional virtual joints. To investigate the accuracy of the compliances identified with the extended link model, verification experiments were conducted. The results show that precise compliance characteristics are obtained from the extended link model. Finally, we reveal the compliance model of the Mitsubishi PA-10 robot, which comprises the numerical values of the joint compliance and a simple kinematic modeling.