“…However, a grasped object cannot be subjected to high acceleration because a high grasping force can damage the grasped object and the gripper. Perera et al (19) have estimated the inertia of a rotary motor by using an acceleration motion test, deceleration motion test, inverse motion acceleration test (16) , and their proposed method, namely, the change of inertia observer method. Between any two methods, there exists 15% to 30% difference of inertia.…”