“…Time synchronization errors could be due to: 1) different robot controllers, 2) different kinematic algorithms, 3) processing time differences, etc. The performance of symmetrical coordinated-motion tasks has been evaluated in various ways: 1) software simulation [5], [6], and 2) independent external sensors, such as laser trackers [9], [10], telescoping ball bars [11], 12], and motion-tracking systems [13], [14]. A laser tracker interferometer consists of a laser interferometer, a gimbal system, and a reflector.…”