Enhancement of feed drive dynamics using additional table speed feedback

The tracking performance and disturbance response of feed drive systems with P-PI cascade control principle are limited by the first natural frequency of mechanical transmission elements. In order to overcome this limitation, a new control principle for feed drives with large inertia ratio is presented. It synthesizes a weakly set motor speed controller with an additional table speed control loop. The bandwidth is increased without any extra sensor or actuator. The large inertia ratio can be achieved by using a high dynamic motor with small inertia and a ball screw with high pitch.