The Application of ZPETC Based on Optimal Design of L2-Norm in Servo Tracking Control

In high precision servo tracking control system, in order to make the output response track perfectly the input command, the phase error between output and input is required to be zero, at the same time the magnitude is required to be uniform. Generally zero phase error tracking controller (ZPETC) is used as feedforward controller to compensate for the phase error, but this will also cause small gain error. To improve the tracking performance of the ZPETC, the optimal design scheme of feedforward controller based on L₂-norm is proposed in the paper. The optimal digital prefilter (DPF) is designed by selecting proper objective function. By cascading the developed DPF to ZPETC, a new feedforward controller is obtained. The scheme greatly improves the gain performance of the system while maintaining zero phase error of the system, thus the tracking accuracy of the system is enhanced. This characteristic is seen from the simulation results