最优ZPETC在数控机床伺服跟踪控制中的应用研究

在高精度数控机床伺服跟踪控制系统中,为使输出响应能完整地跟踪输入指令,不仅要求输出与输入之间的相位差为零,而且要求幅值一致,通常采用零相位误差跟踪控制器(ZPETC)作为前馈控制器,补偿相位误差,但同时也产生一定的增益误差.为改善ZPETC的跟踪性能,提出一种基于L2-范数优化的前馈控制器设计方案,通过选取适当的目标函数,设计出最优的数字前置滤波器.该方案在保持系统零相位误差的同时,改善了系统增益性能,从而提高跟踪精度,这一点已得到仿真结果的证明.

The Application of Optimal ZPETC in NC Machine Tool 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, an optimal ZPETC 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.