数字伺服系统中微分控制律的实现

针对某型高精确度转台系统中，运用传统的PID算法设计数字控制器，由于采用完全微分环节实现微分控制律，输入信号中特定频率的噪声分量被充分放大，使有用信号产生失真，影响控制系统精确度。为了滤除这一噪声分量，保证系统的控制精确度，基于数字滤波理论，给出了几种数字滤波算法，并在数字滤波器的滤波效果及其给系统带来的相位迟后之间作了折衷。仿真和实验结果表明，加入数字滤波器后，数字微分控制器的噪声得到抑制，提高了确转台伺服系统的定位精确度。

Implementation of the differential control law in digital servo system

A digital PID controller was developed for a high precision servo turntable. When passing through the ideal differentiator, noise component at certain frequency of reference signals will be amplified, which distort useful signals and degrades system performance. To filter out the noise component and guarantee the control precision, several digital filtering algorithms were presented based on the digital filtering theory. The tradeoff between filtering effectiveness and phase lag induced by the filter was analyzed. Simulation and experimental results demonstrated that the introduction of digital filter suppressed the noise considerably and in turn enhanced the positioning accuracy of the turntable system.