模拟控制器的离散化方法研究

Research on Discretization Method of Analog Controller

连续控制系统进行离散化时,最方便的办法是将模拟控制器离散化,本文主要讨论后向差分法和双线性变换法.这两种方法都是已知S域传递函数,可以求得对应的Z变换.将两种离散化方法分别编写Matlab程序,由仿真输出波形可知只要原连续系统稳定,两种变换法离散化后的系统一定是稳定的.随着采样周期的增大,两种方法的阶跃响应曲线的调节时间和超调量都同样将随之增大.

When the continuous control system is discretized,the most convenient way is to discretize the analog controller.This paper mainly discusses the backward difference method and the bilinear transformation method.The S domain transfer function is known in both two methods,and the corresponding Z transformation can be obtained.The two discretization methods are programmed in MATLAB.From the simulation output waveform,it can be known that as long as the original continuous system is stable,the discrete systems after the discretization of the two transform methods must be stable.As the sampling period increases,the adjustment time and overshoot of the step response curves of the two methods will also increase.