% ex1_21
% 確定PID控制器參數(shù)的函數(shù)文件
function [Gc,kc,ti,td]=z_n1(k,t,tor,varargin)
controllertype= varargin {1};
switch controllertype
case 'p',
    delta=k*tor/t;
    Gc=tf(1/delta,1);
    kc=1/delta;
    ti=inf;
    td=0;
case 'pi',
    delta=1.1*k*tor/t;
    ti=3.3*tor;
    Gc=tf([ti 1],[ti 0])/delta;
    td=0;
    kc=1/delta;
case 'pid',
    delta=0.85*k*tor/t;
    ti=2*tor;
    td=0.5*tor;
    kc=1/delta;
    Gc1=tf([ti 1],[ti 0])/delta;
    Gc2=tf([td 1],1)/delta;
    Gc=Gc1+Gc2;
end;