www.gusucode.com > control 案例程序 matlab源码代码 > control/UnityGainCrossoverExample.m
%% Unity Gain Crossover % Find the 0dB crossover frequencies of a single-loop control system with plant given % by: % % $$G\left( s \right) = {1 \over {{{\left( {s + 1} \right)}^3}}},$$ % % and PI controller given by: % % $$C\left( s \right) = 1.14 + {{0.454} \over s}.$$ % %% G = zpk([],[-1,-1,-1],1); C = pid(1.14,0.454); sys = G*C; wc = getGainCrossover(sys,1) %% % The 0 dB crossover frequencies are the frequencies at which the open-loop response % |sys = G*C| has unity gain. Because this system only crosses unity gain % once, |getGainCrossover| returns a single value.