ex3_31.m

华东理工大学自动化系《控制系统分析、设计和应用》教材配套程序实例,有关说明： 1. 安装MATLAB软件。安装时

% ex3_31
% 绘制线性系统的相平面图
syms w y;
figure('pos',[50,50,200,150],'color','w');
axes('pos',[0.14,0.14,0.75,0.75]);
y1w=dsolve('D2y+w^2*y=0','y(0)=1','Dy(0)=0');
y1=subs(y1w,{w},0.5);
dy1=diff(y1);
ezplot(y1,dy1,[-100 100]);
hold on;
y2w=dsolve('D2y+w^2*y=0','y(0)=2','Dy(0)=0');
y2=subs(y2w,{w},0.5);
dy2=diff(y2);
ezplot(y2,dy2,[-100 100]);