包含了控制理论的各种仿真程序

				% Fig. 6.49   Feedback Control of Dynamic Systems, 4e 
				%             Franklin, Powell, Emami
				%
				
				clear all;
				close all;
				
				num=0.01*[20 1];
				den=[1 0 0];
				dencl=den+[0 num];
				t=0:1:100;
				y=step(num,dencl,t);
				plot(t,y);
				xlabel('Time (sec)');
				ylabel('y');
				grid;
				title('Fig. 6.49 Step response for PD compensator');