% Chapter 4: Figure 4.27, p. 203%%   Analysis of the open-loop speed control system.%Ra=1; Km=10; J=2; f=0.5; Kb=0.1;num1=[1]; den1=[J,f];num2=[Km*Kb/Ra]; den2=[1];[num,den]=feedback(num1,den1,num2,den2);%% Change sign of transfer function since % disturbance has negative sign in the block diagram%num=-num;printsys(num,den)%% Compute time response to a unit step disturbance   %[yo,x,t]=step(num,den);plot(t,yo)title('Open-loop Disturbance Step Response')xlabel('time [sec]')ylabel('speed')grid%% Steady-state error -> last value of output yo   %yo(length(t))