matlabnyquist

How to see if the nyquist plot is stable or unstable?

Is there a method to determine the stability of the nyquist plot to check if it's stable or unstable ? I currently needs to manually input the transfer function to another m.file to view the pz location to determine

syms s w

    G = (2*s+1)/((s^2)+(5*s)+6); %transfer function
    G_w = subs(G,s,j*w);
    W= [-100:0.1:100]; %[min_range:step size:max_range]
    nyq = eval(subs(G_w,w,W));

    x = real(nyq)
    y = imag(nyq)

    plot(x,y)

This is the code i am using

Solution

  • I have found this video quite useful! Nyquist Stability Criterion, Part 1 All this channel video are really good for control theory and give a better understanding to then move everything on MATLAB.

    Hope this was useful.