How to build PID controller on command Line

Hello, I'm trying to find and built a PID system.But it gets error.I have to find,reponse time,steady stae error,overshot from Kp,Ki,Td.Function I have to work with is (1/s^2+10s+20).

Tune controller is in this sequence;

1.Only P element

2.Enable D, and returne P

3.Enable I and retune P,D.

And I have to plot, P,I,D,PI,PD,PID, bode and nyquist graphs.

P=4;
bode(P)
I=tf([1],[5]);
bode(I);
D=9;
bode(D);
sys=tf([270 50 1],[225 5 0])
[C_pi,info]=pidtune(sys,'PI')
[C_p,info]=pidtune(sys,'P')
bode(sys)
nyquist(sys)
[C_PD,info]=pidtune(syz,'PID')

Answer 1

[Sam Chak]

Hi @Bahar Ebru

Not exactly sure what you are trying to do (your description and code are not tally). After checking the documentation, I think you can try something like this:

% Plant
Gp = tf(1, [1 10 20])

Gp =
 
         1
  ---------------
  s^2 + 10 s + 20
 
Continuous-time transfer function.

% Compensator
[Gc, info] = pidtune(Gp, 'PID')

Gc =
 
             1          
  Kp + Ki * --- + Kd * s
             s          

  with Kp = 39.3, Ki = 116, Kd = 3.33
 
Continuous-time PID controller in parallel form.

info = struct with fields:
                Stable: 1
    CrossoverFrequency: 4.1614
           PhaseMargin: 74.0404

% Closed-loop system
Gcl = feedback(Gc*Gp, 1);
Gcl = minreal(Gcl)

Gcl =
 
     3.326 s^2 + 39.27 s + 115.9
  ---------------------------------
  s^3 + 13.33 s^2 + 59.27 s + 115.9
 
Continuous-time transfer function.

step(Gcl, 5)

bode(Gcl)

nyquist(Gcl)