MATLAB: How to extract values of Kp, Ki, Kd and D of a PID transfer functio

MATLABpid controllersimulink

Hi, I have a transfer function of PID controller, I need to add it to simulink to calculate the anti-windup and other parameters, but I do not find kp, ki and kd. the transfer function is show in the picture, simplifying it:
(29.24) + (15.51/s) – (840.334/(s+35)
Thanks

Best Answer

s=tf('s');
PID=(29.24)+(15.51/s)-(840.334/(s+35))
syms Kp Kd Ki N
NPID_num=[Kp+N*Kd Kp*N+Ki N*Ki];
NPID_den=[1 N 0];
eqn1=PID.Numerator{1}(1)==NPID_num(1);
eqn2=PID.Numerator{1}(2)==NPID_num(2);
eqn3=PID.Numerator{1}(3)==NPID_num(3);
eqn4=PID.Denominator{1}(2)==NPID_den(2);
solx=vpasolve([eqn1 eqn2 eqn3 eqn4]);
Kp=subs(Kp,solx.Kp)
Kd=subs(Kd,solx.Kd)
Ki=subs(Ki,solx.Ki)
N=subs(N,solx.N)
What I did is a simple equation solving. I defined the unknown parameters as symbolic and then obtain the numerical values with the vpasolve function. Note that at the end, the symbolic controller parameters are replaced with their numerical values. After that, in the PID Controller block in Simulink, write Kp, Ki, Kd and N to the parameters repsectively. Hope this helps.
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