how to tune pid controller using genetic algorithm?

Hi friends, I had designed longitudinal flight control system in simulink. In that model i want to tune PID controller by using Genetic algorithm.How can i get Kp,Ki,Kd values ?

anybody knows how to use GA in simulink, Pls help me...

Answer 1

[Amirali Najafi]

Code credit to Steve Brunton

close all; clear all; clc

dt = 0.001;

PopSize = 25;

MaxGenerations = 10;

s = tf('s');

G = 1/(s*(s*s+s+1));

options = optimoptions(@ga,'PopulationSize',PopSize,'MaxGenerations',MaxGenerations);

[x,fval] = ga(@(K)pidtest(G,dt,K),3,-eye(3),zeros(3,1))

function J = pidtest(G,dt,parms)

s = tf('s');

K = parms(1) + parms(2)/s + parms(3)*s/(1+.001*s);

Loop = series(K,G);

ClosedLoop = feedback(Loop,1);

t = 0:dt:20;

[y,t] = step(ClosedLoop,t);

CTRLtf = K/(1+K*G);

u = lsim(CTRLtf,1-y,t);

Q = 1;

R = .001;

J = dt*sum(Q*(1-y(:)).^2+R*u(:).^2)

[y,t] = step(ClosedLoop,t);

plot(t,y,'LineWidth',2,'color','r')

drawnow

end

[SURBHI GOEL]

Can you please tell how J was finally written? I am guessing 1-y(:) is giving steady state error. What is u?

TIA

[JAMES KEEN]

Hi @SURBHI GOEL

I believe u is the controller action that is used in the linear qudractric equation specified as the cost function (J). In other words u is the controller action of the system used.

[SURBHI GOEL]

@James Keen If Y is the controller output and X is the controller input, are you defining controller action as Y/X?

[krishna]

Hi friends, I had designed model of 6DOF quadcopter control system in simulink i'm using cascade PID controller . In that model i want to tune PID controller by using Genetic algorithm.How can i get Kp,Ki,Kd values ? any one give me code for this for tuning PID controller.