How can I limit the PID controller output to a constraint of 0 to 1 for genetic algorithm?
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My real system (buck converter) can only take an input of 0 to 1 (duty ratio) from the PID controller output for the circuit due to it simulating reality (can't have negative or above 1 duty ratio in reality).
How can I constrain the PID controller output so that the genetic algorithm only looks at a controller output of 0 to 1 instead of -inf to inf?
--------------------------------------Start of genetic algorithm------------------------------------
clear all, close all, clc
dt = 0.000001; % this is 10^-6
PopSize = 50 % was 500
MaxGenerations = 15; %was 1000
s = tf('s');
G = (1439928003.68621)/(s*s+5333.33333333333*s+95995200.2457475) % got this by doing feedback cmd
options = optimoptions(@ga,'PopulationSize',PopSize,'MaxGenerations',MaxGenerations,'OutputFcn',@myfun);
[x,fval] = ga(@(K)pidtest(G,dt,K),3,-eye(3),zeros(3,1),[],[],[],[],[],options);
--------------------------------------Start of next tab of live script-----------------------------------
function J = pidtest(G,dt,parms)
s = tf('s');
K = parms(1)+ parms(2)/s + parms(3)*s/(1+0.000001*s)% this is 10^-6
Loop = series(K,G);
ClosedLoop = feedback(Loop,1);
t = 0:dt:0.05; % this indicates length of time to show
[y,t] = step(ClosedLoop,t);
CTRLtf = K/(1+K*G);
u = lsim(K,1-y,t); % line to potenially change for different TFs
Q = [1];
R = 0.00005; % 00000 change these to effect rise, overshoot, settling time?
J = dt*sum(Q*(1-y(:)).^2 + R*u(:).^2)
step(5*ClosedLoop,t)
h = findobj(gcf,'type','line');
set(h,'linewidth',2);
drawnow
--------------------------------------Start of next tab of live script-----------------------------------
function [state, options,optchanged] = myfun(options,state,flag)
persistent history
persistent cost
optchanged = false;
switch flag
case 'init'
history(:,:,1) = state.Population;
cost(:,1) = state.Score;
case {'iter','interrupt'}
ss = size(history,3);
history(:,:,ss+1) = state.Population;
cost(:,ss+1) = state.Score;
case 'done'
ss = size(history,3);
history(:,:,ss+1) = state.Population;
cost(:,ss+1) = state.Score;
save history.mat history cost
end
--------------------------------------end of scripts---------------------------------------------------
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