Controller Examples

 

Contents

% The Controller simulation contains two steps:

% The first step computes the controller gains i.e. tunes the PID
% controller with the Twiddle method
% The second step uses the PID controller and control the AC for tracking a path

% During the simulation several objects are created:
%   my_car which belongs to the 'dacia' class (bicycle model)
%   my_PID which belongs to the 'con_PID' class (the PID controller)
%   my_comp which belongs to the 'comp' class (the comparator)

Tuning the controller

Use the twiddle function which use the error_sim_daci() function in order to compute the Total Error Several simulations are made during the tuning process. The simulated AC belong also to the ‘dacia’ class. The parameters which are used here by the object constructor are: the pose [0;1;0]; the initial steering angle 0; the speed of the car 1m/s the perturbations [0,0].

figure
xlabel 'Epochs'
ylabel 'The total error TE'
grid
Parametrii=twiddle;

Controler_1_01

The simulation

Parametrii=[0.6,9.0,0.0001];
% Simulation parameters:
Timp_simulare=560; %Simulation time
Pasi_simulare=length(1:Timp_simulare);
% Desired trajectory
poz_dor_x=[0,80,80,0,0,-80,-80,0];
poz_dor_y=[-60,-60,20,20,60,60,-60,-60];
% The initial pose of the AC
ppostura=[0;-60;0];

%Creating the objects:
% The AC: pose [x=0;y=-60;alf=0]; gama=0 speed=1, perturbations=[0,0]
my_car=dacia([0;-60;0],0,1,[0,0]);
% The PID controller
my_Pid=con_PID(Parametrii(1,1),Parametrii(1,2),Parametrii(1,3));
% The Comparator
my_comp=comp([poz_dor_x;poz_dor_y]);
[my_comp,eroarea_initiala]=my_comp.go(ppostura);% computing the initial error
my_Pid.Eroarea=eroarea_initiala;
eroarea=eroarea_initiala;

% The control loop
for i=1:Pasi_simulare
    [my_Pid,comanda]=my_Pid.go(eroarea);
    gama=0.5*(2/(1+exp(-0.5*comanda))-1);
    my_car.Gama=gama;
    my_car=my_car.go(0,0,0);
    P=[my_car.Postura.x;my_car.Postura.y;my_car.Postura.alf];
    [my_comp,eroarea]=my_comp.go(P);
end

The graphical representation

    my_car.desen
    title 'The AC trajectory'
    hold;
    plot(poz_dor_x, poz_dor_y,'r','linewidth',2)
    xlabel 'X'
    ylabel 'Y'

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Controler_1_02

Supplementary Simulations

alte_rez1 alte_rez2 alte_rez3

Published with MATLAB® R2013a