index out of bounds

hey i want to ask u about tht probelm i found when i was working on my program

it gives me tht problem

Attempted to access w(2); index out of bounds because numel(w)=1.

Error in ==> MCC_pp1 at 69
e3=w(k+1);

and i will five u my program to help me to correct tht problem plz

clear all;
%commande d'une machine cc 
% Les parametres --------------------------------------------------

Pn  = 3500;
wn  = 183.26;
Van = 240;
Ian = 16;
Vfn = 300;
Ra  = 2.581;
La  = 0.028;
Rf  = 281.3;
Lf  = 156;
M   = 0.9483;
J   = 0.02215;
f   = 0.002953;
Ka  = 1.0113;     % 0.9483;

%conditions initiales ----------------------------------------------

Vf  = 300; 
tetaref = 100 * pi / 180;
If  = Vf / Rf;
Ia  = 0;
w  = 1;
teta= 0;
T   = 0.001;
Np  = 800;

% Criteres de conception -------------------------------------------

ts  = 0.05;       % Settling time < 0.05 second
Mp  = 0.05;       % Overshoot < 5%
Ess = 0.1;  
xi  = sqrt((log(Mp))^2 / (pi^2 + (log(Mp))^2));
wn  = - log(Ess) / ( xi * ts );
alpha = -1;
K=0.5;
K1=alpha*wn^2;
K2=wn^2+2*xi*wn*alpha;
K3=2*xi*wn+alpha;
a1=(-Rf/Lf);
a2=(-Ra/La);
a3=(M/La);
a4=(-f/J);
a5=(M/J);
b1=(1/Lf);
b2=(1/La);
x1=teta;
x2=w;
x3=Ia;
x4=If;
b0=a5*x4*b2;
x4_etoile=Vf/Rf;
K_0=[K1 K2 K3];%K_0 gain%
Cr=10;
C0=(-1/J)*Cr;
% calcul des U1 et U2 et V -----------------------------------------
for k = 1:Np
    Cr = 0;
    if k >= 400
    Cr = 10;
    end
 e4=x4-x4_etoile;
U2=(1/b1)*((a1*x4)-(K*e4));
f=(a4)^2*x1-a4*a5*x3*x4+a4*C0-a5*x4*a2*x3+a3*a5*(x4)^2*x2-a1*a5*x3*x4+a5*x3*b1*U2; 
e1=teta(k)-tetaref;
e2=w(k);
e3=w(k+1);
e=[e1;e2;e3];
V=-(K_0)*e;
U1=(1/b0)*(-f+V);
If(k+1) = If(k) + T * ( - Rf * If(k) + U2(k) ) / Lf;
Ia(k+1) = Ia(k) + T * ( - Ra * Ia(k) - M * If(k) * w(k) + U1(k) ) / La; %#ok<SAGROW>
teta(k+1) = teta(k) + T * w(k); %#ok<SAGROW>
Ce(k)   = M * If(k) * Ia(k); %#ok<SAGROW>
w(k+1)  = w(k) + T * ( -f * w(k) + C0(k) - Cr ) / J; %#ok<SAGROW>

end;

Answer 1

[Walter Roberson]

You initialize w=1 which is a scalar. You use that w(1) in e2=w(k) when k is 1. Then in the next line you use e3=w(k+1), but when k=1 you have no w(2) defined. What value were you expecting to have assigned to e3 at that point?

Answer 2

[noureddine kebaili]

e3 is the integral of e2 friend