The plot for t and ssdot in the following code cannot be displayed as it shows a vector length mismatch. Please suggest how I can get around it...

if true
  % clc;
clear all;
close all;
%to=0;
tf=10;
d=.001;
n=tf/d;
y=zeros(1,n);
r=zeros(1,n);
x=zeros(2,n);
s=zeros(1,n);
u=zeros(1,n);
v=zeros(1,n);
sdot=zeros(1,n);
ssdot=zeros(1,n);
t=zeros(1,n);
e=zeros(2,n);
c=23;
M=0.6;
u(1,1)=0;
for i=1:n+1
  dx1=x(2,i);
  dx2=3*x(1,i)+u(1,i);
  x(1,(i+1))=x(1,i)+(d*dx1);
  x(2,(i+1))=x(2,i)+(d*dx2);
  t(1,(i+1))=t(1,i)+d;
  xd(1,(i+1))=sin(t(1,i)); 
  xd(2,(i+1))=cos(t(1,i));
  e(1,(i+1))=x(1,i+1)-xd(1,i+1);
  e(2,(i+1))=x(2,i+1)-xd(1,i+1);
  s(1,(i+1))=c*e(1,1+i)+e(2,1+i);
  v(1,i)=-sin(t(1,i))-10*x(1,i)+c*cos(t(1,i))-c*x(2,i);
  u(1,i)=v(1,i)-M*sign(s(1,i));
  sdot(1,i)=c*(x(2,i)-cos(t(1,i)))+dx2+sin(t(1,i));
  ssdot(1,i)=s(1,i)*sdot(1,i);
  u(1,i+1)=v(1,i)-M*sign(s(1,i));
  y(1,i+1)=x(1,i+1);
  y(2,i+1)=x(2,i+1);
end
figure(1)
plot(t(1,:),xd(1,:),'r',t(1,:),y(1,:),'b','linewidth',2);
legend('Ideal angular position','Actual Angular Position');
xlabel('time(s)');ylabel('Position tracking x1');
xlabel('e1');ylabel('e2');
figure(2)
plot(t(1,:),ssdot(1,:),'g','linewidth',2);
end

Answer 1

[James Tursa]

Your loop is

for i=1:n+1

So the last iteration increases the size of ssdot when this line is encountered:

ssdot(1,i)=s(1,i)*sdot(1,i);

And inside the loop you have this:

    t(1,(i+1))=t(1,i)+d;

So the size of t is also increased inside the loop, by a different amount than ssdot.

Assuming you have all of these indexes correct, you could simply pick the shortest length and plot that much. E.g.,

k = min(numel(t),numel(ssdot));
plot(t(1,1:k),ssdot(1,1:k),'g','linewidth',2);

[Biswajit Debnath]

Your answer nailed it bro

Thanks a lot.....