Index exceeds matrix dimensions.

hi to all

i have simulate my plant with S-function

i call the outputs with worksapce .then i want use them to plot.

then i get this error

and the error'' Too many input arguments ''

%%%%%%%plant code:

function [sys,x0,str,ts]=s_function(t,x,u,flag)

switch flag,

case 0,

[sys,x0,str,ts]=mdlInitializeSizes;

case 1,

sys=mdlDerivatives(t,x,u);

case 3,

sys=mdlOutputs(t,x,u);

case {2, 4, 9 }

sys = [];

otherwise

error(['Unhandled flag = ',num2str(flag)]);

end

function [sys,x0,str,ts]=mdlInitializeSizes

sizes = simsizes;

sizes.NumContStates = 2;

sizes.NumDiscStates = 0;

sizes.NumOutputs = 4;

sizes.NumInputs = 3;

sizes.DirFeedthrough = 0;

sizes.NumSampleTimes = 0;

sys=simsizes(sizes);

x0=[pi/60 0];

str=[];

ts=[];

function sys=mdlDerivatives(t,x,u)

g=9.8;mc=1.0;m=0.1;l=0.5;

S=l*(4/3-m*(cos(x(1)))^2/(mc+m));

fx=g*sin(x(1))-m*l*x(2)^2*cos(x(1))*sin(x(1))/(mc+m);

fx=fx/S;

gx=cos(x(1))/(mc+m);

gx=gx/S;

%main system

sys(1)=x(2);

sys(2)=fx+gx*u(1);

function sys=mdlOutputs(t,x,u)

g=9.8;mc=1.0;m=0.1;l=0.5;

S=l*(4/3-m*(cos(x(1)))^2/(mc+m));

fx=g*sin(x(1))-m*l*x(2)^2*cos(x(1))*sin(x(1))/(mc+m);

fx=fx/S;

gx=cos(x(1))/(mc+m);

gx=gx/S;

%outputs

sys(1)=x(1);

sys(2)=x(2);

sys(3)=fx;

sys(4)=gx;

%%%%%%%plot code:

close all;

figure(1);

subplot(211);

plot(t,y(:,1),'r',t,y(:,3),'k:','linewidth',2);

xlabel('time(s)');ylabel('Position tracking');

legend('Ideal position','Position tracking');

subplot(212);

plot(t,y(:,2),'r',t,y(:,4),'k:','linewidth',2);

xlabel('time(s)');ylabel('Speed tracking');

legend('Ideal speed','Speed tracking');

figure(2);

plot(t,ut(:,1),'r','linewidth',2);

xlabel('time(s)');ylabel('Control input');

figure(3);

subplot(211);

plot(t,p(:,3),'r',t,p(:,6),'k:','linewidth',2);

xlabel('time(s)');ylabel('fx and its estimated value');

legend('fx','estiamted fx');

subplot(212);

plot(t,p(:,4),'r',t,p(:,7),'k:','linewidth',2);

xlabel('time(s)');ylabel('gx and its estimated value');

legend('gx','estiamted gx');