function [sys,x0,str,ts]= spacemodel(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 = 3;
sizes.NumDiscStates = 0;
sizes.NumOutputs = 9;
sizes.NumInputs = 2;
sizes.DirFeedthrough = 1;
sizes.NumSampleTimes = 1;
sys=simsizes(sizes);
x0=[3;0;0];
str=[];
ts=[0 0];
function sys=mdlDerivatives(t,x,u)
xe=x(1);
ye=x(2);
the=x(3);
v=u(1);
w=u(2);
vr=1.0;
wr=1.0;
sys(1)=ye*w-v+vr*cos(the);
sys(2)=-xe*w+vr*sin(the);
sys(3)=wr-w;
function sys=mdlOutputs(t,x,u)
xe=x(1);
ye=x(2);
the=x(3);
vr=1.0;
wr=1.0;
r=vr/wr;
xr=r*cos(t);
yr=r*sin(t);
thr=wr*t;
th=thr-x(3);
M1=[cos(th)*sin(th);-sin(th)*cos(th)];
M2=[xr;yr]-inv(M1)*[xe;ye];
xp=M2(1);
yp=M2(2);
sys(1)=x(1);
sys(2)=x(2);
sys(3)=x(3);
sys(4)=xp;
sys(5)=yp;
sys(6)=th;
sys(7)=xr;
sys(8)=yr;
sys(9)=thr;
运行SIMULINK的时候报错
Error in 'model/S-Function1' while executing MATLAB S-function 'plant', flag = 3 (output), at time 0.0.

楼主解决了吗？最近也遇到同样的问题