用matlab 7.0编写的滑模变结构仿真的例子。-S-function for continuous state equation

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



switch flag,

Initialization

　case 0,

　　[sys,x0,str,ts]=mdlInitializeSizes

Outputs

　case 3,

　　sys=mdlOutputs(t,x,u)

Unhandled flags

　case {2, 4, 9 }

　　sys = []

Unexpected flags

　otherwise

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

end



mdlInitializeSizes

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

sizes = simsizes

sizes.NumContStates　= 0

sizes.NumDiscStates　= 0

sizes.NumOutputs　　 = 3

sizes.NumInputs　　　= 1

sizes.DirFeedthrough = 1

sizes.NumSampleTimes = 0



sys=simsizes(sizes)

x0=[]

str=[]

ts=[]

function sys=mdlOutputs(t,x,u)



x11d=sin(pi*t/2)

x21d=cos(pi*t)

x31d=1



sys(1)=x11d

sys(2)=x21d

sys(3)=x31d