lorenz.m

《MATLAB在控制系统中的应用》实例程序

function [sys,x0,str,ts] =Lorenz(t,x,u,flag)
      switch flag,
      case 0,
         [sys,x0,str,ts]=mdlInitializeSizes;
       case 1,
         sys=mdlDerivatives(t,x,u);
       case {2，3，9},
         sys=[];
       otherwise
        error(['Unhandled flag = ',num2str(flag)]);
      end
      % mdlInitializeSizes     %初始化子程序
      function [sys,x0,str,ts]=mdlInitializeSizes
      sizes = simsizes;
      sizes.NumContStates  = 2;
      sizes.NumDiscStates  = 0;
      sizes.NumOutputs     = 0;
      sizes.NumInputs      = 0;
      sizes.DirFeedthrough = 1;
      sizes.NumSampleTimes = 1;   % at least one sample time is needed
      sys = simsizes(sizes);
      x0  = [0 0 1e-10];
      str = [];
      ts  = [0 0];
      % mdlDerivatives  %计算导数子函数：它根据t,x,u计算连续状态的导数
      function sys=mdlDerivatives(t,x,u)
      sys(1) = -8/3*x(1)+x(2)*x(3);
      sys(2) =-10*x(2)+10*x(3);
      sys(3) = -x(1)*x(2)+28*x(2)-x(3);