how to konw the meaning of xout of simulink

I am trying to trim a 6DOF aircraft model using Trim, and I got this error

"In the command [X,U,Y,DX]=TRIM('SYS',X0,U0,Y0,IX,IU,IY,DX0,IDX) the length of DX0 should be equal to the number of continuous states in the Simulink model."

The output of the model is set to 1×12, and the DX0 is also set to 1×12. But after getting this error, I use sldiagnostics to check the number of continuous states, and with 12 Integrators (4 integrators used actually, but I guess it is the number of the integrated variables), I unexpectedly get 28 continuous states. The xout of the model is also n×28 (n for total steps).

So, I am trying to know the exact meaning of every row of xout, which variable it is. But I don't know how.

And I want to reduce the number of continuous states in my model. But I don't kow how Simulink make the defination of continuous state, or which block would make continuous states, except the variables after the Integrators.

Answer 1

[Suman]

Hi 盈天 裴,

the xout property refers to the block states at each time point. You can refer to this https://www.mathworks.com/help/simulink/gui/states.html documentation to learn more about it.

You can refer to this MATLAB Answers thread to learn about continuous and discrete states: https://www.mathworks.com/matlabcentral/answers/36663-what-are-continuous-and-discrete-states-in-simulink

You can see the continuous blocks in yoor model by going to the DEBUG > Information Overlays from Simulink toolstrip and enabling the Colors option from Sample Time section.