MATLAB: Are the states out of order when I use FINDOP with LINMOD

Simulink Control Design

I use FINDOP to find an equilibrium point of my model. I use the output with LINMOD or DLINMOD, and the system does not behave as expected because the states are out of order.

Best Answer

Functions FINDOP and LINEARIZE in Simulink Control Design 3.0 (R2009b) define states in a different order than functions in Simulink (TRIM and LINMOD).
The Simulink Control Design functions are intended to be used together, and the Simulink functions are intended to be used together.
The GETXU and GETSTATESTRUCT commands reorder the states output from FINDOP into the order used by Simulink (including LINMOD and DLINMOD). GETXU puts the states in a vector, and GETSTATESTRUCT puts the states in a structure.
There is no direct method to reorder the states output from TRIM into a form usable by LINEARIZE. As a workaround, one can manually reorder the states.
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