Simulink Control Design™ - MathWorks

Validate Gain Schedules in Nonlinear System

Because systune tunes gain schedules against a linearization obtained at each design

point, it is important to test the tuning results in simulation of the full nonlinear system.

Perform nonlinear simulations that drive the closed-loop system through its entire

operating range. Pay special attention to maneuvers that cause rapid variations of the

scheduling variables.

After tuning an slTuner interface, use writeBlockValue to write tuned controller

parameters to the Simulink model for such simulation. This command can write tuned

gain schedules to lookup table blocks, Matrix Interpolation blocks, and MATLAB Function

blocks for which you have specified a tunableSurface parameterization.

Lookup Tables

For lookup table blocks and Matrix Interpolation blocks, writeBlockValue

automatically evaluates the tuned gain surface at the breakpoints specified in the block.

These breakpoints do not need to be the same as the design points used for tuning.

Because the tunableSurface describes the gain schedule in parametric form,

writeBlockValue can evaluate the gain at any scheduling-variable value.

If you have retuned a subset of design points, you can use writeLookupTableData to

update a portion of the lookup-table data while leaving the rest intact.

MATLAB Function Blocks

For gain schedules implemented as MATLAB Function blocks, writeBlockValue

automatically generates MATLABcode and pushes it to the block. The generated MATLAB

function takes the scheduling variables and returns the gain value given by the tuned

parametric expression of the tunableSurface. To see this MATLAB code for a particular

gain surface, use the codegen command.

References

[1] Rugh, W.J., and J.S. Shamma, “Research on Gain Scheduling”, Automatica, 36 (2000),

pp. 1401-1425.

See Also

codegen | viewGoal | viewSurf | writeBlockValue | writeLookupTableData

11 Gain-Scheduled Controllers