- Apply goal to
Use this option when tuning multiple models at once, such as an array of models
obtained by linearizing a Simulink model at different operating points or block-
parameter values. By default, active tuning goals are enforced for all models. To
enforce a tuning requirement for a subset of models in an array, select Only Models.
Then, enter the array indices of the models for which the goal is enforced. For
example, suppose you want to apply the tuning goal to the second, third, and fourth
models in a model array. To restrict enforcement of the requirement, enter 2:4 in the
Only Models text box.For more information about tuning for multiple models, see “Robust Tuning
Approaches” (Robust Control Toolbox).Tips
When you use this requirement to tune a control system, Control System Tuner attempts
to enforce zero feedthrough (D = 0) on the transfer that the requirement constrains. Zero
feedthrough is imposed because the H 2 norm, and therefore the value of the tuning goal,
is infinite for continuous-time systems with nonzero feedthrough.
Control System Tuner enforces zero feedthrough by fixing to zero all tunable parameters
that contribute to the feedthrough term. Control System Tuner returns an error when
fixing these tunable parameters is insufficient to enforce zero feedthrough. In such cases,
you must modify the requirement or the control structure, or manually fix some tunable
parameters of your system to values that eliminate the feedthrough term.
When the constrained transfer function has several tunable blocks in series, the
software’s approach of zeroing all parameters that contribute to the overall feedthrough
might be conservative. In that case, it is sufficient to zero the feedthrough term of one of
the blocks. If you want to control which block has feedthrough fixed to zero, you can
manually fix the feedthrough of the tuned block of your choice.
To fix parameters of tunable blocks to specified values, see “View and Change Block
Parameterization in Control System Tuner” on page 10-26.
Algorithms
When you tune a control system, the software converts each tuning goal into a normalized
scalar value f(x). Here, x is the vector of free (tunable) parameters in the control system.
LQR/LQG Goal