A. TRANSLATION BETWEEN MATLABµ-TOOLS AND Xµ403
The advantageof this is that in order to restart, or reproduce, an iteration, one need
only save the previous controller. The µ-Tools approach requires savingthe rational
approximation to the previous D-scales. The controller is a more applicable data ob ject
to save andthe saving of the previous D-scales depends on the quality of the rational
approximation. The disadvantage is that the upper bound in the next µcalculation
takes slightly longer as the closed-loop system does not have the numerical benefit of the
effects of the previous D-scales. The speed difference is likely to be insignificant in
practical problems.
Fitting DScales
Rational transfer function fitting of magnitude data is required for the D-Kiteration
and has been mentioned above. The relevant functionsare summarizedhere.
Description µ-Tools function Xmath/Xµequivalent
fit Dscale data musynfit musynfit
phase calculation genphase mkphase
transfer function fitting fitsys fitsys,tfid
Note that the µ-Tools version of musynfit does not use the previous Dscale magnitude
data. This has implications in the D-Kiteration and is discussed in more detail ab ove.
The alternative µ-Tools linear programming approach forDsca le fitting, musynflp,is
not supported in Xµ. Similarly, the underlying linear programming approach to transfer
function fitting (µ-Tools functions fitmaglp,magdata) is not available in Xµ. The batch
functionality of the µ-Tools function, muftbtch, is available in the Xµversion of
musynfit.