H-infinity Norm System Approximation with Applications to Controller Reduction

Davut Kavranoglu, EE, Caltech (on sabbatical from KFUPM, Saudi Arabia)

Advanced control design schemes such as, u-synthesis, H-infinity optimal control, LQG lead to high order controllers. In many cases it is desirable and sometimes required (like in real time applications) to have a "reasonable" low order controller. We would like to have a low order controller but we do not want to compromise the optimal performance too much. Optimal model reduction schemes offer a good systematic way to compromise between these objectives.

In the first part of the seminar the relationship between designing low order controllers and optimal H-infinity model reduction problems will be explained. In the second part, two approaches, which were developed by the speaker, for the H-infinity norm system approximation problem will be explained. The results will be illustrated by several examples.