Performance Analysis for Recursive Passive Adaptive Controllers

Computable /spl Lscr/sub 2// and /spl Lscr/sub /spl infin// performance bounds are derived for a recently proposed class of adaptive systems which show that, in addition to global stability and asymptotic tracking, a systematic improvement of transient performance can be achieved. The underlying linear nonadaptive controller is shown to possess a parametric robustness property, but for large parameter uncertainty it requires high gain. A comparison between the adaptive and the nonadaptive performance bounds demonstrates that adaptation improves the overall performance without the undesirable effects of high gain.