9413123 Kaufman Various direct model reference adaptive control (MRAC) procedures developed by the proposed investigator is especially attractive because they do not require full state feedback or adaptive observers. Other important properties of this class of algorithms include (1) their applicability to non-minimum phase systems, (2) the order of the plant may be much larger than the order of the reference model, and (3) this approach considers plants with multiple inputs and outputs. However, it is important to note that in order to guarantee asymptotic model following or even boundedness, it is sufficient to demonstrate the satisfaction of a positive real type constraint. Although various augmentation schemes have been developed to alleviate this constraint, it is not straightforward to design the needed (usually feedforward compensation to satisfy the positive real condition over the desired (or a maximal) range of parameter variations. Thus, it is proposed to consider recent robust compensation techniques that appear relevant to the design of such compensation. These include a robust feedforward compensator developed for single input-single output adaptive systems which will be extended to multiple input-multiple output systems and the Kharitonvoc polynomial analysis, which will be considered for use in single input-single output systems. The resulting augmentation procedures from this proposed effort in conjunction with the MRAC algorithms should result in easily implementable procedures for designing and synthesizing very robust direct adaptive controllers that are applicable to many systems with significant uncertainty. ***
