Robust adaptive regulation with minimal prior knowledge

An indirect adaptive regulator is designed, for time-varying, ill-modeled, and not necessarily stably invertible plants. The regulator provides the persistent excitation property which ensures closed-loop robust stability. The robustness problem in adaptive regulation can be solved without using the usual parameter estimator modifications, namely the dead-zone and the parameter projection or contract. Consequently, this prior knowledge as an upper bound on the plant parameter vector and a lower bound on the plant model degree of admissibility are no longer required