Adaptive output tracking control with reference model system uncertainties

This paper develops new adaptive output tracking control schemes with the reference output signal generated from an unknown reference system whose output derivatives are also unknown. To deal with such reference system uncertainties, an expanded adaptive controller structure is developed to include a parametrized estimator of an equivalent reference input signal. Without using the knowledge of the reference system transfer function and equivalent input, both are the critical components of a traditional model reference adaptive control (MRAC) scheme, the new MRAC schemes, developed for various cases of plant and reference model uncertainties, ensure completely parametrized error equations and globally stable parameter adaptation, leading to the desired closed-loop system stability and asymptotic output tracking properties. (c) 2025 Elsevier Ltd. All rights are reserved, including those for text and data mining, AI training, and similar technologies.