Exponentially stable adaptive control. Part III. Time-varying plants

A state-feedback adaptive control system is proposed for a class of linear systems in the controllable canonical form with time-varying unknown parameters described by known nonstationary exosystems with unknown initial conditions. The solution ensures global exponential stability of the closed-loop system in case a regressor is finitely exciting, and also does not require a priori information about the sign of the high-frequency gain (control direction). The obtained theoretical results are validated via mathematical modeling.