Adaptive control of piecewise linear systems with output feedback for output tracking

This paper studies the adaptive output feedback control problem for single-input, single-output piecewise linear systems with switched parameters. By employing the knowledge of the time instant indicator functions of system parameter switching, a new controller structure parametrization is proposed for the development of a stable adaptive control scheme which is capable of reducing the modeling error in the estimation error signal used for parameter adaptive laws. This key feature is achieved by the new control scheme´s ability to avoid a major parameter swapping term in the error model, with the help of indicator functions whose knowledge is available in many applications. It is shown that under the usual slow system parameter switching condition, closed-loop stability (signal boundedness) and small output tracking error in the mean square sense are achieved. Simulation results on linearized NASA GTM models are presented, demonstrating the effectiveness and performance improvement of the proposed adaptive control scheme.