Adaptive controller based on the affine equivalent model with disturbance rejection for discrete-time switched systems

Abstract

Switched systems often have hard-to-determine models, and the switching time is often unknown. Mismatched model dynamics and/or switching time may lead to performance degradation. Hence, the present work develops an adaptive controller for single-input single-output nonlinear discrete-time switched systems when the mathematical model, switching time and input–output disturbances are unknown. An affine equivalent model-based on Multi-input Fuzzy Rules Emulated Network characterises the unknown system. The control law is derived according to the tracking error, a proposed sliding surface and the affine equivalent model. The controller parameters were set according to the stability analyses (Uniformly Ultimate Bounded-Lyapunov method). Several experiments, including non-switched and switched systems with input and output disturbances, showed a mean perceptual error of less or equal to 1% for all cases, with recovery in the switch cases. This successfully proves the closed-loop performance of the proposed controller on a discrete-time switched and disturbed system.