Practical Prescribed-Time Tracking Control for Jump Systems With Application to Noise Rejection in Secure Audio Communication

Abstract

In this study, a practical prescribed-time tracking strategy is proposed for fractional-order semi-Markov jump systems subject to input delays, external disturbances, nonlinear uncertainties, and hybrid cyber-attacks. To overcome the practical implementation challenge caused by the mode mismatch problem in fractional-order semi-Markov jump systems, an asynchronous observer is incorporated into the improved equivalent input disturbance framework, ensuring accurate disturbance estimation and rejection despite the desynchronization between the observer and the system. Furthermore, a Smith-predictor is employed for input-delay compensation by integrating the delay-free system response into a dynamic output feedback controller, extending its role beyond delay compensation to simultaneously accomplish tracking control. Following delay compensation and disturbance rejection, practical prescribed-time tracking of the augmented closed-loop system is guaranteed, eliminating the stringent exact convergence requirement and the corresponding sufficient conditions are derived in terms of linear matrix inequalities. Moreover, the proposed disturbance rejection framework is extended to secure audio communication to eliminate communication noise during transmission for the first time. Finally, simulation results obtained from a fractional-order electric circuit and a secure audio communication application validate the effectiveness of the proposed framework.