Finite-time synchronization of four-dimensional memristor-based chaotic oscillator and applied to secure communication systems

Abstract

Incorporating memristor-based hyperchaotic (MHC) systems into secure communications increases signal complexity and randomness, while its parameter sensitivity develops chaos that defies synchronization behaviour. This paper assumes the MHC system is exposed to time-varying bounded external disturbances; it proposes a novel time-efficient nonlinear robust control approach for synchronizing two coupled MHC oscillators in a finite settling time. The proposed control methodology eliminates the time-varying bounded external disturbances effects; it establishes a faster, smoother synchronization error convergence to zero. The controller’s structure design does not cancel the closed-loop’s nonlinear terms; this attribute improves the closed-loop robustness. The proposed stability technique is based on the norm-2 inequality that assures finite-time convergence. The paper also studies closed-loop robust performance for the time-varying bounded external disturbances and slow, smooth variations in the system parameters. The theoretical analysis proofs using the Lyapunov theory and computer-based simulations validate that the proposed control technique quickly compels the synchronization error to zero with lesser fluctuations for all signals. The paper includes comparative computer simulations confirming that the outcomes of the proposed controller are better than the reported state-of-the-art finite-time control methods in all key performances. Finally, the article discusses applications of the proposed algorithm for the encryption/decryption of messages in secure communication systems.