| Abstract: |
| This paper investigates the prescribed performance (PP) tracking control issue for uncertain multi-input multi-output nonlinear systems with external disturbances, and develops a time/event hybrid trigger (TEHT) based control framework to reconcile the contradiction between communication resource limitations and system real-time demands. A dynamic gain-based disturbance observer is constructed to strengthen the system`s anti-disturbance performance, which adaptively tunes the observer gain to precisely capture time-varying disturbances. Furthermore, a TEHT control mechanism is proposed to dynamically adjust the triggering frequency: the transmission frequency is raised when the track error (TE) approaches the PP function to keep the TE within the predefined boundary; the triggering frequency is lowered when the TE deviates from the PP function to save communication resources; once the TE violates the small prescribed PP function, the controller switches to the time-triggered mode to give priority to system performance. The backstepping recursive method is used to design virtual and actual controllers. Lyapunov stability analysis proves that all closed-loop system signals are bounded. The feasibility and superiority of the proposed TEHT-PP tracking controller are validated by numerical simulations on a 2-link flexible-joint robot system and hardware experiments on a Quanser 2-link FJR platform. |
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