Adaptive Event-Triggered Output-Feedback Control Against Unknown Control Directions and Unknown Intrinsic Growth

This article addresses global stabilization via disparate event-triggered output feedback for a class of uncertain nonlinear systems. Typically, the systems allow unknown control directions and unmeasurable-state dependent growth simultaneously. Actually, in the context of the latter ingredient, there has been no any continuous control strategy that has allowed the former ingredient so far. Hence, one cannot solve the event-triggered control problem based on corresponding continuous feedback as done in the emulation-based method. In view of the unsolvability, we pursue a nonemulation-based strategy, directly conducting event-triggered control design. First, a parameterized output feedback controller incorporating a dynamic high gain is designed, which would globally stabilize the system once the adjustable parameter therein is suitable. Then, an event-triggering mechanism is developed to not only decide when the controller is sampled/executed but also determine which constant value the adjustable parameter takes. Just due to the instantly varying (discontinuous) adjustable parameter, the feedback ability of the controller is large enough, making it possible to solve the control design problem in the event-triggered framework. A simulation example is provided to verify the effectiveness and advantage of the proposed approach.