Event-driven output feedback control for a class of nonlinear systems subject to disturbances

摘要

In this paper, we propose an event-driven output feedback control strategy for a class of nonlinear systems subject to disturbances. Different from the time-driven control, the event-driven control can be regarded as a more reactive approach where the control actions are taken only when an event is triggered, thus the event-driven control has a better balance between the control performance and other system aspects (such as processor load, communication load, and system cost price). Based on the extended state observer (ESO), we propose a composite event-driven controller, which is asynchronously updated only when an intolerable effect on the closed-loop performance is produced. It is proved that the closed-loop system is globally uniformly bounded, and has a good robustness against disturbances. Meanwhile, the closed-loop system considered in this paper is a hybrid system, thus we need to consider the problem of Zeno behavior, which is a phenomenon unique to hybrid systems, and describes the situation where a hybrid system undergoes an unbounded number of discrete transitions in a finite and bounded length of time. Fortunately, it is proved that the system under the event-driven controller can avoids the Zeno behavior of the sampling, and has the significantly reduced sampling frequency compared with the time-driven controller. Finally, a simulation of DC-DC buck converter is conducted to demonstrate the efficiency of the new scheme.