Event-triggered Control Systems With Input Constraints: Design And Analysis

With the rapid development on cyber-physical systems,event-triggered control,as an alternative to traditional sampled-data control,has received much attention in recent decades.Unlike traditional sampled-data control,where signals are transmitted and updated periodically,the execution of control tasks in event-triggered control is only carried out when certain conditions are satisfied,which helps to conserve energy,reduce computation loads and alleviate bandwidth burden of a control system.On the other hand,actuator saturation and time delay are the most common phenomena in real-world control systems and they are destabilizing factors of control systems.However,the results on event-triggered control for systems with actuator saturation or time delay are very limited.In this dissertation,we focus on the event-triggered mechanism design for systems with either actuator saturation or time delay.The contributions of this dissertation are summarized as follows.1.Event-triggered global stabilization for a general linear system with input saturation:The general linear system is globally asymptotically null controllable with bounded controls(ANCBC),either in the continuous-time setting or in the discrete-time setting.The system dynamics is decomposed into single input subsystems with various dynamic characteristics.Based on the dynamics of the subsystems,both an event-triggered state feedback law and an event-triggered output feedback law are constructed.Event-triggering updating strategies for the two control laws are designed accordingly.These event-triggered control laws are shown to achieve global asymptotic stabilization.The absence of the Zeno behavior is also established for the system in the continuous-time setting.2.Event-triggered global consensus for multi-agent systems with input saturation: The follower agents and the leader agent are described by neutrally stable systems,either in the continuous-time setting or in the discrete-time setting.An event-triggered linear feedback law,either of the state feedback type or the output feedback type,is constructed for each follower agent and an event-triggering strategy is designed for updating these control laws.These event-triggered control laws are shown to achieve global leader-following consensus when the communication topology among the follower agents is strongly connected and detailed balanced and the leader is a neighbor of at least one follower agent.The absence of the Zeno behavior is also established for the multi-agent system in the continuous-time setting.3.Event-triggered stabilization for a linear system with input delay: The linear system is a general one with time-varying input delay.An event-triggered delay independent truncated predictor feedback law,either of the state feedback type or the output feedback type,is constructed.Event-triggering strategies are designed for updating these control laws.Only the information of a delay bound rather than the delay itself is required in the design and implementation of both control laws and the event-triggering strategies.For both the state feedback case and the output feedback case,an admissible delay bound that guarantees the stabilizability of a general linear system is established,and the Zeno behavior is shown to be excluded.For linear systems with all open loop poles at the origin or in the open left-half plane,stabilization can be achieved for a delay under an arbitrarily large bound.4.Distributed event-triggered secondary voltage control for microgrids subject to communication delay: For each distributed generator(DG),a distributed event-triggered control law,which uses its own voltage and those of its neighbors,along with a strategy for its triggering,are designed.When the communication topology among DGs is connected and at least one DG can receive the reference value,under these distributed event-triggered control laws,the magnitudes of the output voltages of all DGs can be synchronized to their reference value subject to a bounded time-varying delay,and no Zeno behavior will occur.