Event Triggered Control For Leader Following Consensus Of Multi Agent Systems

The rapid advancement and use of Internet,embedded systems,wireless communication technologies and novel control strategies have spurred a broad interest and attention to the field of coordination control of multi-agent systems.One of the practical issues in multi agent systems is to prolong the operational life span of the whole system.Another issue is that controllers are generally designed assuming perfect information is available at all times and actuators can be updated continuously.However,due to physical constraints,it is not possible to continuously change a control signal or have perfect information at all times.While it is certainly easier to design controllers for systems that have perfect information at all times,it is just not practical in the real world due to their high communication cost.In this thesis,we will solve some distributed leader following consensus problems of multi-agents systems by means of event triggered control under different communication topologies in order to keep network utilization to a minimum while guaranteeing the control specifications such as stability or closed loop performances.We will take into account case where the agents are governed by linear dynamics,nonlinear dynamics and MAS with a leader whose control input might be nonzero and not available to any follower.A distinct feature of this strategy is that the communication does not occur continuously in both controller updates and triggering condition monitoring.Each agent only needs to monitor its own state continuously to determine if the event is triggered.Additionally,the approach shown here provides consensus with guaranteed positive inter-event time intervals.Therefore,there is no Zeno behavior under the proposed consensus control algorithm.Throughout the thesis,five consensus protocols have been proposed based on event triggered control with state dependent thresholds.The first two consensus protocols are designed for general linear MASs under undirected and directed communication topologies.Two leader-following consensus protocols for linear multi-agent systems with a leader whose control input might be nonzero and not available to any follower and a tracking consensus protocol for nonlinear MAS subject to undirected graphs.In each event-based control strategy designed in this thesis,the proposed controllers are independent of system parameters and only use the relative states of neighboring agents,and hence are fully distributed.Due to the introduction of an event-triggered control scheme,the controller of the agent is only triggered at it's own event times,and thus reduces the amount of communication between controller and actuator and lowers the frequency of controller updates in practice.The Lyapunov based approach is adopted to study the stability and the convergence of our systems by employing some tools from algebraic graph theory and matrix theory.Infinite triggers within a finite time are also verified to be impossible.The effectiveness of the proposed event triggered strategies has been confirmed throughout simulation examples.