Research On Event-triggered Cooperative Control For Interconnected Systems

The interconnected systems generally refer to a group composed of multiple intelligent interacting and coupling through the network.With the rapid development of information technology,cooperation of interconnected systems is widely applied in aerospace,smart grid,intelligent manufacturing,intelligent transportation and other fields.In reality,interconnected systems only have limited communication bandwidth and resources.It is necessary to apply event-triggered communication mechanism to allocate communication resources.However,the hybrid characteristics of the interconnected systems due to eventtriggered communication,the uncertainty,nonlinearity and heterogeneity due to the complexity of the actual environment,as well as the dual time scale characteristics of the system itself,make it more difficult to analyze the cooperative behavior of the interconnected systems,and bring challenges to the cooperative control of the interconnected systems.It has significant practical application and theoretical value to study event-triggered cooperative control of interconnected systems with the above characteristics.Thus,this dissertation aims to investigate the event-triggered output regulation of single time scale systems and fixed-time stabilization of two-time scales systems,and further study the cooperative control of interconnected single time scale and two-time scales systems with event-triggered communication.The main contexts and results are as follows:For the output regulation problem of a class of uncertain nonlinear systems with unknown control direction,an adaptive event-triggered output feedback controller is designed based on the Nussbaum gain technique and internal model principle without control direction.With the designed Lyapunov function,a Zeno-free event-triggered sampling and communication mechanism is proposed,such that the origin of the closedloop system is internal stable subject to external disturbances and the output of the system can asymptotically track the external reference signals.In this case,the plant only communicates with the controller and updates the actuator at the triggering time,which can effectively save energy.This dissertation takes the output regulation problem of the Lorenz system as an example and carries out simulation experiment of comparison to illustrate the effectiveness of the theoretical results.For a class of heterogeneous interconnected linear systems with unknown and nonidentical control directions,the leader-following output consensus problem is investigated under undirected switching connected topology.A distributed adaptive eventtriggered controller and a Zeno-free event-triggered mechanism are designed based on the common Lyapunov function technique,and sufficient conditions for achieving output consensus are obtained.Furthermore,a self-triggered communication mechanism is designed to avoid real-time monitoring of the states of itself and neighbors,which effectively reduces communication cost.For a class of heterogeneous interconnected uncertain nonlinear systems subject to external disturbances and unknown nonidentical control directions,the output consensus problem is discussed under the joint connected topology.An event-triggered output feedback hierarchical cooperative control protocol is designed.In the upper layer,an eventtriggered cooperative controller is designed for interconnected virtual systems.Based on the Lyapunov function analysis method of the time-varying systems,an event-triggered mechanism is proposed to achieve the state consensus of the interconnected virtual systems,which reveals the internal relations among jointly connected switching topology,eventtriggered mechanism design and cooperative behavior of the interconnected systems.In the lower layer,combining internal model with Nussbaum gain function,an adaptive output feedback controller independent of the control direction is designed for each nonlinear system to achieve the output consensus.This dissertation takes the heterogeneous interconnected Lorenz systems as an example to verify the effectiveness of the designed output consensus cooperative controller.For a class of linear systems evolving on both fast and slow time scales,based on the fixed time stability lemma and singular perturbation theory,an event-triggered state feedback controller is designed and two independent Zeno-free event-triggered mechanisms associated with the slow and the fast subsystems respectively are established.In this way,the origin of the system can be practical stable in the finite time independent of the initial states,and the internal relations among the time scale separation parameter,event-triggered mechanism parameters and practical fixed time stability of the system are revealed.Finally,the effectiveness of the theoretical results is verified by simulation experiment of comparison.For the guaranteed-cost state consensus problem of the interconnected linear two-time scales systems under fixed topology,an event-triggered cooperative controller is designed independent of time scale separation parameter.Based on the composite Lyapunov functions,two event-triggered mechanisms associated with the slow and the fast interconnected subsystems are designed to ensure that the states of the interconnected systems can reach consensus asymptotically with limited cost,which reveals the influence of event-triggered mechanism parameters,time scale separation parameters and network size on the cooperative behavior of interconnected systems.Furthermore,the results are extended to the two-time scales interconnected system with structured uncertainty.Based on Lyapunov function analysis method,the constraint conditions of uncertain structural parameters are given,and the sufficient conditions for achieving guaranteed-cost state consensus are proposed,which reveals the internal influence of structured uncertainty on cooperative behavior,and the internal relations between the event-triggered parameters and the cost of achieving state consensus.This dissertation takes the interconnected system composed of three DC motors as an example to illustrate the effectiveness of the theoretical results.For the consensus problem of interconnected linear two-time scales systems under switching topology,a model-based event-triggered cooperative control protocol is designed.Firstly,the overall system is modeled as an uncertain hybrid system.Based on the hybrid system theory,two dynamic event-triggered communication mechanisms associated with the interconnected slow and fast subsystems are designed respectively,the sufficient condition for the state consensus of the interconnected system is proposed,which reveals the internal relations among the average switching interval,the network size and the cooperative behavior.Furthermore,the results are extended to achieve the consensus of interconnected impulsive two-time scales systems,where the effects of impulse intensity and average impulsive interval on cooperative behavior are revealed.