Analysis And Design Of Networked Control Systems Based On Adaptive Event-triggered Mechanism

In recent years,the rapid development of computer and communication technology has promoted progress in different fields.Different disciplines and computer technology have crossed and developed together,and their products fill up the vacant areas of disciplines.Networked control system is one of the outstanding representative of the product.The different modules of the systems are communicated by the network instead of the traditional twisted-pair,thus the shortcomings of complicated wiring,difficult expansion and difficult maintenance are avoided.But it also exists some shortages,such as:networked delay,data packet dropout,and data packet disorder.If these problems are ignored,it will adversely effect on system performance.Therefore,more and more scholars are focusing on how to solve the systems problems from the network.One of them is to avoid network congestion,because network bandwidth is limited.When the data traffic in the network is heavy,data collision and packet dropout will be aggravated,which will reduce system performance.In periodic sampling control,signals are sent periodically,and some data that have little impact on system performance are also transmitted,which undoubtedly increase the burden of the network.Event-triggered mechanism can sent signal according to the trigger condition,meaningless transmission of the signal are avoided.Therefore networked communication resources can be saved and resource utilization can be improved.The trigger parameter in the static event-triggered mechanism is a scalar,and the trigger condition is fixed as an inequality,which reduces the flexibility and functionality of the event-triggered mechanism.For this problem,this paper designs an improved adaptive event-triggered mechanism,whose trigger conditions can be adjusted adaptively according to the system state,which truly realizes the"on-demand"transmission of signals.Based on the adaptive event-triggered mechanism,this paper studies the reliability,conservativeness and safety of system control.The specific research work of this article is as follows:1.The problem on co-design of adaptive event-triggered mechanism andH_?controller for a class of networked control systems with external interference is investigated.Taking into account the shortcomings of the static event-triggered mechanism,an improved adaptive event trigger mechanism is designed.Trigger parameters are adjusted through adaptive laws to save the networked bandwidth resources to the greatest extent.Then introduce it into the system model with external interference,construct a suitable L-K functional,apply Jensen's inequality and reciprocally convex lemma,derive a less conservative stability criterion.Then,on this basis,a solution method for the weight matrix of the adaptive event-triggered mechanism and the controller gain is given.Finally,it is verified by an example simulation.2.The problem on co-design of robust fault tolerant control and adaptive event-triggered mechanism for a class of networked control systems is investigated,in which parameter uncertainties and actuator faults are considered,simultaneously.First,the parameter uncertainty,actuator failure and adaptive event-triggered mechanism are established in a unified model,a suitable L-K functional is constructed,and then derive the functional.When processing the generated integral terms,the reciprocally convex lemma is applied to reduce the conservatism,sufficient conditions for system stability are obtained,and a co-design scheme of robust fault tolerant controller and adaptive event-triggered mechanism are further obtained.Finally,it is verified by an example simulation.3.Considering that most of the actual engineering applications are nonlinear systems,theH_?control problem of T-S fuzzy networked control systems based on adaptive event-triggered mechanism is studied.First,the time delay,external interference and adaptive event trigger mechanism are combined as a unified framework.Taking into account that the premise variables of the system are not synchronized with the controller's premise variables,an L-K functional containing more time-delay information is constructed,and the conditions for system stability and stabilization are given in the form of an LMI.Because of the unsynchronization of the premise variables,the designed controller is no longer a T-S fuzzy point-to-point connection controller,but a T-S fuzzy networked controller.Finally,it is verified by an example simulation.