Study On Event-based State Estimation And Feedback Control For Wireless Networked Control System

Due to the rapid development of wireless communications,sensor networks,embedded computing and other technologies,wireless sensor networks has attracted extensive attention in the industrial control community.However,the network bandwidth of wireless sensor networks and the energy of sensor nodes are limited,which limit the further development of wireless networked control systems.It's worth mentioning that the event-based data transmission strategy can effectively reduce network bandwidth usage and node energy consumption such that lifetime of the network can be prolonged.Therefore,it is of great significance to develop new event-based state estimation strategies and deal with feedback control problems.Focus on the above problems in wireless sensor networks,this paper mainly investigates the event-based state estimation and feedback control for wireless networked control systems,and the main constructions are as follows:(1)The problem of event-based remote state estimation in wireless sensor networks is investigated.For a class of discrete linear stochastic systems with correlated noises,an event-based data transmission strategy which uses Kalman filtering for remote state estimation is proposed such that a trade off between estimation quality and transmission rate can be guaranteed.Under a given policy,one can obtain an upper bound on estimation performance using an approximate value function for the associated Markov decision process.A numerical example is given to verify the effectiveness of the theoretical results and the experimental platform is further construsted.(2)For a class of discrete-time system with unknown input in wireless sensor networks,the state estimator based on event-triggered is designed.A remote estimator with the corresponding event-triggered transmission is investigated for a class of discrete-time stochastic systems subject to unknown input,which satisfies the requirement of unbiased and minimum variance.The proposed event-triggered strategy,which decided the transfer time of the data packet,can be used to reduce the frequency of data transmission.In addition,the upper bound of the system performance index based on event-trigged strategy is addressed.Finally,the feasibility and effectiveness of the proposed strategy are verified by the numerical simulation experiments and platform experiments.(3)We investigate the problem of event-based output feedback control in wireless sensor networks.An event-based output feedback control algorithm for discrete linear time invariant system is proposed.The proposed event-based transmission strategy can determine the data whether can be transferred from the controller.Firstly,the upper bound of the system performance is deduced through a kind of approximate quadratic value function.Based on the event-based transmission mechanism,the system can well balance actuator performance and wireless transmission rate.Subsquently,By employing the given transmission strategy,the corresponding output feedback controller is further designed.Finally,simulation experiments demonstrate the feasibility and effectiveness of the theoretical results.