Research On Event-triggered Security Control For Uncertain Networked Control Systems

Networked Control Systems(NCS)are spatial distributed control systems capable of real-time feedback.The communication between sensor,actuator and controller is realized through digital network with limited bandwidth.Because of its low cost,flexibility,easy installation and maintenance,NCS has attracted the attention of many researchers.NCS has been widely used in many practical systems such as automobile automation,intelligent building,Internet haptic collaboration,UAV and so on.Therefore,the research and development of NCS is a very important and meaningful subject in the field of automation.However,there are a variety of uncertain problems in the practical application of NCS,such as parameter uncertainty,asymmetric information,bandwidth limitation,network security and other problems,which have caused great challenges to its research.Stable NCS enable them to achieve fast and accurate results in practical applications.Therefore,this paper conducts an in-depth study on the hot issues existing in NCS.Firstly,the influence of parameter uncertainty and jamming attack on NCS is considered.A robust control strategy based on event triggering mechanism is proposed,and the optimal attack strategy with limited energy is considered from the attacker’s point of view.The controller gain is obtained by linear quadratic regulator method,and the event triggering parameters are derived by the input to state stability(ISS)criterion.Finally,the effectiveness of the proposed event-triggered control strategy in dealing with uncertainty and jamming attacks is verified by numerical simulation.Secondly,the distributed control of NCS with asymmetric information uncertainty is considered.The controller can share the observation data and part of the historical control input to the neighbor controller,but the information of the neighbor controller cannot be obtained due to the network limitation,so the situation of asymmetric information is formed.An estimator based on Kalman filter is designed to deal with the system noise and measurement noise,and the problem of coupling the prediction error covariance with the controller is dealt with by the Poundriagin maximum principle.Then the expression form of the optimal feedback controller is given.Finally,the effectiveness of the proposed control strategy against asymmetric information uncertainty NCS is verified by numerical simulation.Then,the switching-like event triggering control of uncertain NCS under Denial-ofService(DoS)attack is studied.A kind of switching-like event-triggered communication scheme is designed to deal with intermittent DoS attacks and improve the communication efficiency while maintaining the expected control performance.Under the constraint of maximum allowable data loss caused by DoS attacks,the stability criterion is derived and used to estimate the event-triggered parameters and to solve the controller gain.Finally,numerical simulation is used to verify that this control method can reduce the influence of DoS attacks on the system and save network bandwidth.