Research On The Safety Control Method Of Networked Control System Based On The Memory-type Event Trigger Mechanism

Different from traditional point-to-point connected control systems,components in networked control systems(NCSs)are distributed and connected by a shared wireless network to communicate and collaborate with each other.In general,industrial networks,smart grids and multi-agent systems can also be included in the category of NCSs.Currently,lots of attention about NCSs has been mainly focused on two aspects.First,the controller design problem for NCSs under limited communication resource.Second,safety control for NCSs considering cyber-attacks.Study of NCSs in this paper has been developed conducted by above two hot topics and can be concluded as follows:1)To save limited communication resource,by placing memory buffer to both event generator and controller sides,a novel memory-event-triggered scheme(METS)has been proposed in this paper.This scheme allows event generator consider more previous released packets when release new packet so as to make more precise and intelligent decision.Based on that,we consider network-induced delay and further derive the co-design method of memory-event-triggered parameters and robust feedback controller using Lyapunov functional and LMI techniques.Simulation proves that compared to traditional event-triggered scheme,METS can not only reduce communication frequents but can also improve control performance of system,which further reduce conservatism of event-triggered scheme.2)Considering the fact that there is always external perturbation existing in NCSs,this paper has investigated finite time input-output stability(IO-FTS)problem of NCSs using METS in consideration of both network-induced delay and bounded noises.IOFTS demands that with zero initial condition and given time interval,when system suffers from bounded noises,the output of system can also be bounded in a predefined threshold.Under the definition of IO-FTS,a co-design method of memory-eventgenerator parameters and feedback controller has been given.And an optimal algorithm to solve minimum IO-FTS threshold has also been introduced.3)Safety control or resilient control problem for NCSs under “Denial-ofservice”(Do S)attack has been studied in this paper.We assume the attack signal can be detected and Do S signal is modeled as a kind of periodic pulse width modulated(PWM)signal.Under memory event-triggered scheme,sufficient conditions for exponential stability of system has been derived by using piecewise Lyapunov functional method.Safety feedback controller design method has also been given.At the same time,we also initially study the effect that different groups of METS parameters would have on the safety control performance of the whole system.4)Resilient control problem of NCSs under deception attacks has been studied in this paper.We assume that adversary's energy is limited and s/he can capture packets of NCSs via communication networks and manipulate them.The respective model has been constructed.By constructing proper Lyapunov function,with the proposed METS and using Lyapunov functional and LMI techniques,this paper has developed a codesign method for deception attack parameters,METS parameters and feedback controller gains which can resist the randomly occurring attacks.The simulation validates the effectiveness of developed method.