Output Feedback Control And Fault Detection Of Discrete Systems Based On Event-Triggered Scheme

Networked control systems(NCSs)are closed-loop distributed control systems which integrating communication,computing,and control.They transmit information via shared network,and bring out the low complexity installation and maintenance for the systems.However,when data transmit frequently between nodes or different systems in NCSs,phenomena such as delays,packet loss,and disorder may occur.To solve these problems,researchers propose the event-triggered scheme(ETS),which can reduce the frequency of data transmission effectively in the network,and alleviate the network congestion.Therefore,ETS is significant for maintaining system stability.Faults such as sensor offset and drift often occur in NCSs.To maintain system operation,fault detection(FD)is indispensable.By introducing the ETS to FD,the data transmission can be reduced,and the FD efficiency can be improved.However,ETS will cause information loss,which will affect the accuracy of FD.Therefore,issues of overcoming the shortcomings of ETS and improving the accuracy of FD are worthy of in-depth study.The openness and sharing of the network not only bring out the convenience to the daily life,but also bring out the security risk.The cyber-attacks can affect the normal operation of the entire NCSs,and even lead to accidents.Thus,the issue of cyber-attack deserves in-depth study.Issues of NCSs with ETS and corresponding research plans will be considered,and the main points are shown as follows:(1)The research backgrounds,purposes and significance of NCSs and ETS will be introduce briefly.Based on the issues of delay,quantization error,fault detection and cyber-attack in ETS-based NCSs,the domestic and overseas research advance are analyzed,and the research methods are summarized.(2)The dynamic output feedback control(DOFC)for a class of discrete NCSs is addressed.The ETS is installed for the measurement output,and the induced delay is modeled as a Markov process to simulate the effect of random delay on NCSs.Both the sensor-to-controller channel and controller-to-actuator channel are installed quantizers,and the quantizer density is designed as the function of delay.By constructing the Lyapunov-Krasovskii functional,the stochastic stability criterion is acquired,and the co-design scheme of ETS with DOFC is obtained.(3)A tradeoff FD with ETS is proposed for discrete NCSs with unknown inputs.A new ETS is proposed for the measurement output.The fault detection and isolation(FDI)module is constructed,the residual generator can achieve the sensitivity to the fault and the robustness to the disturbance,and determine whether a fault occurs by utilizing the residual calculated online with time-varying threshold.The proposed ETS can overcome the shortcoming of information loss caused by traditional ETS,improve the accuracy of FD,and reduce the missed detection rate(MDR).(4)A DOFC for discrete Markov jump system with deception attack is addressed.Asynchronous ETSs are installed to reduce the data transmission and the actions of actuator against the attacks,and dual quantizers are set to further optimize the data transmission.By constructing the Lyapunov-Krasovskii functional,the stability criterion and the co-design strategy of ETS with DOFC are acquired to achieve the goals of saving network resources and security control under cyber-attack.(5)The research contents are summarized,the open issues are pointed out,and the future research directions are determined.