Robust Fault-Tolerant Control For Linear Networked Control System Base On Delay-Dependent Method With Time Delay And Packet Dropout

Networked Control System (NCS) was a closed control system by a real time network. It had wild application in the aerospace industry, petrochemical industry, manufacturers and complex system due to its advandages, such as: reducing system wiring, cutting the cost, sharing the information, ease of the system maintenance, extending, diagnosis. However, because of the involvement of the communication network, the network delay and the data pactet dropout are caused inevitably by the limited of the bandwidth and influenced unreliable transmission. In addition, kinds of uncertainty which brought by network characteristic caused the data transmitted in network losing its steadiness, casuality and determinacy. Furthermore, the most NCS has huger scale, more complex structure, and many fault factors. Once the system breaks down, the losses will be tremendous. Then, NCS possesses high safety and reliability through the fault-tolerant control become very complex and important. At present, the research of NCS fault-tolerant control is in the beginning stage, and the existing results are still exist many limitations, such as: delay and data packet dropout are considered soley, and delay is smaller than a sampling period in modeling, and the control strategy mainly uses the state feedback control strategy, and major research of system performance is robust integrity or robust H∞integrity, the conservative conclusion is relative bigger.Based on this, this paper aimed at a class of linear uncertain NCS with delay and data packet dropout, an robust intergrality, having certain performance restraint robust fault-tolerant criterion and the design method of corresponding controller were given in theoretical using dealy-dependent method. All the results were verified correctness and effectiveness using simulation examples. The data packet dropout is as a special kind of delay. Lyapunov stability theory, LMI, integral inequality method were comprehensive application. Some work was done as following by adopting state feedback control strategy and dynamic outpur feedback control strategy.1) The problem of robust fault-tolerant control in linear uncertain NCS was studied using state feedback control starategy.For linear uncertain NCS with delay and data packet dropout, and uncertain bounded disturbances, the delay-dependent sufficient conditions for system with robust integrity, robust H∞integrity, robust guaranteed cost and robust H∞guaranteed cost against actuator and sensor failures are derived using state feedback control starategy, and the corresponding design method of controller with optimal performance index or minimum disturbance rejection rate were presented. In the prove, a proper Lyapunov- Krasovakii functional is constructed, meanwhile, integral inequality and free-weighting matrices method were used.2) The problem of robust fault-tolerant control in linear uncertain NCS was studied using dynamic outpur feedback control strategy. For linear uncertain NCS with delay and data packet dropout, and uncertain bounded disturbances, the delay-dependent or delay-rate-dependent sufficient conditions for system with robust integrity, robust H∞integrity, robust guaranteed cost and robust H∞guaranteed cost against actuator and sensor failures are derived using dynamic outpur feedback control starategy, and the corresponding design method of controller with optimal performance index or minimum disturbance rejection rate were presented. In the prove, a type of Lyapunov-Krasovakii functional is proposed which contains some triple-integral terms, meanwhile, integral inequality method were used.3) When using dynamic outpur feedback control starategy, the delay is dealt with piecewise method, a type of less conservatism Lyapunov-Krasovakii functional is proposed which contains some triple-integral terms and double-integral terms, and the model transformation is not been adopted, and the usefulness item is hold based on less amplificatory, while the delay information is full used especially the lower bound of delay information of each section. These make the results possess less conservativeness. Meanwhile, the introduction of less free-weighting matrices reduce the computation. These improve the feasibility of controller design and the degree of fault-tolerant satisfaction and usability.4) In the above research conclusion, the accuracy and efficiency for all the result of the simulation is dissused using simulation example. All of conclusion is correct and effective.This provides certain theoretical basis for linear uncertain NCS with time-varying delay and date packet dropout.