Modeling And Control Analysis For Several Networked Control System

Networked control system is a distributed real-time feedback control system, it is the syncretic results for computer technology, communication technology and control technology, and has a lot of advantages, such as shared information source, low cost, flexible use, simple maintenance. Thus it makes great sense in industrial automation. However, because of networks introduced in control system, information is delayed, disordered or dropout for the finite bandwidth, time division multiple access and the uncertain data transmission path. All of these will affect the performance of control system in different degree, even make it unstable, and bring great difficulty in system analyzing, designing and controlling. Thus, how to solve the problems above is becoming one of the most challenging tasks in today's academe. This paper studies the modeling, packet detection and controller design algorithm for single-packet and multi-packet transmission, wire and wireless networked control system control system under consideration of delay, packet loss and disorder problems.Firstly, aiming at single-packet transmission networked control system with time-varying delay and packet loss, we assume that the packet will be dropped out if it does not arrive at actuator in one sampling period. Then the time-varying network conditions are considered as the jump of Markov states, and Equivalent Delay, which embodies stochastic character of packet loss and network induced delay (the random times of sampling period), is controlled by those Markov states, networked control system is modeled as discrete time Markov jump system using iterative approach. Thus, the dynamic characteristic of network is satisfied. Then, by stochastic stable analysis method, the sufficient stability conditions and the corresponding controllers are given in terms of Linear Matrix Inequality. Numerical examples show the validity and advantages.Secondly, through augmented matrix method, the paper considers the combined model for networked control system with single-packet transmission under consideration of delay, packet loss and disorder, the networked control system is modeled as a simple discrete time switched system. Based on this model, the qualitative analysis method is proposed, maximum number of packet loss and general stable results are given for the closed-loop networked control system. Meanwhile, the corresponding controller can be obtained. Numerical example shows the validity of our methods.Thirdly, aiming at networked control system with multi-packet transmission, the unknown and stochastic packet loss is considered as a kind of fault, and the quantization error is regarded as disturbance according to the character of packet dropout and quantization error. Networked control system is modeled as augmented discrete time switched linear system with disturbance and fault. Then, by robust fault detection method, optimal packet loss detection filter is designed to detect packet loss successfully. Further, using the networked internal model control algorithm, the high performance controller is design for networked control system with multi-packet transmission. Then the conflict between system performance and network characteristic is overcome. Simulation example shows the validity of our method.Finally, the modeling and controller design are developed for wireless networked control system applying adaptive coded modulation, which can improve the energy efficiency and increase the data rate over a fading channel. Through the introduction of System Delay, the characteristics of varying rate, interference, and routing in wireless transmission channel is contained in the whole system. Based on the time-varying network condition, the analytic lower and upper bounds of System Delays are given. If the actuator is event-driven, the networked control system is modeled as multi-controller switched system, sufficient stabilization condition and state feedback controller is given in terms of Linear Matrix Inequality; When the actuator is time-driven, it is modeled as a discrete-time system with time-varying input delay and structure uncertainty. The guaranteed cost control method of the networked control system is derived by novel techniques of time-delay system. Numerical result shows the validity of our proposed strategies.