Schedule Policy And Guaranteed Cost Controller Design For Networked Control System

Feedback control system in which the control loops are closed through a real-timenetwork is called networked control system (NCS), which consisting of many technologiessuch as computer, communication, network and control. Comparing with the traditionalpoint-to-point connection, NCS has many advantages such as less connecting wires, sharingthe sources online, easily maintained and expanded. However, for the complex transmission,there exists induced delay, data packet loss sequence disordering and actuators or sensorsfailure in NCS, which could cause negative impact on the performance of the system, evenlead instability to the system. The study of networked control system has become a new hotissue in the control field. The schedule policy and guaranteed cost problem are emphaticallyinvestigated in this paper, and the contents of this paper are given as follows.（1）The stability analysis for a class of NCS with uncertain network factors such as timevarying delay and data dropouts is investigated. The time varying delay is modeled as a classof uncertain parameter which results in uncertain affections to the system, and the occurrenceof packet dropouts is expressed as a Bernoulli event. Under the condition that the system isguaranteed to be exponentially mean square stable, a state feedback controller is designed onthe basis of the linear matrix inequality(LMI) approach. Meanwhile, through the augmentingthe state with predicted error, an observer-based controller is designed to render the systemexponentially mean square stable when the state information is not fully available.（2）The modeling and guaranteed cost fault-tolerant controller for networked controlsystem with double faults is proposed. Firstly，in the case that actuators become failure, theguaranteed cost controller is designed for a class of NCS with the affection of uncertainparameters. And then, considering actuator faults and sensor faults occur together, themodeling of NCS with double-faults is investigated. Based on time delay-dependent approachand Lyapunov stability theory, under a certain performance indicators, the control policy isproposed to render the NCS with double faults asymptotically stable. Finally, the simulationsare conducted to prove feasibility and effectiveness.（3）For the limited network bandwidth and the energy of nodes，the high probability ofnetwork conflict, the schedule policy based on predicted error is proposed, which isimplemented by introducing a toggle switch matrix. On the one hand, NCS is modeled as aclass of time-continuous system，and the toggle is stalled at the sensor side to reduce thewhole feedback network’s conflict. On the other hand, NCS is modeled as a class oftime-discrete system，and the toggle is stalled at the controller side to reduce the backwardnetwork’s conflict and save the energy of actuator nodes.Combining Lyapunov theory with LMI approach, the guaranteed control gain is deduced for this class of NCS. Finally, thesimulations are conducted to prove feasibility and effectiveness.（4）The methods of network modeling and guaranteed cost-controller designing aregeneralized to the distributed parameter system. With the network transmission delays, datapacket dropouts and uncertain parameters considered, the modeling approach of distributedparameter NCS with space characters is proposed.Combing Lyapunov-Krasovskii functionand weighted technology，the guaranteed cost condition is derived when the initial state ofdistributed parameter NCS falling in Banach space. Moreover, the design of guaranteed costcontroller in terms of LMI. Finally, the simulations are conducted to prove feasibility andeffectiveness.