Research On Output Feedback Control Of Networked Control Systems With Time-varying Sampling Period And Packet Drop-out

Networked Control Systems?NCS?is a closed-loop feedback control system formed by the network.It is a result of the combination of modern network technology and control technology.It has a series of advantages such as low cost,low power consumption,simple installation and convenient maintenance,and has been widely used in industrial control,motion control,building automation,aerospace and other fields.However,while NCS brings convenience to the system by using the network,it also introduces some new problems,including network induced delay,packet drop-out,and sometimes disorder.These problems can be possible to reduce the stability of the system.In addition,larger load changes can also cause instability in the sampling period of the system.In this paper,we consider the design problem of output feedback controller,which includes both the uncertain delay and the packet drop-out.On this basis,we consider the uncertain situation of the sampling period in original system,the corresponding output feedback protection performance controller is designed.Finally,considering the system parameters by the impact of time-varying sampling period as well as the time-varying delay,the anti-disturbance output feedback guaranteed cost controller is designed.The main contents of this paper are as follows:?1?A dynamic output feedback controller is designed for a class of networked control systemswith uncertain delay and packet drop-out.Considering the network induced total delay less than or equal to one sampling period,Bernoulli random sequence is used to describe the packet drop-out and the probability of data loss is known.The dynamic output feedback network control system is modeled as discrete time-varying system with uncertainties.Based on LMI method and Lyapunov stability theory,sufficient conditions for the existence of robust controllers are given and proved.The controller design problem is transformed into solving feasible solutions of linear matrix inequalities problem.Finally,a simulation example of Matlab is given,which verifies that the designed controller method is feasible and effective.?2?For a class of networked control system with time-varying sampling period and packetdrop-out,a dynamic output feedback controller is designed.Considering the sampling period is time-varying and bounded.Bernoulli's random sequence is used to describe packet drop-out and the probability is known.The time-varying sampling period is decomposed into the continuous variation of the finite interval and the system short delaym,So that the system is modeled as a discrete time-varying system with uncertain terms.Based on LMI method and Lyapunov stability theory,sufficient conditions for the existenceof robust controllers are given and proved.The controller design problem is transformedinto solving feasible solutions of linear matrix inequalities problem.Finally,a Matlabsimulation example is given to verify the effectiveness and feasibility of the proposedcontroller.?3?For a class of networked control systems with time-varying sampling periods,time-varyingdelays and bounded disturbances,the corresponding output feedback guaranteed cost H_?controller is designed.The time-varying sampling period is considered bounded,the time-varying short-time delay is less than or equal to one sampling period,the packet drop-outsatisfies the Bernoulli random sequence and the probability is known.The systemparameters are affected by both time-varying delay and time-varying sampling period.Inaddition,the interference of the limited energy disturbance on the system is considered.According to the principle of interval system,the uncertainties of time-varying samplingperiod and time-varying delay are transformed into the uncertainties of discrete system inmodeling.By using the Lyapunov stability principle and linear matrix inequality,thestability of the system is proved.The controller of the output feedback guaranteed costcontroller is obtained.Finally,a Matlab simulation example is given to verify theeffectiveness and feasibility of the proposed controller design.