Observer-based Control And Filtering Of Nonlinear Networked Systems

Nonlinear networked systems,for simple equipment,expansion,operation,and maintenance,and resource sharing,have been widely applied in practical systems.With the scale expansion of the networked systems,the limited network bandwidth and transmission channels inevitably lead to some network induced problems,such as time delay,packet loss,and signal quantization.These limitations lead to more complex control problems for nonlinear networked systems,which may decrease the stability performance and even result in running error of the whole systems.Since much attention has only been paid to the linear systems,many issues are still within the control and filtering problems of nonlinear networked systems.Therefore,in this dissertation,the observer-based analysis and synthesis of nonlinear networked systems are systematically investigated based on previous works from the points including optimal modeling,performance analysis,controller design,and filtering design.Besides,an important class of nonlinear networked systems--multi-area power systems are modeled.Consider the equipment(component)faults conditions in multi-area power systems,a fault-tolerant based load frequency control problem is developed.The main work of this paper can be summarized as follows:The sliding mode control for nonlinear systems via event-triggered strategy is studied.For networked nonlinear systems,a sliding mode observer with an improved dynamic event-triggered strategy is proposed,the corresponding sliding dynamics meeting the asymptotically stable with a given performance index is proved.The anti-disturbance control for a class of nonlinear systems with signal quantization and time delay based on sliding mode observer is investigated.By implying the quantized output signal,the disturbance observer and state observer are established.Sufficient conditions of asymptotic stability for the closed-loop system satisfying a prescribed performance index are analyzed.Based on some linear transformation,the cross-coupling between matrices is effectively handled,the influence of signal quantization loss is eliminated,and the complexity of the research method is reduced.Finally,a nonlinear sliding mode controller is synthesized.The dynamic output feedback control for a class of nonlinear systems with mixed delays and packet dropouts via event-triggered strategy is discussed.The packet loss under the event-triggered strategy is considered,which is represented by a Bernoulli distributed stochastic sequence.An event-triggered dynamic feedback controller is designed.Sufficient conditions for the closed-loop system to satisfy the mean-square asymptotic stability with a given performance index are obtained in the form of linear matrix inequality.The dynamic feedback parameters are calculated based on the projection lemma and the cone complement linearization method.The H_?filtering problem of a class of nonlinear systems via event-triggered strategy is proposed.By designing an event-triggered filter,sufficient conditions for the corresponding filter error system to be asymptotically stable with a preset performance index are obtained.On this basis,the filtering parameters are derived by using the projection theorem and cone complement linearization method.The fault detection filtering for a class of nonlinear switched systems via event-triggered strategy is considered.By constructing a nonlinear fault detection filter,a residual system is obtained.Based on the average dwell time method and the Lyapunov stability theory,sufficient conditions for the exponential stability of the residual system are derived.By introducing some relaxation matrices,the fault detection filter is subsequently designed,and the filter parameters are given in the form of linear matrix inequality.The fault-tolerant control for multi-area interconnected power systems is analyzed.To be specific,the mathematical model of multi-area interconnected power systems is established.Fault-tolerant based load frequency controllers are designed for each power subsystems,and sufficient conditions for the closed-loop system to be asymptotically stable with the desired performance index are derived.Besides,the existence of the fault-tolerant controller is derived.