Sampled-data Output Feedback Control For Switched Nonlinear Systems

In recent years,computers have acquired widespread applications in various control fields such as astronavigation,agriculture,transportation and military production along with rapid development of digital communication technology,which also provides an opportunity for the advance of sampled-data control theory simultaneously.However,most existing results on sampled-data control mainly focus on linear systems,for nonlinear systems which commonly exist in nature and modern industrial control,the theoretical results are relatively few.In modern industrial control processing,a large number of devices or electronic components have switching characteristics for their own factors or environmental influence.Therefore,these devices or electronic components can be characterized by nonlinear switched systems.How to control such devices or components via computers or digital communication technology,that is,how to realize sampled-data control for nonlinear switched systems is an urgent problem currently,such problem has important theoretical significance and practical value for engineering application.This paper pursues global sampled-data output feedback stabilization problem for several classes of switched nonlinear systems by using the backstepping technique,common Lyapunov function method and dwell-time method.The main work of this paper is summarized as follows:1.Global sampled-data output feedback stabilization problem is investigated for a class of switched nonlinear systems in non-strict feedback structure.Under arbitrary switching case,an observer-based sampled-data output feedback controller is designed by adopting the basckstepping technique and CTD(Continuous-time Plant Model Plus Controller Discretization)method.It is proved that the resulting closed-loop system can be globally asymptotic stable under arbitrary switching.The effectiveness of the control approach is illustrated by simulation examples.2.Global sampled-data output feedback stabilization problem is considered for a class of switched nonlinear systems in non-strict feedback structure under asynchronous switching.Based on the merging virtual switching signal,a Lyapunov function is constructed,under which,we have proved that the designed asynchronous switching sampled-data output feedback control law can render the resulting closed-loop system to be globally asymptotically stable under the given average dwell time constraint.The feasibility of the control strategy is verified by simulation examples.3.Global sampled-data output feedback stabilization problem is addressed for a class of switched nonlinear systems in non-strict feedback structure with time-varying delay.By adopting the average dwell time method,an observer-based sampled-data output feedback controller is developed in the situation of unknown time-varying delay,and a Lyapunov-Krasovskii functional is constructed to obtain the condition for globally asymptotic stable of the resulting closed-loop system with time-varying delay.The effectiveness of the proposed controller scheme is indicated by simulation examples.4.Global sampled-data output feedback stabilization problem is discussed for a class of switched nonlinear systems in non-strict feedback structure with unknown timevarying control coefficients.A sampled-data output feedback controller is designed by constructing a reduced-order observer and combining backstepping technique with CTD method.It is demonstrated that the developed controller can make the corresponding closed-loop system to be globally asymptotic stable under the average dwell time constraint by choosing an appropriate Lyapunov function.Simulation results show the feasibility of the control method.5.Global sampled-data output feedback stabilization problem is focused for a class of switched stochastic nonlinear systems in non-strict feedback structure.A sampleddata output feedback controller design method is proposed for the situation that the investigated systems contain stochastic noises,and based on the stochastic Lyapunov stability theory,it is demonstrated that the developed controller can make the corresponding closed-loop system to be globally asymptotically stable in mean square sense under the dwell time constraint.The validity of the control method is presented by simulation examples.