Output Feedback Control Design For A Class Of Switched Nonlinear Systems With Unknown Measurement Sensitivity

With the rapid development of technology and human society,the structure of the controlled object has become more and more complicated.Therefore,it is necessary to establish hybrid system model which has continuous dynamic characteristics and discrete dynamic characteristics to describe complex objects.As a special class of hybrid systems,switched systems have attracted more and more attention in control theory and practical applications.On the one hand,many practical systems can be described as switched system models,such as hybrid vehicle control systems,ecosystems,economic systems,and so on.On the other hand,unlike non-switched systems,the switched system is composed of subsystems and switching signal.Then the dynamic performance of the switched system is not only formed by simple superposition of individual subsystems,but also related to the designed switching signal.At the same time,in the feedback control system,the output information of system needs to be measured by the sensors.In fact,due to the manufacturing reasons,operating conditions and other factors,there always exists an error between the measured value and the actual output value of system.Therefore,based on switched system theory and average dwell time(ADT)method,this paper investigates the problems of global output feedback stabilization and sampled-data control for a class of nonlinear switched systems with unknown measurement sensitivity.The main results of this thesis are summarized as follows:(1)The problem of global output feedback stabilization for a class of nonlinear switched systems with unknown measurement sensitivity is addressed by exploiting the average dwell time(ADT)method.Firstly,the system states are estimated by designing a switched high gain linear observer.Then,because of the nonlinear structure and unknown measurement sensitivity of the system,a dual-domination approach is proposed to cope with the design difficulties.Secondly,the proposed controllers for individual subsystems guarantee the resulting closedloop switched system globally stabilizable under a class of switching signals with ADT.Finally,two examples,which include a continuous stirred tank reactor(CSTR)system and a numerical example,are presented to verify the effectiveness of the proposed control scheme.(2)The problem of sampled-data control is investigated for a class of nonlinear switched systems with unknown measurement sensitivity.Firstly,the unmeasured states are estimated by constructing high-gain switched state observer,also a dual-domination approach is introduced to solve the design difficulties caused by the nonlinear part and the unknown measurement sensitivity in the system.Then,since the subsystems switching occurs during the sampling intervals while the associated controller is not switched,the asynchronous switching phenomena arise.Therefore,multiple Lyapunov functions(MLF)are constructed to present sufficient conditions for system stability under a class of switching signals with ADT.Finally,the effectiveness and practicability of the control scheme are verified by simulation experiments.The conclusions and perspectives are presented in the end of the thesis.