Event-Triggered Control For A Class Of Uncertain Nonlinear Systems

In recent years,with the increasing scale and complexity of modern industrial systems,many actual dynamic systems have the characteristics of high nonlinearity and uncertainty,and the use of traditional time-triggered control will lead to a large number of redundant data transmission,in addition,when the actuator of the uncertain nonlinear system fails,it is difficult for traditional fault-tolerant control technology to meet the control requirements.Based on this,this thesis takes a type of nonlinear strict feedback system of actuator fault as the control object,introduces the event trigger mechanism,and conducts a detailed study of the system control problem under different conditions,effectively reducing the communication burden between the controller and the actuator,the main work and innovation of this thesis are introduced as follows:(1)For a class of nonlinear systems with uncertain parameters,an eventtriggered output feedback control scheme is designed when the system state is not observable.Firstly,the system state is estimated by designing the K-filters,and the unknown state of the system is transformed into known.Then,by the fixed threshold method and the relative threshold method,the event triggering strategy is designed respectively,and the uncertainty of the system is dealt with by designing the event triggering framework,and the global Lipschitz function requirement of the nonlinear system is eliminated.At the same time,the combination of adaptive controller and trigger event solves the problem that the ISS assumption for measurement error is difficult to achieve.(2)For a type of nonlinear strict feedback system where actuators fail,the output feedback fault-tolerant control based on event triggering is given when the system has an unknown nonlinear function and the system state is unobservable.Firstly,aiming at the problem of unknown nonlinear functions in the system,the fuzzy logic system is used to approximate it.At the same time,in order to solve the problem of unobservable system state,a fuzzy observer is designed to estimate the system state.Then,the eventtriggered control law is designed to reduce the communication burden from the controller to the actuator caused by the unknown actuator fault and the infinite total number of faults.(3)According to the above control method,taking the reference nonlinear system as the object,the simulation examples of each chapter are given,and it can be seen that the system can remain stable through Lyapunov stability analysis,and the system output tracking error can be adjusted to a small neighborhood containing the origin.