Research On The Design Of Interference Observers For Several Types Of Nonlinear Systems

This paper mainly studies the design of disturbance observers for nonlinear systems.For several different types of nonlinear systems,different disturbance observers are designed respectively.Asymptotic estimation of disturbance in the original system by disturbance observer,then by designing the adaptive controller,the state of the system reaches the desired equilibrium point.Nonlinear systems with disturbance have a wide range of physical and industrial backgrounds.Therefore,it is widely used in industrial fields.In many practical control systems,we inevitably need to consider the impact of disturbance to the system.Therefore,many industrial systems need to be modeled as a non-linear system with disturbance.Therefore,the study of nonlinear system with disturbance has more important theoretical significance,especially in promoting the development of nonlinear systems has an important practical value.In addition,relevant scholars at home and abroad through the continuous efforts in this direction,many important research results have been obtained.In this paper,some nonlinear interference observers are designed for several types of nonlinear systems with disturbances:1.Nonlinear disturbance observer design analysisThis section briefly introduces the definition of disturbance observer and its related industrial and physical background.As well as how to design different disturbance observers in different nonlinear systems.Then we introduced the relevant knowledge background,Finally,a common method for constructing a disturbance observer is introduced.2.The application of nonlinear disturbance observer in output feedback adaptive control of nonholonomic systemsThis section mainly studies a class of nonholonomic systems with strong nonlinear drifts and external disturbances,this section presents a new adaptive output feedback control method.Disturbance in nonlinear systems is a generalized system state,it can be used as an extended system state observer.To ensure the asymptotic stability of the closed-loop system,this section designed a new disturbance observer to reduce system disturbance caused by external impact.Finally,we also apply the integral backstepping technique to the design of output feedback adaptive stabilization control.The system simulation verifies the validity of the observer and the controller.3.Sliding mode control is performed on the system with mismatch uncertainty by disturbance observerThis section mainly develops the system of sliding mode control with nonlinear mismatch uncertainty through non-linear disturbance observer methods.By designing a new sliding mode surface based on disturbance estimation,this section develops a sliding mode control-based disturbance observer to counteract mismatched disturbance.The newly proposed method has two main characteristics.First,the switching gain is only required to be designed greater than the bound of the disturbance estimation error rather than that of the disturbance.Second,the proposed method retains itsnominal performance.The disturbance observer designed in this section is simple,and the performance is stable.At last,Simulation results verify the effectiveness and feasibility of the proposed method.