Research On Adaptive Mtn Tracking Control For Several Kinds Of Nonlinear Systems

Adaptive tracking control of nonlinear systems has always been one of the hot issues in the field of control.According to the characteristics and constraints of various nonlinear systems,many scholars in control theory and engineering application still continue to put forward some new methods and tools for tracking control design of nonlinear systems.Considering that the combination of adaptive backstepping technique and stability theorem of solutions of differential equations can effectively solve the problem of system stability,and the property of MTN approximating unknown functions,this paper uses Lyapunov stability theory,adaptive backstepping technique and MTN method to discuss the related tracking control problems of three kinds of nonlinear systems.1.The problem of tracking control for nonlinear systems with unmeasurable states under bounded disturbances is discussed.Firstly,a nonlinear observer is constructed to capture the available system state information accurately.Secondly,the DSC technology is introduced in the adaptive backstepping design process to overcome the "differential explosion" problem in backstepping.By virtue of the approximation property of MTN,a simple structure adaptive MTN tracking control method is proposed.Lyapunov stability analysis demonstrates the stability of the control system and the analysis results show this scheme is very good.Finally,the feasibility and superiority of the method are verified by simulation examples.2.The problem of controller design for some switched time-delay systems with finite-time output constraints is studied.To limit the output tracking error to a predetermined boundary in finite time,an improved FTPF is introduced.In the process of controller design,the BLF is used to deal the output constraint problem.Then,a new adaptive MTN control method is proposed by combining the approximation characteristics of MTN with adaptive backstepping idea.Meanwhile,the LKF is emplied to realize the stability of the switched system in the presence of time delay.Finally,simulation examples are given to explain the validity and usefully of this method.3.The decentralized adaptive MTN control problem for some large-scale nonlinear systems with finite-time output constraints is studied.To ensure the tracking errors constraint within a predefined boundary in finite time,a novel adaptive control method is proposed by combing the modified FTPF with BLF in the first step of iterative process.Besides,the differential mean value theorem and regulating functions are employed to handle the difficulty caused by interconnection functions of large-scale systems.Subsequently,with the approximation performance of MTN,a MTN-based adaptive decentralized control project is developed to make the tracking errors within the specified prescribed performance.Finally,the stability theory analysis and simulation results demonstrate the stability of the control system and the effectiveness of this project,respectively.The results show that the three tracking controllers designed in this paper not only achieve the requirements of accurate and effective control,but also open up new ideas and methods for more general system tracking control research.