| Switching systems widely exist in various fields.As a special hybrid system,they are composed of different subsystems and switching rules,among which the switching rules are used to coordinate the switching between subsystems.For switching systems,their stability and performance indicators are not only related to subsystems,but also closely related to switching rules,thus increasing the difficulty of control.Deeply studying its control methods and solving the control problems of switching systems has great theoretical significance and application value.Based on this,this thesis combines backstepping method,adaptive control,Lyapunov stability theory,and average dwell time method to analyze and study in detail the control methods and stability of switched nonlinear systems.The main works and innovations are as follows:(1)An adaptive tracking control scheme based on average resident time is proposed for a class of switching nonlinear systems with non-affine structure.Firstly,in the implementation of the control scheme,because some functions are unknown,they cannot be used to design the adaptive rate and virtual control rate,which is convenient to control the system model.The average resident time method,adaptive method,backward step method and other control methods are used in the design of the system controller,and the switching filter and switching adaptive rate are designed,which reduces the limitation caused by the same observer and the same update rate of all subsystems.Finally,the stability of switching nonlinear systems is proved by means of the mean residence time method and Lyapunov stability theory.(2)An output feedback preset performance control scheme based on average dwell time is proposed for a class of nonlinear systems with unmeasurable state.In this thesis,we introduce an error conversion function,and make the error accurately within the constraint function through constraints.Then,we use neural network to approximate the unknown term in the system.Finally,we use the average dwell time method to judge the system stability,and verify that the tracking error can converge to the preset function through experiments.(3)Taking switching nonlinear systems as the object,this paper conducts simulation analysis on the above proposed method.The experimental results show that the designed controller can stabilize the system and accurately track the reference signal with the output signal.After adding preset performance control,the system tracking error can effectively converge to the preset value,and the dynamic and steady-state performance of the system can be improved. |
