Adaptive Arbitrary Switching Output Feedback Control For Switched Nonlinear Systems Based On Dynamic Surface

With the continuous development of science and technology and the continuous improvement of control performance requirements,many scholars are devoted to the research of switched nonlinear system control.As a special kind of hybrid system,switched system consists of a series of continuous or discrete-time dynamic subsystems and a rule to regulate the switching between them.Many practical physical and engineering systems,such as network control system,circuit power system,chemical process and so on,can be modeled as switched system.Therefore,the research of switched system has important theoretical and practical significance.Based on the backstepping design method of dynamic surface and the common Lyapunov function theory,this paper studies the design of adaptive controllers and stability analysis for several kinds of switched nonlinear systems,the main contents are as follows:Firstly,for a class of switched nonlinear systems with non-affine form,an adaptive output feedback common control method based on fuzzy reduced-order observer is proposed by combining dynamic surface control technology and fuzzy approximation method.In the design process of the given common controller,the algebraic loop problem caused by the non-strict feedback structure and the repeated approximation problem in the existing results are avoided.By using the common Lyapunov function theory,the designed common controller can ensure that all signals in the closed-loop switched system are uniformly bounded,and the tracking error can converge to a neighborhood of the origin as small as possible.The feasibility and practicability of the method are verified by two simulation examples.Secondly,for a class of switched nonlinear systems with non-strict feedback form,an adaptive output feedback control method based on fuzzy sampled observer is proposed,when the output is only available at the sampling point.This method reduces the conservatism caused by the common control idea in the existing research results of arbitrary switching control,avoids the computational explosion in the iterative process and the disadvantages of high gain of the controller.The switched adaptive law highlights the characteristics of each subsystem,and the established sampling controller saves information transmission resources.The common Lyapunov function theory ensures the uniform boundedness of all variables of the corresponding closed-loop switched system under arbitrary switching.A numerical example and a simulation study of an electromechanical system verify the effectiveness of the proposed method.Finally,for a class of switched nonlinear non-strict feedback systems with unknown control direction,an event-triggered adaptive output feedback prescribed performance control problem is studied.By introducing appropriate constraint transformation function and even Nussbaum-type function,the tracking performance control under unknown control direction is solved.Based on a vary threshold triggering mechanism,a common triggering controller is designed.By combining the common Lyapunov function theory and adaptive backstepping technology,it is proved that all signals of the closed-loop switched system are bounded under arbitrary switching,and the tracking error can converge to a neighborhood of the origin as small as possible within the prescribed bounds.The effectiveness of the method is verified by a numerical example and a practical example.