Design And Application Of Input Quantized Controller Based On Command Filtered Backstepping Control Method

With a large number of low-cost,high-performance digital computers and other digital communication facilities highly applied in control system,the control method is changing from the traditional analog control to digital control.Compared with the traditional analog control,digital control has many advantages such as : strong anti-interference ability,easy transmission and storage.In that case,the information can not be transmitted by arbitrarily high precision.Therefore,how to accurately and efficiently quantize the signal plays an important role in the popularization of digital control.At the same time,the actual system model often has many uncertainties such as nonlinearity and unknown parameters.Therefore,to study the quantized feedback control of nonlinear uncertain systems has great theoretical and practical significance.In this paper,for two kinds of nonlinear systems with quantized input signal,command filtered backstepping quantized controllers are designed.The stability of the closed-loop systems are analyzed by Lyapunov stability theory.Finally,the quantized control of vehicle active suspension system is studied based on the theoretical results and the simulation results verify the effectiveness of the proposed method.The main contents of this paper include:1.For a class of nonlinear systems with lower triangular structure,the problem of quantized feedback control is studied.The quantized controller of the closed-loop control system is designed by using the command filtered backstepping control algorithm.The stability of the closed loop control system is proved by Lyapunov stability theory.The ultimate boundedness of the closed-loop control system is guaranteed and the state signals of the system can be adjusted to any small neighborhood of the zero and the global quantization practical stabilization is achieved.2.For a class of uncertain nonlinear systems with unknown parameter,the problem of adaptive command filtered quantized feedback control is studied.The controller is designed by using the command filtered backstepping control and the adaptive control with dead zone.The stability of the closed-loop system is proved by Lyapunov stability theory and the global quantization practical stabilization is achieved.3.The theoretical results described above are applied to the 1 4 vehicle active suspension system.The controllers are designed for the standard system model andthe uncertain system with unknown time constant parameters of active suspension system.