Output Feedback Control For A Class Of Nonlinear Systems With Quantization

In practical engineering applications,most of the research objects are nonlinear systems.Considering the uncertain factors existing in control systems,such as measurement drifts,un-known parameters and time-delays,how to design a suitable output feedback controller has important research significance.In addition,due to the long-distance transmission and the con-straint of the network transmission bandwidth,the quantization technology is introduced in the network control system.The continuous signals are converted into multi-segment discrete val-ues,thereby reducing the burden of transmitting information in the communication channel.Based on dynamic gain technique,Lyapunov stability theory,Nussbaum function and quan-tizer sector-bounded approach,output feedback control for a class of nonlinear systems with quantized signals is studied in this paper.The main research contents are as follows:1?For a class of nonlinear systems with time-delay and quantized input and output,the adaptive output feedback problem is addressed.The nonlinear terms of the system satisfy the lower-triangle linear growth condition with unknown growth rate.The dynamic gain is intro-duced to design state observer.Time-delays are handled by designing the appropriate Lyapunov-Krasovskii functional.Based on the Lyapunov stability theory,a linear output feedback con-troller is constructed,so that all the signals of the closed-loop system are bounded.With the help of the Barbalat lemma,it can be proved that all states of the system asymptotically con-verge to the origin.Numerical simulation results show the effectiveness of the proposed control method.2?For a class of nonlinear systems with unknown control directions and quantized input,the adaptive output feedback control problem is investigated.Combined with the Nussbaum-type function and dynamic gain technology,the unknown control direction is disposed by de-signing a suitable virtual controller.The dynamic gain technique is utilized to design the full-order state observer,and the output feedback controller is constructed based on the backstepping method.By applying the Lyapunov stability theory,the stability and the boundedness of the closed-loop system are proved.Numerical simulations verify the effectiveness of the control method.3?For a class of nonlinear systems with unknown output functions,the output feedback control problem of both input and output quantization is presented.Since the output function of the system is unknown and the state information of the system cannot be directly measured,the quantized output signal is used to design a full-order state observer which is not directly related to the system state x₁.The output feedback controller is designed based on the backstepping method,and the appropriate parameters are selected to make all the signals of the closed loop system bounded.Numerical examples verify the effectiveness of the controller.