Auto Coupling PD Control Method For Non-affine Nonlinear System

In recent years,the research and application of non-affine nonlinear system tracking control has attracted more and more attention.In the design of the controller,the control input of the system is implicit in the expression,and the non-affine characteristics coupled with the nonlinear state of the system,as well as unknown parameters,external disturbances,measurement errors and other uncertain factors increase the control difficulty of the system.Aiming at the control problem of non-affine nonlinear system,an adaptive auto coupling PD(ACPD)control method based on adaptive speed factor is adopted to study the tracking control problem.This method is combined with the definition of total disturbance of active disturbance rejection control,the advantage of robust stability of sliding mode control and the simple structure of classical PD control.Its uncertainties exist in unknown nonlinear time-varying system,non-affine nonlinear system and input constrained non-affine nonlinear system.The internal and external uncertainties of unknown system are defined as total disturbance The system carries out mapping processing,and then constructs the controlled error system under the total disturbance inverse excitation.The controller model and setting rules are constructed by using a speed factor unrelated to the controlled object,which makes the proportion link and the differential link closely connected,so as to form a collaborative control core with different functions and consistent objectives.Based on the complex frequency domain theory,the stability of the system is analyzed to ensure the global robust stability of the closed-loop control system.The adaptive auto coupling PD control method has the following characteristics:(1)there are uncertain parts or parameters disturbed in the system model,but it is not necessary to reset the PD controller gain,and the response speed and steady-state error accuracy are not affected.(2)The speed factor connects the proportional gain and the differential gain of the controller,and adjusts the speed factor according to the transition time of the controlled system from the dynamic process to the steady process.Experiments are carried out on the MATLAB simulation platform to prove the feasibility of the adaptive auto coupling PD control method,and the effectiveness and good tracking effect of the application in non-affine nonlinear system control.This method is simple in structure,small in calculation,fast in response,high in control accuracy,good in robust stability against disturbance,and has important application value in the field of non-affine nonlinear systems.