Research On Improved Active Disturbance Rejection Control For Hypersonic Vehicle In Reentry Phase

Hypersonic vehicle mainly refers to the vehicle flying in the atmosphere with a speed of 5-10 times the speed of sound.In recent years,many Aerospace powers pay more and more attention to the development and research of hypersonic vehicle.However,the hypersonic vehicle has the characteristics of strong nonlinearity,strong coupling and strong uncertainty.The traditional control methods such as PID control can not meet the control accuracy requirements.In this paper,the control method with stronger anti-interference ability will be adopted.This paper introduces the relevant coordinate system and transformation relationship,gives the parameters of the vehicle and the atmospheric model,and establishes the mathematical model of the reentry phase of the hypersonic vehicle.The aerodynamic characteristics and open-loop characteristics of the aircraft model are analyzed,which lays a foundation for attitude control.This paper analyzes the basic structure and functions of ADRC.The traditional ADRC is mainly composed of three parts.Tracking differentiator is mainly used to arrange the transition process of the system;The extended state observer can measure the state quantity and the total disturbance of the system without the specific state of the system;The nonlinear error state feedback can be used for nonlinear superposition of error signals.The hypersonic vehicle reentry model has strong coupling.In order to facilitate the design of the controller,this paper uses the feedback linearization method to decouple the vehicle model into three independent channels,and establishes the control system block diagram for each channel based on ADRC.Through parameter calculation and setting,single point simulation,overall simulation and simulation analysis with parameter perturbation are carried out.Aiming at the shortcomings of active disturbance rejection control(ADRC),this paper proposes a higher-order sliding mode observer with stronger robustness and higher accuracy from the extended state observer in traditional ADRC.After replacing the extended state observer with this observer,an improved ADRC is obtained.Based on the improved ADRC,the system control block diagram is established,and the attitude control of hypersonic vehicle in reentry phase is studied and analyzed.