Research On Active Disturbance Rejection Control Of Single-point Hybrid Magnetic Levitation Ball System

Maglev technology is an important part of China's transportation power strategy.At present,China's medium-low constant conductivity maglev technology is gradually mature,but the energy consumption of suspension module is always high.Compared with the normal magnetic levitation technology,the permanent magnet electromagnetic hybrid suspension technology has significant advantages of energy saving and low carbon.However,the magnetic field of permanent magnet material is a nonlinear static decay field,and the practical engineering application often faces the problems of disturbance mutation and equipment aging,so the anti-disturbance ability and control precision of the hybrid suspension system are highly required.Traditional control algorithms mostly rely on accurate controlled object or disturbance model,and it is still a great challenge to control nonlinear,large time delay and strong external disturbance object in complex environment.In this paper,the single-point permanent magnet electromagnetic hybrid suspension ball is taken as the research object.Firstly,aiming at the construction of the structure physical model of the hybrid suspension ball,the mathematical model of the hybrid suspension ball system is improved by mechanism modeling method starting from the simplified structure of single degree of freedom,and the open-loop stability of the hybrid suspension ball system is analyzed.Secondly,the active disturbance rejection control algorithm based on Levant differentiator is designed in view of the characteristics of the hybrid suspension ball system,such as nonlinearity,suspension precision requirement and suspension parameter perturbation.The advantages of Levant differentiator based active disturbance rejection control algorithm in step response,dynamic response,adaptability and robustness are verified in SIMULINK simulation environment.Thirdly,the closed-loop stability of ADRC is verified by absolute stability theory according to the stability of closed-loop system and filtering performance of tracking differentiator.The filter performance of three typical tracking differentiators is studied and equivalence analysis is carried out.Through SIMULINK simulation environment for typical tracking differentiator and equivalent linear tracking differentiator simulation,and verify the feasibility of equivalent tracking differentiator and corresponding parameter coupling relationship.Finally,aiming at the feasibility of the control algorithm and the need of performance verification,an experimental platform based on STM32 single point hybrid suspension ball system was designed and built,and physical verification was carried out from two aspects of static suspension and dynamic performance.In addition,static suspension and robustness verification experiments of PID and ADRC are carried out on the full-size single point suspension experimental platform,which further proves the significant advantages of active disturbance rejection control.Simulation and experimental results show that: The ADRC algorithm based on Levant differentiator designed in this paper can achieve fast response speed,strong anti-disturbance ability,good adaptability and robustness in the case of small overshoot,which enriches the application scenarios for the promotion of ADRC.It provides basic theoretical basis and key algorithm support for the future engineering application of permanent magnet electromagnetic hybrid suspension system.