Research On Active Disturbance Rejection Control Method Of EHA

Electro-hydrostatic Actuation(EHA)has the outstanding advantages of small size,high energy efficiency and high reliability,and it is the research hotspot of multi-electrochemical control system in the future.Its performance directly affects the accuracy of the control system.Because the performance of EHA is closely related to model uncertainty(including electrical,hydraulic and mechanical coupling)and external disturbance in the system,how to improve its control performance and robustness has become an urgent problem to be solved.Under this background,from the perspective of advanced control algorithm,this paper further excavates the dynamic characteristic potential of EHA system,improves the control index,and studies the new control algorithm.The main work is as follows:(1)According to the working principle and structure of EHA system,its mathematical model is established.Through reasonable model simplification,the models and closed-loop transfer functions of permanent magnet synchronous motor,piston pump and load are obtained.The accuracy of the model is verified by testing the structural characteristics of the backstepping motor and load under no-load and load.(2)The design of third-order linear active disturbance rejection controller(LADRC).The structure of classical ADRC algorithm is analyzed,and a linear ADRC is designed based on the mathematical model of EHA system.The linear tracking differentiator is given,which solves the problem that the feedback signal is difficult to obtain.The linear extended state observer realizes the effective estimation and real-time compensation of the "total disturbance" and the linear error feedback control rate,and solves the problem of outputting the controlled object control quantity.Many parameters in nonlinear ADRC are simplified into three main parameters.Finally,the stability of the controller is proved by Lyapunov stability theory.(3)The proposed control method is verified by system simulation.The influence of parameters in linear active disturbance rejection controller(LADRC)on the system is analyzed,and the parameters are adjusted quickly.The transient characteristics,position tracking characteristics and frequency characteristics of LADRC algorithm and traditional PID algorithm are compared respectively.The simulation results show that LADRC algorithm can improve the position tracking accuracy and system anti-interference ability when the internal parameters are time-varying and external disturbances are coupled.(4)The integrated structure of EHA is designed,and the experimental platform of EHA system is built.The parameters of EHA system are designed,and the modular design idea is adopted to realize the characteristics of high integration,compactness and expansibility.The overall scheme design of the test-bed is introduced in detail,and the LADRC algorithm and PID algorithm are verified.The test results are basically consistent with the simulation.The research shows that the linear active disturbance rejection control method can significantly improve the control performance and robustness of EHA system,and can become the algorithm scheme of multi-electrochemical control system in the future.