Research On Dual-variable Control Algorithm Of Electro-hydrostatic Actuator

As an important part of hydraulic technology,electro-hydraulic servo control technology is a typical representative of electromechanical-hydraulic integration technology.It has many advantages of hydraulic system and electromechanical system,and has gradually become an important supporting technology in modern high-tech industry.As a representative product of electro-hydrostatic servo control technology,electro-hydrostatic actuator has attracted the attention of many scientific researchers at home and abroad,and are widely used in engineering practice.This paper researched on the control algorithm of the electro-hydrostatic actuator under the working mode of two variables,namely variable speed and variable displacement.First,the mathematical model of the electro-hydrostatic actuator is established.Based on the working principle of the dual-variable electro-hydrostatic actuator and the realization plan of position control,the system is divided into a permanent magnet AC synchronous motor speed regulation subsystem,an axial piston pump variable regulation subsystem and a hydraulic cylinder execution subsystem.The working principle of these three subsystems is analyzed,and the mathematical model is established,which lays a good foundation and conditions for the further study of the dual-variable control algorithm of electro-hydrostatic actuator.Secondly,the two-variable control algorithm of the electro-hydrostatic actuator is studied,and the compound control algorithm is designed to realize the system position control.Analyze the operating characteristics of the system.The load speed of the system gives different speed settings of the motor,and the position error of the system gives the variable displacement settings of the variable pump to achieve the decoupling of the two control variables of speed and displacement control.When the system is working,PID control is used for motor speed control,global fast terminal sliding mode control(GFTSM)is used for hydraulic cylinder position control,and the response characteristics of the system are simulated and analyzed in MATLAB/Simulink.The simulation results show that the designed composite control algorithm combining PID control and sliding mode variable structure control can make the system obtain better dynamic performance.In addition,the model of the mechanical and hydraulic system of the electrohydrostatic actuator is built in AMESim,and the model of the permanent magnet synchronous motor,servo variable mechanism and controller of the system is built in MATLAB/Simulink.Through AMESim and MATLAB/Simulink joint simulation to analyze the system,the control effect of the compound control algorithm designed in this paper is further verified.Finally,an experimental platform for electro-hydrostatic actuator is designed and built,and experimental control software is developed.The experimental results verify the effectiveness of the dual-variable control algorithm for electro-hydrostatic actuator designed in this paper,which can achieve high precision and fast control of the system position requirements for responsiveness and good robustness.