Research On Dynamic Characteristics Of Direct Drive Electro-hydraulic Servo Position System

Direct drive electro-hydraulic servo system is a product with the development of electronic and hydraulic in recent years,its biggest feature is the use of AC servo motor driven dosing pumps to control the flow output,getting rid of the electro-hydraulic servo valve of traditional hydraulic system,so the direct drive volume control electro-hydraulic servo system has the advantages of small volume,low cost,ease of integration,while the introduction of the AC servo motor instead of electro-hydraulic servo valve to control the flow system output changes,the quickness of the direct drive volume control electro-hydraulic servo system is poor,this paper carries out deeply research to the factors affecting direct drive volume control electro-hydraulic servo system dynamics.On the basis of related literature at home and abroad,this paper studies the direct drive electro-hydraulic servo technology development present situation,compares the advantages and disadvantages of the traditional hydraulic system,analyses the ac servo motor speed control method and system for intelligent control of a few directions.The establishment of system mathematical model is based on the working principle of direct drive volume control electro-hydraulic servo system.This paper studies the vector control method of the ac servo motor,which simulates the speeding control model of dc motor,this method makes the ac servo motor easy and convenient to control,improves the dynamic characteristics of ac servo motor.This paper analyzes the stability and steady-state error factor of the system according to the open loop transfer function.In the MATLAB/SIMULINK environment,the ac servo motor simulation model under the vector control method is studied first.the ac servo motor exist power saturated conditions in the different interference and given speed.The dynamic characteristic of direct drive electro-hydraulic servo system is bad according to the simulation in different given input and interference.the factors influencing the dynamic characteristics of the system is analyzed,through the simulation study,the main factors influencing the dynamic characteristics of the system are system structure parameters and controller,set the system parameters reasonable can improve the system dynamic characteristics.Adding the PID controller improves the rapidity of system,but this system exist error in the interference cases.This paper designs the fuzzy adaptive PID controller for the condition of low dynamic characteristics,optimizes the PID controller and adjusts PID controller parameters online through fuzzy control theory.The steady-state error of system is reduced in outside interference cases,and the dynamic characteristic of system is improved.