新型电液比例阀的设计及其控制方法的研究(3)

新型电液比例阀的设计及其控制方法的研究

硕士学位论文

Abstract

Electro-hydraulic proportional valve is the key component of the Electro- hydraulic proportional control system . Because of it’s better accuracy and stability control. Electro-hydraulic proportional valve gradually replace the traditional control valve has become a trend 。

Electro-hydraulic Proportional Pressure Valve is one type of Electro-hydraulic proportional valve. Its function is controling the oil pressure of hydraulic system proportional . Further，control the force and torque of machine.Paper based referencing mature products at home and abroad, using modern design methods and analytical tools designe proportional relief valve structure。First, design a dozen spool and valve cavitys’ geometric structure. According to the theory of computational fluid dynamics, establish Each valve flow mathematical model. Secondly using commercial software and CFX and ANSYS/FLOTRAN Solve velocity and pressure Numerical Solution in flow field of each valve .According to the data, Analyze the form of throttle impact on convective field.Finally according to the conclusions, Make the structure of spool and valve cavity optimization, and find a new type of structure.

When design the Proportional valve control circuit ，reseach MCU to control systems，digital PID algorithm and PWM (Pulse Width Modulation).Under the electro-hydraulic proportional valve control requirements, develop a system control procedures and design the MCU control system and power amplifier circuit. This Make electro-hydraulic proportional valve control performance greatly improving. Abstracting Working conditions of Valve to mathematical model is main methord of Studying Hydraulic System. Using Kinematic and Kinetic theory establish static and dynamic mathematical model of electro-hydraulic proportional valve which was designed. Find the transfer function. In addition, Solving the model parameters become an important issue.The same, in paper CFD as a theoretical basis, using Finite element numerical method calculate pressure and flow coefficients and other important parameters .In order to study the dynamic and static characteristics of valve, Transfer function is converted into MATLAB/SIMULINK package Extender Model. Using computer simulation technology find dynamic response plan of Valve. Research into different structure of the valve impact on dynamic response of valve.It provides good conditions for further optimizing the structure of the valve.