Research On The Screw Cartridge Rotary Electro-Hydraulic Servo Valve

The electro-hydraulic servo valve is a complex component that integrates the mechanical system and electro-hydraulic system into one system.And it has a wide range of applications in the civil industry,military industry,and other fields.However,current electro-hydraulic servo valves have some drawbacks such as complex structures,high processing and maintenance costs,poor pollution resistance,and low integration,which limit their working performance in complex and changing environmental spaces such as aerospace and robotics.Aiming at solving these problems existing in the current servo valve,the research on the threaded plug-in rotary servo valve has been proposed.This article described the overview of the development of Electro-hydraulic servo valves,analyzed the advantages and disadvantages of the present Electro-hydraulic servo valves in electro-mechanical converters and structures.Based on this research,the structural design of the direct-drive screw cartridge rotary servo valve was proposed.After expounding the structure and working principle of the direct-drive screw cartridge rotary servo valve,the important dimensional parameters have been calculated.Then,according to fluid mechanics and tribology,the torque balance equation of the direct-drive screw cartridge rotary servo valve has been established.And the torque balance equation and voltage balance equation of the direct-drive screw cartridge rotary servo valve’s motor assembly also has been established based on the Clarke and Park coordinate transformation.Next,based on the mathematical models of the two,the three-closed-loop system control model of the direct-drive screw cartridge rotary servo valve has been derived,and the SVPWM method was used for drive control.Then,while the flow rate,pressure,steady fluid torque,and other characteristics of the direct-drive screw cartridge rotary servo valve have been simulated and analyzed by using the CFD technology,the rationality of the flow field structure of the direct-drive screw cartridge rotary servo valve has been verified.At the same time,the relevant parameters in the control model of the direct-drive screw cartridge rotary servo valve are determined.After that,a three closed-loop control system model of the direct-drive screw cartridge rotary servo valve has been built in the Simulink platform system,and the flow output characteristics and dynamic characteristics have been analyzed and studied.In order to test the dynamic performance and static performance,the prototypes and the test platform of the direct-drive screw cartridge rotary servo valve have been designed and built.The test results not only prove that the direct-drive screw cartridge rotary servo valve has good performances both in the dynamic characteristics and static characteristics,but also show that the experiments are consistent with the simulation results.Finally,through further analysis of the experimental results,an improved scheme for the screw cartridge rotary electro-hydraulic servo valve has been proposed to further improve the performance of it.After optimizing the structure of the new valve body,the experiment has proved that compared with the direct-drive screw cartridge rotary servo valve,the improved screw cartridge rotary electro-hydraulic servo valve has superior dynamic characteristics.