Research And Design Of Two-Dimensional(2D) Pressure Valve And Its Controller

In the field of Aeronautics and Astronautics,the main brake valves used in airborne brake system are nozzle flapper type pressure valve and jet pipe type pressure valve,but both of them have the disadvantages of large volume,poor anti pollution ability and complex structure.In order to improve the performance of the electro-hydraulic pressure valve,a two-dimensional(2D)pressure valve is designed in this paper.The mass and volume of the valve is only one third of the traditional electro-hydraulic pressure valve,and the anti pollution ability is greatly improved.The research results and contents of this paper are as follows:(1)Because LVDT displacement sensor can still maintain higher accuracy and better reliability in harsh environment,two-dimensional(2D)pressure valve uses this sensor for position closed-loop control.The pilot stage of the two-dimensional(2D)pressure valve is designed based on the working principle of the two-dimensional(2D)servo chute mechanism,while the main valve adopts the slide valve structure,which outputs different working pressures through the movement of the slide valve.The mathematical model of two-dimensional(2D)servo chute mechanism is built,and the simulation analysis is carried out with Matlab / Simulink simulation software.The frequency width is about 120 Hz,and the step response time is about 2.5 ms.(2)The electro-mechanical converter of two-dimensional(2D)pressure valve is studied.Based on the traditional torque motor,a kind of axially movable torque motor is designed to realize the insertion of two-dimensional(2D)pressure valve,and LVDT displacement sensor is installed on the torque motor.At the same time,the static and dynamic characteristics of torque motor are analyzed,and the torque of torque motor is simulated by Maxwell software.(3)In order to realize the control of two-dimensional(2D)pressure valve,analog controller and digital controller are designed,both of which use PID algorithm for position closed-loop control.LVDT displacement sensor feeds back the actual displacement signal of the valve core,and performs PID operation after finding the deviation from the input signal.The result of the operation affects the PWM duty cycle of the control torque motor.That is,the displacement of the valve core is precisely controlled by the input control signal,so as to control its output pressure.(4)The experiment platform of two-dimensional(2D)pressure valve is built,and the experiment flow is designed according to the experiment principle.The static and dynamic characteristic experiments are done by using the controller to control the two-dimensional(2D)pressure valve.According to the experimental results of static characteristics,the hysteresis and nonlinearity are less than 2%,which meet the design requirements.The results show that the step response time is 20 ms,the frequency width is 40 Hz and the dynamic characteristics are good at 21 MPa oil supply pressure.The two-dimensional(2D)pressure servo valve studied in this paper has the advantages of small volume,high reliability,strong anti pollution ability and high integration,which is suitable for aerospace,military and other fields.