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

The electro-hydraulic servo valve has the advantages of fast dynamic response,high control precision and durability,which plays an important role in the industrial field.The two-dimensional(2D)servo valve was invented by Zhejiang University of Technology,who has made a major breakthrough in technology.It has been successfully applied in the aerospace and military fields,but has not yet formed large-scale production in industrialization.Therefore,this paper designs the first integrated industrial two-dimensional(2D)servo valve that embeds the controller in the valve body,which makes up for the lack of separate control of the original controller and the valve body,and improves the overall reliability and stability.The valve body adopts servo screw mechanism to make pilot level and main spool integrates into a single valve spool.This special structure makes the valve's power-weight ratio increased,the pollution resistance enhanced,the frequency response faster,and the cost lower.The valve uses a stepping motor as an electro-mechanical converter,and uses a synchronous tracking algorithm to achieve rapid positioning of the rotor at any position.At the same time,in order to improve the control precision and resolution of the valve,the fullclosed control strategy of the 2D servo valve is proposed on the basis of synchronous tracking control,which realizes the full closed-loop control of the valve core position of the 2D servo valve.The previous 2D servo valve is only a closed loop of the rotor position of the motor,and the position from the rotor position to the spool position is a defect of the open loop control,this strategy makes the valve become a true closed loop control system in real sense.In addition,I designed a matching small controller based on STM32F405.The specific research contents and results are as follows:(1)Modeling and Simulation of industrial two-dimensional(2D)servo valve's electric-mechanical converter.The synchronous tracking control method is adopted,which makes the motor rotor can rapidly locate in any position without out of step.Based on the algorithm,a model is established on Simulink and static analysis is performed.It is concluded that the stepper motor has good dynamic and static characteristics,the bandwidth is 155 Hz.(2)Structural design and full-closed simulation analysis of industrial 2D servo valve.According to the principle of servo screw mechanism,the structure design of 2D servo valve is carried out.A mathematical model is established and the MATLAB is used to simulate the valve's pilot control stage model,then we can obtain the dynamic and static characteristics of valve's pilot control stage.At the same time,combined with the valve model and synchronous tracking algorithm,the idea of full closed-loop control of the spool position of 2D servo valve is proposed.The overall mathematical model is established and fully closed-loop simulation analysis is carried out,then I obtain the 2D servo valve bandwidth is about 40 Hz.In addition,I analyzed the influence of different structural parameters on its performance.(3)Design and experimental study of industrial two-dimensional(2D)servo valve controller.Based on the design concept of miniaturization,STM32F405 is used as a control chip,and the full-bridge driver chip DRV8432 is used to drive motor,both of them are selected to design the hardware of the controller.The controller is embedded in the valve body,which improves the integration and reduces the cost.what's more,it also suitable for industrial occasions.Then the experimental platform is built,and the performance of the motor is tested by the new controller.The experimental results show that the static input and output characteristics of the motor are good,the frequency bandwidth is 120 Hz,the step response rising time is 5.9 ms,which prove the dynamic characteristics are good.(4)The experimental research of industrial 2D servo valve.In order to verify the rationality of the design,an experimental platform was built to test the actual performance of the 2D servo valve.The results show that the hysteresis is 2.1%,the nonlinearity is 1.4%,the leakage of pilot stage is 2.3 L/min under 7 MPa,and the bandwidth can reach 30 Hz.This paper integrates the valve body and controller of the 2D servo valve,and successfully applied the full closed-loop control algorithm of the spool position in the control system,which makes the entire system more stable and reliable.In the subsequent work,the structure will be re-optimized,and the accuracy of current sampling and displacement detection will be improved as always.It is to develop the most suitable products for industrial applications and achieve industrialization.