Research On Flow Smoothing Control Of Three-position Four-way Water Pressure Proportional Valve Based On High-speed On-off Valve

Oil or water is often used as a medium in hydraulic systems,but due to the emergence of environmental problems such as global warming and glacier melting,the development of oil hydraulics is limited.Water hydraulics has become a hot development trend in the hydraulic industry in recent years due to its non-polluting outstanding features.With the rapid development of electronic information and digital industry,its advantages such as high control accuracy and fast frequency response have prompted mechatronics products such as digital valves and valve actuators to obtain substantial innovations and applications.This paper takes the hydraulic three-position four-way proportional directional valve(processed)based on the high-speed on-off valve as the research object,and mainly does the following research:The structure and controller of high-speed on-off valves and related products of water and oil pressure proportional valves at home and abroad have been investigated adequately,and combined with the existing water pressure proportional directional valves as structural support,Establish mathematical models for the three parts of highspeed on-off valve,main valve and high-speed on-off valve control main valve.The flow control characteristics of the duty cycle to the high-speed switching valve,the pressure-flow characteristics of the main valve,and the flow characteristics of the highspeed switching valve-controlled main valve under different duty-cycle PWM signals are analyzed.Mainly design the drive circuit of the high-speed switch valve,which is different from the ordinary power amplifier board,which integrates the power amplifier part,the overcurrent protection part and the circuit of the power supply part.A complete circuit model is built in the Multisim circuit simulation software,and the functions of each part of the circuit are simulated and analyzed.As a result,the goal of suppressing the back EMF of the PWM signal is basically achieved.And use DXP hardware circuit design software to complete the drawing and processing of the circuit PCB board.Secondly,the principle analysis and design of small modules such as STM32F407 main control chip module,CAN communication module,various power supply modules,SDRAM memory module and displacement sensor signal acquisition module are carried out.After the hardware circuit design is completed,the two control algorithms of PID and fuzzy PID are mainly used,also combine with the mathematical model of the valvecontrolled cylinder system,under the simulink module in the Matlab software,PID parameter tuning,fuzzy rule formulation and overall control system module construction are carried out.The two control algorithms are simulated and analyzed to achieve a more ideal optimization effect.Secondly,the programs of the two control algorithms,the A/D conversion program and the PWM signal generation program are successfully compiled and downloaded to the STM32F407 core board in the Keil C software.Finally,the completed valve-controlled cylinder system was built to test the function of the drive board and the two control strategies.The final results of the test can be summarized as follows: Both control strategies have an optimized effect on the flow smoothness of the system,but the fuzzy PID control algorithm has a better optimization effect.And for the digital control of other hydraulic systems,similar control ideas can also be adopted.