Research On Control Method And Embedded Controller Of Independent Metering Valve

With the advancement of computer technology,communication technology,and sensor technology,engineering machinery is developing towards digitalization,automation,and intelligence.As the core control component of intelligent hydraulic systems for engineering machinery,the performance of digital hydraulic valves directly affects the control quality of the machinery.The independent metering valve(IMV)is a programmable digital valve that independently controls the inlet and outlet throttle ports through an embedded valve controller,breaking the limitations of traditional hydraulic valves with rigidly connected valve ports that cannot be independently controlled.This valve allows for flexible linkage and can effectively improve system control flexibility,reduce energy consumption,and significantly enhance the level of digitalization and intelligence of engineering machinery.The IMV control algorithm and its implementation in embedded controllers are currently the bottleneck of this technology’s development.Based on this,this article conducts research on IMV controllers,proposes a IMV control algorithm based on BP neural network,and designs and implements an embedded valve controller.The main research contents are as follows:(1)Firstly,the background and significance of this research topic are introduced,and the current domestic and foreign research status of independent metering control technology and electro-hydraulic proportional valve controllers are elaborated.Based on this,the current problems of IMV controllers are proposed,and the research content and key technical difficulties are summarized.(2)The working principle of IMV controls cylinders is introduced,and mathematical models of the electrical-mechanical conversion link,pilot valve link,and main valve link of the independent metering dual spool valve are established.The transfer function of input duty cycle-pilot valve and pilot valve-main valve links is obtained.Taking the hydraulic cylinder extension condition as an example,the mathematical model of the IMV controls cylinder is established,and the flow gain coefficient,flow-pressure coefficient,and flow continuity equation are obtained.(3)Research was carried out on the IMV control method,and control algorithms based on BP neural network PID for main spool displacement closed-loop,main spool flow closed-loop,and load port pressure closed-loop were designed.The feasibility of the control algorithm was verified by conducting a joint simulation of the IMV control system using AMESim/MATLAB.(4)An embedded IMV controller is designed with ARM as the core,mainly including hardware,software,and PCB design.The hardware design includes power circuit,CAN bus communication circuit,temperature and pressure sensor transmission circuit,LVDT modulation and demodulation circuit,PWM drive circuit,and current sampling circuit.The software design includes the main program,A/D conversion program,CAN bus receive/send program,and PWM signal output program.The PCB design is carried out,and the prototype of the embedded valve controller is completed.(5)Conducted experimental research on a IMV control system,completed experiments on main spool displacement closed-loop control,main spool flow closedloop control,load pressure closed-loop control,and flow-pressure compound control.The speed of step response adjustment for spool displacement increases by 46.1%.The step response adjustment time of flow is 273 ms,and for pressure is 254 ms.During the process of flow-pressure compound control,the flow control accuracy is 1.6% and the pressure control accuracy is 2.1%,verifying the effectiveness of the embedded valve controller’s software,hardware,and control algorithms.