Study On High Response Control Strategy Of The Solenoid Screw-in Cartridge Valve

Digital hydraulic technology as an emergent and important branch of fluid power offers good prospects for intelligence,integration,and energy saving of hydraulic systems.The digital on-off valve as a critical component of digital hydraulics realizes the " Fluid Flow Discretization " function by the high-frequency opening and closing of the spool.The current research on digital on-off valves is mainly focused on the structure and control optimization to improve the response speed of high speed on-off valve(HSV)with ball valve structure,but there are few reports on the high response control research of solenoid screw-in cartridge valve(SCV)with poppet valve in digital on-off valves at home and abroad.This paper takes the SV08 series of SCVs manufactured by Hydra Force as the object of study.Based on the analysis of the factors affecting the opening and closing response speed of the SCV,a positive and negative pulse voltage control strategy is proposed to improve the dynamic response characteristics of the SCV,which provides theoretical reference and technical support for the application of electromagnetic thread cartridge valve in digital hydraulic technology,and promotes the development of digital hydraulic technology.In this paper,based on a comprehensive analysis of the internal structure and working principle of the SCV,a mathematical model of the dynamics of the SCV is established,and the mathematical relationship between the opening and closing delay time of the spool and the opening and closing initial current of the solenoid coil,the loading voltage and the pre-compression force of the spool resetting spring obtained.The influence of parameters such as initial current of solenoid coil opening and closing,loading voltage and pre-compression force of spool resetting spring on the opening and closing delay time of spool is studied,which lays a solid theoretical foundation for the high response control strategy of SCV.A positive and negative pulse voltage control strategy is proposed based on the analysis of the factors influencing the opening and closing delay time of the SCV.The control principle of positive and negative pulse voltage control strategy is analyzed,and the advantages and disadvantages of the proposed control strategy by using three voltage sources and DC-DC converter are compared.On this basis,by combining the PWM technology of the DC converter and the positive and negative pulse voltage control principle,the realization method of positive and negative pulse voltage control strategy based on PWM technology is proposed to achieve the pur pose of generating the required control voltage by using a voltage sourceThe test scheme of dynamic response characteristics of SCV is designed,and the multi-physical field coupling modeling of SCV and its test system is completed by AMESim.The variation laws of coil current,spool speed,solenoid force,differential pressure at the valve port and flow rate of the SCV under different positive and negative pulse voltage durations are studied by the established model to determine the optimal control parameters of positive and negative pulse voltage control strategy when the response speed of SCV is the fastest.The hardware-in-the-loop test platform of the SCV is built by RT-Link semi-physical simulation test system,and the design of positive and negative pulse voltage control strategy and measurement and control operation interface in MATLAB and RTSim Plus is completed.Meanwhile,the dynamic characteristics of SCV under conventional voltage and positive and negative pulse voltage control strategy are compared.The simulation and experimental results show that the dynamic characteristics of the SCV are improved by 55% and 89.93% respectively after adopting positive and negative pulse voltage control,in which the spool opening time is shortened from 30 ms to 13.5ms and closing time is shortened from 139 ms to 14 ms.