Hydro-pneumatic suspension is widely used in heavy vehicles due to its nonlinear characteristics of stiffness and damping. However, the conventional passive hydro-pneumatic suspension can’t adjust parameters accordin...Hydro-pneumatic suspension is widely used in heavy vehicles due to its nonlinear characteristics of stiffness and damping. However, the conventional passive hydro-pneumatic suspension can’t adjust parameters according to the complicated road environment of heavy vehicles to fulfill the requirements of the vehicle ride comfort. In this paper, a semi-active hydro-pneumatic suspension system based on the electro-hydraulic proportional valve control is proposed, and fuzzy control is used as the control strategy to adjust the?damping force of the semi-active hydro-pneumatic suspension. A 1/4?semi-active hydro-pneumatic suspension model is established, which is co-simulated with AMESim and MATLAB/Simulink. The co-simulation results show that the semi-active hydro-pneumatic suspension system can significantly reduce vibration of the vehicle body, and improve the suspension performance comparing with passive hydro-pneumatic suspension.展开更多
A new closed loop flow controlling principle through correcting the valve'sopening area while load pressure is changing is carried out. Further more a principle using only oneproportional valve to compound control...A new closed loop flow controlling principle through correcting the valve'sopening area while load pressure is changing is carried out. Further more a principle using only oneproportional valve to compound control pressure and flow is suggested. By using very simpleproportional throttle valve in structure, the functions that five kinds of proportional valves orany two of them combined possess can be complimented. After analyzing, comparing, and testing thedynamic and static characteristics of valve with different controlling principles and main valvestructure styles, the optimized structure styles and control methods are achieved.展开更多
A kind of cartridge servo proportional valve is discussed, which can be used for controlling large flow rate with high performance. By analyzing the structure principle of the valve, the transfer fimction of the valve...A kind of cartridge servo proportional valve is discussed, which can be used for controlling large flow rate with high performance. By analyzing the structure principle of the valve, the transfer fimction of the valve is derived. With the transfer function, some structure elements that may affect its performance are investigated. Through the numerical simulation and test study, some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works. The paper provides theoretical basis for engineering applications and series expanding design works展开更多
To solve the dead⁃zone in the output flow curve of the proportional flow valve without displacement sensor,a dead⁃zone compensation approach is proposed in this paper.Instead of detection and feedback of the valve spo...To solve the dead⁃zone in the output flow curve of the proportional flow valve without displacement sensor,a dead⁃zone compensation approach is proposed in this paper.Instead of detection and feedback of the valve spool position,the proposed approach adopted the pressure drop across the valve metering orifice to accomplish the dead⁃zone compensation.The first step was to test and get the_(max)imum output flow,Q_(max),at a preset reference pressure drop,such asΔP_(0).The next step was to construct the target compensation flow curve,which is a line through(0,0)and(ΔP_(0),Q_(max)).Then a compensation law was designed to approach the target curve.However,the research results show that the above strategy caused over⁃compensation once the actual pressure drop deviated fromΔP_(0).Thus a correction coefficient,β,was presented to correct the initial compensation law as the pressure drop deviated fromΔP_(0).For example,the test results indicate that the corrected compensation approach could reduce the dead⁃zone from 53.9%to 3.5%at a pressure drop of 1 MPa;as the pressure drop was increased to 5 MPa,the dead⁃zone was reduced from 51.7%to 3.5%.Therefore,the following conclusions can be drawn:the proposed compensation approach is feasible,which can effectively reduce the dead⁃zone and improve the output flow static performance of the proportional flow valve without spool displacement feedback.展开更多
Electro-hydraulic proportional valve is the core control valve in many hydraulic systems used in agricultural and engineering machinery.To address the problem related to the large throttling losses and poor stability ...Electro-hydraulic proportional valve is the core control valve in many hydraulic systems used in agricultural and engineering machinery.To address the problem related to the large throttling losses and poor stability typically associated with these valves,here,the beneficial effects of a triangular groove structure on the related hydraulic response are studied.A mathematical model of the pressure compensation system based on the power-bond graph method is introduced,and the AMESim software is used to simulate its response.The results show that the triangular groove structure increases the jet angle and effectively compensates for the hydrodynamic force.The steady-state differential pressure at the valve port of the new pressure compensation structure was 0.65 MPa.Furthermore,experimental results show that the pressure difference at the main valve port is 0.73 MPa,and that the response time is less than 0.2 s.It is concluded that the new compensation structure has good pressure compensation response characteristics.展开更多
文摘Hydro-pneumatic suspension is widely used in heavy vehicles due to its nonlinear characteristics of stiffness and damping. However, the conventional passive hydro-pneumatic suspension can’t adjust parameters according to the complicated road environment of heavy vehicles to fulfill the requirements of the vehicle ride comfort. In this paper, a semi-active hydro-pneumatic suspension system based on the electro-hydraulic proportional valve control is proposed, and fuzzy control is used as the control strategy to adjust the?damping force of the semi-active hydro-pneumatic suspension. A 1/4?semi-active hydro-pneumatic suspension model is established, which is co-simulated with AMESim and MATLAB/Simulink. The co-simulation results show that the semi-active hydro-pneumatic suspension system can significantly reduce vibration of the vehicle body, and improve the suspension performance comparing with passive hydro-pneumatic suspension.
基金This project is supported by National Natural Science Foundation of China (No.50275102)Provincial Foundation for Abroad Return People of Shanxi (No.101045).
文摘A new closed loop flow controlling principle through correcting the valve'sopening area while load pressure is changing is carried out. Further more a principle using only oneproportional valve to compound control pressure and flow is suggested. By using very simpleproportional throttle valve in structure, the functions that five kinds of proportional valves orany two of them combined possess can be complimented. After analyzing, comparing, and testing thedynamic and static characteristics of valve with different controlling principles and main valvestructure styles, the optimized structure styles and control methods are achieved.
基金supported by Program for New Century Excellent Talents in University of China (No.NCET-05-0528).
文摘A kind of cartridge servo proportional valve is discussed, which can be used for controlling large flow rate with high performance. By analyzing the structure principle of the valve, the transfer fimction of the valve is derived. With the transfer function, some structure elements that may affect its performance are investigated. Through the numerical simulation and test study, some principles of optimality and effective methods for improving the dynamic performance of the valve are proposed. The test results conform to the results of the theoretical analysis and simulation, which proves the correctness of the study and simulation works. The paper provides theoretical basis for engineering applications and series expanding design works
基金Sponsored by the National Natural Science Foundation of China(Grant Nos.51775362 and 51805350)the Natural Science Foundation of Shanxi Province(Grant No.201801D221226).
文摘To solve the dead⁃zone in the output flow curve of the proportional flow valve without displacement sensor,a dead⁃zone compensation approach is proposed in this paper.Instead of detection and feedback of the valve spool position,the proposed approach adopted the pressure drop across the valve metering orifice to accomplish the dead⁃zone compensation.The first step was to test and get the_(max)imum output flow,Q_(max),at a preset reference pressure drop,such asΔP_(0).The next step was to construct the target compensation flow curve,which is a line through(0,0)and(ΔP_(0),Q_(max)).Then a compensation law was designed to approach the target curve.However,the research results show that the above strategy caused over⁃compensation once the actual pressure drop deviated fromΔP_(0).Thus a correction coefficient,β,was presented to correct the initial compensation law as the pressure drop deviated fromΔP_(0).For example,the test results indicate that the corrected compensation approach could reduce the dead⁃zone from 53.9%to 3.5%at a pressure drop of 1 MPa;as the pressure drop was increased to 5 MPa,the dead⁃zone was reduced from 51.7%to 3.5%.Therefore,the following conclusions can be drawn:the proposed compensation approach is feasible,which can effectively reduce the dead⁃zone and improve the output flow static performance of the proportional flow valve without spool displacement feedback.
基金This research was funded by the 2020 Shandong Province Key Research and Development Programs(Major Technological Innovation Projects):Construction Machinery Integration Research and Application of Key Technologies for Intelligent Integration and Matching of Vehicle Assembly(2020CXGC011005)Large Tractor Hydraulic CVT Intelligent Continuously Variable Transmission Integration Research and Application(2020CXGC010806)Development and Application of High-Horsepower High-Efficiency Intelligent Tractors(2021CXGC010812).
文摘Electro-hydraulic proportional valve is the core control valve in many hydraulic systems used in agricultural and engineering machinery.To address the problem related to the large throttling losses and poor stability typically associated with these valves,here,the beneficial effects of a triangular groove structure on the related hydraulic response are studied.A mathematical model of the pressure compensation system based on the power-bond graph method is introduced,and the AMESim software is used to simulate its response.The results show that the triangular groove structure increases the jet angle and effectively compensates for the hydrodynamic force.The steady-state differential pressure at the valve port of the new pressure compensation structure was 0.65 MPa.Furthermore,experimental results show that the pressure difference at the main valve port is 0.73 MPa,and that the response time is less than 0.2 s.It is concluded that the new compensation structure has good pressure compensation response characteristics.
