| Accurate control and green energy saving has become the development trend of modern hydraulic technique. Independent metering reversing valve can achieve good control effect according to the working condition and the structure characteristics of the twin-spool valve make it has large energy saving potential. In this paper, the separate control method of meter-in and meter-out orifices was applied to the loader lifting arm hydraulic system combing with the working conditions of the loader lifting arm rise-and-fall. And the dynamic characteristic of the main valve controlling by priority valve part of independent metering reversing valve was analyzed. The strategy and effect of separate control of meterin and meter-out orifices in the loader lifting arm hydraulic system and energy saving were discussed.Firstly, in this article, the working principle of the traditional single-spool reversing valve and the twin-spool reversing valve were analyzed. The structure and principle of the independent metering reversing valve was determined according to the workplace conditions. Based on the working equipment of loader, the working condition of each work cycle, independent metering control system and the control scheme were analyzed. The result indicates that the application of independent metering reversing valve in hydraulic system of loader working device is practicable.Secondly, the mathematical model of the main valve controlling by priority valve part of independent metering reversing valve was established. According to the control requirement, the location closed-loop control with PID regulation was determined to be applied in the main valve controlling by priority valve system. Through type selection of the priority valve and the design of the key parameters of the main valve, the main simulation parameters was obtained. The AMESim simulation model of the main valve controlling by priority valve system of independent metering multi-way valve was established. According to analysis of dynamic characteristics simulation, the control effect of PID location closed-loop control is proved to be good. At the same time, the influence of quality of the main valve spool, the spring stiffness of the springs and the main spool action area on control performance were analyzed by varying parameter analysis.Then, mathematical model of independent metering control system based on the loader lifting arm cylinder in the process of the loader lifting arm rise-and-fall. The control strategy of the high-pressure chamber and the low-pressure respectively selected flow control method and pressure control method according to the working conditions. After building AMESim simulation model of independent metering control system, the control effect of independent metering control system was found to achieve accurate flow pressure control according to analysis of dynamic characteristics simulation.Finally, the energy consumption of the traditional single-spool reversing valve and the independent metering reversing valve was analyzed. The M4 multiway valve was selected as the comparative objects and established the AMESim simulation model. Based on the lifting condition, the power loss due to the different structure forms of the M4 electrohydraulic proportional multi-way valve and the independent metering reversing valve was compared, thus verified the saving effect of the independent metering control system was derived from the backpressure controlled. Through the rational analysis, it further figured out that there is greater energy saving potential when the independent metering control system dealing with the load fluctuation. |
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