| With the development of control technology, the application of SMISMO (Separate Meter-In Separate Meter-Out) technology in engineering is promoted gradually. SMISMO technology based on the unique design concept which provides favorable conditions for excavator's further energy-saving. This thesis content is about research of the control strategy of a new twin spool valve electro-hydraulic proportional valve system which based on SMISMO technology in the excavator.At first, the article reviewed the composition and characteristics of domestic and foreign excavators'hydraulic system, and Introduced the application and research situation at home and abroad about load port independent control technology. Combined with the work principle of twin spool valve system we put forward three control methods:position control, flow control and pressure control. According to the working characteristics of excavator boom cylinder proposed pressure-flow control strategy when boom moving up and down.It established an electro-hydraulic proportional control model of twin spool valve system. Analysis shows that Flow rate feedback control strategy can effectively improve the system dynamic flow-pressure gain and improve system stability. On this basis, electro-hydraulic proportional valve system parameters on the position control, flow control and pressure control response characteristics are analyzed. The paper established twin spool valve mathematical model of hydraulic system, analyzed the influence of using pressure-flow control strategy on system's energy consumption.Then the paper established a mechanical electrical and hydraulic co-simulation model for twin spool valve system. The paper analyzed the simulation of two-spool system when adopt position control strategy and compared the experimental results also Verify the correctness of the simulation model. It analyzed pressure-flow control strategy of simulation result. The analysis shows that this control strategy can improve the stability of the system, and reduce the system's energy consumption. Analysis the existing problems of hydraulic control system composed of twin spool valve spool and load-sensing pump, the paper proposes the electro hydraulic proportional pump instead of load-sensing pump, the simulation results show that the hydraulic control system composed of electro hydraulic proportional pump and twin spool valve's energy-saving effect is obviousExcavator twin spool valve system Experimental platform is build. Twin spool valve system control program is compiled according to the proposed pressure flow control strategy. Experiments show that the model and simulation data is correct and reliable. Meanwhile analysis back pressure on the impact of twin spool valve system parameters, The results show that the lower back pressure can reduce energy loss under the premise of stability of the system. |
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