| Automation of coal shearer is the premise to realize the unmanned coal mining face, and the shearer drum automatic height adjustment is one of the most important key technologies to realize the automation of the shearer. At present, switch valve controlled cylinder relay system is still widely used in shearer height adjusting system in practical application. Such system are difficult to meet the requirements of high power inertial load and the stability is poor. Therefore, it is necessary to transform the existing system based on electro-hydraulic proportional technology. On the other hand, computer aided modeling and simulation has become an important technical means to carry out the research of coal shearer, with the development of virtual prototype modeling and simulation technology.In this paper, MG2 x 160/710-WD thin coal seam shearer was taken as the prototype. The configuration and calculation for the structure parameters of the drum was carried out, And combined with certain coal bed condition and working condition, the average cutting load of drum was calculated, it established the foundation for the load analysis and Simulation of height adjustment mechanism and building drum’s virtual prototype model at the follow-up.The 3D solid model of shearer was built based on SolidWorks, the dynamic model of shearer’s virtual prototype was built based on ADAMS, The analysis and Simulation of the load in the dynamic model were carried out, and the feasibility of the ADAMS dynamic model was verified by the dynamic simulation test. The structure principle of traditional height adjustment hydraulic system was introduced, the reform scheme of electro-hydraulic proportion and selection of main components were given, the simulation model of open-loop electro-hydraulic proportional valve control cylinder adjusting hydraulic system was built based on AMESim, and the basic conditions were simulated and analyzed, feasibility of the AMESim simulation model was verified. Finally, the configuration requirements of software environment, and the interface method of co-simulation based on AMESim and ADAMS were introduced in detail. The mech-hydraulic coupling simulation model of closed-loop electro-hydraulic proportional height adjustment system was built, and the dynamic analysis of system was studied based on collaborative simulation. In particular, the dithering phenomenon of downing rocker arm was analyzed and improved.Co-simulation analysis results show that, The PID closed-loop electro-hydraulic proportional height adjustment system, which applied to the thin coal seam shearer, can realize the tracking of preset trajectory and control of drum height. In addition, for the height adjustment hydraulic system of the small flow and large inertia load, pilot controlled check valve on the side of the hydraulic cylinder’s rodless cavity open and close repeatedly resulting in severe flow and pressure fluctuations during shearer ranging arm down, which lead to dithering problem of shearer ranging arm. Setting one way throttle valve in the main oil circuit on the side of the hydraulic cylinder’s rodless cavity could be very significant to improve the phenomenon, but this can not completely eliminate its adverse effects. Further on this basis, Adding one way damper for direct action proportional direction valve could reduce the impact of the spool in the moment when shearer ranging arm down, to improve the stability of valve spool work and flow controllability at valve small openings. |
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