Research On Hydraulic System Of Underground Emergency Drainage Car

China, as the power of coal resources and coal consumption, production ofcoal mines are billions of tons each year. With the deepening of coal miningdepth, geological conditions are becoming more and more complex, so manyunpredictable factors that make mine water-permeable disaster occurredfrequently in China, which has become a serious threat to the normal operationof enterprises and the life-property safety of staffs. For the water-permeabledisaster of coal mine, we should take prevention to avoid it at first. Oncehappened, it is of great practical significance to find the fastest way to drainunderground water, to mostly minimize the loss of properties and casualties. Inorder to solve this problem, the research puts forward the design scheme ofunderground emergency drainage car. The underground emergency drainage carmainly includes walking part, drainage operation part and hydraulic drivecontrol part. As an important part of the underground emergency drainage car,the hydraulic drive control section will be analyzed and studied in this paper.Based on the overall design scheme, this project designed the hydraulicsystem of underground emergency drainage car, drew the corresponding hydraulic system schematic diagram, and calculated the important parameters ofhydraulic components, according to the request of agency action and realworking condition under the ground. In the inclined roadway, to prevent thephenomenon of slope sliding and inhaling empty of the underground emergencydrainage car, balance valve and emergency brake hydraulic system are addedinto the running circuit, which could not only reduce possibilities of accidents,but also improve the response capabilities of the underground emergencydrainage car for emergencies.In this paper, the mathematical model is established for the hydraulicsystem of hoisting mechanism, the open and closed loop transfer functions arededuced during the working process of jack cylinder lifting pump, which treatreversing valve core displacement as input, then piston rod displacement asoutput. Using the basic knowledge of automatic control principle, the steadystate characteristics and the frequency characteristics of the system are analyzedtheoretically. Using the software of MATLAB/SIMULINK, the steady statecharacteristics, the dynamic characteristics and the frequency characteristics areanalyzed in simulation. The research results show that: under the effect of unitstep function input, the steady-state error of this system is0, without oscillationand overshoot,but the response speed is slow. After correction, the rise-time isabout0.016s, the adjusting-time is about0.065s and the phase margin of thissystem is about41.8, the amplitude margin is about12.6dB,which meets theperformance requirements of emergency drainage car. Using the power bond graph, the mathematical model of the walking speedbrake hydraulic system is established and the state equations are deduced in thispaper, the software of MATLAB/SIMULINK is used to build simulation model,and the dynamic characteristics of underground emergency drainage car areanalyzed in the process of braking. At the same time, the influence of balancevalve on the hydraulic motor brake characteristic are analyzed by using thesoftware of AMESim. The research shows that: the hydraulic braking timeduring the motor’s braking process will decrease with the increase of dampinghole diameter, which ranges from1mm to3mm; the braking time will increasewith the decrease of the spring stiffness, ranges from14000N/m to42000N/m;the change of other parameters have a little effect on the time of hydraulic motorhydraulic braking.Experimental prototype is built, and it is used in laboratory experiments toverify the rationality between hydraulic system and institutions and thecorrectness of the simulation results besides.