Research About The Travelling Performance Of Heavy Crawler Vehicle On Soft Ground

In order to alleviate the enormous pressure of the energy, our country majority developthe5000ton and hundred million tonlarge coal enterprises during the “12th Five-Year”.Continuous mining equipment such as bucket-wheel excavator, dump machine,stacker-reclaimer and full-mobile crusher station are applied widely in large coalmine.Heavy crawler travel unit is an important carrier of the weight of above mentionedequipment, and the function of moving and steering, whose performance directly effects theworking efficiency and the reliability of the whole machine. To meet the urgent needs of themining industry, it has been a significant task to develop highly reliable heavy crawler travelunit. Combined with the “Ceeusro”, this paper focuses on the study of the riding performa-nce of the heavy tracked vehicle through the soft ground.Base on the extensively review about the information at home and abroad, this studyintroduced the research background and significance of the soft ground driving performanceof the heavy crawler. Overviewed the research status of the action principle between theheavy crawler and the soft ground. From the digital physical prototype and the functionalprototype, this paper introduced the application of the virtual prototype technology on theresearch of the heavy crawler. Pointed out that the giant, the generalization of the compon-ents, remote control and intelligent control is the development trend of heavy crawler.The structure feature, steering method, driving method and function features of heavycrawler are introduced in this paper. Considering the offset of the center of speed and thecenter of mass and combined with the sinkage method proposed by Bekker, forces duringdriving on soft ground such as the sinking resistance, steering bulldozing resistance, steeringfriction, running resistance, inertial resistance, climbing resistance and wind resistance areanalyzed. Calculation of the crawler drive power under different conditions are given. Byconstracting the sinking resistance and sinkage of the track on Michigan soil,sandy loam andclay, the Michigan soil is used in this paper. Width to length ratio influence on driving perfo- rmance of tracked vehicles is researched.The track link relationship between the fixed coordinate system and the geodeticcoordinate system is defined and the track chain is divided into four segments: the upper freesegment, support segment in contact with the ground, segment in contact with the guidewheel, and segment in contact with the driving wheel. The mechanical analysis for the tracklink in each of the four segments is carried out. A mathematical model of the interactionbetween the rigid track ring and the soft ground is established. The location of each tracklink and forces on it are determined.For a heavy double track of dumping machine, steering performance is calculated. Thispaper analyzes the influence of steering radius, mass migration and Width to length ratio,crawler wide longer than the interior and the lateral, caterpillar gauge crawler drive, drivepower, steering torque friction and other factors for the performance，when the drivingwheels on the crawler speed is3.33r/min.A VP model of heavy tracks is constructed in Recurdyn--a large multi-body dynamicssimulation software. Different working conditions such as straight moving on plain, straightclimbing, and turning around on plain are simulated to get the results of reaction forces actedon driving wheels, thrust wheels, balance beam and tracks as well as the driving and tensionforce of the tracks. The results from simulation and those got from theoretical calculationreaches fine mutual verification.The real vehicle test of heavy tracks of a conveyer loader combines wired and unwiredtesting methods to make up the multi-parameter testing system which contains parameters ofelectric motor, torque, rotate speed and stress. Those two testing methods also help fix thelocation of test points and determine the calibration methods as well as testing conditions.The operation law of the heavy track under different working conditions is obtained throughthe test which is contrasted with results from theoretical calculation and VP simulation inorder to prove their correctness.The function principle when heavy tracked vehicle works on soft ground and itsstructural parameters’ influence on driving performance are researched in this paper. Testedby both virtual and physical tests, the results could provide basis when designing running gear of heavy tracked vehicles.