Controlled multi motor crawler drive with adjustable steering radius on open pit mining machines

Bucket wheel excavators, spreaders, mobile crushers, movable belt conveyors and other machines on open pit mines are huge tracked vehicles with slow speed of movement. To be able to move on mine´s terrain, the machines are equipped with crawler mechanism for support and transport. Crawler chain serves for transformation of rotation of drive tumbler to linear movement of tracked vehicle. This transmission mechanism is with variable mechanical coupling, and usually consists of multi motor drive. In extreme operating regime, during steering along the curve, the load of the drive on the outer crawler significantly increases. This additional load originates from the additional friction forces between the crawler plates and the soil, turning torque of the inner and outer crawler and the torsion of the substructure of the mining machine. Among wide variety of multi-motor drives on open pit mine machines two-crawler travel drive can be found on almost any mining machine. This paper presents the analysis of controlled two-motor drive with independent speed control. The results obtained during commissioning of such drives confirm the results from the theoretical investigation.