Intelligent system for automatic selection of front loader operating modes depending on material characteristics

Abstract

Power train tuning of a front loader operating at a site with several stockpiles remains manual, so the same machine handles sand and blasted rock with identical feed and traction settings. Current standards describe the outcome of the digging phase geometrically: bucket capacity is computed under GOST 29290-92 from the struck volume plus the material above the cutting edges at a 2:1 slope, rated operating load follows GOST ISO 14397-1-2015, and the bucket fill factor is not covered by either document. The purpose of the study was to construct and compute a model of a system that recognises the material class from force and kinematic signals of the initial penetration phase and assigns the power train mode without operator involvement. The computation rests on the author's model of the digging process for a modelled 5 t class loader with a 3.0 м³ bucket; the numerical experiment covered a series of 1,240 cycles. Materials are grouped into five classes by the author's digging difficulty index ranging from 1,00 to 2,35. The limiting penetration depth under the traction condition falls from 1,35 to 0,88 m and the fill factor from 1,06 to 0,76, while the mass carried in the bucket varies by only 8,7% between dry sand and coarse crushed stone. The material class is recognised from four features of a 0,4 s window with a correct assignment share of 0,914, the heaviest confusion falling on the pair of adjacent granulometric classes. Adaptive mode assignment raises operational output by 1,4-10,7% and lowers specific fuel consumption by 12,9-17,4% depending on the class. The gain grows with digging difficulty and splits unevenly between output and fuel economy: on cohesive soil the output gain peaks while the specific consumption gain is smallest. This relation shows that the bucket fill factor behaves as a controlled variable rather than a reference constant of the machine and belongs in the control loop alongside pressure and engine speed.