Effect of a traction-assist winch on wheel slippage and machine induced soil disturbance in flat terrain

Abstract

Recently, forest operations are facing unfavorable climatic conditions more frequently. In Central Europe, machine trafficability and induced soil disturbances are negatively affected by periods of high precipitation and less intensive frost during ground-based harvesting operations. Winch-assist technology is assumed to reduce soil disturbance by forest machines in steep terrain. Still, the potential positive effects of winches to assist traction of forest machines in flat terrain have rarely been surveyed. In this study, a field trial was conducted in flat terrain (slope < 5%). There, a forwarder with an integrated traction-assist was monitored during six consecutive machine passes on a permanent machine operating trail. The first section of the machine operating trail was passed without traction-assist, the remaining section with traction-assist, resulting in two treatment groups. To assess soil impacts, three test plots were positioned per treatment group. Within these plots, pre-and post-operational soil bulk density, soil displacement and rutting were determined. Additionally, wheel slippage and cable tensile force were examined, using incremental rotary encoders and a flexible tensile force measurement kit, respectively. It was observed, that wheel slippage responded inversely with tensile force. Traction-assist technology reduced wheel slippage from 5.3 ± 11.9% to 0.37 ± 10.19% along the section of the machine operating trail, as compared to results from the unassisted section. Although wheel slippage was significantly reduced, no mitigating effect by the usage of traction-assist technology on soil disturbance could be observed, probably due to the low volumetric water content of 27%.

Comparison of Selected Terramechanical Test Procedures and Cartographic Indices to Predict Rutting Caused by Machine Traffic during a Cut-to-Length Thinning Operation

“…Overall, only on 2 out of the 47 measuring transects, ruts deeper than 10 cm were observed. These results are in line with findings from other studies, reporting moderate rut depths between 3 cm [69], over 9-12 cm [8,63,70], and up to 20 cm [9,15,71], when measured on designated machine operating trails. In general, rutting that appeared within this study was in agreement with the recommendations of Owende et al [14], who proposed to limit rut depths to a maximum of 10 cm to ensure an eco-efficient wood harvesting in Europe.…”

Trafficability Prediction Using Depth-to-Water Maps: the Status of Application in Northern and Central European Forestry

“…Along with wider and optionally low inflatable tyres [29], numerous technological solutions aim to mitigate traffic-induced site impact. Hereby, a focus is set on increasing machine flotation, traction and contact area, as for example through bogie tracks [30], long-tracked bogie axles [31], triple-bogie axles [32], auxiliary axles [33], rubber-tracked bogie axles with support rollers [34], large radial tyres with alternative treads [35], the utilization of traction-assist winches [36], brush mats [37] and innovative steering concepts [38].…”

Performance Evaluation of a Height Adjustable Mini Combine Harvester

“…The ratio of the actual travel speed of a vehicle to the theoretical travel speed of its wheel is known as slippage or wheel slip (Schönauer et al, 2021).…”

“…Wheel slippage, which is caused by traction loss, substantially increases machineinduced soil impacts in the form of horizontal and vertical soil displacement (Schönauer et al, 2021). As a result, larger wheel slippage can affect the mobility and trafficability of agricultural machinery in paddy fields, especially in soft soil conditions.…”