American Society of Agricultural and Biological Engineers



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Overlap Loss of Manually and Automatically Guided Mowers

Published by the American Society of Agricultural and Biological Engineers, St. Joseph, Michigan www.asabe.org

Citation:  Applied Engineering in Agriculture. 28(1): 5-8. (doi: 10.13031/2013.41277) @2012
Authors:   T. J Shinners, M. F. Digman, J. C. Panuska
Keywords:   Overlap loss, Undercutting, Swath control, Mower conditioner, Precision agriculture, GNSS, GPS, GIS, Guidance, Automatic steering, Automatic guidance, Auto-guidance, Machine management.

Overlap loss in harvesting machinery has been observed as a necessary inefficiency for many years. Each time a non-row-crop machine makes a pass in the field it is favorable for the operator to overlap slightly into the previous pass, for instance where the crop has already been cut, as opposed to undercutting and leaving a strip of crop standing. In this study, overlap loss was explored through a controlled experiment as well as through on-farm survey. The experimental portion employed a factorial design to study the influence of two drivers and three cutting speeds (6.4, 9.7, and 12.9 km/h) of a self-propelled windrower. Driver experience and mowing speed were not found to have a significant effect on overlap. However, the interaction of inexperienced operators and higher mowing speeds increased overlap. The on-farm survey included three mower configurations: pull-type, self-propelled windrower, and mounted, as well as; cutting widths ranging from 4.01 to 9.60 m and a variety of field conditions on fifteen farms. Three of the mounted mowers and one self-propelled windrower utilized automatic guidance. Surveyed overlap ranged from 0.4 to 16.13% of machine cutting width. Average loss was 5% of cutting width. Automatic guidance has been purported to improve efficiency by eliminating time spent covering already mowed ground, reducing operator fatigue, and ensuring a uniform cutting pattern and swath density. The use of a GNSS-based guidance system to steer the mower was shown to reduce overlap loss from 5.03% to 2.34%.

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