Electronic design of a cotton harvester yield monitor calibration system

Authors: Pelletier, Mathew; Wanjura, John; Holt, Gregory

Submitted to: AgriEngineering
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/18/2019
Publication Date: 10/22/2019
Citation: Pelletier, M.G., Wanjura, J.D., Holt, G.A. 2019. Electronic design of a cotton harvester yield monitor calibration system. AgriEngineering. 1:523–538. https://doi.org/10.3390/agriengineering1040038.
DOI: https://doi.org/10.3390/agriengineering1040038

Interpretive Summary: This article talks about a new calibration system developed for crop yield monitors. Crop yield monitors measure total volume of cotton at specific locations within the field. Several yield monitors are available for use on cotton harvesters, but none are able to maintain yield measurement accuracy when the cotton variety changes. This leads to large errors in small test plantings that cotton breeders rely upon to improve the next generation of cotton plants. This research solved this problem by developing a system that can be retro-fitted onto existing harvesters to calibrate their yield monitor automatically while they are in the field harvesting or performing tests. This article details the electronic design of the automatic weighing system. This report is one of three articles that are in support of a master research paper covering the development and overall design of the calibration system. Included with this article are all of the design manufacturing files that are being released into the public domain for the purpose of transferring the technology to the research community and general public.

Technical Abstract: Several yield monitors are available for use on cotton harvesters, but none are able to maintain yield measurement accuracy across cultivars and field conditions that vary spatially and/or temporally. Thus, the utility of yield monitors as tools for on-farm research is limited unless steps are taken to calibrate the systems as cultivars and conditions change. This technical note details the electronic system design portion of a harvester-based yield monitor calibration system for basket-type cotton strippers. The system was based upon the use of pressure sensors to measure the weight of the basket by monitoring the static pressure in the hydraulic lift cylinder circuit. To ensure accurate weighing, the system automatically lifted the basket to a target lift height, allowed basket time to settle, then weighed the contents of the basket. The software running the system was split into two parts that were run on an embedded low-level micro-controller, and a mobile computer located in the harvester cab. The system was field tested under commercial conditions and found to measure basket load weights within 2.5% of the reference scale. As such the system was proven to be capable of providing an on-board auto-correction to a yield monitor for use in multi-variety field trials.