Performance of a Grain Yield Monitor: Varying Flow Rate and Ground Slope Using a Test Stand

Abstract

The main objectives of this study were to measure the performance and accuracy of the Fieldstar® grain yield monitoring system under transient and stepwise grain (corn) flow on a flat surface and also to study the effect of slope on the accuracy of the yield monitor. The mobile grain yield monitoring simulator developed in the Department of Food, Agricultural, and Biological Engineering at The Ohio State University and the ASAE Yield Monitor Test Standard (X578) procedure were used in this study. Three dynamic flow rates; two transient and a step flow, were tested. Also, the effect of slope on the accuracy of the yield monitor was simulated and measured by inclining the clean grain elevator in two planes, sideways and back-forth. During the stepwise flow change test, the flow rate sensed by the yield monitor did not follow the actual step flow changes as quickly and accurately as the reference scale, especially when the flow was changed to a lower flow level. The flow rate sensed by the yield monitor was 15% and 30% higher than the reference scale (actual) flow levels when the flow was abruptly lowered to 75% and 50% of the initial flow, respectively. However, the error in total accumulated mass sensed by theyield monitor during one complete cycle was only 2.31%. The average difference between the instantaneous mass flow sensed by the yield monitor and the reference scale during three oscillating cycles was 11.45%, but the error in total accumulated mass sensed by the yield monitor for the same period was only 4.26%. The simulated effect of the slope indicated that slope could have a significant effect on the accuracy of the yield monitor; however, the yield monitor can perform reasonably well if it is calibrated for a given slope.