Development of a corn stover yield monitor
This research developed a sensor to measure the mass flow of corn stover through a combine and determine what harvest parameters affected the response of the sensor. A sensor was developed by installing a curved plate behind the rotor discharge beater of the combine to intersect the flow path of the stover leaving the rotor discharge beater. The plate was instrumented with load cells to measure the impact force of the corn stover on the impact plate. Instrumentation methods for the impact plate were evaluated to determine the most effective method to instrument the impact plate to measure the impact force of the stover.
Field testing was conducted to examine the effects of stover mass flow rate, stover moisture, and plant cut height on the sensor response. Single parameter regression models were created using the horizontal and magnitude force components of the load cells to predict mass flow through the combine. The horizontal and magnitude force prediction models had adjusted R2 values of 0.324 and 0.599 respectively. Including the stover moisture to the prediction models using horizontal force and magnitude force increased the correlation of the adjusted R of the prediction models to 0.709 and 0.785 respectively. A multi parameter regression model containing the magnitude of the load cells forces, stover moisture, chopper speed, and interactions between stover moisture and chopper speed and chopper speed and the magnitude of forces produced the best correlation (adjusted R2=0.909). The results of this research suggest that this type of sensor is effective at predicting the mass flow rate of stover through a combine.