Authors: Kenneth Smith, Douglas Cook, Carter Noh, Kirsten Steele, Jordan Porter
Mentors: Douglas Cook
Insitution: Brigham Young University
Farmers, breeders, and researchers are working to understand how various mechanical and biological factors affect crop strength and resistance to late-season lodging (breaking of stalks before harvest). Stalk flexural stiffness has been shown to be an accurate predictor of stalk strength. Stiffness measurements are currently collected with a manually-operated device called the DARLING (Device for Assessing Resistance to Lodging IN Grains). This device can take one worker more than an hour to test 120 stalks and is not feasible for use on millions of acres of corn. The purpose of this research project is to develop a method for automating flexural stiffness measurements of maize stalks.
We have developed a novel sensor, the “Flipper”, that is attached to a robot and will enable continuous measurement of flexural stiffness of each stalk in a field more quickly than current methods. Our talk will cover the operating principles behind this novel sensor as well as our work on calibration and validation of the sensor.
The Flipper uses two sets of strain gauges arranged in a Wheatstone bridge configuration on a thin, aluminum bar. As various corn stalks brush along the bar, the pairs of gauges work together to measure both the force that each stalk exerts on the bar and the position at which the force is exerted. This method has been tested repeatedly on artificial stalks in both a static and dynamic environment. A calibration dataset was taken by clamping the flipper to a workbench and using various masses placed at varying distances to exert several different moments on the Flipper, which were measured by the strain gauges. The known forces and distances were used to calculate calibration constants that could be used to accurately predict the rest of the forces and distances in the dataset. The same calibration constants could then be used to validate the model in a dynamic situation where the Flipper is attached to a robot that is used in farming applications and driven along a row of artificial corn stalks. We hope that the Flipper has a future of furthering the agricultural industry across the country.