Fiber Optic Yield Monitor for a Sugarcane Harvester

Abstract

A fiber optic yield monitoring system was developed for a sugarcane chopper harvester that utilized a duty-cycle type approach with three fiber optic sensors mounted in the elevator floor to estimate sugarcane yield. Field testing of the monitor demonstrated that there was a zero intercept linear relationship between the optical sensor response and the actual sugarcane yields with an R2 value of 0.98. The average observed prediction error on 0.5 to 1.6 Mg estimates was 7.5%; however, the magnitude of the error decreased as the harvested area (tonnage) increased, with an estimated error of 0.03% for 57.8 Mg loads. Factor testing indicated that the duty cycle reading was not affected by sugarcane variety, harvester speed, harvested distance, or direction of cut (lay of the sugarcane). Field testing across several locations in the U.S. totaled more than 557 h of operation and indicated that the system was robust, maintenance free, and self-cleaning, but some obstruction of the fiber optic sensors did occur in wet, muddy soils. These obstructions were minimized by relocating the fiber optics closer to the bottom of the elevator and leaving holes on each side of the sensors to enhance cleaning and scouring. This monitoring system compares well with all previously tested methods and is very durable and easy to install.