Performance Evaluation of a Chopper System for Sugarcane Harvester

Abstract

Improving sugarcane chopper harvesters in terms of chopping quality is essential to reduce harvesting loss and costs. In this study, a chopper system used in a sugarcane harvester was developed and utilized to evaluate the effect of rotational speed of chopping drums (X1), overlapping length of upper and lower chopping blades (X2) and bevel angle (X3) on chopping quality and power requirement. Box-Behnken design combining with response surface method was employed to obtain the optimal operating parameters. The significance of independent variables and their interactions were tested by analysis of variance with 95% confidence limit (α = 0.05). The optimal values of the selected variables were obtained by solving the regression models, as well as by analyzing the response surface contour plots. The optimal values of three test variables were computed as X2 of 2 mm and X3 of 21.8°. Based on these conditions, when X1 increased from 200 to 250 rpm, the percentage of undamaged billets decreased from 97.0 to 95.6%, the average maximum chopping power requirements increased from 515 to 625 W, and the standard deviation of chopping length increased from 1.24 to 1.36 mm. Verification experiments indicated that the observed values were in agreement with the predicted values. A high-speed camera system was then applied to capture the stalk trajectory during chopping process. Results suggested that maintaining a stable and low conveying speed of sugarcanes during mechanical harvesting could reduce stalk damage and juice loss, which contributed to high chopping quality.