Experimental study on the sugarcane stubble base-cutting mechanism

Abstract

Base-cutting is essential in sugarcane harvesting, and violent collisions between the base-cutter and stalk can cause stubble damage. Therefore, it is necessary to study the base-cutting mechanism to reduce stubble damage. Based on the mechanical analysis method, this study analysed the base-cutting process of sugarcane vascular bundles and stems from fibber and macro perspectives, respectively. In addition, the base-cutting process was simulated based on Discrete Element Method, and field experiments were conducted to validate the analysis results. The tensile length function L (z) of the vascular bundle was derived from a fibber perspective. A mechanical model of the cutting force on the entire stem was obtained from a macro perspective. From the equations, it can be found that the kinematic parameters of the base-cutter have a significant influence on the cutting force. The simulation test revealed that the cutting force increased sharply when the blade was cut into stems, and the maximum cutting force reached 146.9N. Field tests were conducted to explore the relationship between these factors and the stubble damage rate. To decrease the damage rate to a smaller level, the single-factor test results showed that the forward speed of harvester, rotational speed of disc, and cutting depth should be controlled in the range of 0.8–1.4 m s⁻¹, 600–1000 r·min⁻¹, and 60–120 mm, respectively. The response surface test showed that the order of the effect of each factor on stubble damage was forward speed > rotational speed > cutting depth. The lowest stubble damage rate was 6.20% when the forward speed, rotational speed of disc, and cutting depth were 1.4 m s⁻¹, 800 r·min⁻¹, and 79.07 mm, respectively. After experimental field verification, the damage rate met the harvesting standard.