Investigation of the Trajectory of Expelled Billets from the Chopping Rollers of a Sugarcane Harvester

The ability to efficiently remove impurities from harvested sugarcane billets is one of the key performance indicators of sugarcane chopper harvester. The state of motion and spatial distribution of billets thrown into the extractor fan by chopping rollers affect the process of impurity removal. However, little effort has been directed to the research of the trajectory of billets expelled by chopping rollers. Focusing on this problem, the trajectory of billets expelled by chopping rollers was studied by first theoretical analysis, followed by constructing a test bench and investigation by high-speed photography. In this paper, a test bench based on the dimensions and components of the 4GDLS-132A sugarcane combine chopper harvester was developed, encompassing the various stages of the harvesting process, including stalk conveying, chopping, impurity removal and billet expulsion. Based on projectile theory, kinematic models of billets during the throwing process were established with and without the aid of guiding channels. Following this, the relationship of the upper throwing angle and the resulting declination was obtained, and a guiding channel was designed between the chopper and extractor fan. High-speed photography was utilized to analyze and track the trajectory of expelled billets from the chopper under experimental investigation. The spatial trajectory of the billet was obtained, thereby verifying the existence of different upward throwing trajectories in three different regions during the throwing process of billets. Comparing and analyzing the trajectory at different throwing angles, it was concluded that the billet trajectory was ideal when the rotational speed of the chopper was 470 rpm and the throwing angle was 34°. Under these conditions, the angle adjusting plate of the guiding channel has a better inclination angle of 30°. The research results in this paper can provide a basis for determining the ideal relative positions of the chopper and extractor fan when designing a sugarcane harvester and also provide a reference for studying the expulsion trajectory of stalk crop segments.