Optimization of a Screw Conveying Seed-Metering Device for Pregerminated Rice Seeds Based on a Bonded Discrete Element Model

Abstract

To address the problems of seed damage and poor seeding uniformity in UAV-based direct rice seeding, this study investigated the optimization of a screw conveying seed-metering device for pregerminated rice seeds. A discrete element model based on the bonded particle model (BPM) was established according to the morphological and mechanical characteristics of pregerminated rice seeds. The effects of screw diameter and pitch on seed conveying behavior and metering performance were analyzed through single-factor experiments and multi-factor response surface analysis. The results showed that screw structural parameters significantly affected seed motion, stress distribution, and seeding uniformity. A reasonable gradient screw structure reduced stress concentration during conveying and improved the stability and uniformity of seed metering. This study provides theoretical support for the design and optimization of low-damage precision seed-metering equipment for UAV-based direct rice seeding.