Design Optimization and Experimental Evaluation of a Reciprocating Sweeping Spreading Disc for Agricultural UAVs

To address unclear particle ejection behavior and poor spreading uniformity in reciprocating sweeping spreaders for agricultural UAVs, this study analyzed particle motion and optimized the key structural parameters of the sweeping disc. The particle–vane contact process was first analyzed to determine the forces acting on the particles and the evolution of particle velocity during contact, thereby clarifying the effects of vane structural parameters on particle ejection. Single-factor simulations based on the discrete element method (DEM) were then conducted to identify the vane groups and structural parameters that strongly affected particle deposition. Results indicated that vane groups 1 and 2 significantly affected lateral deposition distribution. Their width, spacing, and tilt angle were therefore selected as six factors for the subsequent response surface optimization. To overcome the limitations of the CV in capturing local peak variations, three supplementary evaluation parameters were introduced: peak consistency (PC), relative peak intensity (IP), and central filling ratio (RC), with PC and IP set as multi-objective optimization targets. After parameter optimization, insufficient deposition remained in the central region of the single-layer disc. A dual-layer vane structure with coordinated inner and outer vanes was therefore developed to further improve the particle deposition distribution. Field tests were conducted using an XAG P150 Agricultural UAV. The relative errors between the measured and simulated values of PC, IP, and RC were 3.15%, 6.08%, and 8.51%, respectively, while the CV decreased from 29.75% to 19.02%. These results can support the structural optimization of reciprocating sweeping spreading devices for agricultural UAVs and the improvement of spreading uniformity.