Design and testing of a lotus root harvester with a collection device

Lotus root harvesting faces significant challenges due to its submerged growth in muddy environments, including high labor intensity (currently 100 % manual collection), 30–40 % rot losses from untimely harvesting, and the inefficiency of existing equipment that lacks integrated collection and balance control. To address these limitations, this study develops an integrated harvester incorporating three key innovations: (1) a rotating grab–conveyor collection system that eliminates manual retrieval; (2) rotating grab nozzles with phased oscillation for continuous, gap-free scouring; and (3) a closed-loop automatic balancing system employing sliding counterweight. Using coupled computational fluid dynamics–discrete element method (CFD–EDEM) simulations, hydraulic parameters were optimized (nozzle diameter: 12.01 mm; flushing angle: 46.59°; clearance: 50.25 mm), achieving a simulated soil fragmentation rate of 29.02 % (simulation error: 0.8 %). Bench tests confirmed a fragmentation rate of 28.90 % (deviation: 0.41 % from simulation) and demonstrated a 60 % reduction in labor intensity. This work establishes the first harvesting–integrated–collection prototype with real-time balance control, offering a mechanized solution for sustainable aquatic crop production.