Design and performance optimization of the pneumatic precision peanut planter with combined positive-negative pressure

To address the issue of insufficient accuracy and stability in pneumatic peanut planters during high-speed operations (above 8 km/h), this study designs a peanut precision planter based on combined positive and negative pressure, and improves its performance via multi-dimensional optimization. The research uses Shandong “Silihong” peanuts as the study subject, determining their geometric characteristics and designing the core parameters of the seed-metering disc: diameter of 255 mm, 21 suction holes, and suction hole diameter of 6.2 mm. A comparative simulation using EDEM discrete element method between the arc-shaped and spoke-wing groove seed disturbance structures shows that the spoke-wing groove structure increases the average seed speed by 17.0%, significantly improving the seed filling effect. A coupled Fluent-EDEM gas-solid simulation confirmed the optimal negative pressure to be 6.0 kPa, achieving a single-seed adsorption rate of 98.6%. Orthogonal experiments were performed to optimize the operating parameters, and the optimal combination with corresponding sowing performance indices was obtained. Field tests indicated that the performance of the planter meets the national standards for precision sowing when the operating speed is ≤12 km/h.