Abstract:Aiming at the problems of low efficieney and high damage rate of manual seedling placement in the seedling feeding link of the existing finger-clamped sweet potato transplanter, a split-type seedling clamping device that can automatically open and close was designed based on the 2ZQX -1 clamp-type bare-root sweet potato transplanter. On the basis of expounding the overall structure and working principle, the rubber clip parameters were optimized through theoretical analysis to reduce seedling damage. The motion equation of the rubber elip was established via kinematic analysis, and the mechanism parameters were determined along with the optimal contour line of the are-shaped plate. The single-factor test results indicated that the conveying speed range was 30 ~ 70 mm/s. Taking seedling clip displacement, rubber clip inclination angle and conveying speed as influencing factors, and clamping qualification rate as the evaluation index, bench tests were conducted by using the Box - Behnken central composite design method. Variance analysis was performed on the test results, and response surface analysis was applied to explore the influence rules of interactive factors on the test index, thereby determining the optimal values of the factors. The results showed that when the seedling clip displacement was 12.6 mm, the inclination angle was 16. 9°, and the conveying speed was 49.5 mm/s, the clamping qualification rate reached 95.3%, achieving the optimal seedling feeding effect. Subsequently, full factor field experiments were carried out with different seedling feeding modes ( split-type/integratedtype) as the categorical factor and conveying speed as the numerical factor. The results demonstrated that the split-type seedling clamping device could adapt to a conveying speed of 44.0 mm/s, with the clamping qualification rate remaining at 97.0% and the damage rate at 3.9%, increasing the overall operating efficiency by 31% compared with the integrated seedling clip. This device featured high operating speed and stability, which can provide a technical solution for the efficient operation of mechanized sweet potato transplanting.
