Theoretical kinematic analysis of a wheel-driven hopper planting mechanism for vegetable transplanters

Vegetable production plays a vital role in the global agricultural economy, and seedling transplanters significantly enhance timely large-scale production, planting efficiency, and the overall mechanization rate.Due to the limited availability of transplanting machinery, manual transplanting remains the predominant method; however, it is time-consuming, inconsistent, and inefficient.This study presents a theoretical analysis of a customized wheel-driven hopper-type planting mechanism for a vegetable transplanter, focusing on the dimensional design of key components and kinematic parameters, including velocity, acceleration, hopper trajectory, and forward speed required for the smooth placement and deposition of vegetable seedlings.A 3D model of the planting device was designed, and a mathematical model was developed for simulation.The wheel-driven planting mechanism consisted of a wheel, wheel support, roller, roller guide, hopper opener, and hopper.To ensure the synchronization of the vertical and horizontal movements of the hopper, and to achieve consistent and safe deposition of seedlings into the soil, the optimal dimensions of the planting unit were determined as follows: a wheel diameter of 250 mm, a wheel thickness of 6 mm, a hopper opener length of 36 mm, and a hopper height of 80 mm.These dimensions collectively generated an optimal planting trajectory along a circular path measuring 249.9 mm in both the vertical and horizontal directions.An optimal forward speed of 150 mms -1 was identified to ensure smooth and upright planting of vegetable seedlings, resulting in a soil contact angle close to 90, with the planting hopper exhibiting a peak velocity of 131 mms -1 and a peak acceleration of 137 mms -2 along both the X-and Y-axes.The findings of this study would offer theoretical background to enhance the design of vegetable transplanting mechanisms.