Design and Experiment of the Follow-Up Seedling Picking and Depositing Mechanism for the Pepper Plug Seedling Transplanter

To address the challenge of improving the accuracy and efficiency of automatic transplanting operations in pepper plug seedling transplanters, this study innovatively designed a follow-up seedling picking and depositing mechanism. The core innovation lies in the synchronization of the seedling picking claws with the moving seedling cups, which was achieved by coordinating the motion speeds of the seedling picking and depositing mechanism with the seedling conveying mechanism. This synchronization ensured relative spatial stillness during seedling deposition, significantly enhancing seedling depositing accuracy. To meet the design requirements of this follow-up mechanism, this study presents a comprehensive design of the transplanter, including a three-dimensional model. Key mechanisms, namely the seedling picking and depositing mechanism and the seedling conveying mechanism, were thoroughly analyzed, with detailed explanations of their working principles. The transmission system was designed for reliability and stability, being towed by a tractor with the ground wheel driving the motion of the seedling conveying and distributing mechanisms. The motion mode of the seedling picking and depositing mechanism combined a crank–rocker mechanism and a crank–slider mechanism, utilizing a gear transmission rod for seedling picking and carrying actions, and rail guidance for follow-up seedling depositing. Experimental results validated the effectiveness of this design. In bench tests, the success rates of the seedling picking and depositing mechanism at operating speeds of 100 seedlings/min, 150 seedlings/min, and 200 seedlings/min were 97.4%, 98.44%, and 95.03%, respectively. In field tests, at operating speeds of 90 seedlings/min, 120 seedlings/min, and 150 seedlings/min, the planting success rates were 99.65%, 94.95%, and 89.18%, respectively. These results demonstrated that the follow-up seedling picking and depositing mechanism met the demands of automatic transplanting operations, offering an effective solution to enhance both the operating speed and quality of the transplanter.