Design and Experimental Study of Intermittent Automatic Grouping Dropping Plug Seedling Mechanism of Fixed Seedling Cups

Abstract

In a vegetable transplanting operation, if the seedling picking mechanism extracts the whole row of seedlings, the seedling separating mechanism needs to place the seedlings in groups. In this study, a seedling separating mechanism based on a fixed seedling cup was proposed to realize faster seedling grouping in a smaller volume. A collision model between the pot and the wall of the seedling dropping cylinder during the seedling dropping process was established. The duration of seedling dropping at different positions was analyzed. Subsequently, the calculation equations between the installation angle and the cam rotation speed and the dropping duration were derived. The net dropping duration of seedlings at different positions was measured. According to the measurement results, the installation angles of the driving cam at each position were calculated as 0°, 72°, 150°, 216°, and 288°, respectively. The seedling uniformity test was conducted according to the optimized installation angles. The test results revealed that the success rate of dropping seedlings was 100%, the coefficient of variation in dropping seedling interval at different positions was 6.25%, and the matrix damage rate was less than 10%, which verified the reliability of the dropping seedling principle. Finally, the stability tests results showed that the mechanism was able to complete the uniform seedling drop operation at a seeding frequency of 75~108 plants/(min · row) under the existing installation conditions. Therefore, the research results can provide a reference for the design and research of a subsequent traction-based automatic pot seedling transplanting machine.