Development of a Pincette-Type Pick-Up Device for Automatic Transplanting of Greenhouse Seedlings

摘要

<abstract><title>Abstract.</title> A new pincette-type pick-up device for automatic transplanting of seedlings in greenhouse was developed and evaluated in a laboratory. The pick-up device is a gantry-structure robotic mechanism consisting of a manipulator, an end-effector and two conveyors. The manipulator consists of a motor, a linear module and a rodless cylinder, which moves the end-effector to the desired working position. The end-effector, which extracts seedlings from a breeding tray, is a pincette-type mechanism using two cylinder fingers and four pins. The conveyors are designed to move the plug tray/pot to the end-effector’s working space. Being the first prototype, its optimal machine parameters and performance were examined under various conditions. In the optimum tests, it was found that the root lump moisture content exerted the greatest effect on the success ratio in picking up seedlings, followed by other influential factors such as the penetration angle, the seedling age, the extraction speed, and the grasping force of the root lump with the least being the penetration depth. For cauliflower seedlings, when the seedling age was 30 days, the root lump moisture content was 55% to 60%, the penetration angle was 8°, the penetration depth was 35 mm, the grasping force of the root lump was 4 N, and the extraction speed was 600 mm/s, the best success ratio was achieved. To verify the optimal machine parameters, the performance tests were further conducted. For the four locally produced vegetable seedlings, when the transplanting rate was 22 seedlings/min, the average success ratio in picking up seedlings was 90.14%. The performance of transplanting was satisfactory.