Reciprocating Mechanism for Whole Row Automatic Seedling Picking and Dropping on a Transplanter

Abstract

The pick-up device is the key to develop automatic transplanting, thus a whole row pneumatic seedling pick-up device was developed with reciprocating movement. In order to develop low-damage and high-efficiency seedling picking, six or eight end-effectors were installed in the pick-up device. We planned the required picking-trajectory by polynomial fit, then the consistency of the simulated trajectory and theoretical trajectory were verified. The air cylinder and photoelectric sensor were used to control the reciprocating motion of the end-effector, and the coordinated control scheme of seedling transporting, picking and dropping were designed in detail, then a control program was compiled. The experiment results showed that when the cylinder stroke was 40 mm and the seedling pushing speed was 0.54 m/s, the optimal seedling pushing time should be 0.074 s. The seedling dropping accuracy tests of the cylinder indicated that the average minimum value of ΔS was 0.25 mm when the frequency of seedling picking was 18 plants/claw/min. To ensure the work efficiency and the success ratio of seedling picking, the working parameters were selected as seedling picking frequency at 18 plants/claw/min, water content at 60%, depth at 40 mm and angle at 10°, and the finally success ratio of seedling picking was 98.08%. This indicated that the designed pick-up device could meet the requirements of seedling picking and dropping reciprocating movement under the operation of the optimized control system, which is of a great significance to the development of automatic transplanter technology.