Development and tests of a transplanting machine in plant factory

Abstract.

During the production process of leaf vegetables in plant factory, seedlings germinated in mats (sponge-like foamed urethane mats consisting of many cubes) are conventionally needed to be transplanted to plant culture panels. However, this procedure is still done manually in China. As the plant factory is widely developed, automatic transplanting technologies are badly needed to change this situation. To achieve this project, an automatic transplanter for seedlings was designed. Firstly, a row of u-shaped sticks was inserted into slits of mats to avoid the translocation of adjacent cubes. Then grippers moved into the slits of the mat and grasped every cube in the first line. After that, grippers were separated by distance of 235 mm to separate cubes. Subsequently, grippers transplanted seedlings to the destination square holes in culture panels and complete the transplantation process. Testing results from the constructed prototype of the transplanter demonstrated that when separation speed was 460 mm/s, air gripper pressure was 0.6 Mpa and penetration depth of pins was 15 mm, the prototype could transplant seedlings at an 88% success rate using 10-day-old lettuce. The performance of transplanting was satisfactory.