Harvesting End-Effector to Minimize Length of Remaining Stem on Fruit by Stem-Cutting with Hook

This paper proposes a harvesting end-effector to minimize the length of the rested stem remaining on the fruit by stemcutting with a hook. The proposed end-effector draws the stem of the target fruit to the cutter with a hook mechanism and decreases the length of the rested stem that can cause damage to other fruits in the process of packaging and transportation. The hook mechanism is composed of two links and a cam moves the hook tip in an arc with one motor to hang the stem. When designing the end-effector prototype, it was sized by considering the range of hook motion and the condition of the harvest. The prototype of the end-effector was fabricated by 3-D printing and its performance was measured by a harvesting experiment using a tomato model and a real stem. In the experiment, the success rate of the harvest and the minimization of the rested stem were measured. Finally, it was verified that the proposed end-effector could increase crop yield and efficiency of the harvest by harvesting the fruit successfully and minimizing the rested stem after harvest.