2024 Volume 59 Issue 4 Pages 163-172
Previous studies have shown that the end effectors of tomato-harvesting robots equipped with fruit-grasping and pedicel-cutting mechanisms, have limitations because of increased multifunctionality and size, which restricts access to cluster-grown fruits and reduces harvesting performance. To address this issue, we developed a smaller end-effector that acts directly on the pedicel to detach the fruit from the abscission layer without gripping it. In this study, we aimed to enhance the harvesting performance of this new mechanism by introducing two support racks: a fruit cluster support rack to restrict the movement of fruit clusters and a main stem support rack to restrict plant movement. Harvesting examinations were conducted using the new end effector, with the robot approaching support racks each with 50 fruits. The results demonstrated that 45 fruits were harvested without damage using a two-string fruit cluster support rack; 42 fruits were harvested with a three-string main stem support rack; and 29 fruits were harvested without any support racks. Although the time required for vine lowering and cluster arrangement increased in comparison to the no- support rack plot, the total labor time was reduced over the course of the year compared to manual harvesting: 361.6 h/10a with the two-string fruit cluster support rack and 338.7 h/10a with the three-string main stem support rack. Notably, the fruit cluster support rack aligned the clusters towards the aisle, potentially enhancing the fruit and pedicel recognition capabilities, suggesting that this cultivation method is more suitable for robotic harvesting.
