Development of a Harvesting End-Effector for Eggplants.

Abstract

A robotic harvesting system, which emulates the fruit recognition, approach, and picking tasks, has been developed for the purpose of automatic harvesting for eggplants (Solanum melongena L.). In this study the harvesting end-effectors for eggplants (prototype-1 and prototype-2) were fabricated. The end-effectors were composed of a fruit-size-judging mechanism, a fruit-grasping mechanism, and a peduncle-cutting mechanism to pick the fruit selectively on the basis of fruit length after the manipulator end closely approaches. An experimental result on picking posture using prototype-1 proved that lifting the fruit at an angle of approximately 30° was effective for separating the fruit from leaves. A basic harvesting experiment using prototype-2, which was improved on the fruit-size-judging and fruit-grasping mechanism, was also conducted. It was found that the success rate of harvesting was 62. 5% and the harvesting time per fruit was about 64 seconds. The main cause of unsuccessful harvesting was that the accuracy of detection of the fruit base was not sufficient. This study showed the great feasibility of automating the basic harvesting motion for eggplants.