Development of a Compact Hybrid Gripper for Automated Harvesting of White Button Mushroom

Abstract Automated harvesting of white button mushroom (Agaricus bisporus) has gained global popularity in recent times aiming to enhance harvesting efficiency while reducing the reliance on human labors. Mushrooms are typically growing on multi-layer Dutch shelves with limited space between every two layers. This requires mushroom grippers to be compact and work in a narrow space. End effectors used in automated harvesting have mostly been pressure suction cups or finger-like soft grippers. The reported grippers are oversized, bulky, and slow, making them unsuitable for commercial harvesting where mushrooms grow on narrow shelves. Furthermore, there has been noticeable absence of analysis on the gripper tailored specifically for cluster mushroom harvesting. The gripper development is a critical step towards fully automated mushroom harvesting. This paper reports the development of a compact hybrid gripper and the harvesting performance on single mushrooms as well as clustered mushrooms. The effect of gripping force on different sizes of mushroom has been analyzed. The safe picking force was found to be 5N for single grown mushroom. For both single and clustered mushrooms, the success rate of picking was 100% with average picking times of 3s and 5.5s, respectively. However, picking clustered mushroom was associated with a high damage rate, which calls for further enhancement.