Mushroom Picking Strategy for a Robotic Harvester: Evaluating Force and Decision-Making
Research Poster Engineering 2025 Graduate ExhibitionPresentation by Sadjad Mahnan
Exhibition Number 209
Abstract
Button mushrooms (Agaricus bisporus) are hand-harvested globally to preserve their delicate skins for the fresh market. The U.S. mushroom industry, a major global player, faces challenges like high production costs and labor shortages due to the labor-intensive process of mushroom harvesting. Consequently, robotic harvesting solutions are becoming increasingly important in the field. The differing growth rates of mushrooms and their close clustering complicate decisions regarding picking strategies and the effective application of the necessary forces for harvesting mature mushrooms. This study aims to dynamically evaluate the developed decision-making strategy for a mushroom-picking robot. Initially, the YOLOv5s model was used to locate mushrooms. The maturity and clustering of the mushrooms were assessed using a pixel-based threshold and the DBSCAN clustering algorithm. Following this, the spatial configurations of the mushrooms were mapped, a picking sequence was established, bending directions were determined, and mushrooms were harvested with a sensory glove. Results indicated a 97% mAP for YOLOv5s, R2 of 97% for maturity, 0.22±0.14 weighted silhouette coefficient for clustering performance, and successful spatial arrangements across different clustering conditions. Importantly, every mushroom in the model evaluation images was correctly assigned a picking sequence and orientation. Moreover, findings revealed that denser mushroom clusters required greater force, highlighting a negative relationship between the sizes of mushroom caps and the picking force necessary. Additionally, force is positively influenced by the pose of targeted mushrooms and the number of nearby mushrooms. This picking strategy has the potential for integration into robotic harvesting systems, bringing us closer to full automation.
Importance
The United States, a leading mushroom producer, experienced a 31% decline in production from 2014 to 2024. Also, the number of growers decreased by 20% between 2008 and 2018. The primary reason is that mushrooms are predominantly harvested manually to preserve their delicate skin to maintain quality, appearance, and shelf-life. Additionally, the selective harvesting of mature mushrooms makes the process more labor-intensive and costly. However, labor shortages have become a growing challenge in agriculture. According to the USDA’s Economic Research Service, finding workers has become increasingly difficult. Like other agricultural sectors, the mushroom industry is struggling with labor shortages that threaten sustainable production. In response, researchers have been exploring the feasibility of robotic automation solutions to address this issue.