Development and Laboratory Assessment of Cutting and Snapping Mechanisms for Green Asparagus Harvesting

<b><sc>Abstract.</sc></b> Green asparagus (Asparagus officinalis L.) is a labor-intensive crop requiring frequent selective harvesting. Due to the lack of appropriate automated harvesting machines, this vegetable is still majorly harvested manually, which entails high labor costs, threatening the sustainability of asparagus production in the United States (U.S.). The clustered growth, random maturity pattern, and fragility of asparagus spears present key challenges to harvesting automation. The present study aimed to develop and preliminarily evaluate two pneumatic rotary actuator-based mechanisms using snapping and cutting approaches for selective harvesting of green asparagus. Laboratory tests were conducted using field-harvested spears to assess success rate, throughput, snapping ratio, and snapping angle. The cutting mechanism achieved a 100% success rate with a throughput of 3.2 spears/s, while the snapping mechanism achieved an 87.2% success rate and a throughput of 3.3 spears/s. Analysis showed that most spears had a snapping ratio between 0.18 and 0.29, retaining approximately 70% of spear length. The results demonstrate the technical feasibility of both harvesting approaches, with the cutting mechanism offering better efficacy. Future work will focus on integrating a vision-based spear perception system, a spear collection system, and validating developed mechanisms under field conditions with the ultimate aim to develop an asparagus harvester capable of efficient selective harvesting.