UGV‐Based Precision Spraying System for Chemical Apple Blossom Thinning on Trellis Trained Canopies

作者：Xinyang Mu, Long He, Paul Heinemann, James R. Schupp, Manoj Karkee, Minghui Zhu · 发表于：Journal of Field Robotics · 年份：2024 · DOI：10.1002/rob.22435 · 被引用次数：2 · 研究领域：Plant Surface Properties and Treatments、Plant Pathogens and Fungal Diseases、Postharvest Quality and Shelf Life Management

ABSTRACT Blossom thinning is one of the key steps in apple crop load management that improves the quality of apples, reduces stress on the trees, and avoids the likelihood of biennial bearing. Conventional chemical blossom thinning such as air‐blast spraying can lead to excessive use of chemical thinner to ensure full coverage, which can also cause leaf damage fruit russeting. In addition, a well‐trained operator is required to use these chemical spraying systems. To address these challenges, a UGV‐based precision spraying system was developed for automated and targeted chemical blossom thinning for apples. The system is capable of automatically driving along the tree row in the orchard environment during blooming stage, locating apple flower clusters to be thinned using a real‐time machine vision system, and precisely spraying the chemical thinner to the targeted flower clusters. A set of field tests were conducted to evaluate the performance of the UGV‐based target spraying system by comparing it to a conventional air‐blast sprayer (ABS) and a previous prototype named the cartesian target sprayer (CTS). Tests showed that the flower cluster detection reached a precision of 93.8%. The UGV‐based spraying system used 2.2 L of chemical thinner to finish the chemical thinning for 30 apple trees, followed by the ABS and CTS with 4.2 and 2.4 L usage, respectively. The robotic system also obtained an average fruit set of 2.2 per cluster after thinning, which was comparable to that w...