Tree fruit harvesting: Recent developments and future challenges for robotic harvesting

Tree fruit harvesting is a vital process in agriculture, involving the collection of ripe fruits from trees. This review examines manual, mechanical and automated harvesting methods, focusing on their benefits, challenges and potential advancements. Manual methods, such as hand-picking and using ladders, are highly labour-intensive and time-consuming. To address these challenges, mechanical systems like trunk shakers, canopy shakers, limb shakers and catch-and-frame methods have been introduced. These systems use vibrations and capturing mechanisms to improve efficiency and reduce labour costs. However, mechanical methods are not commonly used for fresh fruit harvesting due to the risk of damaging soft fruits and trees. To solve this issue, precise shake-and-catch systems with controlled vibration frequency and amplitude are being developed, achieving fruit removal rates of up to 93.3 %. Harvesting speeds vary, with manual pickers managing 0.5 th-1, trunk shakers 10 th-1 and canopy shakers 25 th-1. Automated harvesting offers even greater efficiency by using robots equipped with advanced technologies, such as deep learning, image processing and specialized grippers, to detect and pick fruits. These systems can complete harvesting in just 4 seconds per fruit. This review highlights the strengths and weaknesses of current methods and explores strategies to enhance fruit harvesting technologies.