Development and evaluation of a soft end effector for kiwifruit harvesting

Abstract

ABSTRACT With the continuous expansion of the kiwifruit industry and the decrease in workforce due to the COVID‐19 pandemic, the development of autonomous harvesting robots is of significant importance. Current harvesting robots' end‐effectors face challenges such as lack of flexibility and the potential to damage fruits. This study proposes a soft picking end‐effector that effectively addresses these issues. The soft fingers achieve clamping of the kiwifruit by bending through inflation. Comprehensive assessments of its compliance and fingertip force have been conducted through finite element analysis and experiments. In a free state, applying 90 KPa of air pressure can enable the fingers to achieve bending of over 110° Under a pulling picking method, applying an air pressure of 115 KPa can provide a fruit gripping force of 3.5N, sufficient to separate the fruit from the stem. Experiments in field conditions have shown that the average picking time per kiwifruit is 6.7s, with fruit detachment rate, harvesting rate, and damage rate at 90.90%, 86.36% and 5.00%, respectively, and the fruit gripping damage rate is 0%. The kiwifruit soft‐bodied end‐effector proposed in this study provides a reference for the entire non‐destructive harvesting process of kiwifruit.