Design and Evaluation of a Lightweight Soft Electrical Apple Harvesting Gripper

Abstract

To address apple harvesting labor shortages in Washington State, we are developing an innovative soft growing manipulator that aims to overcome the current limitations associated with conventional robotic solutions, specifically in terms of cost-effectiveness and efficiency. A critical aspect of this technology is the creation of a lightweight apple harvesting end-effector, weighing less than 0.8 kg, to account for the stringent payload restrictions of our custom soft growing manipulator. This paper presents the design of a lightweight cable-driven soft gripper, offers insights into its force characteristics, and provides a case study showcasing its effectiveness in a commercial orchard setting. The gripper's weight is 0.306 kg, and it boasts a successful detachment rate of 87.5% without damaging the fruit. In the future, our work will extend to further enhance the soft gripper by incorporating a twisting motion. It will also be seamlessly integrated with the soft growing manipulator and custom machine vision system, which will subsequently undergo evaluation in a commercial orchard.