A suction cup-based soft robotic gripper for cucumber harvesting: Design and validation

The study introduces a suction cup-based soft robotic gripper for cucumber harvesting that adjusts its shape and surface parameters to respond to the surface and shape characteristics of cucumbers. The gripper shape is optimised for adsorption to the large curvature of the cucumber, increasing the effective radius related to the grasping force. The suction cup surface is also modified to maintain adsorption on uneven cucumber surfaces. The test of the suction cup verifies the validity of these critical parameters and demonstrates that the proposed gripper produces robust adsorption, increasing the adsorption success rate and effective radius. The gripper integrated with the cutting module was verified at three sites with varying cucumber characteristics. The test of the end-effector was conducted 174 times, and the success rate was 86.2%, with a damage rate of 4.7%. The success rate was lowest at Site A (76.8%) and highest at Site C (95.2%), which is attributed to the thickness and length of the cucumber stem. The gripper function is independent of the cutting module, and its analysis motivates the future improvement of the cutting module. The proposed gripper can contribute to effective cucumber harvesting when employed with the improved cutting module.