Researchers at West Virginia University have developed a soft robotic gripper designed to harvest delicate fruits such as strawberries and avocados while assessing their ripeness and reducing damage during handling. The five-fingered gripper is constructed from silicone and polyurethane and incorporates tactile and visual sensing capabilities. According to the researchers, the system can evaluate fruit size, curvature, color and ripeness while handling produce gently enough to avoid bruising. Its sensors allow it to determine when fruit is ready for harvest and, in some cases, remove fruit by twisting the stem rather than cutting it.
The technology was developed by a team that includes Anand Mishra, assistant professor in the Department of Mechanical, Materials and Aerospace Engineering at West Virginia University’s Benjamin M. Statler College of Engineering and Mineral Resources. The research, detailed in Nature Communications, originated at Cornell University’s Organic Robotics Lab and is continuing in Mishra’s laboratory at WVU.
Mishra said automation in fruit harvesting could help address challenges including labor shortages, health concerns and inaccuracies associated with manual picking. Existing agricultural robots are often designed for indoor greenhouse settings, despite most crops being grown outdoors, and rigid robotic systems can damage soft fruits or encounter sensing limitations.
The soft robotic gripper is intended to address these issues through integrated sensing technologies. Stretchable optical fibers embedded in each finger function as tactile and curvature sensors, while a miniature camera and distance sensor are housed in the palm. Researchers reported that the device can open and close in less than two seconds, lift loads of up to one kilogram and achieve near-perfect accuracy in shape prediction during testing. The system can also detect stiffness, bending and slipping, allowing it to adjust its grip when handling unstable objects.
Mishra’s laboratory focuses on bio-inspired robotics, developing soft machines that mimic the movement and sensory capabilities of living organisms. He said these designs draw inspiration from animals such as octopuses, using flexible materials that respond differently to forces and vibrations than conventional rigid robots.
The research addresses challenges in agricultural supply chains, where timing is critical for harvesting fruits with short ripening periods and limited shelf lives. Crops such as strawberries and raspberries can spoil quickly, while fruits like avocados may not show clear visual signs of ripeness. Researchers said improved sensing capabilities could help reduce food waste and economic losses associated with harvesting and distribution. The technology could also expand market opportunities for fruits that are difficult to transport because of their fragility, including pawpaws, which are typically distributed only locally due to their short shelf life.
Beyond agriculture, the researchers identified potential applications for the system in areas including space exploration, healthcare, food handling and underwater operations. Mishra said the integration of tactile and curvature sensing could support developments in wearable devices and rehabilitation technologies, while the adaptability of soft robots may enable them to perform tasks in a range of environments.
Photo credit WVU Photo/Jennifer Shephard
