If you have ever played the claw game at an arcade, you are aware of how challenging it is to grasp and hold onto objects with robotic gripper. Imagine how much more nerve-wracking that game would be if you were attempting to collect a delicate piece of endangered coral or a priceless treasure from a sunken ship instead of soft teddy bears.
Most of today’s robotic grippers use a combination of the operator’s ability and embedded sensors, intricate feedback loops, or cutting-edge machine learning algorithms to grasp delicate or irregularly shaped objects. Researchers at Harvard’s John A. Paulson School of Engineering and Applied Sciences (SEAS) have found a simpler way to do it.
They created a novel soft robotic gripper that ensnares and entangles things in a manner analogous to how jellyfish capture stunned prey by using a network of thin tentacles. Individual filaments, or tentacles, are not very strong on their own. However, when used as a group, the filaments can firmly grip and hold things of all shapes and sizes. The gripper doesn’t need sensing, planning, or feedback control; it only uses straightforward inflation to wrap around items.
The Proceedings of the National Academy of Sciences published the study (PNAS).
The study’s first author and former graduate student at SEAS, Kaitlyn Becker, remarked, “With this research, we aimed to reinvent how we engage with objects.” “We built a gripper that is larger than the sum of its parts and a grasping strategy that can adapt to a range of complicated objects with minimal preparation and perception by taking advantage of the innate compliance of soft robotics and boosting it with a compliant structure.”
At the moment, Becker teaches mechanical engineering as an assistant professor at MIT.
The gripper’s capacity to entangle itself with the target it is attempting to grasp gives it strength and versatility. These foot-long rubber tubes have a hollow inside. Rubber is thicker on one side of the tube than the other, so when pressure is applied, the tube coils like a pigtail or looks straightened on a rainy day.
Each entanglement strengthens the grasp as the curls knot and entangle with the object and each other. Although the overall grip is tight, each individual contact is feeble and won’t break even the most delicate thing. The filaments are simply depressurized to release the item.
The gripper’s effectiveness was tested through simulations and experiments, picking up a variety of objects, including toys and different houseplants. In real life, the gripper could be used to pick up soft fruits and vegetables for farming and distribution, fragile tissue in medical settings, or even oddly shaped items like glassware in warehouses.
This new way of gripping combines the work of Professors L. Mahadevan on the topological physics of entangled filaments and R. Wood on soft robotic grippers.
According to Mahadevan, the Lola England de Valpine Professor of Applied Mathematics in SEAS, Organismic and Evolutionary Biology, and Physics in FAS and co-corresponding author of the paper, “Entanglement enables each highly compliant filament to conform locally with a target object, leading to a secure but gentle topological grasp that is relatively independent of the details of the nature of the contact.”
According to Wood, the Harry Lewis and Marlyn McGrath Professor of Engineering and Applied Sciences and co-corresponding author of the paper, “This new approach to robotic grasping complements existing solutions by replacing simple, traditional grippers that call for complex control strategies with extremely compliant and morphologically complex filaments that can operate with very simple control.” This method broadens the range of objects that robotic gripper can take up.
