Folks blessed with a soft touch seem to have no problem getting to grips with delicate objects, but it can be a tough ask for robots. Researchers at the Harvard John A. Paulson School of Engineering and Applied Sciences (SEAS) have taken a strength-in-numbers approach with a gripper that curls multiple thin tubes around a fragile object.
The SEAS team notes that many of the robotic grippers in use or in the lab combine machine-learning algorithms, complicated feedback control systems and numerous sensors with operator skill to pick up odd-shaped or delicate items. Looking for a simpler way, the researchers turned to nature.
Everything from a venus fly trap to an elephant to an octopus have provided inspiration for a bunch of soft robotic gripper designs over the years, and this latest development looked at how jellyfish tentacles take hold of prey.
While each tentacle on its own isn't strong enough to secure the meal, the jellyfish makes use of many strands to grab on and keep hold. And it's a similar story with the SEAS gripper, which employs a number of foot-long hollow tubes where one side has thicker rubber than the other. When filled with fluid, each tube "curls like a pigtail or like a straightened hair on a rainy day" to wrap itself around a target object.
Each individual tube has a gentle touch to prevent damage to a fragile object, but the combined effort of multiple tubes twisting around even oddly-shaped objects – and each other – gives the gripper enough strength for lift and hold operation.
The researchers boast that this is achieved without needing a suite of advanced sensors, feedback control or prior planning. The entangled object can subsequently be let go by removing the fluid from the hollow tubes to release the pressure.
The SEAS team has tested the gripper with a range of objects, including houseplants and toys, and sees potential applications in pick-and-place operations in product distribution facilities, taking hold of delicate tissue in medical environments, and handling soft fruit and vegetables on the farm or storage hub.
"With this research, we wanted to reimagine how we interact with objects," said first author of the paper, Kaitlyn Becker. "By taking advantage of the natural compliance of soft robotics and enhancing it with a compliant structure, we designed a gripper that is greater than the sum of its parts and a grasping strategy that can adapt to a range of complex objects with minimal planning and perception."
A paper on the development has been published in the Proceedings of the National Academy of Sciences. The video below has more.
Source: SEAS