Imagine eight thin, flexible plastic ribbons which, judiciously intertwined, can carry up to 770 times their weight! Such is the physical prowess of a small woven pliers weighing 130 grams capable of lifting then releasing at will – with a simple twist – up to 100 kilos. The height of surprise is that this prototype can also grasp, at once, with more dexterity than a human hand, a playing card placed flat on a table.
The object, described in Nature Communications but also in a video, was designed by Korean teams from the Intelligent Robotics Research Center of the Korea Institute of Science and Technology (KIST) and the Aerospace Engineering Department of the Korea Advanced Institute of Science and Technology ( KAIST). “Most soft grippers are limited in terms of load capacity. However, this strongly restricts their uses, explains Kahye Song of KIST, signatory of the article. We absolutely wanted to find a more efficient principle that could be used in the field of robotics. »
The challenge is significant, underlines French specialist Joël Marthelot, from CNRS – Aix-Marseille University – IUSTI. “Industrial robotics is currently completely “rigid”, he specifies. Part of global research is now focused on another purpose: imagining how to generate robotic movements with a flexible structure that will be able to adapt to potentially very fragile environments, such as people working in automobile workshops or… the elderly . » Moreover, adds the French researcher, “some teams studying these questions may be close to those designing humanoids or exoskeletons.”
On the principle of kirigami
Korean scientists worked on this research for three years. “Starting from ribbons in closed loops [dont les extrémités se touchent], we encountered many obstaclesexplains Kahye Song. To grasp an object, closed loop systems, by nature, do not extend naturally the way those with open loops do [une pince clique]. We overcame this difficulty using the principle of kirigami [dans la culture japonaise, l’art de découper du papier]. »
The researchers strategically cut a structure composed of closed-loop ribbons connected by two plates. “The relative rotation of these induced structural twists which shaped either a hermetically closed structure, or one which extends widely, like the petals of a flower”, deciphers the scientist. She recognizes that “This simple and easily controllable opening and closing mechanism has transformed into reality a challenge that, initially, [les] impressed ».
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