The Netflix drama "Wednesday" features a hand full of suture marks called "Thing." It is a bizarre being without a body, but it is treated as a full member of the Addams Family. The drama's imagination has become reality with a robot: a robotic hand that detaches from the arm and works on its own.
Research led by Aude Billard, a professor at the Swiss Federal Institute of Technology in Lausanne (ETH), said on the 21st in the international journal Nature Communications that it developed a robotic hand that can crawl and pick up objects. It stays attached to a robot arm and then detaches the hand alone to grasp objects. The team said this widens the robot's operating range.
◇ Able to manipulate multiple objects simultaneously by separating the hand
Robot arms already assemble cars and weld on factory floors. They mimic hand movements to replace people. But most are fixed to workbenches, limiting their range. It is hard to work in tight spaces and impossible to grab multiple objects at once. Billard said, "Raising three children at home, I constantly have to carry several items between my arm and fingers." In other words, simply mimicking the human hand limits robots.
The team developed two versions of the robotic hand. One has five fingers like a human, and the other has six. The disc-shaped palm has a diameter of 16 cm. Identical fingers are attached to it. Each has a symmetrical structure so it can grasp from both sides. In particular, the hand detaches from the robot arm and crawls like Thing from the drama.
The robotic hand learned how to grasp objects in computer simulation and then performed tasks in the real world. In experiments, it safely gripped various objects made of different materials, including a corrugated cardboard cylinder, a rubber ball, a whiteboard marker, and a can. That suggests everyday use.
The robotic hand could sequentially retrieve up to three items and reattach to the robot arm while holding objects. Until now, robot hand motions have been simple, opening and closing fingers, or tailored to specific tasks. The newly developed hand was different. It implemented 33 human hand grasp types and could hold up to 2 kg.
◇ Overcoming limits of human hand motions and range
The researchers confronted the limits of the human hand. Billard said, "To grab something behind you, you have to rotate your hand and make very complex movements," adding, "And the only finger that can oppose and pinch against other fingers is the thumb."
The newly developed robotic hand overcame human-hand limits with a new operating principle. Any finger is identical and can meet an opposing finger to grasp an object. It can move in either direction with the palm as a base. Fingers can wrap objects individually or together, and they can also place an object on the plastic palm and carry it.
Its working range also surpassed conventional robots. Xiao Gao, the paper's first author, explained, "The robotic hand can detach from the arm and move to places ordinary robots cannot reach." The robot's fingers acted as tongs when grasping and moved like spider legs in transit. The team said detaching the hand from the arm could allow inspections in tight spaces such as inside water pipes or submarine engine rooms, and it could pick up and remove foreign objects.
Perla Maiolino, deputy director at the Oxford Robotics Institute, said, "This approach is innovative in that it does not simply mimic biological forms but extends capabilities," adding, "I have never seen a robotic hand that detaches from the arm or grips objects in both directions of the palm."
Of course, many challenges remain. It is unlikely to crawl around the house like Thing in the drama anytime soon. Nancy Pollard, a professor at Carnegie Mellon University, noted, "The fingers of this robotic hand can bend in the opposite direction, but they do not appear able to apply as much pressure to object surfaces as human fingers."
Reference
Nature Communications (2026), DOI: https://doi.org/10.1038/s41467-025-67675-8