In the TV cartoon, the main character Inspector Gadget pulled out various tools from his body whenever he faced a crisis. Young viewers were simply amazed at how a helicopter rotor and robotic arms could be hidden inside a small body.
A domestic research team has developed technology to realize the imagination of cartoons. Professor Cho Gyu-jin's team in the Department of Mechanical Engineering at Seoul National University said on the 27th that it "developed a robot structure that can be folded or rolled up for storage like a tape measure," in an announcement published in the international journal Science Robotics.
The team developed a robot structure that is flexible but, when fully extended, is sturdy enough to bear heavy loads. Cho said, "Expandable structures can increase the reach and functionality of robot systems while not taking up much space."
The team noted that a mobile robot could, using this method, extend a 1.m-long arm to manipulate objects on a shelf, or a 3D (three-dimensional) printer could form a tripod to support the fabrication of a 2.5 m-tall space shuttle model.
◇Weaving origami-like metal panels with ribbon
Like Inspector Gadget, the team developed a "foldable and rollable corrugated structure" so that a robot arm can be gently folded and rolled up for storage and, when unfolded, maintain strong rigidity. A tape measure has a flat cross-section to wind smoothly, but when extended it has a corrugated cross-section so it does not sag. Paper is flexible, but when corrugated in a zigzag shape, adjacent faces prevent each other's deformation and become much stronger—by the same principle.
The problem is that if a typical corrugated structure is wound while layered, the material thickness creates a difference in circumference between the inner and outer layers, which can cause buckling or creases. As the corrugated cross-section grows larger and longer, structural strength increases, but there was a constraint that the width required for storage became wider. The team addressed this by introducing the principle of interlacing into the corrugated structure. An interlacing structure engages components by crossing them without bonding them together.
The team densely wove metal panels arranged parallel in the longitudinal direction with ribbon, without attaching them to each other, to create loop-shaped interlacing joints. The interlacing joints, composed of soft yet strong ribbon, bound the panels tightly.
The team explained, "While creating a sturdy foldable corrugated structure, we also allowed local sliding of panels along the loop gaps so that the layered structure winds smoothly around a hub," adding, "By weaving rigid material panels with ribbon, even structures with any number of corrugations can be layered, gently rolled up, and stored."
◇Robot vacuum can stretch an arm to tidy high places
The team demonstrated that the interlacing origami structure can be applied to a variety of deployable robot systems. Applied to a small mobile robot the size of a robot vacuum, it usually stayed low in height but could extend an arm as needed to tidy shelves and press elevator buttons.
The team explained, "If this technology is commercialized, robot vacuums could go beyond devices that only clean floor dust to expand into 'household robots with arms' that handle labor-intensive tasks throughout the home, such as putting away children's toys or moving laundry."
The team also succeeded when a mobile robot with a diameter of 1 m and a height of 1 m reached a target position, then deployed into a regular triangular pyramid with a base of 3.2 m and a height of 3.4 m to support the printing of a 2.5 m-tall structure. The team said, "In environments where it is difficult for people to go directly, such as the moon or Mars, we opened the possibility of future construction systems in which robots build structures and move on their own."
Co–first authors Jung Soon-pil, Ph.D., and Song Jae-young, M.S. (currently at HD Korea Shipbuilding & Offshore Engineering) at Seoul National University said, "We applied the interlacing principle—crossing and engaging like textiles—to folding structures to structurally absorb the inter-layer circumference difference of multilayer structures," adding, "As a result, we implemented an origami structure that enables compact storage through a double-compression method of folding and rolling, while achieving high strength upon deployment thanks to tight weaving."
Lead researcher Professor Cho Gyu-jin said, "We often look for solutions in a single form called a humanoid (human-like robot), but many field problems vary depending on the environment and task," adding, "These results show that robots that change shape and deploy to fit space and task can become a practical platform for physical AI (artificial intelligence)."
References
Science Robotics (2025), DOI: https://doi.org/10.1126/scirobotics.adv4696