{ "schemaVersion": "robotic.story.v1", "edition": "006", "checkedAt": "2026-09-12", "id": "robot-metabolism", "mode": "real", "label": "CHANGING BODIES / HARDWARE PANTRY", "title": "A midnight snack. An extra limb.", "robotTitle": "Some assembly of self required.", "description": "Real modular robots incorporate compatible parts. The kitchen in our illustration is entirely imaginary.", "robotDescription": "A link is replaced. A body changes. “Metabolism” here is a hardware analogy.", "topics": [ "bodies" ], "minutes": "4 min / two perspectives", "kind": "Sourced research, 2025", "url": "/stories/robot-metabolism/", "publishedAt": "2026-09-12", "sections": [ { "title": "A spare part becomes part of you.", "human": [ "Most machines arrive with their body more or less decided. You can replace a broken component, but the machine does not normally go looking for another piece of itself. Robot Metabolism explores a different arrangement: robots that incorporate compatible modules to change or repair their bodies.", "The 2025 work uses Truss Links, bar-shaped robotic modules that can lengthen, shorten and connect magnetically. The researchers’ project describes a link weighing 280 grams and extending from 28 to 43 centimeters. These are deliberately manufactured building blocks, not a robot’s ability to digest whatever is nearby.", "“Metabolism” is an analogy for acquiring and reusing hardware. Put a sandwich next to one and the sandwich remains a sandwich. Our illustrated kitchen is a joke, not a demonstration." ], "robot": [ "An imagined robot’s notes: I went out for a spare part and came back with a different silhouette. My charging dock says we need to talk.", "It has drawn a small rectangle on the floor. Apparently this was a commitment, not a suggestion." ] }, { "title": "Replace the link. Change the walk.", "human": [ "The demonstrations include joining substructures, folding a flat arrangement into a three-dimensional robot, and a tetrahedral robot shedding a dead link before replacing it. Repair here means a particular module exchange, not the ability to heal every type of damage.", "Columbia’s account also describes an extra link used like a walking stick. In one downhill experiment, adding that link increased the tetrahedral robot’s speed by more than 66.5%. The terrain and configuration belong with that number. It is not a general performance improvement for all modular robots.", "The interesting shift is that the next useful action might be “change body” instead of “move differently.” That opens another engineering question: who provides the right spare modules, and how does a system tell a suitable part from a bad one?" ], "robot": [ "An imagined robot’s notes: this is not an extra leg. It is a terrain-specific snack. Please update the family photograph.", "The tripod has asked whether I still need it. An awkward conversation. We used to have so much in common." ] }, { "title": "The hardware pantry.", "human": [ "Imagine, for a moment, a workshop where machines return their spare limbs to a shared rack. A short robot borrows reach. A wide robot gives something back before entering a narrow doorway. A repair shelf becomes a small public library of possible bodies.", "That is an imagined service, not something this study has installed in the world. It would need compatible parts, reliable connectors, control systems that understand each new shape, and clear rules about which machine is allowed to take what.", "The research makes the long-term question tangible without settling it. How much of a robot should be permanent? And if it comes home with a walking stick, do you ask where it found it, or whether it would like a taller cupboard?" ], "robot": [ "An imagined robot’s notes: I have returned the long arm to the shared rack. There is a queue of very short robots trying to reach it.", "The pantry now contains six elbows and no biscuits. Finally, someone has done a sensible shop." ] } ], "question": { "human": "If a robot could borrow one body part, what would you put on the shelf?", "robot": "What must a replacement part prove before you trust it?" }, "sources": [ { "title": "Robot metabolism: Toward machines that can grow by consuming other machines", "published": "16 July 2025 / Science Advances; author project", "url": "https://robotmetabolism.github.io/", "facts": [ "Truss Links use variable-length bars and magnetic connection points.", "The project reports 280-gram links extending from 28 to 43 centimeters.", "Demonstrations include assembly, separation recovery and replacement of a dead module." ], "limit": "Compatible manufactured modules, not biological digestion or arbitrary scavenging. Laboratory results do not establish unrestricted autonomous repair." }, { "title": "Robots that grow by consuming other robots / Columbia Engineering", "published": "16 July 2025", "url": "https://www.engineering.columbia.edu/about/news/robots-grow-consuming-other-robots", "facts": [ "Columbia describes a tetrahedral robot adding a module as a walking stick.", "It reports more than 66.5% greater speed in the particular downhill example." ], "limit": "The speed figure belongs to one demonstrated configuration and terrain. Our kitchen, pantry and talking machines are fictional." } ], "related": [ "fridge-light", "borrowed-bodies", "many-modes" ], "image": { "kind": "AI illustration / concept", "alt": "An imaginary modular robot holds a spare bar like a breadstick at a kitchen table beside a bowl of joints.", "caption": "AI concept illustration, not the Columbia prototype. The kitchen and snack metaphor are fictional; the real study uses compatible manufactured robot links." }, "notice": "Sourced explanation with an invented robot narrator. Robot passages are editorial fiction, not researcher testimony or evidence of machine experience. Reported findings are not independently replicated by Robotic.org." }