Robots that grow by consuming other robots

(Press-News.org) New York, NY—July 16, 2025—Today’s robots are stuck—their bodies are usually closed systems that can neither grow nor self-repair, nor adapt to their environment. Now, scientists at Columbia University have developed robots that can physically “grow,” “heal,” and improve themselves by integrating material from their environment or from other robots.

Described in a new study published in Science Advances, this new process, called "Robot Metabolism," enables machines to absorb and reuse parts from other robots or their surroundings.

"True autonomy means robots must not only think for themselves but also physically sustain themselves," explains Philippe Martin Wyder, lead author and researcher at Columbia Engineering and the University of Washington. "Just as biological life absorbs and integrates resources, these robots grow, adapt, and repair using materials from their environment or from other robots."

This new paradigm is demonstrated on the Truss Link—a robotic magnet stick inspired by the Geomag toy. A Truss Link is a simple, bar-shaped module equipped with free-form magnetic connectors that can expand, contract, and connect with other modules at various angles, enabling them to form increasingly complex structures.

The researchers showed how individual Truss Links self-assembled into two-dimensional shapes that then could morph into three-dimensional robots. These robots then further improved themselves by integrating new parts, effectively "growing" into more capable machines. For example, a 3D tetrahedron shaped robot integrated an additional link that it could use like a walking stick to increase its downhill speed by more than 66.5%. 

"Robot minds have moved forward by leaps and bounds in the past decade through machine learning, but robot bodies are still monolithic, unadaptive, and unrecyclable,” says Hod Lipson, co-author and James and Sally Scapa Professor of Innovation and chair of the Department of Mechanical Engineering at Columbia University, and director of the Creative Machines lab where the work was done. “Biological bodies, in contrast, are all about adaptation - lifeforms, can grow, heal, and adapt. In large part, this ability stems from the modular nature of biology that can use and reuse modules (amino acids) from other lifeforms. Ultimately, we’ll have to get robots to do the same - to learn to use and reuse parts from other robots. You can think of this nascent field as a form of ‘machine metabolism.’”

Researchers envision future robot ecologies where machines independently maintain themselves, growing and adapting to unforeseen tasks and environments. By imitating nature's approach—building complex structures from simple building blocks—robot metabolism paves the way for autonomous robots capable of physical development and long-term resilience.

"Robot Metabolism provides a digital interface to the physical world and allows AI to not only advance cognitively, but physically—creating an entirely new dimension of autonomy," says Wyder. "Initially, systems capable of Robot Metabolism will be used in specialized applications such as disaster recovery or space exploration. Ultimately, it opens up the potential for a world where AI can build physical structures or robots just as it today writes or rearranges the words in your email."

Lipson concludes with caution: “The image of self-reproducing robots conjures some bad sci-fi scenarios. But the reality is that as we hand off more and more of our lives to robots - from driverless cars to automated manufacturing, and even defense and space exploration. Who is going to take care of these robots? We can’t rely on humans to maintain these machines. Robots must ultimately learn to take care of themselves.”

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