Shape-Shifting Robot For Any Terrain

A robot that changes shape to move like animals? This design can drive, roll, and swim, using less energy and adapting to any terrain.

Animals adapt easily to their environment, whether it’s mountain goats scaling steep rock faces or armadillos curling into a protective ball. In contrast, autonomous robots struggle with even small variations in their pre-programmed paths, facing both physical and computational challenges.

Researchers led by Josie Hughes at EPFL’s CREATE Lab set out to design a robot that could adjust to different terrains as easily as animals. The result is GOAT (Good Over All Terrains), a robot that changes form on the fly, introducing a new approach to robotic movement and control.

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GOAT’s flexible yet sturdy design allows it to shift seamlessly between a flat “rover” shape and a sphere as it moves. This enables it to drive, roll, and even swim while using less energy than robots with limbs or appendages.

Compliance is key

The team designed GOAT by drawing inspiration from various animals, including spiders, kangaroos, cockroaches, and octopuses. This bioinspired approach led to a highly adaptable design that responds to its environment rather than remaining rigid. GOAT’s flexibility allows it to change shape, adjusting its passive properties—more flexible in rover mode and more robust as a sphere.

Made from inexpensive materials, its simple frame consists of two intersecting elastic fiberglass rods and four motorized rimless wheels. Two winch-driven cables adjust the frame, tightening like tendons to form a ball. The battery, onboard computer, and sensors are housed in a 2 kg payload suspended at the center, staying protected in sphere mode, much like a hedgehog curling up for defense.

The path of least resistance

The researchers explain that GOAT’s compliance enables it to navigate with minimal sensors. Equipped only with a satellite navigation system and an inertial measurement unit to track its orientation, GOAT operates without cameras—it doesn’t need to see what lies ahead.

Future research will focus on refining algorithms to maximize the benefits of GOAT’s morphing design and exploring size variations to carry different payloads. The team envisions applications in environmental monitoring, disaster response, and even space exploration.

Reference: Max Polzin, Robotic locomotion through active and passive morphological adaptation in extreme outdoor environments, Science Robotics (2025). DOI: 10.1126/scirobotics.adp6419