Mighty Morphin' Robots

Robots get around in a variety of ways: some walk on legs, others roll on wheels or treads, and some even fly or float. Of course these variations are not about novelty, but rather are a matter of practicality, as different environments and tasks require different modes of locomotion. For robots with a limited scope of operation, simplifying choosing the best option for the application may suffice. But for a robot that can expect to encounter many types of terrain in the course of its duties, adaptability and versatility become essential.

Traditional design approaches, which include a single mode of locomotion, are not well-suited for these cases. However, researchers at the Swiss Federal Technology Institute of Lausanne have developed an innovative solution to this problem. Their latest bioinspired robot, GOAT (Good Over All Terrains), can actively change its shape to adapt to different environments, allowing it to travel across a variety of terrains with ease.

GOAT’s primary innovation lies in its ability to morph between a flat, wheeled rover configuration and a compact spherical shape. This transformation allows it to switch between rolling, driving, and even swimming modes, optimizing energy consumption and mobility efficiency. When encountering downhill slopes, it can passively roll to conserve energy before actively resuming control as a wheeled rover. And in aquatic environments, it can bypass obstacles that would otherwise hinder land-based robots.

Rather than relying on complex perception systems to navigate, GOAT follows the path of least resistance by leveraging its compliance — the ability to adapt to external forces rather than resist them. This bioinspired feature reduces the need for extensive computational processing while simultaneously improving its ability to traverse unpredictable terrains.

The design of GOAT takes cues from animals that naturally adapt to meet the challenges of their surroundings. Constructed with a lightweight yet durable frame, GOAT consists of two intersecting elastic fiberglass rods supporting a payload containing its battery, onboard computer, and sensors. Four rimless wheels enable movement in rover mode, while an internal winch system pulls cables that contract the frame into a sphere when needed.

In its spherical configuration, the robot gains additional protection, as its critical components remain suspended in the center, similar to how a hedgehog shields itself by curling up. This design minimizes the risk of damage during high-impact interactions with rough terrain, making it particularly well-suited for challenging environments.

The ability to autonomously reconfigure its morphology makes GOAT highly versatile for a wide range of applications. From environmental monitoring to disaster response, its capacity to navigate unstructured terrain without requiring extensive sensing equipment makes it an efficient tool for exploring difficult-to-reach areas. Additionally, its energy-efficient movement could prove valuable for future extraterrestrial missions, where adaptability and low power consumption are highly valued.

As research progresses, future developments are expected to focus on refining the robot’s shape-shifting mechanisms, improving its control algorithms, and scaling its design to accommodate different payload sizes. By combining adaptability with efficiency, GOAT has moved the field of autonomous robotic systems forward, offering new possibilities for mobility in complex and unpredictable environments.