Nature offers countless examples of animals responding to their surroundings with agility and resilience, inspiring scientists to design a new shape-shifting robot made to tackle tough terrain by spontaneously morphing according to its environment.
Engineers from Switzerland’s Ecole Polytechnique Federale de Lausanne call their bot GOAT (good over all terrains), and they hope it will live up to its name when navigating a range of extreme outdoor landscapes. The multimodal robot can reconfigure between a flat rover shape and a sphere, allowing it to switch between driving, rolling and even swimming.
“While most robots compute the shortest path from A to B, GOAT considers the travel modality as well as the path to be taken,” Josie Hughes, one of the researchers from the school’s Create Lab who developed the robot, said in a statement. “For example, instead of going around an obstacle like a stream, GOAT can swim straight through. If its path is hilly, it can passively roll downhill as a sphere to save both time and energy, and then actively drive as a rover when rolling is no longer beneficial.”
The team details their research in the journal Science Robotics, describing how their robot successfully switched between different locomotion modes while navigating a 2.8-mile test path across mountainous, aquatic and urban landscapes.
“Robots like GOAT could be deployed quickly into uncharted terrain with minimal perception and planning systems, allowing them to turn environmental challenges into computational assets,” Hughes said.
The study notes that while robotic locomotion has advanced, robots haven’t yet matched the versatility of animals when it comes to navigating complex terrain. The EPFL researchers aren’t the first roboticists to look to nature for inspiration. Ukraine is using remote-controlled robot dogs on the battlefield to explore areas inaccessible by drones, and researchers from MIT and beyond have created snake-like robots to inspect spaces too hazardous for humans. MIT also produced a “cheetah robot” that not only runs like other cheetah bots but executes back flips and yoga moves.
Satellite Navigation System Shows The Way
GOAT features a low-cost compliant fiberglass frame and four motorized rimless spoked wheels that allow it to overcome obstacles, such as boulders, half its own height. Its 4.4-pound central control module — containing a battery, a tiny onboard computer and sensors — is supported by flexible cables which, when adjusted, allow the robot to curl up like a hedgehog or roll like a tumbleweed in the wind. The robot doesn’t have a camera. Instead, it relies solely on a satellite navigation system and an orientation-measuring device to find the optimal route.
“Most robots that navigate extreme terrain have lots of sensors to determine the state of each motor, but thanks to its ability to leverage its own compliance, GOAT doesn’t need complex sensing,” said EPFL doctoral student Max Polzin, a co-author of the research paper. “It can leverage the environment, even with very limited knowledge of it, to find the best path: the path of least resistance.”
The team hopes to further refine GOAT’s algorithms and enhance its ability to accommodate payloads of different sizes. Will GOAT truly be the greatest of all time when mimicking animals’ natural abilities? Time, and terrain, will tell.
