Anyone who's ever seen a dog move around on three limbs knows that canines are remarkably resilient creatures. Scientists are now wondering whether such adaptability could likewise be programmed into robots, in the event they experience damage or malfunction far from a repair shop (look no further than NASA's Mars Spirit rover to see why this is important).
Researchers working on the European Union's Locomorph project—from institutions including the University of Zurich, Friedrich Schiller University of Jena and École Polytechnique Fédérale de Lausanne—will present their work analyzing three-legged canine compensation strategies Thursday at the Society for Experimental Biology annual meeting in Prague. Formed last year, Locomorph's goal is to advance robotic locomotion and movement through a multidisciplinary approach that takes into account biology, biomechanics, neuroscience, robotics and embodied intelligence.
The researchers examined walking and running techniques in dogs with forelimb or hindlimb amputations, using a treadmill and a set of 10 high-speed infra-red cameras. Reflective markers positioned on the dogs' skin allowed the scientists to follow the movement of separate parts of the body through time, tracing out trajectories. Absent forelimbs proved more complicated for the dogs, requiring the remaining limbs to undergo careful adaptation to co-ordinate with each other. The scientists figure this is due to the uneven distribution of a dog's body weight, which is greater over the front legs.
Future work under the Locomorph project to develop a better understanding of locomotive activity will examine voluntary and involuntary changes to body movement in a wide range of different animals, including humans. Boston Dynamics has already achieved some of this understanding through work on its four-legged Legged Squad Support System (LS3) for the U.S. military, which can maintain balance on ice or when kicked from the side. It's unclear, however, whether the LS3 could continue to serve as a mechanical pack mule if one if its legs were to be lost to an improvised explosive device (IED) in combat.
Both images courtesy of Martin Gross, who is carrying out the research at the University of Jena in Germany