How Three-Legged Dogs Help Robo-Design

886 3 leg thumb.jpgWhether you think of them as victims, strong survivors or youtube gold, you probably haven’t thought that three-legged dogs would be useful models for robo-design.

But a German research scientist, Martin Gross from the University of Jena, has realised he could learn some interesting things about locomotion from how three-legged dogs move. Research on how dogs with three legs learn to run like normal dogs provides interesting robotics findings and could answer the age-old question of how they do it.

Martin Gross first got the idea of studying dogs when staying with his brother-in-law who has four dogs one of which is missing a hind leg. Gross noticed though that less-legged pet was actually faster than the other three.

Robots don’t handle losing legs so well. In a press release, Gross said robots are not meant to operate on an odd number of legs. “Natural terrestrial locomotion is designed for an even number of limbs. After limb loss (e.g. by an injury) a reorganization of the locomotive system is required,” he explained.

So take a leg off a robot and most likely it will just fall over. And lie there. Twitching, until the batteries die. Gross is looking at helping robots recover from injuries, and learn to cope with fewer resources. Resources like legs.

This study is part of the European Union’s Locomorph project to improve robot efficiency and usability, the latest in a string of interesting research projects the EU has commissioned. This project is meant to help develop robots that can adapt in the event of an “injury.”

To explore the movement of the dogs, reflective stickers are placed on parts of them, they are placed on a treadmill and run for a bit in front of a camera. It records how their different legs move. According to the press release, they found that the locomotion of a dog’s front legs don’t seem to change much, if it has lost a hind leg. But dogs that have lost a front limb had to compensate more for motion. A dog carries much of its body weight on its front limbs and those legs are also used for braking, so more compensation is needed. Back legs are used more for propulsion.


Anna Leach


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