EUROPE: Three-legged dogs needed for robot research

European scientists are looking for three-legged dogs to support a European Union-funded project to improve robot design and mobility. The four-year Locomorph - Robust Robot Locomotion and Movements through Morphology and Morphosis - project is based at Friedrich Schiller University in Jena, Germany.

Its aim is to develop robotic locomotion and movements, increasing robots' efficiency, robustness and thus "usability in unknown environments".

Locomorph combines multidisciplinary approaches from biology, biomechanics, neuroscience, robotics and embodied intelligence to investigate locomotion and movements in animals and robots, focusing on the two concepts of morphology and morphosis.

The EU is supporting the project, which started in 2009, with EUR2.7 million (US$3.6 million) from the Embodied Intelligence initiative within the information and communication technologies thematic area of the European Commission's Seventh Framework Programme.

"Canines are known for their resilience in the face of limb-loss, often managing to move about admirably on three legs," says a summary report on the project. So the researchers, led by biologist Martin Gross at Friedrich Schiller, examined the walking and running techniques of dogs missing a fore-leg or hind-leg to find out how they could move so capably.

The researchers analysed the movements of the three-legged dogs running for two minutes on a treadmill, synchronised to 10 high-speed infrared cameras. Reflective markers on the dogs' skin followed the movements of separate parts of their bodies, recording the trajectory of their movements.

Comparisons were made of the 'kinematics' - characteristics of movement - of the dogs with different missing limbs; and of those of the three-legged dogs with the 'normal' movements of four-legged dogs.

The research found the three-legged dogs adopted different coping techniques or 'compensation strategies' to retain mobility, depending on which limb was missing.

Dogs missing a front limb found it more difficult to manoeuvre than those missing a back leg.

With an amputated hind-leg the fore-limbs continued to act as they would normally, showing little or no compensation strategy. But, the research found, with a missing front leg the remaining limbs were forced to undergo careful adaptation to coordinate with each other via a process called 'gait compensation'.

The researchers suggested the difference was due to the higher loading of fore-limbs compared with hind-limbs because of the distribution of the dogs' body weight.

The research findings so far were presented in July at the annual meeting of the Society for Experimental Biology in Prague.

While the project is based at the university in Jena, biologists, physicists and engineers taking part are from institutions including the University of Zurich and the Ecole Polytechnique Fédérale of Lausanne in Switzerland, the University of Syddansk in Denmark, Belgium's University of Antwerp and Ryerson University in Toronto, Canada.

Gross told University World News the dogs were injured naturally. "In some cases they lost their limb through car accidents and some were born with leg deformations."

He said he needed more dogs to verify the data. "We want to have five with fore-limb and five with hind-limb amputation, more if possible. It's hard to find them and to convince the owners to take part."

Animals other than dogs are also taking part in the Locomorph experiments to increase knowledge about locomotive activity. Future research will examine 'voluntary' and 'involuntary' changes to body movement in species including lizards, okapis, baboons - and humans.

"Voluntary changes in pedality are those, for example, in baboons who first walk on four limbs, then they lift their body and walk on two limbs. Or maybe they walk on three limbs with something in one hand," explained Gross.

"Involuntary changes are, for example, performed by the three-legged dogs. They are only able to locomote on their three remaining limbs. Here we analyse gait pattern and control strategies to compensate the lost limb as well as joint and segment kinematics of the limbs and back."

"For the [voluntary change] experiments with humans we have between 10 and 20 subjects and make several trials of each single experiment with every person," said Gross. "They run on four limbs, and then they have to lift up their body during the trial and run bipedally."

jane.marshall@uw-news.com