Salamander robot sheds light on evolution

Swimming to walking transition all in the spine

Ian Williams, vnunet.com 12 Mar 2007

A group of Swiss and French scientists have created a segmented salamander-like robot that may help explain how some creatures moved from sea to land.

The 3ft-high robot, dubbed Salamandra Robotica, is made up of segments that imitate the amphibian's spinal cord, which allows it to alternate between swimming and walking.

As well us helping to understand the evolutionary move from sea to land, the device provides a good model for robot design based on living creatures.

Professor Auke Ijspeert, of the Swiss Federal Institute of Technology at Lausanne, said that the robot's electrical controls were based on the same principal as the electrical signals in the salamander's nervous system that make it change its speed and gait.

"Nature found a nice way of making a sophisticated circuit in the spinal cord and then controlling the muscles from there," he said.

"It is a fantastic solution for coordinating multiple degrees of freedom in a simple, distributed way."

Much like its living counterpart, the robot has four rotating legs and a flexible spine that twists as it walks. When the robot gets into the water, the spine flexes faster and it swims using its tail for propulsion.

"The robot was very useful to validate that our model could effectively modulate speed, direction and gait, aspects that need a mechanical 'body' to be properly evaluated, and also to verify that the generated movements are close to those of a real salamander," continued Ijspeert.

Fast, agile robots capable of changing speed and movement could be very useful in a variety of fields such as search-and-rescue operations, according to the scientists. The Salamandra Robotica could also turn up in toy stores.

"This would definitely be a toy you could take to the beach or the swimming pool. We have not yet been approached by any toy companies, but I would certainly love to collaborate with one," Ijspeert mused.

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