July 6, 2012

New Pair Of Legs Allow Robots Better Walking Pattern

Lee Rannals for redOrbit.com - Your Universe Online

Robots are receiving a new pair of legs that are the most accurate to the human walking gait so far.

Researchers have developed a set of robotic legs that they believe are the first to fully model walking in a biologically accurate manner.

Reporting in the Journal of Neural Engineering, the team said they built the neural architecture, musculoskeletal architecture and sensory feedback that humans have into the robot legs.

They said the accuracy of the robot has allowed the researchers to investigate the processes underlying walking in humans, and ultimately may help grow theories about how babies learn to walk.

A key component of the human walking system is the central pattern generator (CPG), which is a neural network in the lumbar region of the spinal cord that generates muscle signals.

The CPG produces these rhythmic signals by gathering information from different parts of the body that are responding to the environment. This allows humans to be able to walk, without needing to think about it.

The robot contains an artificial half-center, which is the simplest form of CPG that consist of just two neurons that fire signals alternatively. It also has sensors that deliver information back to the half-center, including load sensors that sense force in the limb when the leg is pressed against a stepping surface.

"Interestingly, we were able to produce a walking gait, without balance, which mimicked human walking with only a simple half-centre controlling the hips and a set of reflex responses controlling the lower limb," Dr. Theresa Klein, who co-authored the study, said in a press release.

The researchers believe that babies start off with a simple half-center, and over time "learn" a network for a more complex walking pattern. This theory could explain why babies have been seen to exhibit simple walking patterns when placed on a treadmill, even before they have learned to walk.

"This underlying network may also form the core of the CPG and may explain how people with spinal cord injuries can regain walking ability if properly stimulated in the months after the injury," Dr. Klein said in the release.