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NASA 'Earbot' to Help 'Walker' Robots Keep Their Balance
Scorpion Robot NASA scientists are developing 'Earbot,' an artificial inner ear for legged, ‘walker’ robots that will help prevent them from toppling.

Image left: Scorpion Robot. Click on image to view higher resolution.

The prototype Earbot – golf ball-size, energy efficient and cushioned in a Styrofoam core - is made of special electronic sensor chips that can mimic the motion detection of the human inner ear.

"We will process signals from the sensors in the Earbot in the same way that a human brain does to provide balance control," said Xander Twombly, a scientist at NASA Ames Research Center, located in California's Silicon Valley.

A human inner ear has clusters of sensory hair cell receptors and nerve fibers within hollow areas that interconnect like a system of tiny caves – a labyrinth – or a coiled, shell-like structure – the cochlea. This system helps a person maintain stability and hear.

"(In Earbot) we are using tiny sensors that can sense direction of motion," Twombly explained. Special chips -- micro-electro-mechanical sensors (MEMS) -- in the Earbot measure its acceleration and rotation. These sensors are similar to the organs in the human inner ear that measure the acceleration and rotation of the head.

Robotics researchers say there will be a much larger role for legged robots in the future, according to Twombly. Earbot could have much broader use in these legged robots, controlling not only robot 'eyes,' but also far more complex robot 'arms' and 'legs,' Twombly ventured.

"A walking robot is able to move across dangerous and rocky terrain such as a hillside or inside a cave. We expect to be able to explore areas on this planet or other planets that would otherwise be inaccessible," Twombly said.

CAD drawing of the Scorpion robot The ability of a walking robot to explore difficult terrain not only will be dependent on Earbot balance control -- but also, more importantly -- will hinge on the robot's general design. "Earbot will aid the control of an appropriately designed robot significantly, but it will not be the sole deciding factor about whether or not a robot can handle difficult terrain," cautioned Twombly.

Image right: CAD drawing of Scorpion robot - earbot located in front and indicated in blue.

One scenario that scientists envision is a 'mother,' wheeled robot carrying one or more legged robots on its body. "The mother rover will drive through safe terrain to an area of interest that it cannot safety enter," Twombly explained. "Then the mother will dispatch the legged robot or robots to explore the target area."

Plans call for a cadre of students, using unique NASA testing facilities, to conduct tests of the Earbot. Researchers later will install the device in an eight-legged 'Scorpion' robot, which is about the size of a dog. The first task of the Earbot will be to stabilize a camera on the robot's head when the robot is walking, much in the same way the human inner ear sensors stabilize the eyes in their sockets during walking and running. The stabilization results in a clear image of the world. These early tests will not evaluate Earbot as a total robot balance aid.

The Earbot research team consists of principal investigator Richard Boyle, a vestibular neurophysiologist; computer scientist Twombly; electrical engineer Tony Intravaia and robotic engineer Silvano Colombano.

Publication-size images are available on the World Wide Web at:

John Bluck
NASA Ames Research Center, Moffett Field, Calif.
Phone: 650/604-5026