Snakebot could revolutionize search and rescue

February 16, 2006
Contact: Laura Bailey

ANN ARBOR—A remote-controlled cylindrical robot with an onboard power supply could vastly improve recovery efforts in search and rescue missions, eventually even talking to victims trapped in rubble.

The serpentine robot developed at the University of Michigan, sometimes called a snakebot, is formally named the OmniTread OT-4 Serpentine Robot. A similar U-M machine (OT-8) received widespread attention last year.

The smaller OT-4, at half the size, is its improved little brother. The OT-4 was introduced Feb. 12 at the American Nuclear Society’s Sharing Solutions for Emergencies and Hazardous Environments conference in Salt Lake City, and won a Technology Innovation Award by a panel of judges who observed the technology demonstrations.

Like its predecessor, the OT-4 can snake through holes and undulate up stairs and over rocks The two key differences are that the OT-4 is smaller, so it can pass through holes as small as four inches in diameter and its on-board battery power makes the cumbersome power cord of its predecessor unnecessary.

“It hampers the mobility of the robot if we have to bring a tether along with it,” said Johann Borenstein, a research professor in the U-M College of Engineering and leader of the Mobile Robotics Lab. The lithium polymer battery gives one hour of run-time, he said.

The body of the OT-4 robot is comprised of seven box-shaped segments connected by six pneumatically powered joints that move the segments in different directions independently of one another. Each segment is covered on all sides with different textured rolling tracks?similar to bulldozer treads ? so that when OT-4 flips, it still muscles forward without pause. The different textured treads are used for different surfaces, Borenstein explained. OT-4’s middle segment features runner wheels that allow operators to curl the ends of the body into a U-shape, with only the wheeled segment touching the floor for quick rolling across a smooth surface.

It takes three people to control the robot by feeding it commands through a device resembling a video game joystick.

During test runs in Borenstein’s lab, students order OT-4 to climb a set of wooden stairs. It undulates and flips, much like a human would if attempting to ascend stairs without using arms or legs. The pneumatic bellows in the joint provide enough torque for OT-4 to lift three of its front segments at a time, Borenstein said. The operators can also disengage each of the segments tracks individually to save power.

Ultimately, a single operator will steer the robot based on a video camera in the nose of the robot, and the computer software in development by another team will take care of steering the segments, Borenstein said. The robot could even be outfitted with a speaker to communicate and comfort trapped victims.

“We know that the urban search and rescue community is very interested in this,” Borenstein said.

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