Servo - March 2014

Stickybot has Space Potential

It can't save you 15 percent on auto insurance, but a gecko-like six-legged robot designed by researchers at the European Space Agency ( www.esa.int) and Canada's Simon Fraser University ( www.sfu.ca) appears to have potential as a hull-crawling repair technician on spacecraft.

A gecko derives its climbing abilities from its feet which achieve stickiness using a flock of tiny hairs (100 nm to

200 nm in diameter) that creates atomic interactions with the surface. Somewhat similarly, the Abigaille robot is equipped with small "footpad terminators" that use a dry adhesive to cling to vertical surfaces. This feature was of particular interest to the ESA folks, as other methods of achieving adhesion are not well-suited to space applications.

Materials like duct tape tend to collect dust over time and lose their stickiness, plus they give off problematic fumes in vacuum conditions.

Velcro™is also unsuitable as it requires a mating surface. Tests of Abigaille's sticky stuff in space-like conditions showed that it retains its adhesion even in a vacuum and throughout the applicable range of temperatures.

Because the bot's six legs each have four degrees of freedom, it is highly dexterous and may someday be deployed for servicing satellites, as well as such mundane tasks as cleaning high-rise buildings.

"Abigaille" wall crawler.

Courtesy of Simon Fraser University School of Engineering Science/MENRVA.

8 SERVO 03.2014

by Jeff and Jenn Eckert

Robytes

Mechanical Cooter Seeks Shipwrecks

On the other hand, if you want a bot for exploring shipwrecks, it seems prudent to pattern it after an aquatic reptile as did Taavi Salumäe — an engineer at the Centre for Biorobotics, Tallinn University of Technology ( www.ttu.ee).

Using four independently driven flippers, his turtle-inspired U-CAT is highly maneuverable and can swim up and down and move forward and backward, and make zero radius turns as necessary. According to Salumäe, "Conventional underwater robots use propellers for locomotion. Fin propulsors of U-CAT can drive the robot in all directions without disturbing water and beating up silt from the bottom which would decrease visibility inside the shipwreck."

The little terrapin carries a video camera so researchers can use its footage to reconstruct the underwater site later on. Development of the U-CAT was sponsored by a European Union organization called Archaeological Robot Systems for the World's Seas project, torturously given the acronym ARROWS. The amount of funding was not specified, but it was revealed that U-CAT has both size and cost advantages over conventional underwater machines used in the oil and gas industry and the military.