April 27, 2009

Carnegie Mellon University has Wallcrawling Tankbot

Carnegie Mellon University (CMU) Robotics has "Enhanced Adhesion by Gecko-Inspired Hierarchical Fibrillar Adhesives" for makgin wall crawling robots


The CMU work will be presented at 2009 IEEE International Conference on Robotics and Automation, May 12 - 17, 2009, Kobe, Japan.

Tankbot is a simple, energy efficient, lightweight (60 g), and robust climbing robot. It uses the continuous detachment force (peeling) of the flat, bulk tacky elastomer tread to climb. An optimum peeling angle with a preliminary analysis of the pretension effect, and the tread force distributions are presented. A passive tail transfers the peeling force from the rear wheel to the front and ensures intimate continuous contact with the surface. Tankbot works in any orientation on smooth surfaces, such as glass and acrylic , of all slope angles (i.e. 0−360 degrees). However, the robot can only work vertically on relatively rough surfaces in any direction, such as wood, metal, painted wall, and painted brick. Tankbot can carry a payload of up to 0.4 N and 1 N on inverted and vertical surfaces respectively. In addition, the robot can go over obstacles up to 15 mm tall on smooth vertical surfaces. Internal transitioning from horizontal to vertical and vertical to horizontal and external transitioning from vertical to the horizontal is also achieved. The potential applications of this robot include inspection, exploration, maintenance, cleaning, repair, and search and rescue.escue in both earth and space environments.

New Scientist has an article covering the work.

So for scampering on ceilings, the pair are working on another design with stronger adhesion: the FourBar robot. This has four tough plastic bars that move parallel to one another driven by a motor. Each bar has four tacky elastomer footpads, mounted in pairs on rockers. When the eight footpads on the interior bars are stuck to a surface, the outer bars unpeel their footpads and move forwards. When they are safely restuck, the inner bars unpeel and move forwards.

In tests, Sitti and Unver got the robot to move 30 metres upside down. But one problem with both robots is that their elastomers can clog with dirt and dust and lose their crucial tackiness. Sitti hopes to overcome this on future bots by using his hairy gecko-like elastomers. Ultrafine nanoscale hairs do not provide micro-scale dirt particles with enough contact - so they simply roll off.

Other researchers reckon the climbing technology has potential. "These robots could extend the work of robotic builder's assistants. And there are often diagnostic and repair jobs for plumbers and electricians that are tricky to reach," says Noel Sharkey at the University of Sheffield in the UK. Tony Pipe at the University of the West of England in Bristol envisages the robots in search and rescue. "A small robot that can negotiate contorted spaces from any angle, whilst carrying a significant payload of medicines and other recovery equipment, could be very useful."

There could be sinister uses though: "A less palatable idea would be a surveillance robot that hugs the ceiling," Sharkey adds.

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