RoboticsManhole covers help orient urban robots

Published 16 February 2011

It is critical for robots to check their calculated position every now and then against a known GPS position — because robot wheels can slip (their rotations are counted to give position estimates) or a robot’s leg stride can be miscalculated, leaving dead reckoning dead in the water; the solution: have robots in urban environments orient themselves by manhole covers; manhole covers are amongst the more permanent of objects in our built environment and, better still, they are made of metal — and so are easily detectable by a simple metal detecting scanner

No more embarrassment of robots asking directions // Source: dailygizmo.tv

If, some years hence, you see a shopping robot standing in the street sweeping its foot back and forth over a manhole cover, it might not have a screw loose: it could be checking its whereabouts.

So say Hajime Fujii and colleagues from Shibaura Institute of Technology in Tokyo, who have worked out that manhole covers are amongst the more permanent of objects in our built environment. Better still, they point out, they are made of metal — and so are easily detectable by a simple metal detecting scanner. New Scientist reports that in the latest edition of the Journal of Robotics and Mechatronics, they reveal how the shape of each manhole cover in a locale can be used to give a robot a position fix.

Why bother? It is critical to check your calculated position every now and then against a known GPS position - because robot wheels can slip (their rotations are counted to give position estimates) or a robot’s leg stride can be miscalculated, leaving dead reckoning dead in the water.

GPS, the researchers complain, cannot be received well in downtown concrete canyons, and cameras that compare buildings with Google Street View style databases are no good when the light is fading.

So in Fujii’s future robotopia, every manhole cover is pre-scanned and its precise shape — including unique patterns of indentations from years of footfalls or traffic — are logged in the robotic population’s memory banks.

To get a fix, the droid simply has to wave its foot, which contains a scanner over a handy manhole cover to find out where it is.