There are several different approaches to determining a robot's position "absolutely" (okay, relative to the Earth) such as GPS. There are others for determining position relative to beacons and walls where sound, light or RF are at least partially unobstructed.
But... suppose you want to build a tethered (remotely powered) tunnel crawler to explore and map complex networks of metal piping, such as sewers, conduits, and ventilation ducts? Odometry would be a bit "sloppy" (especially in sewer pipes), and one couldn't depend on light or sound.
Is there some simple method for determining where one end of a cable is relative to the other end? (Okay, how about a complex method?) I know that if you throw enough money at the problem one can measure the _length_ of the cable (via signal travel time), but what if you want to know the far end's XYZ location relative to the beginning of the cable after your robot has snaked its way through fifteen air-duct conduit joints and created a replica of the Gordian knot?
If I build the cable out of "bend resistor" material I can presumably determine the total amount of bending, but not what directions the bends took. Likewise (I think) with measuring the refraction in a fiber optic cable.
With a crash (e.g. 20-year) research effort I suppose I could create something out of microscopic flexible links with a built-in pair of nano-potentiometers per joint that would tell me where every bend was and the exact bend direction (within micro-pot tolerance ). Trouble is, with the current state of the Frderal budget getting research funds could be more difficult than it might otherwise be.
Can anyone think of any other approaches? Even silly ones?
Frank McKenney, McKenney Associates Richmond, Virginia / (804) 320-4887 Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all)
-- Totalitarianism is the crushing of ordinary, intractable, human reality by a political idea. -- David Horowitz / The Politics of Bad Faith
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