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Posted by Frnak McKenney on October 7, 2005, 9:23 am
> "Frnak McKenney"
>>
>> 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?)
> may be complex ($$$): Inertial Navigation?
Martin,
I really like the "smart cable" Brent found (see previous post),
but it's off in the future. The inertial approach (measure where
the end of the cable travels rather than try to obtain an after-
the-fact position) is already "here" (and it's wireless --
the cable is invisible<grin>):
IMU 6 Degrees of Freedom - v2 with USB Bluetooth and Battery
Holder
http://www.sparkfun.com/shop/index.php?shop=1&cartB1120&
cat=1&itemidI3&
Description: Complete wireless Inertia Measurement System -
6 degrees of freedom. Version 2 uses the single IC triple axis
accelerometer from Freescale MMA7260Q and combines it with three
iMEMs gyroscopes. Roll, Pitch, and Yaw gyro sensors including a
total of 3 tilt axis. All measurements are transmitted via a
wireless Class 1 Bluetooth link that is extremely easy to use
with a range of 100m (330ft) line-of-sight and 30m (100ft)
indoors.
Only minor flaw (for me) is the $350 price tag. TANSTAAFL.
Frank McKenney, McKenney Associates
Richmond, Virginia / (804) 320-4887
Munged E-mail: frank uscore mckenney ayut minds pring dawt cahm (y'all)
--
Those who profess to favor freedom, and yet depreciate
agitation, are men who want rain without thunder and
lightning. -- Frederick Douglass, 1817-1895
--
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> 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?)