[mowbot] Absolute location

robin nospam at acm.org
Mon, 14 Oct 1996 14:09:55 +0100

Just saw this on comp.robotics.misc. I thought the time difference
IR/ultrasound technique mentioned might prove useful.


R.M.O'Leary <robin nospam at acm.org> +44 973 310035  P.O. Box 20, Swansea SA2 8YB, U.K.
>From: onat nospam at turbine.kuee.kyoto-u.ac.jp (Onat Ahmet)
>Re: A Way To Go Home
> In "Richard T. Vannoy II"'s opinion;
>: I want my robot to go "home" and drop off an object it picks up.
>: I don't want a light that makes it obvious to observers what is going on,
>: so I want to have an invisible homing beacon.
>: Sounds like I need IR... Correct?  Do humans interfere with IR?  Is there
>: a sensor or a frequency that works best as a homing beacon?
>: --
>: Richard T. Vannoy II                 richardv nospam at abac.com
>: PO Box 103                         Computer Programmer
>: La Mesa, CA 91944-0103  College Electronics Instructor
>You can always flood the area with IR. Use many IR diodes attached to
>an easily seen position (ceiling?).
>IS Robotics (I think) have a precise homing system that uses one IR
>emitter, and two ultrasonic transmitters. There is a semi-intelligent
>controller at the base that blips the IR emitter, and pings one of the
>ultrasonic transducers. The robot picks up both transmissions, and from
>the delay of sound, computes one distance. The base then blips the IR and
>pings the other ultrasonic, and the robot gets the other distance, to
>calculate its position. I guess you can calculate the orientation
>by taking two position readings, but moving on a straight line in between,
>and then finding out the orientation vector...
>The system is sold for thousands of dollars, but a hobbyist can probably
>do it cheaply.
>| Ahmet ONAT  Kyoto Univ. Japan                                 |
>| E-mail    : onat nospam at kuee.kyoto-u.ac.jp                           |
>| WWW page  : http://turbine.kuee.kyoto-u.ac.jp/staff/onat.html |
>|             My 6 leg walker, RC airplanes & more in home page |