Newsgroups: comp.robotics
From: lyndond@roverpte.demon.co.uk (Lyndond David)
Path: brunix!news.Brown.EDU!noc.near.net!howland.reston.ans.net!europa.eng.gtefsd.com!uunet!news.sprintlink.net!demon!roverpte.demon.co.uk!lyndond
Subject: Ultrasonics - room mapping
Distribution: world
Organization: Rover Group
Reply-To: Lyndond@roverpte.demon.co.uk
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Date: Wed, 13 Oct 1993 23:29:06 +0000
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I hope that there are some ultrasonics gurus out there.

I am building a robot that has an ultrasonic transmitter and receiver sticking
out of the top that can be rotated in steps. I want to be able to stop the
robot and do a sweep blatting out pulses every 10 deg or so. 
The transducers I have are very small. They belong in a car alarm and were
left over from developement. They are only 10mm in dia and run at 40k. The
problem is that they have a very wide beam and this needs to be drastically
reduced in width without producing excessive side lobes.
If I use a horn to improve directionality how big does it have to be and where
can I look to find the theory? Are there alternatives to horns?
Is there any particularly good literature that I could look at covering the
accoustics and the signal processing of the returning signal or could anyone
out there post any knowledge they may have.

When the design is finished would anyone be interested in a copy of the
schematics and the Gerber files for the PCB? You are also welcome to have
a copy of the schematics in machine readable form if you are able to read
Mentor Graphics v7 files. 

Anyone interested in being on a mailing list for the discussion of the design
info please send 
your request to the one below giving your address and what projects you are 
working on. I would be interested in a joint developement if anyone out there
is interested and is willing to put the finished design into the public domain.
I hope that all being well between us we can produce a professional design in
the public domain that is accessable to all via the net that performs as well
as commercially available systems.
I will post design information in microsoft rich text format as it becomes
available. Please indicate if you cannot handle rtf and I will try to
generate postscript instead.

lyndond@roverpte.demon.co.uk

Any know of any good research papers on navigation and utrasonics I know of
the following to far and would be interesed in others particularly if they are
avalable on the net

Exploration and model building in mobile robot domains
Sebastian B Thrun
Proceedings of IEEE international conference on Neural networks April 1993

Sonar based real world mapping and navigation
IEEE journal of robotics and automation
RA-3(3)249-265 June 1987


-- 
Lyndon David
Rover Group - Vehicle and Powertrain Electronics
My views not of my employer etc.....
