Newsgroups: comp.robotics
Path: brunix!uunet!spool.mu.edu!sgiblab!sgigate!odin!sgihub!sgitokyo!exagw!nkkgw!hattori
From: hattori@csrd.nkk.co.JP (Mato Hattori)
Subject: Re: making 90 degree turns
In-Reply-To: chu@waikiki.tti.com's message of Fri, 25 Jun 1993 22:49:11 GMT
Message-ID: <HATTORI.93Jun29115558@athena.csrd.nkk.co.JP>
Sender: news@csrd.nkk.co.jp
Organization: Computer System Research Dept., Elec. R. Center, NKK Corporation,
	Kawasaki, JAPAN
References: <1993Jun25.224911.3512@ttinews.tti.com>
Date: Tue, 29 Jun 1993 02:55:58 GMT
Lines: 35

In article <1993Jun25.224911.3512@ttinews.tti.com> chu@waikiki.tti.com (King-Hang Chu) writes:

 |   If I want to make a robot to turn 90 degree, how can I determine if
 |the robot have finished the turn ? (i.e no overshoot/undershooting) 
 |assuming a Big Track type mobile base platform is used. 

That's really big stuff here in robotics world.  Here is a few
possible solutions.

1. Directional Gyro
	This device is used by many Aircrafts. Even a Radio-Controled
	Helicopter can have one (usually, RC Heli uses Rate Gyro, not
	Directional).  Turnning degrees can be directly read from the
	device as analog value.  Very accrate, but expensive.

2. Sensoring Fixed External Landmark
	Using Super-Sonic Sonar Sensors or Light Eletric Switches,
	keep detecting the landmark(s) fixed in external environment.
	Bit difficult, I guess.  It's depend on what application the
	robot would be used. (hard to find landmark in some case)

3. Controling Wheels' Odmetery Presicely 
	Using Two Rotaly Encoders, determine rotation of wheels,
	calcurate length of circumference of the circle drawed
	by wheels.  It may have error.  I believe this is the most
	popular way of controling robots.


If there's another solution, please post an article in this news
group.  I guess, many people are interested in this matter.
--
Mato  Hattori                      Computer System Research Department,
email : hattori@csrd.nkk.co.jp     Electronics Research Center, NKK Corporation
voice : 81+44-322-6281 (office)    1-1 Minamiwatarida Kawasaki-ku
      : 81+44-246-9665 (home)      Kawasaki-city, 210 JAPAN
