Newsgroups: comp.robotics
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From: hinkle@rdd.lmsc.lockheed.com (David Hinkle)
Subject: Re: RWI B21 vs. NOMAD 200
Message-ID: <Cvq17M.JrK@butch.lmsc.lockheed.com>
Sender: news@butch.lmsc.lockheed.com
Reply-To: hinkle@rdd.lmsc.lockheed.com
Organization: Lockheed Missiles & Space Co.
References: <33uojp$30s@wega.rz.uni-ulm.de>
Date: Tue, 6 Sep 1994 18:40:33 GMT
Lines: 118


Hello,


We here at Lockheed's Artificial Intelligence Center have had a
Nomad 200 for a couple of years and have found it to have both
very reliable hardware and quite sophisticated software.  The 
hardware has performed quite reliably throughout two years of heavy 
use and multiple cross country shippings.

The Nomad has a very strong base and a complete sensor suite. The 
robot base is quite stable, very powerful, and has an exceptionally
strong bumper.  In the 1993 AAAI Robot Competition (Washington D.C.) 
we successfully used the robot to autonomously push very large boxes 
around the arena.  The robot has two rings of tactile sensors built
into the bumper.  The robot has a modular sensor suite design.  
For example, in the 1993 robot competition we used the standard configuration of
infrared sensors as our bottom floor.  This allowed us to reliably
determine the box orientation while we were pushing it.  For the
1994 AAAI Robot Competition (Seattle, Washington) we wanted to switch
to two rings of sonars, one high and one low, to create a wall of
sonar which no chair or table top could penetrate.  The Nomad's 
modular sensor design allowed us to rapidly substitute an extra
sonar ring for the infrared.  If necessary, we could have even kept 
the infrared ring and had three sensor floors.

In addition to the standard infrared and sonar sensors, the Nomad also
has a very accurate laser range finder, which can detect the range to 
objects within a tenth of an inch.  We have used the laser to build
quite accurate feature maps as we manuver through rooms. This, coupled 
with the independent turret axis, allows the robot to point the laser 
in one direction while traveling in another.  The independent turret 
is very important if you want to, for instance, scan a wall for door 
openings.  The independent turret becomes especially important if we 
decide to add Nomadic's new manipulator arm later this year.

When we were considering which robot to purchase, one of the key
ingredients (in addition to very reliable hardware) was sophisticated
software.  We were looking for a software development environment that
would allow us to program both at the lowest levels of the hardware 
(when necessary) and at the much higher cognitive level, where our 
real research interests were.  Nomadic, through their software
toolkits provide this high level software which makes advanced
software development much easier.

In our experience what has made the Nomadic robot a success is the
high level of integration between the sensors and the software.  The
robot comes with a very good simulator which allows you to develop 
programs quickly, and literally with a click of the mouse, switch
from the simulator to the real robot.  We have found this to be quite
useful.  For example, if we want to develop code which performs a 
particular behavior, we would develop the software and test it on the 
simulator.  Then, when the code is ready, we choose the "Real Robot" menu 
option and instead of the program's commands going to the simulator, 
they go directly to "Argus" (our Nomad 200 robot).  

Some people might complain that just because something works on a 
simulator doesn't mean that it will work on real hardware, and of 
course that is true.  But the reverse is true also, if it doesn't 
work on a simulator, it definitely won't work on the hardware.  
There is no substitute for having real hardware in the loop, but for 
rapid code development a full simulator makes life a lot easier.


David Hinkle
Senior Scientist
Lockheed Artificial Intelligence Center
Orgn. 96-20,  Bldg. 254F
3251 Hanover Street
Palo Alto, CA, U.S.A.  94304


hinkle@aic.lockheed.com
(415) 354-5237 (Phone)
(425) 354-5235 (FAX)



=====================================================================

> Hi!
>
> Is anybody out there who has experience with either the B21 platform 
> sold by RWI or the NOMAD 200 platform from NOMADIC technologies? I am
> thinking of a configuration which includes 
> 
>  *  a mobile base
>  *  a sonar ring
>  *  a ring of IR sensors
>  *  a programming environment 
>     - which provides a higher-level control language with commands
>       like move(A,B) or turn(X)
>     - which also allows one to access the lower levels of control 
>       and set and read parameters such as the motor velocity.
>
> Both companies seem to offer such a configuration. Besides the price - 
> the NOMAD 200 platform seems to be cheaper - what is the difference 
> between both systems, what are their advantages and disadvantages, and 
> which one is better?
>
> Any information is welcome!
>
> -- Erwin Prassler
   
> **********************************************************************
> Erwin Prassler                        
> Research Institute for Applied        
> Knowledge Processing                  
> Helmholtzstr. 16                      Phone:   +49-731-501-621
> D-89081 Ulm                           FAX:     +49-731-501-999
> GERMANY                               E-Mail:  prassler@faw.uni-ulm.de
> **********************************************************************






