Alt-BEAM Archive
Message #11363
To: beam@sgiblab.sgi.com
From: Ian Ian@beam-online.com
Date: Sat, 04 Mar 2000 23:41:53 -0700
Subject: [alt-beam] 3 motors vs. 4 motors vs. 5 motors
Hi BEAMers. After seeing the "4 motor walkers" thread I thought I'd add to
this. These are a few things I have found...
4 Motor walkers:
There are two main types of 4 motor walkers. Those that have the motors
mounted vertically (Stryder, Roswell) and those that have that have the
motors mounted horizontally (Scoutwalker II). There are some advantages and
disadvantages of both.
Vertical::
This method has been used a lot. In old walkers like Walkman, and new
walkers like Roswell. The main advantage of this is that it can carry lots
of weight. Little force is used to lift the bot, most is used to propel the
walker forward. The big disadvantage is that you don't get much lift on each
leg which means your going to be limited to tables and other smooth
surfaces.
Horizontal::
The horizontal method, I would say, is more universal. It has a good balance
between climbing and still moving fast in a forward direction. The
disadvantage is that it can't carry much weight. You may be able to get lots
off stuff on there but the batteries won't last very long (not long at
all!). This is a good method, but like mounting the vertical you still don't
get much "climbing" ability.
What to chose?::
From my experience I would say "Do a 3 motor walker!". I know you might be
like "more the better" but I would have to say that a 3 motor walker will
give you better performance. But...
-------
5 motor walkers:
From what I've seen a five motor walker is the way to go! Just look...
Walkman, Lobster, Chiu's walker. They all have five motors and hey perform
VERY well. You get the advantages of a four motor walker with another motor
for lift which means you will get amazing climbing performance. You don't
need all five motors to be the same. The waist motor can be of a different
type as long as the RPM isn't more than the leg motors. I am building one
right now in fact. I promise I will get all the info on it as soon as I'm
done onto my web site.
-------
So.... 3 vs. 4 vs. 5?::
3::
Use if you can't find 5 motors.
4::
I would advise against this. You can get better performance out of a three
motor design or a five motor design if you have the motors. Although a
vertical type four motor would be good as a sensor test platform.
5::
This would have to be my recommendation. If you can get the motors it will
give you very good performance in both the walking speed and climbing
aspects.
Happy Building
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