Alt-BEAM Archive
Message #09042
To: beam@sgiblab.sgi.com
From: Dave Hrynkiw dave@solarbotics.com
Date: Tue, 11 Jan 2000 11:37:44 -0700
Subject: [alt-beam] Re: Pager Motors (Was parts source)
At 06:24 AM 1/11/00 , Jonathan D Rogers wrote:
>Are there more effecient motors than pager motors out there? Because I'm
>about to go buy some, but I'm not going to do that if there are better
>motors out there...
You bet. Pager motors are relatively efficient, but there's always better
ones, especially depending on the application. Pager motors are designed
for RPM, not torque, so if you want a slower, torquier motor, select one
with a bigger outside diameter. If you want speed (rpm), narrower is
better. I've got some killer "pancake" motors that are wide and flat, and
have TONS of low-rpm torque. They were originally used for tape-transport
mechanisms in old audio tape recorders.
>And what exactly is a coreless motor?
In a "traditional" motor, you have the magnets on the outside, and a
spinning coil on an armature on the inside of the magnets. A coreless motor
is like making a coil in the shape of a pop can with one end clipped open,
and having a large magnet "inside" the can.
>Could you modify the windings on a pager motor, or are they too small?
WAAAAAAY too small. No chance of tweaking the windings, I'm afraid. They're
little works of art, and much too find to alter.
>Cos I wsa reading about DC motors that they rewound with bigger wire and
>less turns to give more power for R/C racing cars.
Yes, for traditional core-type motors, this is much more to be a possibility.
>Heck, a BG Micro lens motor would be great, if they were for sale
>anywhere...
They are very nice indeed....
Regards,
Dave
---------------------------------------------------------------
"Um, no - that's H,R,Y,N,K,I,W. No, not K,I,U,U, K,I,_W_. Yes,
that's right. Yes, I know it looks like "HOCKYRINK." Yup, only
2 vowels. Pronounciation? _SMITH_".
http://www.solarbotics.com
9043 Mon, 10 Jan 2000 22:47:29 -0500 [alt-beam] Re: BIPEDS -- reflections on the Honda Humanoid Robot. beam@sgiblab.sgi.com "Peter A. Low" Insightful. Can I give you a call sometime when I'm stuck trying to figure
out what a company's strategy is going to be?
At 05:14 PM 1/10/00 -0800, you wrote:
>Be clear in your minds. Honda is not giving a bunch of money to their
>engineers so they can play and have fun. This is a commercial venture.
>
>Having said that; the typical North American manager thinks of "long
>term" as roughly 3 to 5 years. That is very approximately how long the
>typical manager stays in one particular position before moving on. The
>typical Japanese manager thinks of "long term" as roughly 3 to 5
>decades. That is very approximately how long the typical manager is
>EMPLOYED.
>
>Honda is taking the long term view here. What happens when automobiles
>are too expensive for middle class families to operate? What happens
>when cities are so crowded that there is no place to park; when public
>transit is cheap and convenient for just about everybody? What's Honda's
>product going to be then? Motorcycles, for sure, but what will replace
>automobiles in their product line?
>
>How about a household appliance, roughly the same price as an economy
>car, that can actually do all those mundane housekeeping chores?
>
>Note the name of the project "... Humanoid ...", which means "having
>human characteristics". It doesn't mean "looking exactly like a human".
>In fact, the Japanese aesthetic sense is quite different from ours. Much
>of their art, their cartoons, their theatre exagerates certain
>characteristics (by western standards). So they are NOT trying to make a
>machine that looks (or moves) exactly like a human.
>
>Don't ever get the idea that their walker motion is "right", or "the
>best". They are trying to make an appliance that can move around a
>typical home and do chores. This is not just a biped walker project.
>They are dealing with vision, recognition, obstacle avoidance, picking
>things up and manipulating them. Walking is just a small part of the
>project.
>
>Kyle commented on the "bodywork". Why spend all that effort on a one-off
>prototype, anyway? I can think of several reasons:
>
> - The finished product will have to be easy to clean and maintain.
> May as well plan for that right from the start.
> - The weight of the shell is going to affect the motion. Better to
> develop the two together, rather than build a viable skeleton and
> then screw it up by adding a body.
> - Better learn about production problems with the shell right
> at the start. When you finally market it, you'll be way ahead
> of the competition.
> - Free advertising. The media loves it whenever that robot makes an
> appearance. And it looks finished -- just needs some refinement,
> right? When the first robot hits the market, whose are you going
> to buy? The other guys'? Or the one you saw a prototype of twenty
> years earlier? Now THOSE guys must know what they're doing.
> - Ever seen a video of this robot with the shell off? Not likely. If
> they had taken out any patents on their earliest developments, those
> patents would be expiring in the next couple of years. Perhaps it's
> better to just keep everything hidden and don't give away your
> secrets until closer to marketing time.
>
>I'm sure you will see a P4 and a P5 over the next decade. I wouldn't be
>surprised if at least one of them is on the drawing board right now.
>Perhaps you'll see an extra degree of freedom in the lower leg, and
>perhaps toes will appear sometime.
>
>So don't limit your ideas by what people with big budget dollars are
>doing -- they have a different agenda. Look at what they do, understand
>what and why, and then go do what you planned to do in the first place.
>And never be afraid to build a simple version first before tackling the
>more complicated one. The time is never wasted, as long as you learn
>from it.
>
>Cheers,
>Bruce
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