Alt-BEAM Archive
Message #12905
To: beam@sgiblab.sgi.com
From: Joe [mailto:doodle@teleport.com]
Date: Sat, 1 Apr 2000 09:05:01 -0800
Subject: Fttaba servo as motor/gearbox combo.
Hi,
Maybe this subject is old news? I've been thinking about doing a Ch=
iu style walker, but have not found similar gear box motors. I now plan to =
use three old Futaba servos, as I discovered how to modify them.
If anyone is interested in the process please let me know. I could =
write up the conversion and forward it.
The main point is that they are reversable DC motors and not steppe=
r motors. Perhaps I'm the last one on earth to discover this ;-)
Joe
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x; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
----- Original Message -----
Sent: Friday, March 31, 2000 3:10 =
PM
Subject: RE: Fttaba servo as =
motor/gearbox combo.
31032000>I =
leave them on the gear train. It's a bit complicated without talking it =
through, but I will try. Attached is an ugly ugly sketch, but legible I =
hope.
31032000>The =
resistance to ground in the neuron is only important when the pulse is =
actually in that neur
AN =
class=3D211541021-31032000>on. The pot=
position =
corresponds to the leg position. So when a leg is too far off center, the=
=
resistance is higher than 'normal', causing the pulse to remain in the ne=
uron =
longer, making the leg move further the other way. The walker will straig=
hten =
itself back out (and exhibit some other interesting behavior, such a shuf=
fling =
or sidestepping depending on your motor setup) in three or less steps if =
left =
alone.
class=3D211541021-31032000>
31032000>I =
really like it because the walker has more feedback on where its legs are=
and =
can straighten them out itself. You could alter that behavior a little by=
=
making your capacitors smaller and putting an additional resistor between=
the =
pot and ground. That should keep the legs from straightening too =
quickly.
class=3D211541021-31032000>
31032000>To =
make up for the lower resistance in the pot however, you will have to inc=
rease =
the size of the capacitor and it will create more current =
drain.
class=3D211541021-31032000>
class=3D211541021-31032000>Hopefully that helps,
class=3D211541021-31032000>
class=3D211541021-31032000>Vincent
class=3D211541021-31032000>
class=3D211541021-31032000>
class=3D211541021-31032000>
class=3D211541021-31032000> -----Original =
Message-----
From: Jeffrey B. Williams =
[mailto:jeffrey.williams@prodigy.net]
Sent: Friday, March 31, 2=
000 =
17:22
To: beam@sgiblab.sgi.com
Subject: Re: Fttaba se=
rvo =
as motor/gearbox combo.
I've been meaning to ask this question=
, are you =
just using the servopots for tuning or are they left connected to the g=
ear =
train???
Jeff
style=3D"BORDER-LEFT: #000000 2px solid; MARGIN-LEFT: 5px; MARGIN-RIGHT=
: 0px; PADDING-LEFT: 5px; PADDING-RIGHT: 0px">
----- Original Message -----
Sent: Thursday, March 30, 2000=
10:12 =
PM
Subject: RE: Fttaba servo as =
motor/gearbox combo.
class=3D592480806-31032000>This may also be old news:
DIV>
class=3D592480806-31032000>Consider using the pot in the servo (if it=
has =
one) as the resistors in a (micro)core. It will center the legs if th=
ey =
get off (the capacitors get pretty big though). It worked for =
me.
class=3D592480806-31032000>
class=3D592480806-31032000>Vincent
Hi,
Maybe this subject is old news? =
I've been =
thinking about doing a Chiu style walker, but have not found simila=
r =
gear box motors. I now plan to use three old Futaba servos, as I =
discovered how to modify them.
If anyone is interested in the process pl=
ease =
let me know. I could write up the conversion and forward =
it.
The main point is that they are reversabl=
e DC =
motors and not stepper motors. Perhaps I'm the last one on earth to=
=
discover this ;-)
face=3DCourier>Joe
CKQUOTE>
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