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 -----


style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black">Fro=
m:
=


title=3DVermeulenV@health.missouri.edu>Vermeulen, Vincent

To:
href=3D"mailto:'beam@sgiblab.sgi.com'" =

title=3Dbeam@sgiblab.sgi.com>'beam@sgiblab.sgi.com'

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 -----


style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: black"> >From: =


title=3DVermeulenV@health.missouri.edu>Vermeulen, Vincent

To:
href=3D"mailto:'beam@sgiblab.sgi.com'" =

title=3Dbeam@sgiblab.sgi.com>'beam@sgiblab.sgi.com'

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


=3DTahoma =

size=3D2>-----Original Message-----
From: Joe [
href=3D"mailto:doodle@teleport.com">mailto:doodle@teleport.com
]=

Sent: =

Thursday, March 30, 2000 23:33
To:
href=3D"mailto:beam@sgiblab.sgi.com">beam@sgiblab.sgi.com

>Subject: =

Fttaba servo as motor/gearbox combo.


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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