Alt-BEAM Archive

Message #06197



To: beam@sgiblab.sgi.com
From: "George Rix" rix.g@bmts.com
Date: Mon, 27 Sep 1999 12:30:41 -0400
Subject: [alt-beam] Re: master/slave bicore walker problems


> Curious... when I hold the bot in the air, the motors seem to be just fine.
> It's just when I put it on a surface when it starts freaking out. I assumed
> that meant it was getting feedback. Is there something else going on?
What you might try is changing the value of the resistors on the neurons
that control the back legs. Take the value down a bit until it stops going
too far.
Just a thought.
Signing off,
Rob Rix

___________________________________________________________________________
'Your simian countenance suggests a heritage unusually rich in species
diversity' - Calvin & Hobbes, by Bill Watterson



6198 Mon, 27 Sep 1999 17:28:50 +0100 [alt-beam] Re: master/slave bicore walker problems beam@sgiblab.sgi.com James G Watt In article ,
Phillip A. Ryals writes
>I'm new, so please forgive my ignorance...
>
>I put together the master/slave bicore circuit (Using a 74HCT240)on
>beam-online. I have the motor leads running into a 74HCT245 to bump up the
>signal, and it's driving two R/C servos.
>
>When I turn it on, the bot will take two or three steps ok, then the back
>legs will turn about 30 degrees too far. In no time it's on it's side and
>helpless.

I'm a newbie to this stuff also and I was having similar problems. I can
see no discernible feedback from the motors what so ever. I'm told not
to expect to see much from inefficient motors but I'm curious as to what
the experts have to say on the subject.

I did find a low tech solution to the problem you're describing though.
At first my machine took 3 steps then promptly tied its self into a
knot. Instead of putting in a STOP to prevent the motors going to far (I
found that lead to a jam and the bicore resetting) I put in 4 very light
springs so that they exert just enough force to keep the legs in trim
(usually). This appeared quite successful and my walker trots along
quite happily now although it does require quite a lot of power I think.
--
James G Watt

http://www.kinetic-arts.demon.co.uk
Part of the Video Arcade Game Collectors WebRing.

You are in a maze of twisty little passages, all alike.



6199 Mon, 27 Sep 1999 12:19:51 -0500 [alt-beam] Re: master/slave bicore walker problems "Phillip A. Ryals" >I put in 4 very light springs so that they exert just enough
>force to keep the legs in trim (usually). This appeared quite
>successful and my walker trots along quite happily now although
>it does require quite a lot of power I think.

Where did you attach the springs? Just a central point, or did you tie
opposite legs together?

Home