Alt-BEAM Archive

Message #13422



To: "'beam@sgiblab.sgi.com'" beam@sgiblab.sgi.com
From: Wilf Rigter wilf.rigter@powertech.bc.ca
Date: Fri, 14 Apr 2000 18:01:07 -0700
Subject: RE: Core-less walker


The SPU design by David Winchell is a true servo controller which will work
with unmodified servos. It produces a PWM signal and is quite different
compared to Ben's design which is a "motor driven pot in a servo feedback
loop with hysteresis".

wilf

> -----Original Message-----
> From: Scott Burns [SMTP:s-burns@uiuc.edu]
> Sent: Thursday, April 13, 2000 4:21 PM
> To: beam@sgiblab.sgi.com
> Subject: RE: Core-less walker
>
> At 12:18 PM 4/13/00 -0400, you wrote:
> >Hey I just breifly checked the list today, and I saw this. I don't know
> >how many people remeber, but there was a servo/pot feedback circuit
> posted
> >a LONG LONG time ago. I remeber it well because it was 'big fanfair'
> >because it was touted as a microcore type circuit that would never
> >saturate and worked on PWM. This circuit looks significantly simpler
> >however. Very nice!
>
> Is this what you are thinking of?
> =========================================================
> Date: Fri, 22 May 1998 14:31:41 -0700
> From: "David@Winchell.Net"
> To: "beam@palladium.corp.sgi.com"
> Subject: It's alive !! STOP HACKING THOSE SERVOS!! Throw away your
> springs.
> Reply-To: "David@Winchell.Net"
>
> Hello World, Tomorrow we WALK. It's time for the next step!!
> It's alive !!
> STOP HACKING THOSE SERVOS!!
> Throw away your springs.
> Stop falling over in mid stride.
> Stop trying to build pager motor gear boxes
> and start building killer walkers.
> A given from M. Tilden:
> Watch as machine evolution occurs.
> In other words, robogenetics through robobiologics.
>
> NOTE: THE FOLLOWING CIRCUIT DESCRIPTION IS COPYRIGHTED BY
> DAVID WINCHELL AS OF 22 MAY 1989 AND MAY ONLY BE USED BY
> BEAM MEMBERS FOR ENTERTAINMENT. NO COMMERCIAL APPLICATIONS
> ARE AUTHORIZED WITHOUT WRITTEN PERMISSION. WHAT BELONGS TO
> MARK TILDEN IS HIS AND MINE IS MINE. OH JUST HAVE FUN
> BEAMer'S
> My new walker NON-MODIFIED SERVO brain has run for 24 hours
> without going in to saturation.* I used 2 * 74HC14's and one
> 74HC125. One 74HC14 acts as a dual channel SERVO POSITION
> UNIT "SPU" Two of the inverters are wired to form a BI-core.
> two more inverters are wired to form half monostable one
> shots. R1*C1 AND R2*C1 are set to generate a 45 HZ rate
> triggers to the R3*C3 and R4*C4 half mono's. The R3*C3
> half mono is set to generate a 1.25 ms positive going pulse
> or 45 degree CCW position. The R4*C4 half mono is set to
> generate a 1.75 ms positive going pulse or 45 degree CW
> position. By using an SPU you can build and test your frame,
> legs and test it with one chip on a tether.
> --------------------------------
> | 1 2 3 4 |
> ----|>--+--C1--+--|>--+--C2--+--
> | | | |
> | R1 | R2
> | | | |
> | G | G
> | |
> | | 5 6 9 8
> | ----C3--+--|>----|>---- CCW POSITION
> | |
> | R3
> | |
> | G
> | 11 10 13 12
> ------------------C4--+--|>----|>---- CW POSITION
> |
> --|>-- 74HC14 R4
> |
> G
> If you use two push buttons you can test run your servo.
> ___________
> +6VDC | |
> ----------- | Servo red wire ---------
> | | -------------------+ |
> | | CW___ | |
> | +------o o----- Servo white wire | |
> | SPU | CCW___ +--------------------+ Servo |
> | +------o o----- | |
> | | | |
> | | -------------------+ |
> ----------- | Servo white wire ---------
> G
> Now that the SPU is working add the 74HC125 SERVO CONTROL
> UNIT or SCU.
> 1 ___
> ---RS-CW--o o--G
> 2 | 3
> ----------- --------|>----------------------+
> | | | 4 ___ |
> | | | ------- FS-CW--o o--G |
> | | CW | 5 | 6 |
> | +------+--|>---+ |
> | | | |
> | SPU | +--Front Servo White +--Rear Servo White
> | | CCW | |
> | +------+---|>--+ |
> | | | 9 | 8 ___ |
> | | | -------FS-CCW--o o--G |
> | | | 10 |
> ----------- ---------|>---------------------+
> 12 | 11 ___
> --RS-CCW--o o--G
> 13
> 74HC125
> ---- Tri-State Control, Ground to enable.
> |
> In --|>-- Out
> Note: I put 10K pull ups in 74HC125-PINs 1,4,10 & 13
> 74HC125-PIN 1 = G Then Rear Servo = CW RS-CW
> 74HC125-PIN 10 = G Then Rear Servo = CCW RS-CCW
> 74HC125-PIN 4 = G Then Front Servo = CW FS-CW
> 74HC125-PIN 13 = G Then Front Servo = CCW FS-CCW
> Now for the final step add the a Stabilized BEAM Quad Core. This
> design may be expanded to drive a 12, 16 and so on servo walker.
> Lookout MIT this may be the new wave. But the TIMING may Vary
> with user and cause variant and deviant behavior.
> --------------------------------
> | 1 2 3 4 | Core Stabilizer
> ----|>--+--C5--+--|>--+--C6--+--
> | | |
> --------- R5 R6
> | | |
> | G
> |
> |
> | Open loop Quad Core.
> | G1 G2 G3 G4
> --C7-+-|>-+-C8-+-|>-+-C9-|>-+-C10-+-|>---
> | | | | | | |
> R7 | R8 | R9 R10 |
> | | | | 1N914 Diodes
> | | | --+--|>|-- TO 74HC125-PIN 4 - FS-CW
> | | | |
> | | | ---|>|-- TO 74HC125-PIN 10 - RS-CCW
> | | |
> | | |
> | | --------+--|>|-- TO 74HC125-PIN 4 - FS-CW
> | | |
> | | ---|>|-- TO 74HC125-PIN 1 - RS-CW
> | |
> | |
> | ----------------------+--|>|-- TO 74HC125-PIN 13 - FS-CCW
> | |
> | ---|>|-- TO 74HC125-PIN 1 - RS-CW
> |
> |
> --------------------------------+--|>|-- TO 74HC125-PIN 13 - FS-CCW
> |
> ---|>|-- TO 74HC125-PIN 10 - RS-CCW
> Bi-Core State:
> Quad-Core Front Servo Rear Servo
> ===================================
> G1 = LOW CCW CCW
> G2 = LOW CCW CW
> G3 = LOW CW CW
> G4 = LOW CW CCW
> * Use .01 ceramic caps on all power leads.
> Use 10uf electrolytic on servo power leads.



13423 Fri, 14 Apr 2000 21:01:25 EDT Re: free form bots beam@sgiblab.sgi.com BUDSCOTT@aol.com If it's pointing up, its positive, i don't like that symbol myself. It gets
kinda confusing so i alway try to put (V+) instead, hope that helps!

-Spencer

<http://www.botic.com/users/beamstop>

not a robot scientist
not a college major
not a grad student
not a professor
not a very organized person
just Spencer (isn't that impressive enough?)



13424 Fri, 14 Apr 2000 21:07:03 EDT Nother walker! beam@sgiblab.sgi.com BUDSCOTT@aol.com !!!!!!!!!!HIP HIP HOORAY!!!!!!!!!!!!! I finally finished that little bugger
of a walker i've been working on for the past three some weeks! I used those
RM-1's with a KTU (kitchen timer unit) gear box, so if you want a good motor
for those darn KTU's, get yerself a couple of RM-1's, preferably from
solarbotics, because those still have the gear attached. I'll have pictures
up sometime this weekend after i've gotten to a point that it would look nice
enough for a picture! In the process of making this, i've kinda come up with
a new motor configuration for all of those bots with hyperactive legs. The
front motor is at a 45 degree angle, and the back motor angles in at a ten
degree angle, so they make a valley. Thanks for any indirect help you guys
might have thrown my way! C'ya

-Spencer

<http://www.botic.com/users/beamstop>

not a robot scientist
not a college major
not a grad student
not a professor
not a very organized person
just Spencer (isn't that impressive enough?)



13425 Fri, 14 Apr 2000 21:16:48 -0400 (EDT) Solar powered pendulumn project beam@sgiblab.sgi.com Jeffrey D Spears Greetings;

A few weeks ago I stumbled onto BEAM and have become interested in
the whole thing. Seeing how I am taking the second-term circuit
analysis course (FOCs, SOCs, diodes, mosfets--all both time and freq
domain)--Beam technology provides excellent test-bed to hammer it
all home. Fooling around at home, siren RC circuits are boring.
Beam circuits/applications look cool!

So I have in mind to build a Beam style solar powered pendulumn to
hang in my window. What I imagine is some sort of simple linear
motor--a magnet and big coil--delivering a little kick at the right
time. Once the appratus is built I can experiment with different
triggering methods, be it detecting the position of the pendulumn or
a resonate circuit tuned to the period of the pendulumn.

The motor itself may consist of a magnet attached to the pendulumn
via an arc of stiff metal rod. This arrangement would pass through
the coil, mounted to the base, as the pendulumn swings.

Intuition tells me that the push wants to be applied during the
time when the pendulum starts to move down from either side.
Playing with my pencil and a paper, I cannot see any easy way to
configure it this way. Therefore my idea is to have the coil in
the center of pendulumn travel. It will be pulsed with one
polarity when the pendulumn is traveling one way, and the other
polarity when the pendulumn is moving the other way. The pendulumn
itself will be traveling by this point at varying velocites which
will probably need compensating for.

If all this works out, then a seperate circuit could be added to
maintain operation overnight.

The PM-1 from Mike Tilden--a super-cap and timing network
contraption--looks like a fun little circuit and may be suited for
this application.

Any thoughts from the group? What would N. Tesla do?
What say you?

ok..jef


Jeffrey D. Spears
University of Michigan
College of Engineering

``Double-E, can't spell gEEk without it!''
-Captain Gerald M. Bloomfield II, USMC
(my brother)

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