Re: [CAD_CAM_EDM_DRO] Digest Number 3521

There is another place, other than EMC, where you can get Stewart Platform
kinematics code to play with.

I have Stewart Platform kinematics available to those who work under Linux
and can build code. Connections to other stepper drivers would be required
for specific systems.

Platform geometry is largely but not completely handled through a
configuration file. In particular, joint locations are in the
"joints.txt" configuration file, tool shapes (square endmill, ball endmill,
V-shaped) are in "/usr/etc/tool_table.txt", but screw-pitch is written into
the code.

This does not include a G-code reader. I'd like one, maybe even to write
one, but the G-code spec didn't seem to be much help, as there seemed to be
more variations than there were specifics. If someone has an example of
5-axis G-code, I could start from that as the spec.

This does include the kinematics handler for my pose language. It also
includes raster-to-toolpath conversion and some higher-level tool path
generation tools.

I never haven't found, with my Stewart Platform, that I need to take into
consideration acceleration dynamics, so the kinematics is first order. The
velocity can be (roughly) controlled. The kinematics processor does not
worry about the momentum of the platform. The hardware I have in the first
machine doesn't move all that fast (about 3/4 IPS), and the head isn't very
massive. The next machine (finally being assembled in my NEW workshop!)
will be faster and more massive, so I may need to extend the kinematics to
allow for controlled acceleration and jerk.

I can make CVS access to my repository available through SSH to developers.

This is my personal code, and anyone working with it will, no doubt, make
improvements. I'd hope that the improvements would be shared back with me,
[ and that it not go commercial without my involvement. :) ] .

-- Carl

At 07:56 AM 12/11/2003 -0600, you wrote:

>On Thursday 11 December 2003 5:56 am, CAD_CAM_EDM_DRO@yahoogroups.com
>wrote:
> > Message: 3
> > Date: Wed, 10 Dec 2003 15:07:59 -0500
> > From: "Simon M. Arthur" <chroma@...>
> > Subject: Re: Hexapod question
> >
> > I was messing around with EMC the other night and found that it only
> > let me tilt the platform in one direction, and wouldn't tilt it back.
> > Now it's giving me an error, saying that I must be in "teleop mode" to
> > move the platform, whatever that is.
> >
> > EMC seems to be functional, but it sure is a pain to use.
>
>Where elese are you going to find robot or Stewart platform kinematics for
>play?
>
>Ray
>
>
>
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