Re: Probing

[Carl Mikkelsen <cmm-at-alum.mit.edu>]

Hi Doug,

At 12:53 AM 1/16/02 -0500, you wrote:


> > I need to get onto EMC, if for no other reason than that the development I
> > do can be shared.  I'm running with regular linux, with the clock rate
> > turned up to 1000 HZ.  This works well for me, especially with the new
> > motor drivers I should be getting back from the PCB shop in a about two
> > weeks.
>
>So does this mean you are using some kind of comercial controlling
>software?

No, I'm doing everything with homebrew software and Linux.  I wrote a 
kernel driver that does 6-axis coordinated movement in hexapod leg 
coordinate system, and fronted that with a user-mode process which breaks 
linear 6-axis Cartesian movements (XYZPRW) into leg movements.


> > This is a picture of my probe:
>
>
>Tried the link but I could'nt get there.  Sure would like to see it.

My error.  I pasted the URL from inside my firewall, not from 
outside.  This should work.

http://www.foxkid.net/cgi-bin/next-res.pl?home_album=/Processed/Carl%27s%20Projects&basedir=./Processed/Carl%27s%20Projects/Stewart%20Platform/Truck%20Signs&res=svga&name=PA250761.JPG&album_name=Truck%20Signs

> >
> > My application was much simpler than determining the 3D shape of a model.
> > I needed to carve some line art, photographs, and lettering into cherry
> > panels.  For the photograph to look good, I needed to be able to carve
> > closely to the surface, which required that I know where the surface was.
> > Being glued-together wood boards, there was warpage and more unevenness
> > that I could ignore.  I used the probe to map the surface height in a grid,
> > and then bilinear interpolated the Z offset I needed at each point.
> >

Here is a picture of the sign, before applying finish to the wood.

http://www.foxkid.net/cgi-bin/next-res.pl?home_album=/Processed/Carl%27s%20Projects&basedir=./Processed/Carl%27s%20Projects/Stewart%20Platform/Truck%20Signs&res=svga&name=PB040782.JPG&album_name=Truck%20Signs


>Interesting.  I was thinking of making a similiar utility to take the Deskcam
>Font output and use the probe "point cloud" so that you could conform the text
>onto a curved surface.

It would be pretty simple within my software to take the Z-axis 
interpolation I'm doing now and change it to output a normal vector to the 
surface along which the cut should be made.  My Stewart Platform machine 
has limits on the angles, depending on where in the working volume the tool 
need to be.  How curved a surface are you intending?

Sounds like tk/tcl is the tool of choice.  Is there any code you'ld 
recommend I read to learn it?

-- Carl


Carl Mikkelsen
cmm-at-alum.mit.edu
www.foxkid.net