Re: [CAD_CAM_EDM_DRO] Re: Hexapod question

Take a look at http://www.hexel.com/ at the Hexabot. It looks like a
Bridgeport mill with the knee and table replaced by a round t-slotted table
that is controlled by a hexapod mechanism. There are some neat videos of
the machine working. Makes you want to build one.

At 04:27 PM 2003/12/10 +0000, you wrote:

>Hello everyone,
>Can someone answer this stupid question for me????
>What would be the need for a hexapod machine anyway?
>I think it is cool & would probably build one myself if I had the
>time, but can't seem to figure out a use for one??? haha!!
>Any Ideas?
>Thanks, Tim Bostic
>
>--- In CAD_CAM_EDM_DRO@yahoogroups.com, Ray Henry <rehenry@u...>
>wrote:
> >
> > > From: Jon Elson <elson@p...>
> > > Subject: Re: Hexapod question
> > >
> > > Simon M. Arthur wrote:
> > > >I've started building a hexapod on the cheap. Some photos:
> > > >http://www.tinyplanet.com/images/hexapod-portrait-reduced.jpg
> > > >http://www.tinyplanet.com/images/dscf0011-reduced.jpg
> > > >
> > > >I noticed that the platform can be rotated and tilted more or
>less
> > > >freely, even with power going to the steppers. Translational
>movement
> > > > is a lot harder. This makes me think that I misunderstood
>completely
> > > > how a hexapod is supposed to work. I have a universal joint on
>the
> > > > frame so that the motor can tilt, and another on the platform.
> > > >
> > > >Can this setup be made to work? Why doesn't my hexapod lock the
> > > > platform in place?
> > > >
> > >
> > > The only way a hexapod (Stewart platform) maintains alignment of
>the
> > > platform
> > > is by controlling the lengths of all 6 struts in a coordinated
>way.
> > > EMC can drive a hexapod, but it doesn't really allow tilting of
>the
> > > platform. But, you can translate the platform in 3 cartesian
> > > coordinates rather nicely.
> > >
> >
> > Hi Jon, Simon
> >
> > As of a while ago, the EMC motion planner can tilt the hexapod's
>platform.
> > Till Franitza in Stuttgart has been doing this with his desktop
>models.
> > You can see both stepper and servo version photos and a movie at
> >
> > http://www.isw.uni-stuttgart.de/personen/t_franit/modell/index.html
> >
> > There is some pretty novel work on platform geometry with Model 2
>where
> > three of the the struts interact with the three other struts rather
>than
> > with the platform itself. This allows for a much larger angle of
>tilt
> > before the system approaches a singularity.
> >
> > If your German conprehension is as poor as mine, there is a Queen's
> > English version that can be reached by clicking on the Brit flag.
> >
> > Ray
>
>
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