Re: [CAD_CAM_EDM_DRO] Re: Hexapod question

----- Original Message -----
From: "Mariss Freimanis" <mariss92705@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Wednesday, December 10, 2003 10:02 AM
Subject: [CAD_CAM_EDM_DRO] Re: Hexapod question


> Aren't ful motion flight-simulators hexapods?
>
> Mariss
>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Tim" <luvindaddy@y...> 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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