Re: degrees of freedom - Hexapod

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "Graham Stabler" <eexgs@...>
wrote:

>
> --- In CAD_CAM_EDM_DRO@yahoogroups.com, "Raymond Heckert" <jnr@> wrote:
> >
> > Look closer... If you have 'fixed' length struts (I mean really
> fixed, not
> > extensible or retractible) the platform cannot move. On a hexapod,
> at least
> > two adjacent struts must be extensible to have even one degree of
> freedom.
> > four adjacent extensible struts should allow you 3 degrees of
> freedom, and
> > all 6 struts movable should give you your 6 degrees of freedom.
> ...Unless
> > my observations are greatly in error...
> >
> > RayHex
> >
>
>
> The struts do not have to change length you can change the position of
> there bases as is done in hexaglides and triaglides and delta robots.
>
> Graham

The video clip showed fixed struts and moving bases. Very clever to
be sure.

The only thing it did not show was the table going striaght up and down.

But since the I had thought that the struts needed to be in some form
of tension, and the round table has all the struts at roughtly a 45
deg, it seems they are at a mechanically weak location. Yes, bigger
motors solves that problem.

How many people acutally offer such a thing on a new machining center ?

Dave