Re: Hexapod design drawings

--- In CAD_CAM_EDM_DRO@y..., Doug Fortune <pentam@h...> wrote:
> rab@r... wrote:
>> >
>> > Doug,
>> >
>> > How are the joints for backlash ?
>>
>> The socket universals that I purchased, have no backlash.
>> And of course being designed for high torque (a hundred or
>> more foot pounds of torque) they are up to the task (for a
>> small machine).
<S>
>I was wondering if the way the pivot point is on the univesal joint
>going to complicate figuring positioning because it is not going to
>pivot from the same point like ball joint would.

With the possible exception of an imaginary, perfectly geometric hexapod,
with point swivels and zero length overhang on the struts, figuring the
lengths and angles is going to be complicated no matter how it is
constructed.

One fellow I visited in Stuttgart Germany had gotten all of his numbers
close to size and was about to bore a rectangular pattern of holes in a
2' square chunk of aluminum at known temp and then check them with a cmm.
He did have the advantage of having a very accurate cmm right in the shop.

Ray