Re: Digitizing arm - CMM

Don Lancaster has some stuff on his Guru's Lair website about Virtual Ways.
What it boils down to is a series of six adjustable length rods that carry a
platform. By using trig to calculate the proper lengths of the rods and then
adjusting their lengths to match, you can make the platform move as if it
were on "virtual ways". Such a device might work very well for a 3D
digitizer.

A Virtual Ways platform could be constructed fairly easily with six motor
mount/gymbals, six ball joints, six linear steppers with the built in acme
nuts and two Camtronics three axis boards each connected to its own parallel
port.

The programming of such a beast is left as an exercise for the student ;-)

Jon Croad