Re: degrees of freedom Was: Angle Iron Ways

Dennis,

What you might not have noticed as that they are examples of PARALLEL
kinematics.

Kinematic can just mean motion, if you get a book on kinematics it is
often full of linkages and cams and shows how their motion can be
predicted or designed for. Parallel kinematics uses several things
that move separately (in parallel) to each other but affect some
common element so you get things like hexapods, stewart platforms and
lots more.

See some stuff from me here:

http://www.indoor.flyer.co.uk/kinematics.htm

However, in terms of a positioning stage, especially those used in
optics the term kinematic is used to mean that the position is fixed
by (at least 3) rigid points. The typical mirror mount used in optics
has three points of contact that fully define the tilt and sometimes
one linear axis (if you have three screws rather than two and a ball).

Check out:

http://www.thorlabs.com/Navigation.cfm?Guide_ID=71&Visual_ID=1892

I think the term is used to distinguish between this sort and gimbled
mounts.

Graham