Re: [CAD_CAM_EDM_DRO] Re[1]: digitising arm

you could use an LVDT to mesure the joint angle of a polar based probe
arm if you built the arm like a mini-backhoe with the LVDT in place of the
hydraulic cylinders but the range of motion would be limited
a high quality potentiometer or two (differential signals) at the joint pivot
might give a better range and there are resolvers and high count encoders
to look at as well
the EMC source includes kinematics for a PUMA 560 polar coordinate
robot arm

Brian
PS; where would you zero an incremental encoder ? ;-)

> This makes sense for a cartesian based probe. Does it make sense for
> the multi-axis (encoders at the joints) digitser? I mentioned earlier
> that loading "arm" kinematics into EMC should work (using just the
> feedback portion of the code).
> Ballendo