Dave wrote: > Who really cares where your motors are at if you can accurately control > the actual position > via the scales? Backlash will not be compensated but the velocity > mode stepgen won't care. The PID loop will try and compensate. > Yes, but with larger amounts of backlash, the motor may tend to hammer back and forth across the backlash. > Does anyone know if Stuart is using screw or backlash comp on that big > horizontal mill that is setup with a dual loop and direct reading scales? > > I would bet that he is not. > I believe he was using screw compensation, and is either still using it or has integrated it into a general 5-axis kinematics correction system, for the 5-axis Cincinnati machine. His main goal there was to correct some orthogonality error on the 3-axis base, as well as correct for misalignments of the centers of rotation on the A & B axes in the head.
I think it is his Giddings and Lewis horizontal mill that has the dual loop control. Since Stuart's shop has a Renishaw (I think) laser interferometer, he can measure the error on these big machines relatively easily to build the correction tables. Jon ------------------------------------------------------------------------------ This SF.net email is sponsored by Make an app they can't live without Enter the BlackBerry Developer Challenge http://p.sf.net/sfu/RIM-dev2dev _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
