On Sat, 15 Mar 2008, [EMAIL PROTECTED] wrote: > The second thought is EMC2 related. The linear scales, while very > accurate in themselves have not proven to be very good for use with EMC2 > control. The problem has to do with backlash in the drive components. > Our backlash compensation counts encoder pulses to find the other edge of > the lash whenever the direction reverses. Since the linear scale is > connected on the work piece side of the lash EMC will not see pulses > until the lash has been taken up. Even small amounts of lash will cause > a well controlled servo system to hunt and overshoot. We've talked about > using a motor driven encoder connected to one PID loop in our software to > handle this lash problem and another PID connected to the linear scale to > handle final positioning. I don't know that any real tests of such a > system have been reported.
Done and done. See http://jmkasunich.com/cgi-bin/blosxom/shoptask/wichita-trip-02-20-08.html ------------------------------------------------------------------------- This SF.net email is sponsored by: Microsoft Defy all challenges. Microsoft(R) Visual Studio 2008. http://clk.atdmt.com/MRT/go/vse0120000070mrt/direct/01/ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
