Honestly - I think servos are the way to go in this situation.. The hardware for true closed loop servo with emc is getting very inexpensive (with ebay and all ;))
but - if you are serious about playing with it.. Take a look at the motion.adaptive-feed pin. http://www.linuxcnc.org/docs/2.2/html/gcode_main.html#sec:M50:-Feed-Override someone has already shown that emc can be used with stepper-encoder to throw a following error.. http://cnczone.com/forums/showthread.php?t=43517&highlight=emc2+error another good thread here. http://cnczone.com/forums/showthread.php?t=37309 sam ----- Original Message ----- From: "John Harris" <jdhhar...@customstage.net> To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> Sent: Sunday, January 04, 2009 10:49 AM Subject: Re: [Emc-users] A wish - Closed Loop Steppers > In any feedback motor control system when an torque overload occurs, you > have two choices, stop or slow down. In a CNC environment there is a good > chance the slowing down would remove the torque overload, so the trick > would > be too slow down all of the machine motors in a strictly proportional > manner. > > JohnDHH > > ----- Original Message ----- > From: "RogerN" <re...@wildblue.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Sent: Sunday, January 04, 2009 8:36 AM > Subject: Re: [Emc-users] A wish - Closed Loop Steppers > > >> I've thought about trying the following in EMC2. Set up the stepper axis >> with encoder feedback. Have the step rate be the commanded step rate + >> proportional to error. Have a following error shut the system down if >> error >> is greater than maybe 10 steps. If the axis is stalled, the error should >> grow greater than 10 steps real fast, if not it should be able to make up >> lost steps. The idea I was interested in was to use linear scales from a >> DRO for actual position feedback. This could get you to position with or >> without lead screw errors, step errors, etc. It wouldn't prevent >> stalling >> an axis but at least detecting the following error could shut down before >> ruining the part. (assuming it stalled out on a roughing cut that can be >> cleaned up on a finishing cut, and didn't gouge) >> >> RogerN >> >> ----- Original Message ----- >> From: "Roger" <vrsculp...@hotmail.com> >> To: <emc-users@lists.sourceforge.net> >> Sent: Sunday, January 04, 2009 9:07 AM >> Subject: Re: [Emc-users] A wish - Closed Loop Steppers >> >> >> Snip >>> _______________________________________________ >>> Emc-users mailing list >>> Emc-users@lists.sourceforge.net >>> https://lists.sourceforge.net/lists/listinfo/emc-users >> >> >> ------------------------------------------------------------------------------ >> _______________________________________________ >> Emc-users mailing list >> Emc-users@lists.sourceforge.net >> https://lists.sourceforge.net/lists/listinfo/emc-users >> > > > ------------------------------------------------------------------------------ > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG - http://www.avg.com Version: 8.0.176 / Virus Database: 270.10.2/1873 - Release Date: 1/3/2009 2:14 PM ------------------------------------------------------------------------------ _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
