On Dec 22 2015 10:18 AM, Jon Elson wrote: > On 12/21/2015 11:59 PM, Chris Morley wrote: >> >> That version of jerk-limited just didn't quite work right >> with spindle-synch. IIRC the person doing it didn't need >> spindle-synch and got little help - lost interest. Not >> that i blame him - it looks very difficult! > Yes, I think combining jerk limiting with spindle synch > REQUIRES a compromise. There are probably a couple ways to > do it. One is to just turn off jerk limiting when in > spindle synch. The other is to warn users that there is > some initial part of the motion which will not be fully > synched to the spindle, until the jerk limit has been > integrated out. This latter scheme will break taps on > spindle reversal, so doesn't seem like the right approach. > Maybe somebody else knows a better way?
I think there are at least two issues here: *) thread turning -- where the spindle is already in motion and you want to sync up to chase a thread. Here you do not care about acceleration profiles of the tool (as long as you have enough room to sync them). *) coordinating the spindle with full start/stop motion control. In either case, once you get everything moving you can keep them synchronized to a stop and reverse. One the other hand, if you are chasing threads, then you might want to back the threading tool out and leave the spindle running a full speed. As a note, this discussion totally ignores large machines which can be broken or worn when moving without jerk limits. I have never worked on a machine that big, but when a friend was working on one of the NRAO's VLA radio antennas <http://www.vla.nrao.edu/>. Those thigns are three stories TALL! EBo -- ------------------------------------------------------------------------------ _______________________________________________ Emc-developers mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-developers
