Jon Elson wrote: > Ray Henry wrote: >> Are there swivel joints between the two screws so that the motors can >> move independent of each other? > Excellent point, and no, there do not appear to be any joints > between the two sides. (Dr. Lie has sent me photos of the > machine.) That is going to make it MUCH harder to properly home > the thing without bending the rails or ballscrews. > > I wonder if it would work better to home one side, with the > other side's servo amp disabled, and then home the second side > the last few encoder counts. Or, home the system with the servo > P gain turned WAY down, just high enough to get movement, and > then turn it up after the axes are in sync.
That solution assumes that one side can back drive the other. That isn't necessarily the case. It might be worth considering a home switch on just one side and a squareness indicator on the other side. (Somehow, measure the offset or flexing between the two screws.) Then drive one side to make the axis square. Then lock the two axes to each other and home the whole thing. > > This is, in general, a bad idea to have a rigid tandem axis. > > Jon > > ------------------------------------------------------------------------- > Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! > Studies have shown that voting for your favorite open source project, > along with a healthy diet, reduces your potential for chronic lameness > and boredom. Vote Now at http://www.sourceforge.net/community/cca08 > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users Ken ------------------------------------------------------------------------- Sponsored by: SourceForge.net Community Choice Awards: VOTE NOW! Studies have shown that voting for your favorite open source project, along with a healthy diet, reduces your potential for chronic lameness and boredom. Vote Now at http://www.sourceforge.net/community/cca08 _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
