On Sun, Apr 20, 2008 at 11:19:29PM +0300, Anders Wallin wrote: > > The last pic shows moves at different feed-rates. All of them show > around 16 to 25 count spikes during the acc/dec. phases. Presumably at > the moment when acceleration changes and jerk is infinite. How much have > other people been able to reduce these spikes?
Since it is worse on decel, I suspect integrator windup. I always tune FF1,FF2 with I=0. Otherwise you just can't see how to set them properly. My 2c is that a good tuning shouldn't let I do any of the work that FF can. This way I won't wind up unless the situation really merits it. The problem with letting I contribute substantially in normal operations is that it takes just as long to unwind after it's not needed. My experience so far is that FF2 is exactly balanced and affects the accel and decels equally. I have not seen this effect where you can only get one of them zeroed out. Chris ------------------------------------------------------------------------- This SF.net email is sponsored by the 2008 JavaOne(SM) Conference Don't miss this year's exciting event. There's still time to save $100. Use priority code J8TL2D2. http://ad.doubleclick.net/clk;198757673;13503038;p?http://java.sun.com/javaone _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
