At first glance I would say that you are getting too aggressive with the gain. Back Pgain off to 8 and dial in some D to kill the oscillations.
Dave On 3/1/2010 10:10 PM, Flying Electron Inc wrote: > Hi all, > > Hoping some people that have tuned their servos with EMC2 might be able to > share some of their insights that they learned during their tuning with me. > I built a pick and place machine with a servo on the X axis and I started > running tests to tune the PID loop for the servo. Right now, I have > everything set to zero, a deadband set to 0.00001 and I am adjusting the > Pgain to find the optimal Pgain before I start varying the other parameters. > > The test I am using is to start from a standstill at X=0, move to X = 8 > inches with an acceleration of 25in/sec^2 and a maximum velocity of 9in/sec, > come to a full stop and wait for 0.5 seconds, then reverse back to X=0 with > the same acceleration profile. > > I tried different Pgain values of 4, 8, 10, 12, 13, and 14 to see what the > error looked like. at Pgain of 16 the machine began oscillating badly. > I've attached a link to an image of the screenshots i took from hal scope > for the different Pgains that I tried. To my inexperienced eye, it looks > like Pgain 12 is the best, but I'm not sure if the error graphs are even > supposed to look like this. > > http://i.imgur.com/hefCf.png > > If anyone can tell me if these error graphs look normal or not, I'd > appreciate it! > > Thanks > > Lawrence > ------------------------------------------------------------------------------ > Download Intel® Parallel Studio Eval > Try the new software tools for yourself. Speed compiling, find bugs > proactively, and fine-tune applications for parallel performance. > See why Intel Parallel Studio got high marks during beta. > http://p.sf.net/sfu/intel-sw-dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > ------------------------------------------------------------------------------ Download Intel® Parallel Studio Eval Try the new software tools for yourself. Speed compiling, find bugs proactively, and fine-tune applications for parallel performance. See why Intel Parallel Studio got high marks during beta. http://p.sf.net/sfu/intel-sw-dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
