On Thu, 9 Jul 2009, Leslie Newell wrote: > Date: Thu, 09 Jul 2009 14:40:09 +0100 > From: Leslie Newell <les.new...@fastmail.co.uk> > Reply-To: "Enhanced Machine Controller (EMC)" > <emc-users@lists.sourceforge.net> > To: "Enhanced Machine Controller (EMC)" <emc-users@lists.sourceforge.net> > Subject: Re: [Emc-users] Servo tuning > > After a bit of playing around I am within about +/- 8 counts, no matter > what I throw at it. Feeds are within about 6 counts. Grabbing hold of > the servo shaft and trying to turn it by hand as hard as I can deflects > the position by about 8 counts before it returns to 0. > > I first tuned PID as good as I could get then turned I down to 0 and the > other two down to about 20%. I then set up FF1 and FF2 to give the > minimum following error. Finally I turned P,I,D back up to their > previous values. > > I think that is pretty much as good as I am going to get. > > Les
Depending on the mechanical frequency response of your system, you may be able to get a little better performance by speeding up the servo thread. This will improve the phase margins of the system, possibly allowing a bit more gain (and damping to go with it). A very rough rule of thumb is to have the sample rate (servo thread rate in this case) 10 to 30 times the mechanical frequency response. > > ------------------------------------------------------------------------------ > Enter the BlackBerry Developer Challenge > This is your chance to win up to $100,000 in prizes! For a limited time, > vendors submitting new applications to BlackBerry App World(TM) will have > the opportunity to enter the BlackBerry Developer Challenge. See full prize > details at: http://p.sf.net/sfu/Challenge > _______________________________________________ > Emc-users mailing list > Emc-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/emc-users > Peter Wallace Mesa Electronics (\__/) (='.'=) This is Bunny. Copy and paste bunny into your (")_(") signature to help him gain world domination. ------------------------------------------------------------------------------ Enter the BlackBerry Developer Challenge This is your chance to win up to $100,000 in prizes! For a limited time, vendors submitting new applications to BlackBerry App World(TM) will have the opportunity to enter the BlackBerry Developer Challenge. See full prize details at: http://p.sf.net/sfu/Challenge _______________________________________________ Emc-users mailing list Emc-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/emc-users
