shouldn't this be done systematically? (it could be done all in emc with halscope)
First tune the velocity loop in amp -send a step response to the drive (square wave) and scope the responce. -Adjust the loop gain of the amp to get the best waveform - (match the square wave the best you can) Then from that point Tune the PID FF0-FF2 I found what got me close is something Chris had said on irc. Make sure you calculate the output scale for what you want. Like for me 200ipm at .9v out (200/60)/.9=3.7 for output_scale. I made sure FF1 was 1 (set P to 10 and D to 1 iirc for starters) than I commanded a slow move (1ipm) and adjusted the gain of the amp until the following error was 0 or as close as I could get it. Instantly - my movement was smooth with no overshoot. I still need to tune better - but that sets the amp very well. sam (sorry - I seem to be rambling) On 9/13/2010 9:37 AM, Igor Chudov wrote: > I posted a message to this list that my servo motors cannot calm down > after a motion. > > Right now my amplifiers are set to velocity mode and I use a > tachometer for velocity feedback. So, the amps themselves have a > velocity loop that they close. There is essentially two loops per > axis, one in EMC2 and one in the amplifier. > > Unfortunately, my efforts to tune PID to calm the mill down, have not > been successful. If I turn down the gain parameters, the mill starts > getting following errors, if I turn them up, the motors have hard > times calming down. > > If, when the mill cannot calm down, I hit F2 (which for me inhibits > the amps), and then F2 again, the bothersome buzzing stops. > > I am now thinking that I should reconsider my entire approach and use > a different mode to avoid two loops per axis. > > My amplifiers offer the following modes: > > 1) Velocity (tachometer) mode, which is the current setting > 2) Current or Torque mode (amplifier controls torque/current) > 3) Voltage mode (amplifier maintains voltage) > 4) IR compensation (not sure what it is exactly, probably compensated > for resistance losses in windings). > > So... Would you think that I should switch to, say, torque mode or voltage > mode? > > Any thoughts? > > - Igor > > ------------------------------------------------------------------------------ > Start uncovering the many advantages of virtual appliances > and start using them to simplify application deployment and > accelerate your shift to cloud computing > http://p.sf.net/sfu/novell-sfdev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Start uncovering the many advantages of virtual appliances and start using them to simplify application deployment and accelerate your shift to cloud computing http://p.sf.net/sfu/novell-sfdev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
