I had the same exact situation with inner velocity loop. I am sure that it is fixable, but I did not have the time and instead went to a torque loop. Velocity loop, if tuned properly, has better characteristics, so one day I will try to go back to it.
i On Fri, Oct 29, 2010 at 7:29 AM, James Louis <[email protected]> wrote: > Caner, > > I had a similar situation with my servo amps and I found out that my system > was a cascaded position-velocity loop. I suspect that is what yours is too. > That means that my external amp, which closes a velocity loop, is nested > inside of EMC2, which closes a position loop. > For your Toshiba VLASX-012P2 using Mode 1 Analog Input will make it a > velocity amplifier using PI (proportional / integral) and will make EMC2 a > position controller using only P with FF1 and FF2. No I or D terms are used > in the *.ini file. > Your amplifiers have Auto-Tuning right? With EMC2 disconnected, I would > suggest first tuning the Toshiba to be as stiff as possible. Then connect > your analog input. Use Halscope to view your commanded velocity profile > compared to your actual output, and use Calibration to slowly increase only > your P while jogging at maximum velocity. Use FF1 and FF2 to make the two > profiles match as close as possible. > The secret to having no oscillations is to have the bandwidth of the velocity > loop be greater than or equal to the bandwidth of the position loop. It > sounds like right now you have the opposite. > Be safe, and good luck. > > Jim > > -----Original Message----- > From: Caner [mailto:[email protected]] > Sent: Friday, October 29, 2010 2:29 AM > To: emc-users > Subject: [Emc-users] Two control loop (EMC and Servo Driver)? > > Hi, > > I am trying to test my Mesa boards (5i23 and 7i33) with my servo motors. > But there is an unexpected problem that EMC2 can't control servo. When I > jog, servo motor tuns with oscillation and when i stop jogging, it > continue oscillation some seconds more then stop. My servo motor has > resolver with 24000ppr and i am getting differential encoder output from > its driver. Also servo driver has own control loop inside, i have tried > to disable its control loop but i could only set "target loop gain" to > 1. Also i have tried to change PID values of EMC2. > My servo period is recommended (1000000ns), and PWM/PDM frequency is > recommended (100000 Hz). Following Error is 0.5, and Minimum Error is > 0.01. I don't know why it happens but i guess two control loop is > overlapping. Do you have any idea about my this problem? Am i using too > slow servo-thread? Did anyone have tried to use Toshiba Servo Driver > (VLASX-012P2) with EMC2? > > Thanks. > --- > Caner Durmusoglu > > > ------------------------------------------------------------------------------ > Nokia and AT&T present the 2010 Calling All Innovators-North America contest > Create new apps & games for the Nokia N8 for consumers in U.S. and Canada > $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing > Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store > http://p.sf.net/sfu/nokia-dev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > > This communication is for the use of the intended recipient only. It may > contain information that is privileged and confidential. If you are not the > intended recipient of this communication, the disclosure, copying, > distribution or use hereof is prohibited. If you have received this > communication in error, please advise me by return e-mail or by telephone and > then delete it immediately. > > ------------------------------------------------------------------------------ > Nokia and AT&T present the 2010 Calling All Innovators-North America contest > Create new apps & games for the Nokia N8 for consumers in U.S. and Canada > $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing > Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store > http://p.sf.net/sfu/nokia-dev2dev > _______________________________________________ > Emc-users mailing list > [email protected] > https://lists.sourceforge.net/lists/listinfo/emc-users > ------------------------------------------------------------------------------ Nokia and AT&T present the 2010 Calling All Innovators-North America contest Create new apps & games for the Nokia N8 for consumers in U.S. and Canada $10 million total in prizes - $4M cash, 500 devices, nearly $6M in marketing Develop with Nokia Qt SDK, Web Runtime, or Java and Publish to Ovi Store http://p.sf.net/sfu/nokia-dev2dev _______________________________________________ Emc-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/emc-users
