Dynomotion

Group: DynoMotion Message: 2438 From: judrandom Date: 11/25/2011
Subject: More questions about tuning.
Hi Tom
I have some new questions.
First some times when my motor return to zero it makes a small hissing noise while standing idle. I can grab the screw and turn it a little and it will stop. Do you know what could cause this and how to fix it?
Second I am working to tune my motors. I read that you recommend using a first or second order low pass filter over using the d settings. How is this implemented properly and are there any other filters you recommend to smooth things out?
Third my motors do not seem to have near as much holding torque as they did before. How can this be improved?
Last for now is I have a lot of resonance and vibration that I did not see before. Will motor tuning help with these issues and if yes what settings can help?
Thanks again.
Jared

Ps. I have been a long time member at the cnczone and I have seen they finally gave dynomotion it's own forum. Yay. If you don't mind I would like to repost my questions there also with your replys if that's ok with you. I think it would help out at the zone.
Group: DynoMotion Message: 2442 From: Tom Kerekes Date: 11/26/2011
Subject: Re: More questions about tuning.
Hi Jared,
 
Those all sound like motor tuning issues.  The first step would be to make Plots on the Step Response Screen while making a reasonable sized move of maybe 1000 counts or whatever size seems to have the most problems.  Increase the P gain in steps of around 50% until the system starts to oscillate or goes unstable (increasing violent oscillation).  You may want to set a Max Following Error limit such that as soon as the servo starts to oscillate it disables.  Then decrease the gain back down by to about 1/2 where it should be stable.  When adjusting gains only use simple numbers as tiny relative numbers won't have a significant effect (1.2 and 1.20034 will respond the same).
 
If you would then like to post plots on cnczone then we can go from there.
 
Regards
TK