Thread: PID Help
View Single Post
  #7   Spotlight this post!  
Unread 21-01-2015, 01:37
Alan Anderson's Avatar
Alan Anderson Alan Anderson is offline
Software Architect
FRC #0045 (TechnoKats)
Team Role: Mentor
 
Join Date: Feb 2004
Rookie Year: 2004
Location: Kokomo, Indiana
Posts: 9,112
Alan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond reputeAlan Anderson has a reputation beyond repute
Re: PID Help

Quote:
Originally Posted by wildaburk3160 View Post
Here is a picture of our gains, outputs, etc:

http://i.imgur.com/PKx6P7i.jpg
My first impression is that your proportional gain is very high, which is likely to result in lots of overshoot and oscillation. My second impression is that your integral time is very short, which is likely to result in lots of overshoot and oscillation.

Start by setting the gain very low and the times to zero (which will disable the integral and derivative terms). Put the appropriate load on the motor and start increasing the gain until it becomes unstable, then back the gain down again. If you don't get to the set point in a reasonable amount of time, set the integral time to a value slightly longer than you think it should take to get to the set point, and tweak it from there. You might be able to ignore the derivative term completely.
Reply With Quote