PID: P+D or P-D
I have a light grasp on the PID control concept. There is one portion of it that I have seen presented with contradictory information. Currently, I understand the purpose and function for all three parameters: P, I & D. In the control system we will be using, we plan on just using a PD loop.
Here is the question: I have seen the equation represented as (Perror*KP)+(Derror*KD), I also have seen it as (Perror*KP)-(Derror*KD). So which is it, and when would I use one or the other? 
__________________
CalGames 2009 Autonomous Champion Award winner
Sacramento 2010 Creativity in Design winner, Sacramento 2010 Quarter finalist
2011 Sacramento Finalist, 2011 Madtown Engineering Inspiration Award.
2012 Sacramento Semi-Finals, 2012 Sacramento Innovation in Control Award, 2012 SVR Judges Award.
2012 CalGames Autonomous Challenge Award winner ($$$).
2014 2X Rockwell Automation: Innovation in Control Award (CVR and SAC). Curie Division Gracious Professionalism Award.
2014 Capital City Classic Winner AND Runner Up. Madtown Throwdown: Runner up.
2015 Innovation in Control Award, Sacramento.
2016 Chezy Champs Finalist, 2016 MTTD Finalist
|