Use of PID

Technical Java
1

hi everybody

I’m just preparing myself before the season begin and I heard a lot about the concept " PID controller ". I know it’s kind of stabilizer something like that. But I would like to know his real role and how we used A "PID controller " at FRC ?

thank you in advance for any help.

2

The results for searching “PID” on screensteps: http://wpilib.screenstepslive.com/s/currentCS/searches?text=pid

Read through the first three or four articles for how to use PID in FRC.

You should also learn what PID is and what the values mean. Searching “PID controller” on Youtube also gives some good videos explaining PID. WPI also has a good video: https://www.youtube.com/watch?v=2Yif6PdXPWg

3

A PID controller is a control algorithm for the purpose of moving a system to or keeping a system at a given setpoint.

Examples:

  • maintaining a constant speed on a flywheel mechanism while firing game elements
  • moving to a point on the field during autononous
  • maintaining the angle of an arm holding a game element
  • moving a mechanism to a predetermined position
  • maintaining a constant heading/rotation while driving

PID is based on error - that is, how far you are from the setpoint. P is proportional to the error, that is P = (constant) * error. I is proportional to the integral or sum of all previous error. D is proportional to the derivative or instantaneous rate of change of the error. These three values are combined to give one output, which your program uses to move the system closer to the setpoint.