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PI control resources

  1. Feb 24, 2012 #1
    Does anybody know of any good resources they can point me to for implementing PI control in an embedded system? I'm not necessarily looking for PID control - just PI.

    Books, websites, etc. - any suggestions are welcome.
  2. jcsd
  3. Mar 9, 2012 #2
    Use Google or Google Scholar
  4. Mar 9, 2012 #3
    You need to understand feedback control theory, and then you can shift into the z domain for your emebedded system application. You have a different set of criteria for stability that is the digital versions of your analog controller criteria (you need to be within the unit circle of your z-domain pole zero plot). Your sampling period determines your criteria, and it is a compromise between stability and computation/number precision. You will need to come up with z domain equivalents of your plant system transfer function and your controller's transfer function, and then the z domain transfer function easily synthesize into a very simple 1 code line equation, since its basically a digital filter.

    I can suggest the book: feedback control systems by phillips and harbour and also the book: signals and systems continuous and discrete by ziemer, tranter, and fannin.
  5. Mar 9, 2012 #4
    chrischak - if only I had thought of searching google first....

    I wanted to get recommendations from those who use these systems regularly as to what they find to be the most insightful resources. Google is just the shotgun approach.

    Thank you DragonPetter.
    I am relatively familiar with feedback control theory, but I haven't put any PI/PID systems into practice in quite a while.
    Thank you for the recommended literature. It is much appreciated.
  6. Mar 9, 2012 #5
    Since you are already familiar with feedback control theory, you might just want to read about the bilinear z transform. This is the step you take to get from an analog controller+plant feedback system to a digital one.

    It is pretty much the exact same approach as a digital filter, except now you are held to other criteria to ensure it is stable.
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