> You have to damp the loop, the same as you have to damp the suspension > in a car. The general form of a commodity industrial controller > involves adding proportional, differential and integral terms, hence > they are called PIDs. > > You stop the overshoot by adding a term based on rate at which you are > changing the value. There is particular level of correction that > produces the fastest convergence without any over shoot. Although I > forget it, the actual formula is high school level mechanics. > > You don't need an integral term, because you are not trying to zero the > phase error.
I've thought about my own schemes for doing this kind of thing, but I was hoping to benefit from the experience of NTP to find a proven scheme rather than just something I hack up. Everything I read is so heavy on the jargon of control theory and electrical circuits that it's difficult for me to have confidence in the way I turn it into code. My ad hoc schemes sorta work, but I want a more solid understanding of feedback systems rather than the more statistical approach I've been taking. I'll check out PIDs. Thanks. _______________________________________________ questions mailing list [email protected] https://lists.ntp.org/mailman/listinfo/questions
