PID Controller Explainer (2022)
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PID Controller Explainer (2022)
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Re: PID Controller Explainer (2022)
#2The most succinct and intuitive explanation I’ve found on PID is this one: https://www.youtube.com/watch?v=4Y7zG48uHRo
Re: PID Controller Explainer (2022)
#3In the ‘what is a PID controller’ section, it doesn’t mention time delay. PID controllers solve problems where there is a time delay in the system between inputs and corresponding outputs. If there is no time delay, then a PID controller won’t help.
My favorite analogy is a suspension, like a car or mountain bike shock absorber. A PID controller is basically a unitless suspension system. P is like the spring, I is (sort of) like the compression damping and D is like the rebound damping, again, sort-of. Tune those 3 values and you’ll have a smooth ride and be able to respond to big bumps. The analogy to a physical suspension isn’t precisely perfect, but to a first approximation, a PID really is just a digital shock absorber.
Re: PID Controller Explainer (2022)
#4The most succinct and intuitive explanation I’ve found on PID is this one: https://www.youtube.com/watch?v=4Y7zG48uHRo
Just watched, and yes this is a very good explanation. My intro to PID controllers was when writing AI vehicle steering for video games. I wasn’t taught about PID controllers in my CS degrees, so I started naively with what I would later learn is a P controller, and then got really surprised when lowering the gain turned into larger error. Like trying to smooth out the steering makes the problem worse, it was surprising to me. I told a very smart guy near me what I’d learned and he was like, “Oh yeah, you just need a PID controller”.
Re: PID Controller Explainer (2022)
#5Any recommendations for an algorithm for safe online PID tuning? Maybe something involving pole placement or frequency response analysis?
Re: PID Controller Explainer (2022)
#6In the ‘what is a PID controller’ section, it doesn’t mention time delay. PID controllers solve problems where there is a time delay in the system between inputs and corresponding outputs. If there is no time delay, then a PID controller won’t help. My favorite analogy is a suspension, like a car or mountain bike shock absorber. A PID controller is basically a unitless suspension system. P is like the spring, I is (s…
Why won't it help if there is no delay? What system truly has no time delay and no inertia?
PID systems are basically a differential equation and optimal coefficients are just solutions to that system which maximize responsiveness and minimize ringing, so I would think the effect of decreasing time delay just adjusts the Ki and Kd to account for the smaller Tc value.
Re: PID Controller Explainer (2022)
#7In the ‘what is a PID controller’ section, it doesn’t mention time delay. PID controllers solve problems where there is a time delay in the system between inputs and corresponding outputs. If there is no time delay, then a PID controller won’t help. My favorite analogy is a suspension, like a car or mountain bike shock absorber. A PID controller is basically a unitless suspension system. P is like the spring, I is (s…
Time delay is covered in the "How do PID controllers work?" section right after "A simple controller"
Re: PID Controller Explainer (2022)
#8Any recommendations for an algorithm for safe online PID tuning? Maybe something involving pole placement or frequency response analysis?
I've used this successfully for some hardware projects: https://pidtuner.com/#/
Re: PID Controller Explainer (2022)
#9I liked https://www.wescottdesign.com/articles/pid/pidWithoutAPhd.pd... though I’ve not looked at the OP so I don’t know how it compares.
Re: PID Controller Explainer (2022)
#10Any sources that approach the subject from a mathematical formulation?