A practical guide of PID Tuner [pdf] (github.com)

note: title incorrect, this link does NOT point to PDF, just to Github's preview page.

You can still get the pdf if you click download button, but this is optional.

see also https://en.wikipedia.org/wiki/PID_controller

This has nothing to do with Linux PIDs!

A PID tuning guide with almost no math. But very important thing to consider when making an system identification test indeed.