pidtune - what algorithm is used to tune the pid controller?

I was wondering if there was a source where it is explained, what algorithm(s) is used in the pidtune command of the control system toolbox.

Answer 1

[Arkadiy Turevskiy]

It is a patented frequency-domain algorithm developed by MathWorks. Hi-level description is provided in the help for pidtune, under "Algorithms" section towards the bottom of the page.

Answer 2

[Jay]

Thank you for your fast reply!