Why a falling pole can be held up: feedback, and the PID controller
30seconds
A pole on a cart wants to fall, and a controller that watches the lean and shoves the cart can hold it up. But how hard it pushes matters: too weak and it topples, P only and it wobbles forever, and adding a term that reacts to tipping speed makes the wobble die out.
Drag the pole, tune the two gains yourself, and meet the PID idea that Nicolas Minorsky wrote down while testing automatic steering on a battleship in 1922.
Deep dive · 4 min
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