paper: Understanding Feedforward Models for FRC

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Understanding Feedforward Models for FRC
by: nickbrickmaster

A broad overview and derivation of some common feedforward models used in FRC. Also includes discussion of what feedforward is and basic motor voltage balance.

This paper talks about feedforward, what it is, why we use it, how to derive models, and walks through the derivation of several common models using these techniques. A basic understanding of physics is assumed.

Part three-ish of my continuing quest to try and teach control systems in an accessible and practical fashion. Occupies a bit of an odd place in the curriculum, focused towards those who know what PID is, but not how feedforward works. However it’s I think a fairly big subsection, as when I started learning about control systems in FIRST a few years ago, there were a lot of resources about PID, and almost zero mention of feedforward, and if there was, it was just the basic flywheel F*setpoint.

The point of this quest is to refocus away from the magic PID constants and towards a more organic understanding of viewing the control loop as an entire system, without forcing it into the narrow framework that PID provides.

As always, I’d love feedback. Hah!

understanding-feedforward-models.pdf (270 KB)