The Definitive FRC Team 937 Guide to PID

WORK IN PROGRESS: How To PID

THIS IS A WORK IN PROGRESS. ANYTHING AND EVERYTHING IT CURRENTLY SAYS COULD BE WRONG. WE WILL UPDATE IT AS WE LEARN MORE.

We're hoping to learn more about PID over the next year or so. As we do, this guide will grow and mature. For now, here's a bunch of links that help explain How To PID.

PID control is really complicated, but at a basic level it's a form of closed-loop control, so it uses a feedback sensor (for our purposes, almost always an encoder) to quickly and efficiently move to and maintain a set velocity or position, known as the setpoint. It uses a number of gains, namely Proportional gain, Integral gain, Derivative gain, and nowadays usually a feedforward. This is where the name PID comes from - Proportional, Integral, and Derivative.

This explains the basic concept behind a PID controller:

PID Controller Explained • PID ExplainedPID Explained

WPILib documentation for PID:

In ALMOST ALL CASES, we DO NOT use WPILib classes for PID. Instead, we use the built-in PID support on our motor controllers, since they are generally more advanced, easier to use, and have a much faster referesh rate.

Therefore, this documentation is useful for matters of principle, but most of its code examples aren't super helpful for us.

Introduction to PIDFIRST Robotics Competition Documentation

A little more basic-overview type stuff about PID control on FRC bots:

PID Control — FRC Programming Done Right 0.2 documentation

A Chief Delphi post that discusses velocity tuning with Talon SRXs:

Talon SRX PIDF velocity tuningChief Delphi

A Chief Delphi post that discusses position tuning with Talon SRXs:

Talon SRX Position ControlChief Delphi

Information about tuning velocity PID on a SPARK MAX, specifically for a shooter:

Note for 2022 Cow Town

This will be VERY useful for tuning the flywheel on OwOange Juice

Tune REV Spark Max PID for shooterChief Delphi

Information about how to tune a flywheel such that it will change speed based off of the distance from the target reported by the Limelight (our computer vision camera), as opposed to running the flywheel at a set speed and physically moving the bot.

Flywheel Shooter Software for FRCMedium

A lovely Github project made by Team 2930 Sonic Squirrels that makes it easy to tune a PID loop for a shooter:

Side note: we haven't personally tested this project