The Definitive FRC Team 937 Guide to PID
WORK IN PROGRESS: How To PID
Last updated
WORK IN PROGRESS: How To PID
Last updated
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:
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.
A little more basic-overview type stuff about PID control on FRC bots:
A Chief Delphi post that discusses velocity tuning with Talon SRXs:
A Chief Delphi post that discusses position tuning with Talon SRXs:
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
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.
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
