Tuning PID Parameters

[apalrd]

In the past two years, we never used an I or D term (except for a controller that was I only...)

For VRC this fall, on the Cortex controller, we worked with the Zeigler-Nichols method to get good PID gains for our arms. It worked really really well, as we calibrated with one game piece in, so the mass changes with none or two game pieces (most use cases in that game) wasn't very bad. After writing all of the spreadsheets to calculate the gains (and figuring out that the equations give you integral and derivative time instead of gain), I just did a data capture on the serial port, found some data in Excel (space delimited text FTW!), punched the gains back in, and it ran beautifully.

I've always manually found a good P-only gain anyway, so increasing kP until the system oscillates isn't very hard and doesn't take much time.