Heading PID tips

[cjl2625]

Originally Posted by Jared Russell

1) Figure out what the minimum required output is to get the robot to turn at all. If the PID output is less than this magnitude, output this magnitude (with the same sign as the PID output).

Wouldn't this cause oscillations, if the output switches between positive and negative of this magnitude?

As a related idea that I had, I wonder if it would make sense to find some magnitude where the robot almost turns (but is still stopped) and add it to the PID output. Maybe it would simulate low friction or something.

[Jared Russell]

Originally Posted by cjl2625

Wouldn't this cause oscillations, if the output switches between positive and negative of this magnitude?

As a related idea that I had, I wonder if it would make sense to find some magnitude where the robot almost turns (but is still stopped) and add it to the PID output. Maybe it would simulate low friction or something.

In practice you are typically moving so slowly at this minimum output that the oscillation shouldn't be a problem (you probably have a small deadband around the setpoint at which point you say "good enough" and cut power).

Adding a minimum term to the output is also a totally valid approach that accomplishes the same thing and only differs in the details.