PID: what is it exactly?

[Wildcats1378]

Hey guys,

I've been trying to upgrade my Labview knowledge over the last few days in prep. for the kickoff. I've found quite a bit of threads on here about PID controllers and such, and yet I'm still finding it difficult to understand what exactly they do, and how they are useful in FRC and Robotics.

I've looked at this
https://decibel.ni.com/content/servl...20Tutorial.pdf

My (probably wrong) current understanding is that you set a value, and the PID loop will read what the actual value is and adjust the motor to match the set value?

A really dumbed down, simple explanation of what is going on would be wonderful

Thanks