The article has a lot of words and a lot of fluff. Long story short, any PID is always minimizing error (target value - desired value). You can imagine the prop

The article has a lot of words and a lot of fluff. Long story short, any PID is always minimizing error (target value - desired value). You can imagine the proportional (the P) is just a linear scale like maybe 10W is required to increase the mass 1 degree). The intergration (the I) of the error takes care of steady state error (since you’re always taking the area between the target and desired). The derivative (the D) takes care of response since you’re taking the derivative of the error, aka the rate of change.