Another interpretation: P is a spring (the spring equation is k * delta x, same as the P term, but in terms of the error). Adding a P term will make the contro

Another interpretation: P is a spring (the spring equation is k * delta x, same as the P term, but in terms of the error). Adding a P term will make the controller “want” to eliminate any error. D term is a mass damper (again, equation is the same). It will fight oscillations, but it is extremely sensitive to noise in your input (calculating discrete derivatives in noisy signals is hard). The I term makes your output converge to the desired value. Your system will have an inherent friction or stiction which can’t be overcome with just a P term. The I helps with that but introduces other issues like windup.