On the Equivalence between PID-like controller and LADRC for second-order systems

In this paper, the equivalence is established between the linear active disturbance rejection control (LADRC) and the two-degree of freedom (2-DOF) proportional-integral-derivative (PID) with lead-lag compensators. This allows advantage of LADRC, particularly its bandwidth-parameterization strategy, to be incorporated into the run-of-mill PID controllers. Specifically, the competing design objectives in disturbance rejection, tracking, and noise sensitivities can now be handled with ease.