Self-tuning two-degree-of-freedom PID controller reducing the effect of disturbances

This paper proposes a new design scheme for a self-tuning PID controller. To improve the transient property for a reference signal and the robustness to disturbance, the proposed controller is designed in the form of two-degree-of-freedom. Expressions to calculate PID parameters from the identified plant coefficients are given. These expressions are derived by approximating the PID controller to an extended generalized minimum variance control (GMVC) law, which can adjust both of reference response and disturbance response independently. Using a numerical example, the control performance of the proposed method is compared with those of PID controllers designed by other schemes.