Demonstrating effects of a dynamical feedforward control for the first order system

An analysis of different 2DOF PI controller tuning methods in [1], [2] showed significant advantages of a noise attenuation oriented predictive disturbance observer based filtered PI control (PDO-FPI) against the traditional two degree of freedom (2DOF) PI control. Analytically, as well as by the numerical performance portrait method it discovered that the potential improvements in the disturbance response are significantly higher than those in the setpoint response. This paper shows that the PDO-FPI does not make use of the whole control potential regarding the analysed first order plants with a possible dead time. The corresponding control structures will be derived by augmenting the well known control loop with a reference model by an additional disturbance observer for an input disturbance. The theoretical analysis will be illustrated by experimental results.