A magnitude optimum approach for tuning Reduced-order ADRC with FOPDT models

In this paper, the Reduced-order Active Disturbance Rejection Control (RADRC) is tuned with a new set of tuning rules based on the First Order Plus Dead-time plant models. The tuning rules are developed to achieve the desired robustness
$(M_{s})$
level. The tuning process is carried out in two stages. In the first stage, a set of non-linear equations is formulated using the magnitude optimum method and are solved with the desired settling time requirement resulting in controller bandwidth
$(\omega_{c})$
, observer bandwidth
$(\omega_{0})$
and high-frequency gain
$(b_{0})$
. The parameter
$b_{0}$
is further adjusted to meet the robustness
$(M_{s})$
and stability requirements. The data collected from stage-I is used as input to the next stage. In stage-II, tuning rules for
$\omega_{0}$
and
$b_{0}$
are formulated in the form of a polynomial model. Finally, the proposed tuning rules are tested on standard benchmark systems and experimentally verified to control a DC motor.