  A new tuning rule is introduced for linear active disturbance rejection
control (ADRC), which results in similar closed-loop dynamics as the commonly
employed bandwidth parameterization design, but with lower feedback gains. In
this manner the noise sensitivity of the controller is reduced, paving the way
for using ADRC in more noise-affected applications. It is proved that the
proposed tuning gains, while rooted in the analytical solution of an algebraic
Riccati equation, can always be obtained from a bandwidth parameterization
design by simply halving the gains. This establishes a link between optimal
control and pole placement design.
