Low-Pass Filter Property of Dynamic Output Feedback Passivation Controller

We present a state-space approach to design a passivity-based dynamic output feedback controller that achieves stabilization and set-point regulation. A frequency domain analysis is performed in order to test the performances of the low-order control law against measurement noise. It is shown that the proposed control law inherently has low-pass filter property as well as it can successfully replace the measurements of derivative terms in PD control laws. Motivated by the low-pass filter property a higher-order controller is also introduced to enhance the noise reduction property. The effectiveness of the proposed control law is illustrated by numerical simulations and experimental results with a rotary inverted pendulum