  Power-based output feedback compensator for oscillatory systems is proposed.
The average input-output power of an oscillatory signal serves as an equivalent
control effort, while the unknown amplitude and frequency of oscillations are
detected at each half-period. This makes the compensator adaptive and discrete,
while the measured oscillatory output is the single available signal in use.
The resulting discrete control scheme enables a drastic reduction of
communication efforts in the control loop. The compensator is designed for 2nd
order systems, while an extension to higher-order dynamics, like e.g. in case
of two-inertia systems, is also provided. Illustrative experimental case study
of the 5th order oscillatory system is provided.
