Simple disturbance observer for disturbance compensation

Disturbance observer (DOB) without using additional sensors is an attractive method to attenuate the effects of disturbances as they are highly cost effective. This study proposes a simple form of DOBs, which does not need to solve the plant model inverse, and uses H_∞ control method to design the Q-filter in the DOB. The conventional form is proved to be a special case of the proposed form. Comparison to the conventional form of DOBs is made and the significance of the proposed method in DOB design and disturbance attenuation is verified via simulation and experimental results.