A novel disturbance observer design and application in HDDs for disturbance compensation

Conventional disturbance observer (DOB) requires plant model inverse to retrieve the input to the actual plant in order to estimate the input disturbance imposed on the plant for compensation. This paper proposes a general form of disturbance observers, which does not need to solve the plant model inverse, and uses H∞ control method to design the Q-filter in the disturbance observer. The conventional disturbance observer is proved to be a special case of the generalized form. Comparison to the conventional form of disturbance observers is made and the significance of the proposed method in DOB design and disturbance attenuation is verified via simulation and experimental results.