Robust feedforward tracking servo system considering force disturbance for optical disk recording system

In optical recording system, the tracking servo system must follow the track of optical disk against the influence of the track eccentricity and the force disturbance. In tracking servo system, the influence of the track eccentricity becomes a periodic disturbance. The influence of force disturbance is a sudden disturbance. This work proposes a new robust tracking servo system for an optical disk recording system with feedforward controller and sudden disturbance observer. In order to suppress the periodic disturbance, This work designs the feedforward control system with the prediction of tracking error. For suppressing the sudden disturbance, This work proposes the sudden disturbance observer by using the predictive tracking error. The experimental results point out that the proposed tracking servo system has a precise tracking response against both periodic disturbance and sudden disturbance.