Minimum tracking & focusing trajectory control based on two-dimensional equivalent PTC for optical disk

Pickup systems for optical disks operate in the horizontal and vertical directions for tracking and focusing, respectively. Control systems for optical disks consist of focusing control and tracking control for each operation direction. Therefore, this paper proposes a new minimum tracking & focusing trajectory control based on two-dimensional feedforward control system. Two-dimensional feedforward control system makes the error vector combined focusing error and tracking error. The error vector is the input variable into the feedforward compensator on the basis of a zero phase error tracking control. Because, it is difficult to perform high-speed sampling in a conventional two-dimensional control system, the proposed two-dimensional feedforward compensator can perform high-speed sampling, which is based on an equivalent-perfect tracking control. The experimental results show the effectiveness of the proposed control system.