High-Speed Positioning Control in Optical Disk Drives.

This paper presents a practical construction of a minimum-energy positioning control using an optimal regulator. The positioning control system with various positioning times can be realized with only one basic time-varying feedback coefficient vector, that is calculated for the maximum positioning distance Xmax. Calculation results show that the proposed control method can position an optical head with consistent accuracy and power consumption per unit time for various positioning times, when the positioning time T is determined in proportion to the square root of the positioning distance X, that is, T p √(X). An optical head positioner with an air slider is examined. The motion straightness is verified to be sufficient for precise positioning of optical heads. Experimental positioning results demonstrate the effectiveness of the proposed control method and the positioning mechanism for high-speed positioning.