Adaptive focusing control of DVD drives in vehicle systems

As DVD players become standard auxiliary parts in vehicles, environmental vibration from harsh driving conditions may cause unacceptable rates of focusing errors. This article presents the implementation of an adaptive servo controller for DVD drives to suppress focusing errors caused by vibrations transmitted through the chassis of a recreational vehicle. This study is divided into two parts: (1) The design and construction of an optical disk drive platform mounted on a vibrating shaker created to imitate a vehicle system in various driving situations, and (2) the realization of adaptive feedforward servo control (AFSC) techniques using the modified variable step-size filtered-x-LMS algorithm (MVSS-FXLMS) in the optical disk drive employed. Experimentation indicates that the feedforward signal generated as an anti-vibration input by the adaptive controller can effectively suppress the focusing errors introduced by the environmental vibration disturbance in vehicle systems.