Robust H∞ control of a DVD drive under parametric uncertainties

This paper is devoted to the control system design and implementation of an industrial DVD-video drive. A standard H∞ approach is proposed to control the linear displacement of the optical head actuator along the disc radius, and to reduce the effect of external disturbances affecting the system, like eccentricity and vertical deviations. Uncertainty model, based on a parametric description of the DVD mechanism, and norm-bounded real perturbations are considered, and an H∞ controller is designed by following industrial oriented control objectives. An a-posteriori performance and robustness analysis is finally performed, without applying μ-synthesis tools. Since in the existing industrial solution the digital signal processor (DSP) provides finite precision of digital computation and rounding errors, controller order reduction is performed to allow its practical implementation and test robust stability and performance.