Nonlinear control of optical storage drives with improved shock performance

An experimental demonstration is given of a nonlinear dynamic filter applied to an optical playback device (CD-drive) for automotive applications. The filter is based on a static input-output nonlinearity that transforms the standard linear control design into a shock-dependent control design. To relax the sufficient condition imposing stability, a dynamic filter is introduced. The combination of dynamic filter and static input-output nonlinearity forms a nonlinear dynamic filter that enables a large amount of loop gain increase. With this filter, the controlled lens dynamics in radial (tracking) direction are studied both experimentally and numerically in terms of shock suppression, and show a significant improvement in shock performance.