Fault predictive control of compact disk players

Optical disk players such as CD-players have problems playing certain disks with surface faults like scratches and fingerprints. The problem is to be found in the servo controller that positions the optical pick-up, such that the laser beam is focused on the information track. A scheme handling this problem, called feature-based control, has been presented earlier. This scheme is based on an assumption that the surface faults do not change from encounter to encounter. This assumption is unfortunately not entirely true. This chapter proposes an improvement of the feature based control scheme including a prediction step. The proposed scheme is compared with the feature-based control scheme, in the perspective of handling surface faults, by simulations. These simulations show the improvements given by the proposed algorithm. It is clear that the proposed predictive method is better to handle surface faults than the standard industrial solution and a non predictive feature based fault removal scheme. © 2007