Fault Residuals for Compact Disc Players based on Redundant and Non-linear Sensors
Publikation: Forskning - peer review › Konferenceartikel i proceeding
In the process of achieving good performance of Compact Disc players it is important to handle surface defects as good as possible. The first thing in handling these defects is to detect their beginnings and ends.Two servo loops are formed to keep the optical pick-up focused on and radially tracked at the information track on the Compact Disc. The pick-up feeds the controllers with two sensor signals for each of the loops. The difference between these two signal pairs is an approximations of focus and radial tracking distances. The sum of these signal pairs is used for fault detection. But due to optical cross couplings, detection based on the sum signals can at times give false or no detections. In this paper a method to estimate important fault residual is designed in such a way that the cross couplings are removed. This is done based on a model from the physical focus and radial distances to the four detector signals. Based on a fault model the inverse problem is solved for finding the distances as it would have been if no faults had occurred, by using the redundancy of the detector signals. Two different approaches are pursued in this paper, but both are based on the Newton-Raphson method. The differences in the approaches are the used fault model. Both methods solve the respective inverse problems.
|Titel||Proceedings of 2004 American Control Conference|
|Konference||2004 American Control Conference|
|Periode||30-06-04 → 02-07-04|