TY - JOUR
T1 - Detection of Surface Defects and Servo Signal Restoration for a Compact Disc Player
AU - Odgaard, Peter Fogh
AU - Stoustrup, Jakob
AU - Andersen, Palle
AU - Fløe Mikkelsen, Henrik
PY - 2006
Y1 - 2006
N2 - Compact disc (CD) players have been on the market for more than two decades, and the involved technologies, including control are very mature. Some problems, however, still remain with respect to playing CDs having to surface defects like scratches and fingerprints. Two servo control loops are used to keep the optical pick-up unit (OPU) focused and radially locked to the information track of the CD. The problem is to design servo controllers which are well suited for both handling surface defects and disturbances like mechanical shocks. The handling of surface defects requires a low-controller bandwidth which is in conflict with the requirement for the handling of disturbances. This control problem can be solved by the use of a fault tolerant control strategy, where the fault detection is very important. The OPU feeds the controllers with detector signals. Based on these, focus and radial distances can be estimated and a pair of residuals can be computed. This paper introduces a model-based method to estimate focus and radial distances as well as residuals, which have the potential to improve the control of a CD player in case of a surface defect. The methods are applied to experimental data of a scratch. The results of this experimental work show the potential of the method.
AB - Compact disc (CD) players have been on the market for more than two decades, and the involved technologies, including control are very mature. Some problems, however, still remain with respect to playing CDs having to surface defects like scratches and fingerprints. Two servo control loops are used to keep the optical pick-up unit (OPU) focused and radially locked to the information track of the CD. The problem is to design servo controllers which are well suited for both handling surface defects and disturbances like mechanical shocks. The handling of surface defects requires a low-controller bandwidth which is in conflict with the requirement for the handling of disturbances. This control problem can be solved by the use of a fault tolerant control strategy, where the fault detection is very important. The OPU feeds the controllers with detector signals. Based on these, focus and radial distances can be estimated and a pair of residuals can be computed. This paper introduces a model-based method to estimate focus and radial distances as well as residuals, which have the potential to improve the control of a CD player in case of a surface defect. The methods are applied to experimental data of a scratch. The results of this experimental work show the potential of the method.
KW - Compact Disc Players
KW - Fault Detection
KW - Kalman Estimators
KW - Surface Defects
KW - Servo Systems
U2 - 10.1109/TCST.2005.860528
DO - 10.1109/TCST.2005.860528
M3 - Journal article
SN - 1063-6536
VL - 14
SP - 189
EP - 203
JO - IEEE Transactions on Control Systems Technology
JF - IEEE Transactions on Control Systems Technology
IS - 2
ER -