Frequency-shaped high-gain compensator for optical disk drive control system

A frequency-shaped high-gain (FSHG) compensator is proposed and implemented for optical disk drive control systems, such as CD or DVD servo systems. The FSHG compensator is obtained by modifying an error-based disturbance observer. The FSHG compensator can be easily realised as a form of a low cost analogue circuit. The disturbance rejection performance can also be easily improved by filter parameters in the FSHG compensator. Design guidelines for the filter parameters (numerator order and filter time constant) are also suggested in this paper. Finally, the effectiveness of the FSHG compensator is shown through experimental results showing disturbance rejection performance evaluated under forced disturbances.