Patent ID: 7119511

Claim:
A servo controller for controlling movement of a scanner, comprising: a servo unit for generating a first-axis motion and a second-axis motion under a track-follow-scan mode and a turn-around mode, wherein a scan rate is programmable by choosing an appropriate slope for a ramp trajectory for the servo unit when generating the first-axis motion, wherein said servo unit comprises: a first servo for the X-axis and a second servo for the Y-axis, wherein said first servo comprises: an analog-to-digital (A/D) converter for receiving position information signals of said scanner, and converting said position information signals to digital values; a digital controller including: a position controller for receiving an output from said A/D converter; a velocity estimator for receiving an output from said A/D converter; a velocity controller for receiving an output from said velocity estimator; a reference trajectory for providing an input to said velocity controller; and a post filter bank for receiving an output from one of said velocity controller and said position controller, to provide a control signal; a digital-to-analog (D/A) converter for receiving said control signal and generating an analog signal; a current amplifier for receiving said analog signal; and an actuator for receiving an output from said current amplifier to drive said scanner.