Improvement of Bending Vibration Suppression Performance for Galvano Mirror by Self-Sensing Actuation

This paper presents a method for suppressing the bending vibration of galvano mirrors used in laser positioning systems. Fast and highly precise positioning of the mirror is vitally important for these systems. Thus, the flatness of the mirror should be maintained to ensure highly precise laser positioning. However, mechanical resonant vibrations of the mirror, which are excited by the moment force during positioning, lead to residual vibrations after positioning; these vibrations degrade the flatness of the mirror and the laser manufacturing accuracy. In this paper, therefore, a vibration suppression method is proposed in which a piezoelectric element is mounted on the mirror so as to utilize the multifunctionality of the piezoelectric element by applying it as both actuator and sensor in the vibration suppression controller design. The applicability of the proposed approach to industrial galvano scanners has been verified by performing experiments with a prototype.