Piezoelectric Asymmetric Indirect-Driven Self-Sensing Actuation

Self-sensing actuation allows combining the actuator and sensor into a single piezoelectric element. In this paper, the Asymmetric Indirect-Driven Self-Sensing Actuation (AIDSSA) circuit for piezoelectric actuators has been proposed. Unlike conventional self-sensing circuits relying on a differential amplifier, the proposed circuit uses active feedback mechanism in op-amps to reject the common-mode interference. The analysis results reveal that the proposed circuit requires simpler matching conditions and is able to sense the mechanical strain in a uniform gain without compromising the actuation stroke. To show the usefulness in piezoelectric-actuated systems, the AIDSSA circuit has been synthesized into a dual-stage hard disk drive. Experimental results show that the position error variance, a measure of disturbance rejection, has been reduced by more than 15% in the track-following mode. The proposed circuit should be of usefulness in a wide range of applications involving piezoelectric actuators.