Self-sensing actuation for improved audio-induced vibration rejection in dual-stage hard disk drives

In this paper, a general circuit topology of enhanced indirect-driven self-sensing actuation (EIDSSA) is proposed to allow independent design of actuation and self-sensing in piezoelectric-actuated systems. Sensitivity analysis is performed in terms of suspension structural dynamics, geometric amplification and material property. The proposed EIDSSA circuit topology is realized and incorporated into a commercial dual-stage hard disk drive to improve the rejection capability of audio-induced vibrations. Experimental results show that the on-track total-runout has been reduced by 8.89% in pink noise audio-induced vibrations and 25.2% in single-tone 2.5 kHz audio-induced vibrations without additional loop tuning efforts.