LAUSR

This paper presents a new self-sensing actuation (SSA) circuit for using the piezoelectric (PZT) micro-actuator as both an actuator and a sensor simultaneously. The proposed SSA circuit senses the voltage signal generated by the PZT micro-actuator at operating frequencies, while the control voltage applied to the same PZT micro-actuator is not affected. The components of the proposed SSA circuit are minimized to allow easy balancing and implementation. In simulations, the proposed SSA circuit had similar characteristics to the conventional SSA circuit. In experiments, the proposed SSA circuit was tested with a commercial hard disk drive (HDD). The results show that the proposed SSA circuit does not affect the conventional read/write (R/W) head positioning control system. The frequency response of the PZT micro-actuator measured by the proposed SSA circuit had similar to the frequency response of the R/W head displacement at both the resonant frequency and the operating frequencies. The proposed SSA circuit was also tested at various operating temperatures of the HDD. Errors in the sensing voltage signal caused by the unbalanced SSA circuit clearly correlated to the temperatures from 10 °C to 60 °C.