Vibration suppression of a hard disk driver actuator arm using piezoelectric shunt damping with a topology-optimized PZT transducer

The actuator system of a hard disk drive (HDD) is very sensitive to vibration circumstances. It is of great importance to study the dynamic characteristics of the actuator system and to control its vibration response. Piezoelectric shunt damping is an emerging vibration suppression technique used to control structural vibration. In this paper, two methods are proposed to improve vibration damping efficiency of the classical piezoelectric shunt damping system and suppress the vibration of the actuator arm. Based on the analysis of the effect of the generalized electromechanical coupling coefficient on the amplitude of the transfer function and damping ratio, the distribution area of the PZT transducer of the shunt damping system is defined as a design variable of topology optimization to maximize the effective area and hence to maximize the converted vibration energy of the actuator arm. Moreover, the vibration control efficiency is improved by introducing a negative impedance converter to eliminate the additional loss resistance of the coil inductor of the shunt circuit. Then the vibration control experiments for the actuator arm of an HDD are carried out to verify the proposed methods. According to the results of FE analysis and modal tests of the actuator system, topology optimization for the PZT transducer is performed on the target modes while the effects of additional stiffness and additional mass of the coupled PZT transducer are also considered. The high damping efficiency of this improved piezoelectric shunt damping system is demonstrated by a 323% maximum increment of damping ratio and 20.36dB, 8.22dB and 12.02dB reduction for its three modes of vibration, respectively.