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
20.36 dB, 8.22 dB and 12.02 dB reduction for its three modes of vibration, respectively.