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

Abstract

The actuator system of a hard disk drive (HDD) is very sensitive to vibrationcircumstances. It is of great importance to study the dynamic characteristics of theactuator system and to control its vibration response. Piezoelectric shunt damping is anemerging vibration suppression technique used to control structural vibration. In thispaper, two methods are proposed to improve vibration damping efficiency of theclassical piezoelectric shunt damping system and suppress the vibration of theactuator arm. Based on the analysis of the effect of the generalized electromechanicalcoupling coefficient on the amplitude of the transfer function and damping ratio, thedistribution area of the PZT transducer of the shunt damping system is defined asa design variable of topology optimization to maximize the effective area andhence to maximize the converted vibration energy of the actuator arm. Moreover,the vibration control efficiency is improved by introducing a negative impedanceconverter to eliminate the additional loss resistance of the coil inductor of theshunt circuit. Then the vibration control experiments for the actuator arm of anHDD are carried out to verify the proposed methods. According to the resultsof FE analysis and modal tests of the actuator system, topology optimizationfor the PZT transducer is performed on the target modes while the effects ofadditional stiffness and additional mass of the coupled PZT transducer are alsoconsidered. The high damping efficiency of this improved piezoelectric shunt dampingsystem is demonstrated by a 323% maximum increment of damping ratio and20.36 dB, 8.22 dB and 12.02 dB reduction for its three modes of vibration, respectively.