Active Control of Flow-Induced Vibrations on Slider in Hard Disk Drives by Suppressing Pressure Fluctuations With Virtual Sensing

This paper presents numerical simulations on a feedback active control strategy for flow-induced off-track vibration of a head gimbals assembly (HGA) bearing a slider in hard disk drives (HDDs). In the proposed active control strategy, a physical pressure sensor is assumed on the HDD cover to detect the pressure fluctuations and a pressure actuator is on the inner surface of the HDD cover to actuate feedback acoustic pressures to suppress pressure fluctuations in airflow turbulence around the HGA. A virtual sensing method is employed to enable the system feedback signal changeable from the physical pressure sensor to specific “virtual pressure sensors” closely around the HGA. The performance of the proposed active control strategy has been numerically examined based on a turbulence model of a 2-D channel flow with large eddy simulation. The results show that successful active control on the HGA off-track vibration can be achieved if the feedback signal is configured by virtual sensing to minimize the pressure fluctuations at specific positions closely around the HGA. It is also shown that the wake zone of the HGA is a typical virtual sensing position for pressure fluctuations in the feedback control system in order to achieve suppression on the HGA off-track vibration.