Self-sensing actuators for adaptive vibration control of hard disk drives

In this paper, self-sensing piezoelectric actuators (SSAs) incorporating an adaptive mechanism for vibration control of suspensions in dual-stage hard disk drives (HDDs) is investigated. In the piezo-based SSA configuration, the signal sensed due to mechanical deformation is mixed with the control input signal, which would be corrupted due to the variation of the piezoelectric capacitance when a fixed bridge circuit is used. In this study, a self-tuning adaptive compensation is used to combine with the SSA technique to extract the true sensing signal for the vibration control of suspensions in HDDs. An assembled suspension with micro piezoelectric actuators is tested to demonstrate the vibration suppression performance of this adaptive structure under an external hammer excitation. The experimental results show that the target vibration modes have been suppressed effectively with using the adaptive positive position feedback controller.