Structural dynamic modification of an active suspended handle with a parallel coupled piezo stack actuator

This article presents the structural dynamic modification technique, applied to an active suspended handle, to overcome the displacement limitation of a piezo stack actuator by increasing the stiffness of the lower beam of the handle that supports the piezo stack actuator. The increased stiffness shifted the modes of the structure beyond the operating frequency range. The structural dynamic modification model with linearized piezo stack actuator hysteresis showed better performance compared to the original-active suspended handle model. A proportional feedback gain (P) step-up method is used for counter voltage to the piezo stack actuator in a real-time active vibration control system. The effective frequency range of isolation, with transmissibility smaller than unity, was expanded from 250-450Hz to 200-510Hz, and the anti-node transmissibility was lowered from -18 to -26dB. Laboratory testing using a die grinder with a nominal operating speed of 25,000r/min showed that the structural dynamic modification-active suspended handle reduced vibration transmissibility by up to 96%.