Abstract
A dumping system for micro piezo actuator was studied. The actuator is designed for nano precise positioning with high speed motion control to apply the trucking system that follows an under 10nm width truck on a disk rotating over 6000rpm. So the required servo band of the actuator is closing to 10kHz even though the actuator has the first resonance near 5kHz. A dumping material is applied to reduce the magnitude of the resonance as a servo band goes beyond the resonance frequency with control system design. The dumping material consists of four layers that are adhesion tape, PET film, adhesion tape and a SUS plate. The first adhesion tape is pasted on the actuator frame. The viscoelasticity of the adhesion films dumps the vibration of the actuator by the differential mode between the frame surface and the SUS plate in operation. The dumping effect gets larger as the SUS plate getting thicker because the heavier SUS plate, greater inertia, makes larger differential mode. On the other hand, the heavier SUS plate makes the resonance frequency lower. In this paper, an idea of design to reduce the magnitude of resonance while maintaining the resonance frequency that converges the mass on viscoelasticity layers at where larger stress seemed to be occurred. The larger stress points were inspected by using FEM analysis. Effects of the method was evaluated experimentally. The result shows good. Both greater resonance mode reduction and higher resonance frequency are simultaneously obtained.
