Pseudo-resonant effect on a flexure-guided nano-positioning system

Abstract

This study shows that the system performance of a positioning system composed of a PZT (lead zirconate titanate)-driven flexure guide depends largely on the preload applied on the flexure guide and the driving input amplitude. We used a flexure-guided system that had an original resonant frequency of 54 Hz. Our experiment showed that we could increase the driving bandwidth above the original resonant frequency for a case involving a large preload and a small input amplitude. Results showed that there was a specific '' separation frequency '' where the response of the moving mass of the flexure system decoupled from the response of the PZT and that this specific separation frequency could be selected by a proper choice of the preload and the input amplitude. Near the separation frequency, the pseudo-resonant phenomenon, for example, a large peak and an abrupt phase change between the PZT actuator and the moving body of the flexure guide, occurred. To find the separation frequency, we performed sine sweep tests. To confirm the increased system bandwidth frequency, we performed open-loop sine tracking experiments. Test results showed that the system responded very well up to a frequency 130 Hz, which is higher than the original natural frequency (54 Hz).