Construction and verification of a linear-rotary microstage with a millimeter-scale range

This paper presents a second-generation linear-rotary (Z-θ_Z) micro-stage driven by impact friction. The micro-stage was constructed by miniaturizing a previously developed linear-rotary stage. The moving element of the micro-stage, which was a steel cylinder, could be actuated along and around the Z-axis in millimeter-scale range. The steel cylinder was supported by two driving units. Each unit consisted of a permanent magnet and two piezoelectric actuators (PZTs) for generating the impact friction motions in the Z- and θ_Z-directions. The size of the micro-stage was made to be 11.0 mm (L) × 11.0 mm (W) × 5.7 mm (H). For enhancement of the stage velocity, the transfer function of the micro-stage with the voltage applied to the PZT as the input and the PZT displacement as the output, was established. An improved waveform of the input voltage was then obtained based on the established transfer function for getting a triangular-shaped PZT displacement, which was an ideal waveform for the impact friction motion. The characteristics of the stage velocity before and after the improvement of the input voltage were verified and the effectiveness of the improved input voltage for enhancement of the stage velocity was confirmed.