A Five-Axis Monolithic Nanopositioning Stage Constructed from a Bimorph Piezoelectric Sheet

The paper describes design, modeling and control of a five-axis monolithic nanopositioning stage constructed from a bimorph piezoelectric sheet. In this design, actuators are created by removing parts of the sheet using ultrasonic machining. The constructed nanopositioner is ultra-compact with a thickness of 1 mm. It has a X and Y travel range of 15.5 μm and 13.2 μm respectively; a Z travel range of 26 μm; and a rotational motion about the X- and Y-axis of 600 μrad and 884 μrad respectively. The first resonance frequency occurs at 883 Hz in the Z-axis, and the second and third resonance frequency appears at 1850 Hz, rotating about the X- and Y-axis. A decentralized control strategy is implemented to track Z, θ_x and θ_y motions. The controller provides good tracking and significantly reduces cross-coupling motions among the three degrees-of-freedom.