Positioning To Nanometer Resolution With Ultrasonic Actuators

This paper deals with ultrasonic motors based on the bimodal vibrations and their application to the stepper positioning systems. A concept of the linear ultrasonic motor drive capable of nanometric steps, centimetres travel range, reversible controlled motion is presented. The developed motor concept is based on the superposition of a longitudinal and bending vibrations of a rectangular resonator. The ultrasonic motor model based on systems identification with prediction have been developed for control applications, The open two stages positioning system with designed stepper ultrasonic drive have shown 5% trajectory repeatability. The system with close loop position control have shown 0,3 micron positioning accuracy and 50 nm resolution.