Machining, Measurement, and Control Laboratory

Nano Positioning Drive with Piezoelectric Actuator Integrated into Support Bearing Unit of Ball Screw
A. Matsubara, T. Fujita, D. Kono, N. Tanaka and Y. Watanabe

This paper presents a new fine positioning device with a piezoelectric actuator integrated into the support-bearing unit of a ball screw. By moving the outer race of the support bearing, the piezoelectric actuator gives a preload to the bearings, which translates the screw shaft and table. Since the rotation of the screw shaft gives coarse motion to the table, the whole system can perform the positioning of the table in a long stroke with a high resolution. On the developed system, open loop and closed loop tests are carried out to evaluate its positioning performance. It was found that the piezoelectric actuator translates the table on the order of nanometers in the open loop test and the designed closed-loop control system can control the table position with a resolution of 20 nanometers.
Key Words: Dual stage, Precision positioning, Piezoelectric actuator, Ball screw drive, Closed loop control