A small, linear, piezoelectric ultrasonic cryomotor

A small, linear-type, piezoelectric ultrasonic cryomotor has been developed for precision positioning at extremely low temperatures (greater than or equal to-200 degreesC). This cryornotor consists of a pair of Pb(Mgl(1/3)Nb(2/3))O-3-PbTiO3 single crystal stacks, which are piezoelectrically excited into the rotating third-bending mode of the cryomotor stator's center, which in turn drives a contacted slider into linear motion via frictional forces. The performance characteristics achieved by the cryornotor are: (i) a maximum linear speed of >50 mm/s; (ii) a stroke of >10 mm; (iii) a driving force of >0.2 N; (iv) a response time of similar to29 ms; and (v) a step resolution of similar to20 nm. (C) 2005 American Institute of Physics.