A small, linear, piezoelectric ultrasonic cryomotor

A small, linear-type, piezoelectric ultrasonic cryomotor has been developed for precision positioning at extremely low temperatures $(⩾−200°C)$⁠. This cryomotor consists of a pair of $Pb(Mg1∕3Nb2∕3)O3−PbTiO3$ 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 cryomotor are: (i) a maximum linear speed of $>50mm∕s$⁠; (ii) a stroke of $>10mm$⁠; (iii) a driving force of $>0.2N$⁠; (iv) a response time of $∼29ms$⁠; and (v) a step resolution of $∼20nm$⁠.