Ultrasonic actuators have been widely used for precise positioning for its exclusivecharacteristics such as high energy density, high torque at low speed, short respondingtime and anti-interference of electromagnetism which mean they are highly suitable forminiaturization. Various ultrasonic linear actuators have been proposed for particularpositioning tasks requiring high thrust as well as compact structure at specificconditions. Among representative implementations, ultrasonic lead screw actuator wasdeveloped to provide both sufficient travelling range and high accuracy. A novel screw-thread-type ultrasonic actuator based on a Langevin-type piezoelectric vibrator whichassembly comprised of a threaded shaft and, engaged, a transducer formed statortherewith, is presented. The actuator is highly suitable for the applications of highaccuracy positioning requirement with a relative higher thrust force and lower linearspeed. When applying as positioning actuators, no other driving components are neededleading to a simple construction of the total, for instance, linear stage. The actuator andits linear stage was designed by finite element method (FEM) and a prototype of theactuator as well as the tip/tilt stage was fabricated. Different PZT ceramics were alsoapplied for obtaining a higher thrust force and better performance. The actuator showeda good performance with a maximum linear velocity of9mm/s and maximum thrustforce of4.2N at300Vp-pof applied voltage. |