Rotary-linear ultrasonic motor based on second bending vibration mode of hollow cylindrical stator

To improve the utilizing efficiency of PZT plates and simplify the fixing in the application of ultrasonic motor, a novel plate-attached rotary-linear ultrasonic motor was proposed. For the prototype, the second bending vibration modes of a hollow cylindrical stator were excited orthogonally both in time and space. And a traveling wave was synthesized in the free end of stator. The output shaft was driven by the traveling wave to move in a rotary-linear motion through the screw thread. The bending vibration mode of stator and excitation mode of PZT plates were simulated by finite element method. And then a prototype was developed, whose stator adopts a hollow square column structure. A testing system based on virtual instrument was established and the basic output characteristics of prototype were tested. Testing results indicate that the resonant frequency of the prototype is 38.90 kHz, and can be driven availably under a peak-peak value of 20 V.