Design and fabrication of a linear ultrasonic motor using push-pull type L-B hybrid Langevin transducer with single foot

A linear ultrasonic motor using longitudinal and bending (L-B) vibration hybrid Langevin transducer was developed to achieve high output power. The motor consist two exponential shape horns intersected at tip ends where located a single driving foot. L-B vibrations were superimposed in the elastic body of the motor and generated elliptical trajectory at driving foot which can actuate linearly. The sensitivity analysis of structure parameters to the L-B resonant frequencies were performed using finite difference method based on the classical horn theory and flexural horn transfer matrix analysis method, and then degenerated frequencies to 27.476 kHz by choosing the most sensitive parameter. FEM simulation and impedance characteristic test agreed well with the calculated results. The coupling effect between two vibrations was studied and discussed through one phase driving phenomenon. Typical output performances of the prototype were no-load velocity of 1280mm/s and maximum driving force of 45N.