Ultrasonic linear motor using longitudinal and bending multimode bolt-clamped langevin type transducer

The proposed motor forms elliptical trajectories on driving tips by exciting longitudinal and bending vibration of a double mode Langevin type transducer with input phase difference. Exponential shape transducer horn is adopted to achieve high linear speed. Classical theory of transducer horn is used to determine transducer's longitudinal resonance frequency and configuration dimensions. Combined with FEM design method, the longitudinal and bending resonance frequencies are degenerated. The different locations of driving tips on the horn caused different elliptical trajectories, and how variation influence on motor mechanical output is studied through FEM method. The motor got best performance when positioning driving tips on antinodes of the bending wave Typical output of the prototype is no-load velocity of 480 mm/s and maximum thrust force of 25N.