In this study, a novel miniature I-shaped linear ultrasonic motor is proposed. The motor is constructed by two rectangular piezoelectric vibrators which are mounted in parallel with the slider to make the structure look like the letter "I". The symmetric and antisymmetric modes of the motor based on the first-order flexural vibrations of the two vibrators are chosen as the working modes. The finite element method is adopted to optimize the structure and study the vibration behavior of the motor. A prototype of the proposed linear ultrasonic motor is fabricated and its mechanical characteristics are tested. The dimension of the stator is 39.8 × 17.6 × 6 mm3 and the weight of the prototype is only 18.2 g. The typical outputs of the prototype are maximum speed of 364 mm/s, maximum thrust of 500 g and thrust-weight ratio of 24.47. The experimental results confirm that the developed linear ultrasonic motor has the advantages of structural design and miniaturization.
Keywords: Finite element method; Linear ultrasonic motor; Piezoelectric vibrator; Structural design; Symmetric and antisymmetric modes.
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