A New Linear Ultrasonic Motor Using Hybrid Longitudinal Vibration Mode

This paper proposes a new linear ultrasonic motor using hybrid mode of the first symmetric and anti-symmetric longitudinal modes. The stator is constructed by two Langevin transducers in combination with two isosceles triangular beams. The triangular beams can transform the displacement in axial direction into the displacement in perpendicular direction and generate the oval trajectory of the driving foot, which is the merit of the simple structure. For better mode degeneration result, the influence of the triangular beam dimensions on the vibration frequency difference of the stator was analyzed by Finite Element Method (FEM) analysis. The overall dimensions of the prototype stator are 70 mm (length)
$\times15$
mm (width)
$\times $
10 mm (thickness). Driven by ac signals with the driving frequency of 55 kHz and voltage 400
$\text{V}_{p-p}$
, the motor can provide the no-load speed 63.87 mm/s and maximum thrust force 3.14 N, respectively. The frequency matching process of ultrasonic motor is simplified by adjusting the structure dimensions of the triangular beams.