Introduction to PZT Linear Motors

The goal of this work was to explore the motion interaction of two rectangular pieces of piezoelectric material joined at a 90° angle (Λ shape) and its functionality as a linear ultrasonic motor. Since the resulting combined motions of two exited piezoelectric material leads to elliptical and circular motion at the junction or tip, this motion translates into linear displacement of a load by friction. Several methodical designs were simulated using Finite Element Method (FEM) Atila software. Then, selected simulation designs displaying the largest displacement at the motor’s tip and smaller bandwidth between resonant frequencies (modes) were realized using piezoelectric (PZT) type 8H material. The frequency response, motion shape, load displacement, driving voltage, and number of driving inputs were tested for the realized design. The chosen motor design, elicited a 4.2 to 4.8KHz bandwidth between modes and an additional negative 6KHz bandwidth. The later allowed for larger pressures at the motor’s tip without loosing displacement because of frequency shifts between modes. This linear ultrasonic motor displayed elliptical motion of 7μm and 8μm at its minor and major axis, moving a 10oz Teflon load at a ...  more detail

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