A bending hybrid linear piezoelectric actuator using sectional excitation

A bending hybrid linear piezoelectric actuator with sectional excitation was proposed, designed, fabricated and tested. The proposed actuator used sectional excitation to generate two orthogonal 3rd bending vibrations, which enabled the PZT ceramics of two vibrations to be placed at the same optimum excitation position simultaneously. Four excitation voltages with 90° phase difference in sequence were applied on the four sectional electrodes. Then two orthogonal 3rd bending vibrations of the actuator and elliptical trajectory of the driving foot were generated. When a guide rail is in contact with the driving foot and a vertical preload is applied, the vertical component of the elliptical trajectory will overcome the preload, while the horizontal component of elliptical trajectory will push the guide rail into linear motion. Operating mechanism of the proposed actuator and sectional excitation were discussed. Experiment tests of vibration characteristics and mechanical output ability were then carried out. The tested resonance frequency and vibration amplitudes agreed well with the calculated ones. The prototype achieved a maximum speed and an output thrust density of 850 mm/s and 124.3N/kg, respectively. The sectional excitation enabled the prototype to achieve a higher output thrust density with less amounts of PZT ceramics.