How Piezoelectric Motors Work
Authored by: Nanomotion Ltd.'''
(Originally published here. Reproduced with permission.)
The Piezoelectric Effect in piezoceramics converts electrical field to mechanical strain. Under special electrical excitation drive and ceramic geometry of Nanomotion motors, longitudinal extension and transverse bending oscillation modes are excited at close frequency proximity. The simultaneous excitation of the longitudinal extension mode and the transverse bending mode creates a small elliptical trajectory of the ceramic edge, thus achieving the dual mode standing wave motor patented by Nanomotion.
By coupling the ceramic edge to a precision stage, a resultant driving force is exerted on the stage, causing stage movement. The periodic nature of the driving force at frequencies much higher than the mechanical resonance of the stage allows continuous smooth motion for unlimited travel, while maintaining high resolution and positioning accuracy typical of piezoelectric devices. Travel can be linear or rotary, depending on the coupling mechanism.
Closed loop servo control can be provided with standard off-the-shelf servo controllers, or with the Nanomotion servo controller that offers full PID control at 20 kHz servo rate. Further, the motors can operate in actuation mode.
While the driving voltage is not applied, the ceramic plate is stationary and generates holding torque on the stage. Unlike any other braking device, the holding torque of the Nanomotion motor does not cause any position shift.
- How Piezoelectric Motors Work.
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