Aerotech QNP3 Series Hardware Manual page 45

QNP3 Hardware Manual
F. The electric field is driven to the coercive limit for the opposite polarization direction and the dipoles
reorient to their original polarization.
G. The piezo actuator expands with the applied electric field to its physical limit.
For positioning applications, piezo actuators are generally operated with a semi-bipolar voltage over an area
of the curve (ABC) away from the saturation and coercive field limits. An example of displacement versus
applied voltage for a piezo actuator stack in this region of the curve is shown in
Figure C-2: Typical hysteresis curve of a piezoelectric stack actuator operating from -30V to
Aerotech amplifiers take full advantage of the semi-bipolar operation of piezoelectric stack actuators. Our
actuators are designated to operate from -30 V to +150 V with very high voltage resolutions. Over this
voltage range, open-loop hysteresis values can be as large as 10-15% of the overall open-loop travel of the
piezo stage. Operation of the piezo stage in a closed-loop effectively eliminates hysteresis of the actuator
enabling positioning repeatabilities in the single-digit nanometer range.
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+150V
Appendix C
Piezo Engineering Tutorial
Figure C-2.
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