Notes on Specifications for Piezo Actuators and Components

Operating voltage
For PICMA® ceramic equipped piezo actuators: 0 to 100 V typ. Max. recommended operating voltage range is -20 to +120 V (extremes for short durations only).
For PICA™ ceramic equipped piezo actuators: 0 to 1000 V typ. Voltages in excess of +750 V should not be applied for long durations. Operation in the range of -200 to +750 V is recommended for maximum lifetime and displacement.
For shear and bender type piezo actuators, bipolar voltage is applied, ranging from ±30 V up to ±250 V typ.

Motion and Positioning

Performance specifications are valid for room temperature (22 ±3 °C) and closed-loop systems are calibrated at this temperature (specifications for different operating temperatures on request). Recalibration is recommended for operation at a significantly higher or lower temperature. Custom designs for ultra-low or ultra-high temperatures on request.

Integrated feedback sensor
Absolute measuring capacitive and SGS sensors are used to provide position information to the controller. For details see the tutorial "Piezoelectrics in Positioning" Section (see link).

Open-loop travel for PICMA® Ceramic Equipped Piezo Stages and Actuators
Minimum open-loop travel at 0 to 100 V operating voltage.

Open-loop travel for PICA™ Ceramic Equipped Piezo Actuators
Minimum open-loop travel of high-voltage piezo actuators at 0 to +1000 V operating voltage.

Closed-loop travel for PICMA® Ceramic Equipped Piezo Stages and Actuators
Travel provided in closed-loop operation. PI piezo amplifiers have an output voltage range of -20 to +120 V or -30 to +135 V to provide enough margin for the servo-controller to compensate for load changes, etc.

Open-loop / closed-loop resolution
Resolution of piezo actuators is basically infinitesimal because it is not limited by stiction or friction. Instead of resolution, the noise-equivalent mo tion is specified. Values are typical results (RMS, 1 s), measured with E-503/E-508 amplifier module in E-500/501 chassis.

Mechanical properties

Static large-signal stiffness
Typical tolerance ±20%. Static large-signal stiffness of the stage in operating direction at room temperature. Small-signal stiffness and dynamic stiffness may differ because of effects caused by the active nature of piezoelectric material, compound effects, etc. For details see the tutorial "Piezoelectrics in Positioning" Section (see link)

Unloaded resonant frequency
Typical tolerance ±20%. Low est resonant frequency in operating direction (does not specify the maximum operating frequency). For details see the tutorial "Piezoelectrics in Positioning" Section (see link)

Push/pull force capacity (in operating direction)
Specifies the maximum forces that can be applied to the system along the active axis. Limited by the piezo ceramic material and the flexure design. If larger forces are applied, damage to the piezo ceramic, the flexures or the sensor can occur. The force limit must also be considered in dynamic appli cations.

Example: the dynamic forces generated by sinusoidal operation at 500 Hz, 20 µm peak-to-peak, 1 kg moved mass, are approximately ±100 N. For details see the tutorial "Piezoelectrics in Positioning" Section (see link)

Shear force limit
Maximum lateral force orthogonal to the operating direction. Limited by the piezo ceramics.

Torque limit (on tip)
Maximum torque that can be applied before damage occurs. Limited by the piezo ceramics.

Drive properties

Electrical capacitance
Typical tolerance ±20%. The piezo capacitance values indicated in the technical data tables are typical small-signal values (measured at 1 V, 1000 Hz, 20 °C, no load). Largesignal values at room temperature are 30 to 50% higher. The capacitance of piezo ceramics chan ges with amplitude, temperature, and load, up to 200% of the unloaded, small-signal capacitance at room temperature. For detailed information on power requirements, refer to the amplifier frequencyre sponse graphs in the Piezo Drivers / Servo Controllers (see link) Section of this catalog.

Dynamic Operating Current Coefficient (DOCC)
Typical tolerance ±20%. Average electrical current (supplied by the amplifier) required to drive a piezo actuator per unit frequency and unit displacement (sine-wave operation). For example to find out if a selected amplifier can drive a given piezo stage at 50 Hz with 30 µm amplitude, multiply DOC coefficient by 50 x 30 and check if the result is smaller or equal to the output current of the selected amplifier. For details see the tutorial "Piezoelectrics in Positioning" Section (see link).

Miscellaneous

Operating temperature range
The temperature range indicates where the piezo actuator may be operated without damage. Nevertheless, recalibration or zero-point-adjustment may be required if the system is operated at different temperatures. Performance specifications are valid for room temperature range.

Material
Housings are usually made of stainless steel. Small amounts of other materials may be used internally (for spring preload, piezo coupling, mounting, thermal compensation, etc.).

Al: Aluminum
N-S: Non-magnetic stainless steel
S: Ferromagnetic stainless steel
I: Invar
T: Titanium

See also "Options and Accessories" (see link).