"; _cf_contextpath=""; _cf_ajaxscriptsrc="/cfthorscripts/ajax"; _cf_jsonprefix='//'; _cf_websocket_port=8578; _cf_flash_policy_port=1244; _cf_clientid='7FAF056B6CB54B419127735C45790819';/* ]]> */
Piezoelectric Drives & Actuators
These piezo-assisted actuators contain a piezo stack mounted in series with the leadscrew. Each actuator is equipped with a Ø0.50" stainless steel bushing or a Ø9.5 mm (Ø3/8") mounting barrel for compatibility with a wide range of components.
PE4 Piezo ConnectionBNC Male
0 - 150 V
|Displacement Sensor Pin Designations|
|1||+15 V for Instrumentation Amplfier and Operational Amplifier|
|2||+ Oscillator Signal, Bridge Drive Sine Wave at 18 kHz (Nominal) When Used with KSG101 K-Cube™ Strain Gauge Reader, 4 V Peak-to-Peak|
|3||0 V Ground Reference|
|4||0 V Ground Reference|
|5||+ AC Signal Out, Proportional to Deflection, 18 kHz, 2 V Peak-to-Peak|
|6||-15 V for Instrumentation Amplifier and Operational Amplifier|
|7||2 kΩ Resistor, Identifies the Distance Travelled When Used with
KSG101 K-Cube™ Strain Gauge Reader
Knowing the rate at which a piezo is capable of changing lengths is essential in many high-speed applications. The bandwidth of a piezo controller and stack can be estimated if the following is known:
To drive the output capacitor, current is needed to charge it and to discharge it. The change in charge, dV/dt, is called the slew rate. The larger the capacitance, the more current needed:
For example, if a 100 µm stack with a capacitance of 20 µF is being driven by a BPC Series piezo controller with a maximum current of 0.5 A, the slew rate is given by
Hence, for an instantaneous voltage change from 0 V to 75 V, it would take 3 ms for the output voltage to reach 75 V.
Note: For these calculations, it is assumed that the absolute maximum bandwidth of the driver is much higher than the bandwidths calculated, and thus, driver bandwidth is not a limiting factor. Also please note that these calculations only apply for open-loop systems. In closed-loop mode, the slow response of the feedback loop puts another limit on the bandwidth.
The bandwidth of the system usually refers to the system's response to a sinusoidal signal of a given amplitude. For a piezo element driven by a sinusoidal signal of peak amplitude A, peak-to-peak voltage Vpp, and frequency f, we have:
A diagram of voltage as a function of time is shown to the right. The maximum slew rate, or voltage change, is reached at t = 2nπ, (n=0, 1, 2,...) at point a in the diagram to the right:
From the first equation, above:
For the example above, the maximum full-range (75 V) bandwidth would be
For a smaller piezo stack with 10 times lower capacitance, the results would be 10 times better, or about 1060 Hz. Or, if the peak-to-peak signal is reduced to 7.5 V (10% max amplitude) with the 100 µm stack, again, the result would be 10 times better at about 1060 Hz.
For a piezo actuator driven by a triangle wave of max voltage Vpeak and minimum voltage of 0, the slew rate is equal to the slope:
Or, since f = 1/T:
For a piezo actuator driven by a square wave of maximum voltage Vpeak and minimum voltage 0, the slew rate limits the minimum rise and fall times. In this case, the slew rate is equal to the slope while the signal is rising or falling. If tr is the minimum rise time, then
For additional information about piezo theory and operation, see the Piezoelectric Tutorials page.
The PE4 actuator is a manual adjuster with 4 mm of manual travel, while an integrated piezoelectric element provides 15 µm of fine adjustment. It can be mounted by the Ø3/8" mounting barrel. A BNC cable is attached to the body of the actuator.
The POLARIS-P20 is the piezoelectric actuator used in our Ø1" and Ø2" Polaris Mirror Mounts with Piezoelectric Adjusters. The actuator can be manually adjusted for up to 0.375" of travel, while the piezoelectric fine adjustment has a maximum travel range between 15.4 µm and 19.4 µm. The adjuster screw and bushing are machined from stainless steel, which has a low coefficient of thermal expansion (CTE) for stability in environments with large temperature fluctuations. For details on using this piezoelectric actuator, please see the spec sheet.
The piezo actuator features a male SMB connector; an SMB-to-BNC cable is not included. We offer the PAA236R cable with a 90° SMB connector on one end and a straight BNC connector on the other. The actuator includes an adjuster lock nut that can be tightened or loosened by hand or with a 12 mm thin-head, open-ended hex wrench. Holding the adjuster in place with the lock nut will not affect the piezoelectric adjustment.
Note: The POLARIS-P20 actuator has 3/8"-100 threads and is not compatible with the POLARIS-K05P2 mount, which incorporates 1/4"-100 adjuster screws. This actuator includes a 12 mm 3/8"-100 locking nut, which can be removed in order to install a POLARIS-LN4 locking nut. By using this 13 mm locking nut, users may take advantage of the TW13 preset torque wrench.
The DRV517 is a differential micrometer with an integrated piezoelectric element. The manual adjuster is a capable of up to 1/2" of travel. The adjuster knob features graduated tick marks for every 5 µm of travel, while the main body has tick marks at every 1 mm. The piezo element is equipped with a strain gauge that is capable of providing positional feedback over the 30 μm of piezo travel with 10 nm of resolution. A PAA622 piezo control cable is also included.
This piezo actuator can be driven by the KPZ101 K-Cube™ 150 V Piezo Controller with a KSG101 K-Cube Strain Gauge Reader for closed-loop operation. The BPC301 or BPC303 USB Closed-Loop Piezo Controllers also provide closed-loop operation.