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Piezoelectric Inertia Actuators
13 mm Travel Range
50 mm Travel Range
Two PIAK10 Inertia Actuators Being Used
25 mm Travel Range
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The Control Cable Can be Adjusted up to 110° for Space-Constrained Applications
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Simplified Illustration Showing the Operation of an Inertia Piezo Actuator
Piezoelectric Inertia "Slip-Stick" Motor
A piezo stack mounted perpendicular to the lead screw axis actuates the screw via a design based on the system's inertia and coefficients of friction. Two decoupled arms, or jaws, are located on either side of the piezo. These arms then extend around the top and bottom of the main lead screw. This is illustrated in the diagram to the left.
The piezo reacts to a custom sawtooth voltage waveform, causing it to expand or contract. The waveform is asymmetric, slowly ramping up to the specified voltage and then quickly dropping the voltage to zero on a nanosecond timescale. As shown in the bottom illustration to the left, the jaws will "stick" to the lead screw during the slow voltage ramp, similar to how a person would turn a screw with their thumb and forefinger. The nanosecond voltage drop will cause the arms to "slip" due to the screws' inertia and the different coefficients of friction, and return the arms to their original position. The "slip-stick" nature of this device uses very short pulse widths and continuous stepping of the actuator will result in an audible noise at a typical level of 60 to 70 dB. This mechanism allows a single piezo element to translate a lead screw along its entire length.
Due to a number of factors that include the application condition, piezo hysteresis, component variance, and the axial load, the achieved step size will vary and is not repeatable. To help overcome this variance, an external feedback system will need to be used. Alternatively, a stepper motor actuator can also be substituted depending on the application.
Thorlabs' Piezoelectric Inertia Actuators provide high-resolution linear motion control with long piezo-controlled translation ranges in a compact package. Each actuator can support loads up to 2.5 kg (5.51 lbs) and preloads up to 30 N with typical movements of 20 nm and no backlash. The step size can be adjusted up to 30% to a maximum of approximately 30 nm using the KIM101 Controller. However, due to the open-loop design, hysteresis, and application conditions, the achieved step size of the system can vary over 20%. An external feedback system will need to be used to overcome this variance.
The actuator is self-locking when at rest and when there is no power supplied to the piezo, making these actuators ideal for set-and-hold applications that require nanometer resolution and long-term alignment stability. Manual adjustments can be made at any time, as long as the piezo is not actively translating the screw, by using the rear-located thumbscrew or with a 5/64" (2 mm) hex key.
Powered by a 10 mm (0.39") long discrete piezo stack, these actuators operate at speeds of up to 3.5 mm/min. The design of the piezo motor, detailed below, will rotate the tip of the lead screw during translation. As shown in the image above, the control cable for each actuator can be rotated up to 110° for space-constrained applications.
This K-Cube Controller is a compact, four-channel controller for easy manual and PC control of our piezoelectric inertia actuators. It is capable of single- or dual-channel operation and has an adjustable voltage output from 85 V to 125 V. The top panel display screen enables operation as soon as the unit is turned on, without the need for connection to a PC. Alternatively, USB connectivity provides easy 'Plug-and-Play' PC-controlled operation with two available software platforms: our new Kinesis® software package or our legacy APT™ (Advanced Positioning Technology) software package. The controller can be configured to operate up to four piezo inertia actuators or up to four PD1(/M) stages. One controller cannot be used to concurrently drive actuators and stages.
The unit has a very small 121.0 mm x 60.0 mm x 47.0 mm (4.76" x 2.36" x 1.85") footprint and may be mounted directly to the optical table using the 1/4" (M6) counterbored slots in the base plate. This compact size allows the controller to be positioned close to the motorized system for added convenience when manually adjusting motor positions using the top panel controls. Tabletop operation also allows minimal drive cable lengths for easier cable management.
For more information, please see the full web presentation.
Power Supply Options
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A location-specific adapter is shipped with the power supply unit based on your location. The adapters for the KPS101 are shown here.
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The KPS101 Power Supply Unit
The KPS101 power supply outputs +15 VDC at up to 2.4 A and can power a single K-Cube or T-Cube with a 3.5 mm jack. It plugs into a standard wall outlet.
The KCH301 and KCH601 USB Controller Hubs each consist of two parts: the hub, which can support up to three (KCH301) or six (KCH601) K-Cubes or T-Cubes, and a power supply that plugs into a standard wall outlet. The hub draws a maximum current of 10 A; please verify that the cubes being used do not require a total current of more than 10 A. In addition, the hub provides USB connectivity to any docked K-Cube or T-Cube through a single USB connection.
For more information on the USB Controller Hubs, see the full web presentation.