Picomotor actuators rely on the basic difference between dynamic and static friction. An example of this is the magician's "tablecloth trick," in which a quick pull (low dynamic friction) of the cloth leaves the dishes on the table, while a slow pull (high static friction) would pull the dishes off the table and cause a big mess! Our Picomotor actuator uses the same principle with a threaded jaw, similar to two halves of a split nut, clamped around a precision 80-pitch screw. One jaw is connected to one end of a piezoelectric transducer, and the other jaw is connected to the other end of the transducer. A slow electrical signal applied to the piezo slowly changes the length, causing the two jaws to slide in opposite directions. This slow sliding motion makes the screw turn (static friction). At the end of the transducer motion, a fast electrical signal quickly returns the jaws to their starting positions. Because of the screw’s inertia and low dynamic friction, it remains motionless, holding its position. Simply reversing the order of the fast and slow signals reverses the direction of rotation.
Our Picomotor actuators have a step size of less than 30 nm per step, allowing for very small, controlled movements. Note that the step size for open-loop picomotors varies from step to step and between forward and backward directions, and is directly related to payload – hence, position feedback should be provided by an external signal when operating an open-loop picomotor. For applications requiring absolute position calibration and high repeatability, consider a Closed-Loop Picomotor actuator.
The small footprint of the Tiny Picomotor actuators make them ideal for your compact-area needs. Even in this small package they offer up to 3 lbs (13 N) of push force.
Our Open-Loop Picomotor controllers and drivers are modular. You can daisy-chain up to 31 drivers together with four channels each, so you can have a network of up to 124 standard Picomotor actuators. You have two interface options with the controller system: hand pad or computer, both providing plug-and-play use. Alternatively, you may choose to use our TTL/Analog Picomotor driver.
The Tiny Picomotor actuator moves when voltage is applied to the piezo, changing its length and in turn moving the jaws which turn the screw. When no power is applied, the actuator does not move. You can feel confident that your set-up will stay put, even when you power down your system.
With two mounting options, a standard 0.25" shank and a 1/4-40 thread version, it is straight-forward to incorporate it into your design.
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