The 8310CE Closed Loop Picomotor™ Actuator is ideal for applications where closed-loop control and absolute position calibration is required. With an integrated rotary encoder, and forward and reverse limit switches, this unique device offers the best attributes of the standard Picomotor™ actuator -- <30-nm resolution, >5 lb. (22 N) of force along with set-and-forget long-term stability -- with the added benefits of exceptional accuracy and ±1-μm bi-directional repeatability over the entire half-inch travel range.
Choose between operating the Closed-Loop Picomotor actuator in closed-loop mode where it can hold a set position, or command it to move a specified distance. You can also choose between position or velocity profiled movement. Either way, when the actuator reaches its target location, the controller will adjust the motor to the precise requested encoder count and then stop motion. Even if you keep the servo loop enabled, the motor will only move in response to any system disturbances which cause rotation of the screw. Because the inherent resolution of the motor is finer than the resolution of the encoder, zero-count encoder error is always achieved. You can query the encoder to determine the rotation of the screw at any time.
Operating in open-loop mode, the Closed-Loop Picomotor actuator has a step size of < 30 nm, allowing for very small movements. In closed-loop mode, the encoder has a resolution of 52.9 nm, allowing for very small, controlled, and repeatable movements.
Our Closed-Loop Picomotor controllers and drivers are modular. You can daisy-chain up to 31 drivers together with two channels each, so you can have a network of up to 62 Closed-Loop Picomotor actuators. You have two interface options with the controller system: hand pad or computer, both providing plug-and-play use.
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.
The Closed-Loop 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.
The standard sized 0.375 inch shank of the Closed-Loop Picomotor actuator allows it to easily be integrated into standard micrometer mounting holes.
With load capacity of 5 lbs (22 N), our closed loop Picomotor actuators have a substantial push force.
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