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[February 2010]
NEXLINE®: High-Force Ceramic Linear Drive for Long-Range Nanopositioning
Physik Instrumente (Karlsruhe, Germany) has introduced N-216 NEXLINE® high-load linear motors – ultra-precision nanopositioning actuators with travel ranges to 20mm and push/pull forces to 600N (130lb). The operating principle is based on coordinated motion of a number of highly preloaded linear and shear piezo elements acting on a runner and does not involve rotation/linear conversion. The working principle is non-magnetic, vacuum and clean room compatible.
N-216 comes in two versions for open- or closed-loop operation, as well as in two different load configurations. Closed-loop versions are equipped with a linear encoder for direct position measurement of the moving runner. The encoder features 5nm resolution over the full travel range. In open-loop operation a positioning resolution to 30 picometres can be realised by use of the (high-dynamics) analogue operation mode.
NEXLINE® drives have many high-end applications from ultra-precision manufacturing and semiconductor test equipment to astronomy and high energy physics applications. They are said to excel when the requirements for high forces, precision, lifetime and stability are paramount. The extreme reliability makes them ideal for applications in difficult-to-access internals of instruments, where nanometre-realm adjustment and/or vibration cancellation are required. To promote long lifetime, the PiezoWalk® controller can reduce the operating voltage on all the piezo elements to zero at any position without affecting the full holding force (up to 800N or 177lbs).
NEXLINE® drives overcome the limitations of conventional nanopositioning systems in their combination of long travel ranges and high resolution and stiffness. The piezoceramic clamping and shear elements act directly on a moving runner coupled to the load. For maximum velocity and long distance movements, the runner can be driven in full step mode. Extremely uniform motion and constant velocity is achieved with the nanostepping mode. In addition to combining long travel ranges with piezo-class precision, NEXLINE® PiezoWalk® drives also offer a high-dynamics analogue operation mode (100's of Hz) over smaller distances (to 6µm).
In the highly responsive analogue operation mode (distance less than one fullstep), the position resolution is only limited by the stability of the control signal (typically 10s of picometres are feasible). This mode can be used for ultra-precise adjustments, scanning, dithering and also for active vibration control. Customised NEXLINE® drives for different loads, travel ranges and dynamic requirements are feasible, because PI fully controls the manufacturing process of the ‘piezo engines’ internal to the NEXLINE® motors.
www.physikinstrumente.com
ENDS