Focused in-flight

Paul Boughton

A miniature autofocussing stage which can operate under flight conditions for shock and vibration with extreme temperature variation and intense orientation changes has been developed by the piezo-ceramic motor and systems manufacturer Nanomotion.

Represented in the UK by motion control specialist Heason Technology, Nanomotion’s direct-drive piezo-ceramic motor technology is characterised by extreme accuracy and precise movement with high resolution and low settling times, coupled with extensive velocity and force dynamics.

The single-axis linear focussing stage and motion system directly drives an optronic device with a mass of around 25 to 35 grams over 20mm travel to within 2.5 microns accuracy, based on an encoder resolution of 0.25 microns.

With shock to 40g and vibration to 12g, the stage, which features a preloaded bearing arrangement, achieves the high accelerations and fast settling times required to maintain focussing.

The stage mechanics fit into a footprint of less than 65 x 45 mm and weighs less than 50 grams. Temperature extremes of -40°C to +50°C can be tolerated.

The piezo-ceramic motor used in the focussing stage is Nanomotion’s Edge 4X which provides 1.3N of force with a maximum velocity of 200mm/sec. With a linear encoder integrated into the stage, the micro-sized motor is powered and controlled by a XCD2 drive/control chip which would typically interface with an OEM specific motherboard, and is programmed using a simple user interface that facilitates set up and downloading of motion scripts.

Proven applications for Nanomotion’s piezo-ceramic technology includes non-uniformity correction (NUC) shutters and variable aperture devices on aeronautical and military instruments as well autofocus stages for target acquisition and FLIR spectroscopy equipment.

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