Piezoelectric Stage for nanometer level precision

ProfHankD wrote:

mawyatt2002 wrote:

Awhile back the surplus market made some Physik Instrumente piezoelectric devices available. The devices offer the potential for extreme resolution and high precision when operated "Closed Loop" with position feedback. The complete OEM Closed Loop controllers/drivers/amps are very expensive, so an effort began to develop a custom solution at a much lower cost. One solution is a full Custom Complete Closed Loop system adaptable to various piezoelectric stages (P601K, P603K for example), another was a Custom Controller to interface with the OEM P603K Driver/Amp which are available on eBay at reasonable costs. Both operate from a Raspberry Pi with a single +12V at <1/2 amp supply.

Pretty slick....

If I were doing this, I think I'd just wildly gear-down a stepper... perhaps to drive a movement extracted from a cheap micrometer (e.g., like this ). Less driver circuitry needed, but a bunch of 3D-printed parts for mounting.

Thanks,

Gears have all sorts of issues with backlash, moving surfaces, mechanical noise and so on, and suspect even quality micrometers can't achieve these levels.

The piezo ceramic elements expand or contract at the molecular level based upon electric field, so there is no mechanical surface to surface movement. The cleverly engineered "flexures" in the Piezo Stages are like bending gears without any noise, hysteresis or other effects that plaque conventional bearings, however they have limited movement range. The piezo elements are held in position at the ends by natural compression and don't move during general excitation. So in normal operation these Piezo Stages have no surface to surface mechanical movement.

PI has some nice videos that show how these work.

https://www.pi-usa.us/en/products/piezo-flexure-nanopositioners/

You can follow more details on the PM thread previously indicated and these threads.

https://www.photomacrography.net/forum/viewtopic.php?t=40679

https://www.photomacrography.net/forum/viewtopic.php?t=40681

https://www.photomacrography.net/forum/viewtopic.php?t=40682

This certainly was an involved undertaking as you can gather from the above threads. The Close Loop Controller is one of the most complex analog closed loop systems I've ever encountered. Here's a few more images of the Piezo Stages, P601K and P603K, custom Controller/Driver/Amp and custom Controller for OEM P603K Driver/Amp.

Best,

P601K Stage, machined from solid block of SS

P601K with XYR Stage and ARCA clamp

Beat Up P601K Stage showing Piezo Element Stack, Flexures cuts, Stain Gauges on top for position sensing

P603K Stage

P603K Backside

Custom Controller/Driver/Amp

Another View

OEM P603K Driver/Amp with Custom Controller

Mounted Custom Controller

Another View