Optomechanics – Secret Sauce

Colleagues:

Optomechanical engineers are a lot like professional chefs.  Each has a “secret sauce.”  Just like chefs we sample and adjust our sauces all the time to be sure they’ll come out consistently good.

AEH’s secret sauce is selections from W. J. Smith and R. J. Roark blended into K-J. Bathe.  Below I use the optical prescription to determine the optomechanical constraint equations (OCE) between each of its ten optical elements and the image on the detector (pink).  I then estimate the required stiffness properties of the structure between the elements, I define a lumped mass for each of the optical elements and connect them together with the nine beams (yellow) with the (estimated) proper stiffnesses.  I run it for the LOS error:

This initial run is usually off-target but it provides a starting point.  I replace the lumped masses with the actual lenses (from step files) and adjust the stiffness of the beams until I’m in the ballpark of the required LOS error.  Then I guide the design of the CAD structure to have the proper proportions to meet the required LOS error…

Voi-la!

1.3 ur rms . . . LOS . . .  1.4 ur rms
from Proposal    ——————————————————>    to Product.

AEH’s sauce provides the project a continuous and traceable record of the adequacy of the structural stiffness supporting the optical system from the earliest concepts to the final tested product.  AEH’s sauce is a little different every time, just like its culinary counterpart.

Bon appetite!

Al H.
2-7-18

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