Colleagues:

An interesting, and challenging, recent job was:

“Find a way to assure a 7 microradian boresight shift
and image jitter performance specification for a mid-wave FLIR
in an airborne thermal and random vibration environment”.

The solution used the Unified Modeling mode of the Ivory Optomechanical Modeling Tools.  Ivory accurately modeled the imaging behavior of the FLIR and generated a NASTRAN optomechanical finite element model for the dynamic analysis. 

The model’s results were validated against Zemax environmental analyses, longhand (Excel, actually) calculations and rigid body checks in NASTRAN giving the instrument’s focal length.  (Yes, NASTRAN can calculate the focal length of on optical instrument.)  The indicated uncertainties were all less than 1.8%.

The model turned out to be a very effective design tool.  It was run more than 50 times over a few weeks.  We were able finally to demonstrate safety margins of between 25 and 1000 on the image jitter and boresight shift requirements. 

You may see some of the product from this effort in the attached “pdf” file.  My client has all of my modeling files, which are heavily annotated, so he can “mesh” his ProE solid models as they mature and replace the beam and shell elements of my early model.  Ivory’s Unified Optomechanical Model will work, of course, in any NASTRAN model he chooses to put together to check the progress of the design.

The Ivory Optomechanical Modeling Tools answered the challenge.  If you have any interest in these kinds of things, please feel free to give me a call.  I’d be happy to talk with you.

I hope you all survived Spring Break!

Al Hatheway
5-3-07