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Entry  Thu Aug 11 16:09:05 2011, Nicole, Summary, SUS, Bode Plot for TT Suspension 6x
    Reply  Fri Aug 12 14:15:07 2011, Nicole, Summary, SUS, Bode Plot for TT Suspension EXPrigidvsflex.jpg
       Reply  Fri Aug 12 15:34:16 2011, Nicole, Summary, SUS, Bode Plot for TT Suspension RIGIDexp_model.jpgflexmodcomp.jpg
Message ID: 5195     Entry time: Thu Aug 11 16:09:05 2011     Reply to this: 5206
Author: Nicole 
Type: Summary 
Category: SUS 
Subject: Bode Plot for TT Suspension 

All of my plots have already taken into account the calibration of the photosensor (V/mm ratio)

Here is a bode plot generated for the transfer function measurements we obtained last night/this morning. This is a bode plot for the fully-assembled T.T. (with flexibly-supported dampers and bottom bar). I will continue to upload bode plots (editing this post) as I finish them but for now I will go to sleep and come back later on today.

 

flexwithbase.jpg

Here is a bode plot comparing the no eddy-current damper case with and without the bar that we suspected to induce some non-uniform damping. We have limited data on the NO EDC, no bar measurements (sine swept data from 7 Hz to 50 Hz) and FFT data from 0 Hz to 12.5 Hz because we did not want to induce too much movement in the mirror (didn't want to break the mirror).  This plot shows that there is not much difference in the transfer functions of the TT (no EDC) with and without the bar.

stage1.jpg.jpg

From FFT measurements of  the no eddy-current damper case without the bar (800 data points, integrated 10 times) we can define the resonance peak of the TT mirror (although there are still damping effects from the cantilever blades).

The largest resonance peak occurs at about 1.94 Hz. The response (magnitude) is 230.

The second-largest resonance peak occurs at about 1.67 Hz. The response (magnitude) is 153. This second resonance peak may be due to pitch motion coupling (this is caused by the fact that the clamping attaching the mirror to the wires occurs above the mirror's center of mass, leading to inevitable linear and pitch coupling).

 

Here is a bode plot of the EDC without the bar. It seems very similar to the bode plot with the bar

FULL_BODE.jpg

 

 Here is a bode plot of the rigidly-supported EDC, without bar. I need to do a comparison plot of the rigid and flexibly-supported EDCs (without bar)

 

 FULL_BODErigid.jpg

 

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