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QUAD08 model fitting

I ran the model fitting algorithm on QUAD08 to see if any more insight could be gleaned from the measured TFs towards what is causing the error in the 2nd pitch mode. The fitting algorithm is on the svn at:
.../SusSVN/sus/trunk/QUAD/Common/MatlabTools/QuadModel_Fit/QuadPend_GaussNewton_fit_v3_X1QUAD08.m

The results confirm what others have already seen, in that increasing dm or dn (the top mass wire flexure heights relative to the center of mass) makes the model match the measured pitch modes. Specifically, the model says that either

+1.4 mm on dm

or +1.7 mm on dn

equivalently brings the model in line with the measurements. You can also trade offset between one and the other because these two parameters are degenerate in the model. I also changed

h1 = 0

to 

h1 = 2 mm.

h1 is a horizontal front-back shift in the center of mass for the UIM stage. Betsy and Arnaud observed that the pitch adjusters here are pushed far forwards. This parameter reproduces much of the vertical to pitch cross coupling seen the the vertical-vertical and pitch-pitch TFs. It does not influence the mode frequencies.

I put a QUAD08-tuned model on the svn here:
.../SusSVN/sus/trunk/QUAD/Common/MatlabTools/QuadModel_Production/quadopt_wireloop_QUAD08.m


The physical cause of the increased pitch frequencies remains a mystery. Drooping top mass blades would do this, as would improperly seated wire clamps for the top most wires. Since the top mass blades have been replaced without altering the pitch modes, it is unlikely to be those. A 0.15 mm increase in the top wire diameter would also do this, but Arnaud and Betsy checked the wire with calipers and it is correct.


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wireloop model updates


In the process of doing this analysis, I updated the wireloop model on the svn, which was quite out of date. See:
.../SusSVN/sus/trunk/QUAD/Common/MatlabTools/QuadModel_Production/quadopt_wireloop.m

Based on the most recent drawings for the wireloop quad (all metal, wireloop under PUM) I updated
* all mass and inertia values
* 3 of 4 wire lengths: ln, l1, l2  (these were based mostly on previous work with Mark Barton on the fiber quad model updates)
* transverse wire spacings: n3, n4, n5
* and the d values: d2, d3, and d4

The adjustments on the n parameters helped bring roll more in line. The pitch inertias helped pitch a bit as well. The other parameter corrections had little influence on the dynamics, but are at least more representative of the as-built system.

This work also found an error in some of the assembly drawings where the PUM wire clamp was flipped upside down. This has now been corrected in the drawings. The clamps had been installed correctly.


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The attachment shows a comparison of TFs of the original wireloop model, the new wireloop model, the QUAD08-tuned wireloop model, and the QUAD08 measured TFs.

Andres R. & Jeff B. 

   The regluing of the LL magnet/standoff was successfully completed. The repair jig has been removed from HAM5 and the AOSEMs have been remounted. They have been gross aligned. The suspension EQ stops have been released. 

NOTE: Found several Top Mass EQ stops touching the mass, (these stops were not put on for the magnet repair). When I released these stops there was a visible jump movement of the top mass. We will see if this is a contributor to the SR3 pitch misalignment. 

Particle Counts
Before Work:
 In cleanroom cover on: 0.3 = 0, 0.5 = 0, 1.0 = 0
 In chamber cover on: 0.3 = 17, 0.5 = 10, 1.0 = 2

During work:
 In chamber cover off: 0.3 = 46, 0.5 = 27, 0 

After work: 
  In cleanroom cover on: 0.3 = 0, 0.5 = 0, 1.0 = 0
  In chamber cover on: did not get   


 

Day's Activities:

• 8:50am:  HAM5 Oplev alignment work from HAM4 (Thomas)
• 9:00:  HAM5 Magnet Repair (Jeff/Andress)
• Checked that EX & EY SUS/SEI Watchdogs are NOT TRIPPED
• 9:48:  ITMy IAS set up (Jason)
• 10:10 Nathan (SURF) beginning laser work in Optics Lab
• 10:30 Jeff/Andres Done at HAM5 & ready for Viewport installation handoff
• etmy isi changed to be damped only for detchar study
• 10:45:  Apollo installing viewport for output HAM
• 10:48:  PSL went down over 24hrs ago due to Chiller issue (Peter restored)
• 11:54:  HAM5 Oplev alignment (Thomas & Hugh)
• 12:10pm:  LVEA Transitioned to Laser Hazard (for SR3 pitch alignment work)
• 2:15:  Beginning to search for PSL beam in Input HAMs (Arnaud, Jeff, Kiwamu)
• 3:40:  HAM4 oplev work (Thomas & Hugh)

Nathan will work past 4pm in the Optics Lab, but he will be with Dick G ("they will be done by 5").

I was informed this morning that the laser was off, as there was no infrared light showing up on the video cameras.  Went to the diode room and saw that the crystal chiller was indicating a flow sensor error.  The water level was about the same as it was previously, so there were no water leaks.

I turned the crystal chiller on from the PSL Computer, the flow rates indicated were normal.  Turned the laser back on, everything seems okay.  I do not know what triggered the flow sensor error in the first place.

The WHAM5 HEPI was locked for the Septum pull 23 April-- believe it has been locked since that time.

The HEPI Position Sensors (IPS) have been real since 18 April and during these five days I managed to do TFs & other static test.  As I say, these measurements tend to destress the system and shift the IPS readings but the Cartesian numbers tend to not change much as the local shift cancel out in the cartesian basis.  Attached are the cartesian trends and I'll use these values to update the position loop's target.  Remember these channels are calibrated in nano units so the locked drifts and shifts from initial zero are pretty small.

Updated the safe.snap to save these.  The position loops have not been done yet so these can't turned on.  So lots more matlab work and more safe.snaps to go.

Since the platforms are unlocked, closing the loops seems right.  No issues with HEPI.  The ISI drives seem a bit high for level 1 even though I zero'd out the position biases.  THis could just be the purge air or neighboring floor activities.

HAM5 SR3:  magnets found, osems to replace, lock up sus until HAM5 isi balanced.  Most morning locking and BOSEM adjust

• Balance ISI
• Travis/Jeff--working on SR3 for pitch to SR2

BSC3:  rebalanced BSC3 & locked ISI for SUS (ACB swung back)

BSC1 (Travis):  checked ESD cables (some issue), coarse PIT work complete & ready for IAS check, spool out & ready for IAS (will take ~day for set up), really want to determine if a HEPI translation will be needed, because this would be a major schedule hit

EX Vent Prep:  Laser Hazard at EX, Sheila staged for QPD work, EX first cleaning complete (2nd cleaning Fri or Mon), Doors off on Tues, 1st week:  ISC & PCal 2nd week

HAM4 TF:  tripped last night, so will want to run 8hr TF (after Apollo noisy work):  avoid noisy work near HAM4

Output Arm Oplevs:  ready for HAM4/5 retroreflection

Viewport Inspection work brought up with chambers being closed soon.

Business:

• Monday there will be a film crew (Dale)
• Detchar F2F next week
• DetEng Training at 11am & Journal Club of non-SURF presenters at noon

please see attached. only unexpected h1fw0 restarts up to the time the solaris QFS box was power cycled. 

[Thomas Greg Gerardo Arnaud]

Today we finished setting back the optical lever at ETMx, all went well, we just need to check for digital comp filters.

• Removed the receiver box from the pylon (this was tricky since we couldn't remove one of the screws. We had to torque it until breakage to be able to remove the plate. The thread was cut and polished, but is still in the pylon)
• Elevated the pylon by a few inches
• Swapped the mounting plate with a one adapted to the new level, mounted it on the pylon
• Mounted the two motorized translational stages on the plate , with the photodiode circuit board
• Centered the pd on the main reflected laser beam by changing the position of the motorized stages
• Plugged the pd to the whitening chassis, verified the signals for the 4 quadrants (we had to turn the analog switch gain from the circuit board to get a signal of ~thousands counts/quadrant)
• Took a spectra comparing with a reference from april (cf attached screenshot). High frequencies differ, probably because of bad digital whitening compensation filters, otherwise the signal looks healthy

Pulled the covers away from the ISI table.  Attempted to close position loops on HEPI but was not stable in horizontal, decided to leave it off.  After I got the TFs started, I looked again and found the HP L4C blend filter off so this signal was getting through and I'll guess is the problem.  Don't want to stop the TF so I'll check that tomorrow.

Andres R. & Jeff B.

   We reglued the second magnet broken off the Intermediate Mass (the Lower Left). There were no problems encountered during the repair. We will remove the jig after 24 hours. If the bond is good, we will remount and align the BOSEMs and put the baffle (mover for access to the magnets) back into its position for ISI balance work. 

   Both broken magnets were removed from the chamber.


Particle Counts

Before Work: 
   Cleanroom Cover on: 0.3 = 0, 0.5 = 0, 1.0 = 0
   In Chamber Cover on: 0.3 = 0, 0.5 = 0, 1.0 = 0

During work
   In chamber: 0.3 = 17, 0.5 = 10, 1.0 = 0

After Work:
   Cleanroom Cover on: 0.3 = 0, 0.5 = 0, 1.0 = 0
   In Chamber Cover on: 03. =0, 0.5 = 0, 1.0 = 0  

Andres and Jeff to HAM5

Travis and Betsy to BSC1

Patrick ConLOG work

Arnaud working at EX with Gerardo

Hugh to work on BSC3

Cyrus working on script0

Hugh working at HAM4

eth0 on script0 was running at 100/Full instead of 1000/Full, so a number of things were likely taking longer to run on it (most notably the daily pull of the aLog and SVN backups).  I un/replugged it to get it to renegotiate at 1000/Full, and restarted the screenshot processes to ensure that the web pages will stay current.

The adapter spool at GV 5 has been removed and the hard cover with the custom slots for IAS placed on the Y arm tube.

Apollo Scott, HughR, GregG, JimW

The 3rd 3IFO BSC-ISI went into the can this morning, and is sitting in the SB garage waiting for transfer to the LVEA. No problems, we were done before it got too hot by 11. After Scott helped me flip and move the first plate for the 5th, and final, ISI onto the test-stand. Unit #4 is on the other test-stand and awaiting some parts from clean and bake, before we can start testing.

I went into ITMX to rebalance this afternoon. Largely uneventful, all I had to remove was optical table ballast that compensated for fiber-guards missing from the wire-hang, and everything went right to where it belonged. The ISI is now re-locked, and SUS's optic covers are re-installed. ITMY won't be so easy, because it is missing the compensating ballast. When we re-balance, it will have to be done by removing weight from the sides of stage 2. I would prefer we did that before we jammed the ACB in there, if at all possible.

After the alignment of the ITMX, I failed to do this to capture the 70urad yaw we are holding.  I was checking for tilts caused by the ACB swing out and notice some large position shifts wrt free hang locations.  There must have been a reboot/burtrestore ~ 1 July.  The ACB being swung out has tilted HEPI ~5urad RX an ~20urad RY.  This should not impact our balance but I can hold it with HEPI.  I set the location targets to the 70urad rz and these tilts and the otherwise free hang position.

OK so remember the safe.snap!

Andres R. & Jeff B.

   We reglued the UR magnet on the SR3 Intermediate Mass this morning. We will check the bond tomorrow. When all is well with the repair of the UR magnet, we will replace the LL magnet, which was also knocked off. Both missing magnets have been found and are not in or on the suspension. 

   To use the magnet repair jig we had to remove the baffle located behind SR3. Its location was marked. The baffle will be returned to its installed position when the magnet repairs are completed.