Reports until 12:06, Friday 19 September 2014
H1 SEI
hugh.radkins@LIGO.ORG - posted 12:06, Friday 19 September 2014 (14040)
WHAM6 HEPI unlocked and position controlled--But not well

With the looming weekend I bit off a mouthfull this morning when I suggested I unlock the HEPI.

I did so but while doing that I noticed much of the Actuator ranges were very consumed--talk to me if you want more info.  Range of motion tests failed on several Dofs but only because the offsets were so large that the test criteria was satisfied at the start--obviously I need to work on the test script.

Back in October 2013, TFs were run and controllers developed--I don't know who at this point.  Regardless, these loops are too aggressive and the Boosts ring up.  I've got the controllers on manually now without the boosts controlling to the cartesian position before I unlocked the platform.  However, some of the loops aren't quite getting to the Set Point.  I don't know if it is the controller without the boost or if it is interference with something in the platform.  Given that I see the Postion approaching the Set Point but not quite getting there has me leaning toward the interference issue.

To do:

* I should install the Generic 2hz loops already on HAMs 4 & 5 and see if the loops can be turned on with the boosts and if the error point will go to zero.

* Run more range of motion/linearity tests to assess interference more thoroughly.

* Collect Spectra to confirm intereference

* If motion range can be confirmed, collect Transfer Functions; if interference is a problem, see below.

* Redo filters with good TFs and get under control.

**** Do more with HAM6 ISI, currently only damping!

Interference problem solutions:

1)--May be able to remove Bellows shields and modify to give more room--not easy but not too bad.  It seems to me that building the Actuator with lots of welding distorts things enough that the ideal Actuator floating/relaxed/center position isn't always the center position.

2)--Disconnect Actuator from Foot and rezero.  May be the better solution but will take a day at least.  We are pretty good at connecting the Actuators without shifting the platform too much but that is the main risk--Disconnecting the actuator and rezeroing will lose the reference IPS position.