40m QIL Cryo_Lab CTN SUS_Lab TCS_Lab OMC_Lab CRIME_Lab FEA ENG_Labs OptContFac Mariner WBEEShop
 40m Log Not logged in  Thu Oct 30 02:12:59 2014, diego, Update, IOO, IMC WFS sensing matrix measurement 12x  Thu Nov 20 22:43:15 2014, Koji, Update, IOO, IMC WFS damping gain adjustment Message ID: 10728     Entry time: Thu Nov 20 22:43:15 2014     In reply to: 10653
 Author: Koji Type: Update Category: IOO Subject: IMC WFS damping gain adjustment

From the measured OLTF, the dynamics of the damped suspension was inferred by calculating H_damped = H_pend / (1+OLTF).
Here H_pend is a pendulum transfer function. For simplicity, the DC gain of the unity is used. The resonant frequency of the mode
is estimated from the OLTF measurement. Because of inprecise resonant frequency for each mode, calculated damped pendulum
has glitches at the resonant frequency. In fact measurement of the OLTF at the resonant freq was not precise (of course). We can
just ignore this glitchiness (numerically I don't know how to do it particularly when the residual Q is high).

Here is my recommended values to have the residual Q of 3~5 for each mode.

```MC1 SUS POS current  75   -> x3   = 225 MC1 SUS PIT current   7.5 -> x2   =  22.5 MC1 SUS YAW current  11   -> x2   =  22 MC1 SUS SD  current 300   -> x2   = 600```

```MC2 SUS POS current  75   -> x3   = 225 MC2 SUS PIT current  20   -> x0.5 =  10 MC2 SUS YAW current   8   -> x1.5 =  12 MC2 SUS SD  current 300   -> x2   = 600```

```MC3 SUS POS current  95   -> x3   = 300 MC3 SUS PIT current   9   -> x1.5 =  13.5 MC3 SUS YAW current   6   -> x1.5 =   9 MC3 SUS SD  current 250   -> x3   = 750```

`This is the current setting in the end.`

```MC1 SUS POS 150 MC1 SUS PIT  15 MC1 SUS YAW  15 MC1 SUS SD  450```

```MC2 SUS POS 150 MC2 SUS PIT  10 MC2 SUS YAW  10 MC2 SUS SD  450 ```

```MC3 SUS POS 200 MC3 SUS PIT  12 MC3 SUS YAW   8 MC3 SUS SD  500```

 Attachment 1: MC_OLTF_CLTF.pdf  15.877 MB        ELOG V3.1.3-