A set of matlab transfer functions has been ran on the TMSX this afternoon after BSC9 was closed out, and while the ISI was damped. The pitch degree of freedom shows some excess noise between 0.7Hz and 3Hz, which is something I was not expecting to see since the measurement after the last work accomplished on TMSX was clean.
It might be related to some excess motion at the time of the measurement during the afternoon, which I will check by running undamped and damped TFs overnight in a quiter environment. We will see how repeatable the measurement is tomorrow morning.
It might also be the position of the cables that could have changed by themselves because of their weight. Or maybe some work that I'm not aware of that was done after the last measurement taken. In those cases we would probably need to physically check what is going on.
Results attached are described below :
(1) Comparison between the model and last TMSX TF
(2) Comparison between TMSX after the work done on Nov 20th (Orange trace), after the last time work has been done on Nov 22nd (black trace), and today (pink trace).
See the 5th page of (1) and (2) for the pitch dof
Looking at the new results from this morning, everything seems fine, and tf from overnight are not showing any problems. Plots pending.
In fact, after investigating a little bit more, and looking at the pitch motion at the suspension point of the TMSX, it looks like the ISI was moving in Pitch at low frequency during that measurement. The 3rd attached pdf shows in blue the pitch input motion during yesterday afternoon's TF (noisy measurement), and in green during the overnight TF.
The other two pdfs are showing the results with :
(1) a comparison between yesterday afternoon's TF and the one taken overnight
(2) a comparison between and LLO and LHO undamped TMSX tfs
Results are very clean and similar to model and LLO's data.