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 Thu Apr 18 22:35:23 2019, gautam, Update, SUS, ETMY actuator diagnosis Fri Apr 19 11:36:23 2019, gautam, Update, SUS, No consistent solution for output matrix Fri Apr 19 15:13:38 2019, rana, Update, SUS, No consistent solution for output matrix Fri Apr 19 16:19:42 2019, gautam, Update, SUS, Actuation matrix still not orthogonal Fri Apr 19 19:22:15 2019, rana, Update, SUS, Actuation matrix still not orthogonal Mon Apr 22 22:43:15 2019, gautam, Update, SUS, ETMY sensor diagnosis Thu Apr 25 00:30:45 2019, gautam, Update, SUS, ETMY BR mode
Message ID: 14558     Entry time: Fri Apr 19 16:19:42 2019     In reply to: 14557     Reply to this: 14559
 Author: gautam Type: Update Category: SUS Subject: Actuation matrix still not orthogonal

I repeated the exercise from yesterday, this time driving the butterfly mode [+1 -1 -1 +1] and adding the tuned PIT and YAW vectors from yesterday to it to minimize appearance in the Oplev error signals.

The measured output matrix is $\begin{bmatrix} 0.98 & 0.64 & 1.5 & 1.037 \\ 0.96 & 1.12 & -0.5 & -0.998 \\ 1.04 & -1.12 & 0.5 & -1.002 \\ 1.02 & -0.64 & -1.5 & 0.963 \end{bmatrix}$, where rows are the coils in the order [UL,UR,LL,LR] and columns are the DOFs in the order [POS,PIT,YAW,Butterfly]. The conclusions from my previous elog still hold though - the orthogonality between PIT and YAW is poor, so this output matrix cannot be realized by a simple gain scaling of the coil output gains. The "adjustment matrix", i.e. the 4x4 matrix that we must multiply the "ideal" output matrix by to get the measured output matrix has a condition number of 134 (1 is a good condition number, signifies closeness to the identity matrix).

 Quote: let us have 3 by 4, nevermore so that the number of columns is no less and no more than the number of rows so that forevermore we live as 4 by 4
ELOG V3.1.3-