Recently, a 6.35Hz peak is visible in END pitch and yaw oplev spectra (Fig 1). For END oplev diagonalization, I changed the rotation angle for END oplev so that the 6.35Hz peak disappears in oplev yaw spectrum, assuming that the 6.35Hz peak is a natural pitch peak. I changed the oplev rotation angle from 0 deg to 1 deg. The END oplev spectra before/after this rotation are shown in Fig 2 (red, blue: after rotation, green, brown: before rotation).

To check END actuation, I put an excitation (12 Hz, amplitude 1000, sine wave) in END length (K1:FDS-END_LEN_ex2). The 12 Hz peak is visible in both pitch and yaw oplev spectra (Fig 3). The 12 Hz peak height was 13.5 and 20.8 for pitch and yaw, respectively. The current EUL2COIL matrix is shown in Fig 4. This matrix might not be optimized for L2P, L2Y coupling.