Masayuki, Sheila
When we step the alignment sliders in pitch or yaw on PR2, we see 1 Hz ringing for 15-20 seconds.
Keeping an eye on PR2, took an osem spectra of the inmons and don't see anything abnormal in the suspension right now - but will keep investigating it if these oscillations returns.
This is Sheila
It seems like this ringing at 3Hz has been seen in PR2 for about the last month. A step of 2urad in pitch causes a ringing with an intial amplitude of 5 urad at 1 Hz that damps down over about 20 seconds. For yaw the magnitudes are similar, the ringing amplitude is about twice the amplitude of the step.