Fabian, Terrence
As reported in 19068, there's a huge hysteresis in the BS IP that I am worried about. It also makes the suspension a bit harder to work with.
Therefore, we decided to do a short experiment to see how severe it is compared to other suspensions.
We put offset in the TEST filter and move the IP in the longitudinal direction so the displacement goes over ~1000 um.
Below results shows that the BS has a comparably high hysteresis compared to other suspensions (17.3% (BS) vs 3.8% (SR2), 9.5% (SR3), 2.7% (SRM)).
The resonance frequency as measured by time series in ndscope is around 47.6 mHz (shown in Fig.1), which is a bit low compared to others which ranged between 60-90 mHz.
The temperature of the BS is quite high compared to its operating temperature (23.7 C vs 23.0 C). According to Fabian, a higher temperature makes the IP softer. So the result here might not be conclusive.
We will do another test to comfirm when the temperature returned to normal.
BS
Temperature as read by Odontori: 23.7 C (O3GK temperature: 23.0 C)
7000 counts of actuation in IP L
Resonance frequency: ~47.6 mHz (See Fig. 1)
Longitudinal, Transverse, Yaw (before actuation): -486.78, 104.52, 247.88
Longitudinal, Transverse, Yaw (with actuation): 701.53, -284.96, -875.29
Longitudinal, Transverse, Yaw (after actuation): -281.7, 18.52, -0.44
Hysteresis: ~(-281.7+486.78) / (701.53 +486.78) = 17.3 %
We also compared with other suspensions.
SR2 23.7 C (O3GK 23.5 C)
Longitudinal, Transverse, Yaw (before actuation): 125.99, -300.25, 4032.83,
Longitudinal, Transverse, Yaw (with actuation): 1858.53, -265.65, 4036.78,
Longitudinal, Transverse, Yaw (after actuation): 191.77, -306.49, 4033.31
Hysteresis: ~(191.77-125.99) / (1858.53 - 125.99) = 3.8 %
SR3 23.0 C (O3GK 23.0 C)
Longitudinal, Transverse, Yaw (before actuation): -219.7, 664.02, -4028.48
Longitudinal, Transverse, Yaw (with actuation): 1041.733, -439.08, -4059.21,
Longitudinal, Transverse, Yaw (after actuation): -99.70, 530.34, -4029.12
Hysteresis: ~(-99.7+219.7) / (1041.733 + 219.7) = 9.5 %
SRM 22.9 C (O3GK 22.9 C)
Longitudinal, Transverse, Yaw (before actuation): -521.56, -151.14, -3591.19
Longitudinal, Transverse, Yaw (with actuation): 601.24, -265.37, -3586.47
Longitudinal, Transverse, Yaw (after actuation): -491.54, -159.9, -3590.99
Hysteresis: ~(-491.54+521.56) / (601.24 + 521.56) = 2.7 %
