Jeff K, Oli P

In alog 75947 part3, we had modeled the BBSS using what we thought were the correct Final Design parameters and then adjusted the d1 and d4 values* in order to get our model to match how the actual BBSS was responding. However, the parameter set we were using had the boolean variable stage2** set to 0, when the parameter set from the BBSS Final Design document(T2000503) had stage2 = 1. This was a change that I had made due to a misinterpretation.

Because of this mistake, the parameters that we had thought were correct were actually wrong, and so when we adjusted d1 and d4, we were unknowingly fitting to an incorrect model. These results were shared with the SUS group, where it was mentioned that stage2 was supposed to be 1.

We've now rerun the model with the actually correct Final Design(FD) parameters, and have adjusted d1 and d4 to fit our data. This adjustment has d1 = FD - 2.5mm and d4 = FD - 1.0mm, which are smaller changes than when we were using the wrong parameter set (d1 and d4 were increased by 5.0mm and 1.5mm respectively). Attached are our results in pdf form, along with pngs of the transfer functions for Pitch and Longitude, since those are the two most affected by the changes to d1 and d4. This adjusted parameter set can currently be found at $sussvn/Common/MatlabTools/TripleModel_Production/bbssopt_pendstage2on_d1minus2p5mm_d4minus1p0mm.m, but eventually will replace the bbssopt.m that is in that same directory.
Figure legend:
- Black - Model using the wrong Final Design parameters
- Dark blue - Model using the wrong Final Design parameters plus adjustments for d1 & d4 to match data
- Dark green - Model using the correct Final Design parameters
- Light Green - Model using the correct Final Design parameters plus adjustments for d1 & d4 to match data
- Gray - BBSS M1 Transfer Function data

Appendix:
* d{top, 0, 1, 2, 3, 4} is the vertical distance between the break off point of a wire and the CoM for each mass. These values are important for calculating the locations of fundamental modes for each DOF. There are two different types of d's, effective d's and physical d's.
    - The physical d's are the vertical distance between the break-off point of the wire and the CoM of the mass. These values assume an infinitely flexible wire, which isn't the case in real life.
    - The effective d's are the vertical distance between where the wire leaves the clamp and the CoM. Since the wires aren't actually infinitely flexible, they'll start bending before they reach the break off point, meaning we'll have a larger effective d as compared to the physical d.
These two relate to each other as  physical d = effective d - effective flexure point, with the effective flexture point being the extra distance between the clamps and the breakoff point.
In the building of the suspension model, both types are used at different times, so there is a need to be able to swap between them. That's what the stage2** variable is used for.

** stage2 is a boolean variable that determines whether the effective(stage2 = 0) or physical(stage2 = 1) d's are used.
    - If stage2 = 0, the d values are used as effective values, and there are no corrections made to account for the flex of the wires.
    - If stage2 = 1, the d values are taken to be the physical values, and so an effective flexture point is calculated and added to account for the flexing of the wires.
Since we entered in the physical d's, me changing stage2 to 0 meant that the model wasn't adding in the effective flexture point distances, changing our results.