NHTSA: Coding WorldSID RibEye

[bjoern.hohage]

Hi,

NHTSA has a puplication for the certification of WorldSID 50%.

In this document they use a new coding:

Code: Select all

D0TRRIRUMIWSDSLB

Remark from NHTSA:

Thorax ribs 1, 2 and 3 length changes at the middle LED are calculated by the RibEye software.

This "DSL" is new.

The Manual from Boxboro (the manufacturer of the RibEye-System) - Chapter 4.2: https://www.boxborosystems.com/RibEye%2 ... 202026.pdf

The channel names for the calculated Length Change channels will be the channel name for the LED, but with the
direction code set to L. For example, the length change channel for left-side impact, shoulder rib, rear LED,
WorldSID 50th would be:

Code: Select all

SHRI LE RE WS DS L B

and

The Length Change is calculated as follows:
Lo = sqrt (Xo^2 + Yo^2)
Where:
Lo is the initial distance from the LED to the RibEye origin
Xo = pre-Time0 RibEye X – X Offset (from Table 6)
Yo = pre-Time0 RibEye Y

L(t) = Lo – sqrt (X(t)^2 + Y(t)^2) = Length Change at time t
X(t) = RibEye X data at time t – X Offset (from Table 6)
Y(t) = RibEye Y data at time t

What shut we do with "DSL"?

[DiVe]

Dear Björn,

In the manual they hav used before the "U" and "C" direction, when they provide
an output that should be equivalent to 1D and 2d MTRAC (based on ENCAP calculation rule).

So the DSL is something new?
The character "L" is an expired code in the database that has been used earlier for steering column
displacement in longitutinal direction of the local coordinate system.

Does the referenced "RibEye origin" correspond to the 1D-MTRAC origin?
I understood that they calculated in the XY-plane the resultant distance change.
So, it is a 2D resultant.
That is actually not the same as you can derive from MTRAC devices.

The options I see are:
a) Use DS0 (as change in length) in combination with the specifc RibEye code:

Code: Select all

D0TRRIRUMIWSDS0B

RUMI = Right Upper Middle (LED)
That is then a special projected change in length just in XY-plane.

b) Find an approach to code a resultant just made out of some components X,Y or X,Z or Y,Z
If this can be realized via a one character direction code we can use this code.

c) Reintroduce "L", as length change in 2D ?

Any other ideas?

Is that processing just a Boxboro option/measurement for their calibration procedure
or the official criterion to be used in the future FMVSS 214/US-NCAP?

Kind regards,
Dirk

[bjoern.hohage]

Hi,

what I understand:
RibEye optically measures the angle from the sensor to an LED - but as an user you can see this curves.
It is then calculated by triangulation in the global coordination system X/Y/Z - this you can see as user.
From this it calculate the DSL based on the global X and Y - that is something different then a 2D-IR-TRACC is calculating with DSX and DSY regarding the rotation of the IR-TRACC around the x-axis!
Also from this, it calculates what a 2D-IRTRACC would measure as DSY and a 1D-IRTRACC in length changes DC0.