Any way to analyze EDR data skewed by vehicle rotation?
Posted: Sat Feb 13, 2016 11:54 am
Q: In an eccentric collision the EDR data likely gets skewed along with the vehicle rotation. It seems to me that this would be a great application for the collision phase of SMAC, something that would get from the vehicle based reference frame of the EDR to a Global or ground based reference frame. Basically, input vehicle specs and EDR accel or dV data and output a ground based dV. Initially I was thinking of putting together an Excel spreadsheet to do this. Then I thought this is a SMAC application. Any thoughts?
A: Over the years many have has issues with good test results due to the differences in accelerometer readings (also w/r to EDR readings) when not at the CG (which they rarely are due to differences in vehicle loading and other factors!)
The differences are more dramatic when either a lot of rotation and/or a secondary collision is involved.
We discussed these issues in our paper on re-evaluation of the RICSAC full scale tests:
See FMVSS 563 and the summary page below for what data elements you may be able to get, however depending on make, model and most importantly year, the EDR you are evaluating may not this information.
A: Over the years many have has issues with good test results due to the differences in accelerometer readings (also w/r to EDR readings) when not at the CG (which they rarely are due to differences in vehicle loading and other factors!)
The differences are more dramatic when either a lot of rotation and/or a secondary collision is involved.
We discussed these issues in our paper on re-evaluation of the RICSAC full scale tests:
- You’ll find in our SAE paper the steps that you can use for an excel spreadsheet and what information is needed/required. Checking/verifying with simulation results provides a more detailed correlation with full scale tests and ability to refine the more simplified excel spreadsheet analysis.
See FMVSS 563 and the summary page below for what data elements you may be able to get, however depending on make, model and most importantly year, the EDR you are evaluating may not this information.
- For example, many early EDR’s stopped recording once the airbag fire command was issued
- We currently that have in our smacthp option which simply asks for the accelerometer/EDR location and then provides time history (in charts and csv output) of accelerometer, deltaV and PDOF. However without mentioning EDR folks probably don’t realize that it can be used for a comparison.