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asam-oss / OSC-ALKS-scenarios

ALKS scenario interpretation in OpenSCENARIO
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Use of 'sinusoidal' dynamicsShape and 'rate' dynamicsDimension #56

Open nmorbitzer opened 1 year ago

nmorbitzer commented 1 year ago

Hello, we noticed that a few ALKS scenarios define a LaneChangeAction with, among other things, the following LaneChangeActionDynamics: dynamicsShape="sinusoidal", dynamicsDimension="rate". According to the OpenSCENARIO standard, the "rate" value is only used for the dynamicsShape="linear". Now I would like to ask why this combination is used e.g. in the ALKS_Scenario_4.4_1_CutInNoCollision_TEMPLATE.xosc? Thank you in advance!

arauschert commented 1 year ago

Thanks for your comment!

I couldn't find the place in the OpenSCENARIO 1 standard which mentions that DynamicsDimension "rate" shall only be used with DynamicsShape="linear". Maybe you could point me to that statement.

In the ALKS regulation there is sadly no statement about a required shape of the lane change, so I assume you're free to choose a shape. We chose a "sinusoidal" shape to have a more realistic lane change behaviour than with a "linear" shape (no discontinuities in orientation of the lead vehicle). "Cubic" would give very similar results as "sinusoidal". The parameter "rate" (=lateral velocity) is given as a requirement in the regulation for variation. It is also not pointed out in the ALKS regulation, how the "rate" parameter should be interpreted (maximum or average rate during lane change). We interpreted the parameter "rate" as the maximum lateral velocity during the lane change (so right in the middle of the lane change for sinusoidal/cubic shape) because the ALKS test spec originates from the UNECE GRVA/VMAD group and there the Japanese delegation pointed out this interpretation somewhere. I'll check, if I can find references for this interpretation.

nmorbitzer commented 1 year ago

Thank you for your answer!

In the OpenSCENARIO V1.2.0 Model Documentation, which can be downloaded from here, the "linear" case/literal is the only case that uses the "rate" parameter within the formula for calculating the transition function (Enumeration DynamicsShape).

However, thank you very much for sharing those information about how you interpreted the "rate". It would be great if you could share the references for this interpretation (if you find any).

nmorbitzer commented 1 year ago

I just found an issue in the official ASAM OSC 1 standard repository which clarifies the TransitionDynamics::dynamicsShape definitions (however, the status of the issue is still Open).