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Errors in events analysis

Hello everyone, when I was performing vehicle simulation, I simply rotated a section of uphill road to create a downhill road condition, and then the simulation log displayed the following error message:

WARNING: SolveForGivenRHS failed (NaN encountered)!

Residual idx=2574, Phi 0

ERROR: Static analysis failed at time = 0

Additionally, no H3D file was generated, and the uphill road section could be simulated normally. What could be the cause of this issue?

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MotionView/MotionSolve

Accepted answers

GTT Adam

Hi @xiejiyin,

Please delete the road graphics in your model and try to recreate them, as I just did. I would like to confirm if you receive the same error as I do.

I was also curious about the road reference marker orientation, so I created a double lane change on a flat road that featured the same upside down reference marker orientation. This looks to dramatically effect the vehicle's ability to find a static position and unfortunately breaks the tire-road contact:

Please adjust the road profile in the CRG file, and not using this marker orientation method.

Hope this helps!

Adam Reid

GTT Adam

Hi @xiejiyin,

Based on the results, the most amount of sinkage occurs from 2.5 to 5.0 seconds. This coincides with the transition of the vehicle from flat to the slope.

With regards to slip rate, the wheel speed remains very constant during that (no significant oscillation or spike in wheel speed) so I think the sinkage is purely due to the vehicle slamming into the slope.

Hope this helps!

Adam Reid

All comments

GTT Adam

Hi @xiejiyin,

I'm sorry you are having trouble with your vehicle simulation. How did you go about rotating this road surface? In the RDF file?

Can you please provide the model as a zipped model archive? (File >> Export >> Model >> Archive Model & Create Zip File)

Hope this helps!

Adam Reid

xiejiyin

Thanks very much！Here is my model

Uphill_20m_5_archive.zip

GTT Adam

Hi @xiejiyin,

I tried to use the Road Tools utility and rebuild the graphic for your road file, but the operation failed. It looks like there is an issue within your RDF file, possibly created after your 'rotated' the surface. If you try to rebuild the graphic, do you have the same issue?

Hope this helps!

Adam Reid

xiejiyin

After importing the rdf file using the Road Tools, I modified it here to rotate the road. Previously, I only modified Dx in the 2nd Axis to -1, and then performed an uphill simulation. However, when I modified it as shown in the figure to change the road to a downhill condition, I encountered an error.

xiejiyin

Yes, I used the Road Tools utility to generate graphics for ‘Uphill_20m_5.rdf’, which worked fine. I modified Dz in the 2nd axis to -1 to make the graphics uphill so that the simulation could proceed normally, but when I changed it to downhill as shown in the figure, problems arose.

xiejiyin

Thank you very much. I completed the terrain creation by modifying the crg file.

However, when I checked the data, I found that the data I had previously collected for vehicle uphill driving seemed unreasonable. I exported the vehicle's speed curve and sinking curve. According to the results curve, when the speed slows down on the slope, it means that the slip rate increases, and the corresponding sinking amount should also increase. However, according to the curve, the sinking amount is decreasing.

Best regards！

Uphill_50m_30_archive.zip

GTT Adam

Hi @xiejiyin,

Based on the results, the most amount of sinkage occurs from 2.5 to 5.0 seconds. This coincides with the transition of the vehicle from flat to the slope.

Hope this helps!

Adam Reid

GTT Adam

Hi @xiejiyin,

Based on the results, the most amount of sinkage occurs from 2.5 to 5.0 seconds. This coincides with the transition of the vehicle from flat to the slope.

Hope this helps!

Adam Reid

xiejiyin

Thank you very much for your answer!

BEST!