Climbing and descending stairs ground reaction forces

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1

Good afternoon, I'm analyzing the ground reaction forces when climbing and descending stairs. However, I get the following error:

ERROR
ERROR1906×982 109 KB

I've tried increasing the tolerance, but it reaches 2464 frames and stops.

Thank you for your attention.
Best regards,
Catarina Rocha

2

Hi Catarina,

That seems to be an error in kinematics and I am not sure why that is happening. It looks like the left leg is bent in a strange way, or maybe that's just my impression from the image. Can you check if the kinematics in the bvh file is reasonable at this frame. There could be something odd about this posture that is breaking the kinematics.

Best regards,
Dave

3

Good morning, I'm sorry I'm only replying now, I've been analyzing the bvh file and the left leg seems to be tilted, it may have been some sensor that perhaps wasn't placed correctly. I think it's best to discard this test.

Thank you very much for your help :slight_smile:

Best regards,
Catarina Rocha

4

Good morning,

I agree, it doesn't make sense to analyze incorrect motion.

I want to also point you to a previous post that discusses GRF prediction for stairs. It may be useful for you.

Best regards,
Dave

5

Good morning,

Yes, I was having the same problem, thank you very much for sharing.

Best regards,
Catarina Rocha

6

Good afternoon, I apologise for bothering you again, regarding the ascent and descent of stairs, I've been changing the minimum and maximum distance between the foot and the surface and it already detects the ground reaction forces. Regarding the following line (// See: #include "<ANYBODY_PATH_AMMR>/Tools/GRFPrediction/FootPlateConditionalContact.any" ), for ascending and descending stairs, is it necessary to uncomment or do I keep it the same, as shown in the attached image?

Force plate
Force plate1900×904 103 KB

Thank you for your attention.

Best regards,

Catarina Rocha

7

Hi Catarina,

You can leave the line as it is. It is just a shortcut to take you to the definition of the class template, where you can read more about all the settings available.

Best regards
Dave

8

Good morning, I understand, thank you very much.

Best regards,
Catarina Rocha

9

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