Hello Everyone,
I am using OpenSim to calculation joint angles during gait. I define a markerset, scaled the model and do the IK calculation(see attachments). However, when I plot the results, I found unreasonable hip flexion (~25degrees) at neutral standing position where obviously it should be about 0. I changed the weights of different markers, and the results just changed to 12.5 degrees, so the results largely depends on the specified value, is there a standard on how to define the weights, otherwise how can I believe the results. I attached the files so that you could kindly help me check what is going wrong. Thank you!
One more thing to mention is that when defining the markerset, I added some markers, since I didn't find any reference on the coordinates of these markers, I input an estimated value, will this largely influence the results?
Happy weekend!
Unreasonable IK results
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shuyang han
- Posts: 15
- Joined: Mon Jan 05, 2015 9:52 am
Unreasonable IK results
- Attachments
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- walking.zip
- model file
- (179.54 KiB) Downloaded 69 times
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shuyang han
- Posts: 15
- Joined: Mon Jan 05, 2015 9:52 am
Re: Unreasonable IK results
I just came into mind two possible reasons, one is the unit, the marker trajectory collected in Motion Analysis is in Unit mm, while OpenSim uses Unit m. The other one is misplacing of markers on the subject during motion capture. Might the above two cause the unreasonable results? Thank you.