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  #1  
Old 04-17-2017, 04:50 PM
PhoebeHsu PhoebeHsu is offline
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Default Force plates in wrong position

Dear AnyBody,

I am using MoCap data provided from a new group of collaborators to generate musculoskeletal models. There are two type-II forceplates used in the experiment.

As seen in the attached picture and Any files, the two plates are on top each other. The subject is running on Plate I, but the Plate I coincides with Plate II. Not surprisingly, the locations of the CoP points are wrong, as well. I also checked the TransDucerLocation.r, TransducerLocation.sRel, which are both {0,0,0}.

It seems to me that all forceplate-related data were exported in their own local-coordinate system. How can I fix this problem? Shall we try to export data in global coordinate-system? If that is not possible, how do I modify the Environment.any to correct this problem?

Thanks!
-Phoebe
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  #2  
Old 04-19-2017, 03:25 PM
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toerholm toerholm is offline
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Hi Phoebe,


I see these options:
  1. The best solution would to re-export the data,
  2. Manipulate the C3D file to correct these data please see this post...http://forum.anyscript.org/showthread.php?t=3924&page=2 look towards the end.
  3. Edit the forceplate class to take into account an additional input argument which should the origin... so instead of finding it in the C3D file it would be an input argument

Best regards
Søren
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  #3  
Old 04-20-2017, 04:17 AM
PhoebeHsu PhoebeHsu is offline
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Thanks! I will follow your recommendation.

Is there any documentation about how CoPs is calculated from the force plates in AnyBody?
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  #4  
Old 04-20-2017, 12:39 PM
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toerholm toerholm is offline
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Hi Phoebe,

As you know the CoP is basically found by finding the point of zero moment.
This is normally done using first a forcemoment measure to sum up the loads from the transducers (if more than one) then solving some simple equilibrium equations to find the point of zero moment.

Best regards
Søren
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