Plug-in gait markers of upper body for MoCap

Main Forum
1

Hello,

as I mentioned in the AnyBody Managed Model Repository forum, I cannot setup my model due to missing markers. I do not have any markers on the back of the subject because the subject is a handcyclist and was lying in his handcycle during the measurement.
Now I tried to set the RPSI and LPSI marker position manually but didn’t get it right.
Thank you very much for your help!

Best regards,
Max

2

Max,
I had a quicl look, I just duplicated the LASI and RASI to represent RPSI and LPSI, it loaded and looked ok.
I also deleted lower extremities, as there is no info on them.

I think you need an activity with a real motion in order to get a proper optimisation, but otherwise it does something.

3

Thank you very much Amir!
The model loaded quite well. So far I have four c3d files with motion of a test subject. Three of them stopped at time step 0 at the kinematic analysis and one made it to time step 129. But I will try with the data of the main subject and maybe shortening the c3d files will also help (they are about 12 cycles at the moment). I think I will have to play around a bit.
Thank you for your help so far.

Best regards,
Max

4

Try to edit the marker position on the segments, initial position of the subject and segment lengths of the subject:

  • Marker position can be edited in the marker.any file (sRel): the red marker on the skeleton needs to be where the real marker was on the subject
  • Initial position needs to be as in the start of the recording, this is done in the Trialspecific.any
  • segment lengths can be edited as well in the Trialspecific.any; if you have enough marker you can optimize the segment length, the value in the Trialspecific.any will be used as starting point and the rest will be optimized in order to fit the kinematics (big motion is better); On/Off switch in Trialspecific.any
5

Hello again Amir,

my model does the optimization and inverse dynamics but when I add additional environment in form of a handbike (just two segments with a revolute joint so far) nothing works anymore.
Kinematic analysis failes at the initial conditions because constraints exceeding the error tolerance. When I comment the new section in environment, everything works fine. Can you have a look at my model?

Thank you very much,
Max

6

Cannot open the zip file, can you try it again?

7

I don’t need to. I solved my problem. It was quite easy.
I forgot to connect the new segments with GlobalRefFrame and searched the whole day for this mistake :(:eek:
Thank you anyway, your support and quick responses are great!

8

great news :slight_smile:

9

Hi again,

I still can’t get my Study working with the environment. I tried to get the Contact Points between the model and the environment very close but i still cannot load initial conditions because of kinematical error above tolerance. Is there a possibility to raise the error tolerance because it is not too far away.
Or do you have a different idea to get this model working?
If you want to see the motion of the model you can remove comments from 3 drivers in the environment section I marked. Then movement of the environmet is determinated but then there is no connection with the model.

Best regards, Max

10

Hi Max,

I have taken a look at your model.

The reason why it does not solve is that the the extra joints and nodes you are adding are not included in the studies you are running. So the universal joints between the hands and the pedals are loaded in the model but not part of the studies, which means that the pedals are effectively not driven by anything.

The quick fix is to include them form the environment folder instead like this:

A

nyFolder EnvironmentModel ={
  
  
    #include "ExtraNodes.any"
  
  #include "ExtraJoints.any"

since the environment folder is already referred to by the studies everythin in this folder will be part of the study.

Best regards
Søren