MoCap model using local coordinate system

Dear experts:

I am using MoCapModel in AMMR 1.6.1, ABS6.0.1 to calculate the muscle / joint forces. I wanted to define a local coordinate system at the knee by adding the following in the environment.any:

[SIZE=3] AnySeg[/SIZE] &LeTibia = Main.Studies.HumanModel.BodyModel.Left.Leg.Seg.Shank;
LeTibia = {
[SIZE=3]AnyRefNode[/SIZE] localrefframe = {
sRel = {0.05,-0.45,-0.02};
[SIZE=3]AnyDrawRefFrame[/SIZE] drws = {ScaleXYZ = {1,1,1}*0.3; RGB={0,0,1};};
};
};

I am having the following problems:

  1. if I simply used the knee or shank segment, the coordinates showed up at the hip. That’s why I changed sRel and now the location of the local coor. seems right.
  2. Then I started Inverse dynamic analysis, and got the following error messages. I didn’t have such errors if I use global coordinate system.

Any suggestion will be greatly appreciated!!

[SIZE=1] WARNING(OBJ.MCH.KIN9)[/SIZE] : [SIZE=1]C:/P…s/A…y/A…0/AMMR/Body/A…n/T…x/W…s/WrappingCylinder5PointFit.any(36)[/SIZE] : [SIZE=1]cyl[/SIZE] : Problems at calculation of closest point : Newton algorithm for finding closest point not converged, result could be inaccurate!
[SIZE=1] WARNING(OBJ.MCH.KIN9)[/SIZE] : [SIZE=1]C:/P…s/A…y/A…0/AMMR/Body/A…n/T…x/W…s/WrappingCylinder5PointFit.any(36)[/SIZE] : [SIZE=1]cyl[/SIZE] : Problems at calculation of closest point : Newton algorithm for finding closest point not converged, result could be inaccurate!
[SIZE=1] ERROR(OBJ.MCH.MUS4)[/SIZE] : [SIZE=1]D:/Gait …ysis/M…0/M…l/InverseDynamics.any(29)[/SIZE] : [SIZE=1]InverseDynamicStudy.InverseDynamics[/SIZE] : Muscle recruitment solver : solver aborted after maximum number of line-search iterations

Hi,

This section is the ‘Self-Supported Forum’ where you can’t expect our official support.

Please upload your model here if you want to get our official support:
http://forum.anyscript.org/forumdisplay.php?f=21

Without viewing your model, we can’t tell anything regarding your problems.

Best regards,
Moonki

Hi Moonki:

I figured this out. It seems that I cannot reduce the sampling frequency randomly - which makes sense that there are a minimum number of timepoints required to represent the whole walking process. Now I am using nstep = 15 (still significantly lower than the original value 197) and it worked.

Thanks for the suggestion. I will post similar questions on the debug forum in the future.

Best regards

Phoebe