Foot on Angle

Main Forum
1

Dear AnyBody

For some reason the foot is on an angle, and in some cases it causes the
MotionAndParameterOptimizationMode, to take a long time to process, and sometimes even causes failure to process MotionAndParameterOptimization.

How can we fix this?, please see the attached picture.

Sincerely thank you
Damon

2

Hi Damon,

To better address your questions, please send us your model as a zip file.

Thanks,
Mohammad S. Shourijeh, PhD
AnyBody Team

3

Hi Mohammad

Here is the model with the foot problem, I’ve also included the mesh string problem.

It was too large to send with the AMMR v.1.5 “Body” folder so can you add this in please. For the model to run, the Body folder needs to be added into the model folder.

Is this what you mean by send you the model, or did you want me to send another way?

Thank you very much for helping me with this
Damon

4

Hi Damon,

Sorry for the belated reply.
I looked at the model. First thing that I fixed was the initial orientation of the box. I rotated it for 90deg (Axes0 = RotMat(pi/2,z); ). This helps the motion and parameter optimization to move forward. However, it still fails at some iterations.
By looking at the box markers, I think there is an in consistency between the marker pairs, i.e., the kinematic solver cannot decrease the error. This will be the first thing you need to look into and possibly fix because it affects the kinematic analysis.

Additionally, the markers on the bodies don’t look right (similar to above for the box). As an example, check the left or right toe markers; they are way off the feet. You can change their locations by changing sRel of them. This will significantly improve the results.

Lastly, for the feet, there are only two markers; therefore, the eversion will be unspecified and the kinematic analysis can pick any eversion angle based on the initial position provided. I suggest you lock this degree of freedom.

Hope it helps.

Mohammad

5

Hi Mohammad

Thank you very much for everything you did to for the model.

Also can you please explain how to lock this degree of freedom?

Sincerely thank you again very much!

Damon

6

Hi Damon,

There are multiple ways to do so, for example by changing the type of the joint to a revolute joint, simply driving it to a fixed value, etc.

Here is an example for the 2nd approach:
AnyKinEqSimpleDriver AnkleDriverRight=
{
AnyKinMeasureOrg &Ankle = Address to the joint for example …HumanModel.Interface.Right.ElbowFlexion;
DriverPos = pi/180*{0}; // Your angle of interest
DriverVel = pi/180*{0};
Reaction.Type={Off};
};

Hope this helps,
Mohammad

7

Hi Mohammad

I am using Motion capture to make the motions. Is the above approach used for when the model is driven by motion capture?

Sincerely thank you
Damon

8