simtk.org

hello all.
I am still training to handle OpenSim as part of my practical semester.
My task is to create a new model, but not with motion capture rather with an inertial sensor system (shimmer sensors).
These Data I want to transfer with MatLab into OpenSim.
So, does anyone have experinces in working with these sensors?
Sorry for my bad english, I try to improve.
Thanks for your advice.

I have done something similar:

https://www.dropbox.com/s/6hzza0kd9hmhf ... 3.mp4?dl=0

However, you cannot do this in Matlab, because OpenSim does not support tracking of IMU in its inverse kinematics implementation. Fortunately, Simbody supports orientation sensor tracking therefore your task is possible through the C++ API:

https://github.com/opensim-org/opensim- ... matics.cpp

The above implementation is old and not very generic. The transformation between the different reference frames (L187) is counter intuitive. At present, I have re-implemented inverse kinematics to support both markers and orientation targets. As you may see on the video, you can attach a dummy body representing the sensor through a weld joint. If the dummy body is properly oriented according to the IMU reference system, then this acts similarly to the virtual markers for marker-based tracking. Therefore, you can add the virtual bodies of the sensor on the different parts of the musculoskeletal system.

Thank you.