Importing IMU data

[Katie Farris]

I have IMU data formatted into quaternions that I am trying to import following the OpenSense example. I am able to place my IMUs using the IMU Placer Tool and assign a calibration pose, but the movement that is created is not what is expected. The expected movement is a t-pose, followed by three repetitions of a bicep curl, with no lower body movement.

In my model, the arms are abducting and the torso is also flexing laterally, neither of which should be happening. The odd thing is that at the frame of the calibration/orientation pose, my model reaches the desired t-pose, and then diverts again from the expected movement. I am not sure if my process for importing the data into OpenSim has errors, or if my data was somehow corrupted in the conversion from raw data to quaternions. The IMUs used were generic and not APDM or XSens specific. I don't seem to have any problems uploading the data, so I'm assuming that my formatting isn't causing the issue.

I've attached an example of the created motion, my .osim file, my data file (.sto), and my calibration pose (.sto). The .osim model I am using is just a model adapted from Rajagopal 2015_Opensense.

Since I am not using a specific brand of IMU, am I missing something in the import process that could be affecting my data? Or is my data being accurately represented, indicating that the data is just corrupted?

Thanks in advance.

[Carmichael Ong]

One way to check if the data is being correctly represented in OpenSim (or perhaps, there could be some difference in the OpenSim ground frame versus the data's ground frame) is to look at the orientations of the input sensor data. This page has some directions on how to use "Preview Sensor Data": https://simtk-confluence.stanford.edu:8 ... ensor+Data

This could at least be the first step to understanding if the quaternions are formatted correctly for OpenSim.