Hello Félix ,

I am a Master students and I am using that system for my research. As you say they are prone to drift and magnetic disturbances. 

I use them inside of a Human Motion Lab therefore magnetic disturbances are high. You are suppose to use the KiC no magnetometers when you expect non-homogeneus disturbances, however switching to that fusion engine didn´t help much because then drift is worse than magnetic distortions. One way around it is to find a "magnetically safe" spot and calibrate it always there. I find the need to calibrate them on top of  a 40cm high wooden step to avoid disturbances from the ground.

That is the main issue I've found. If you use them outside the lab it might get better, I cannot give you feedback about that. 

Regarding the wireless system I haven't had problems with that. I record about 3hours per experiment but I do notice that instabilities are  more likely to occur when battery is about 50%, so you kind of have to hurry up with your experiments.

I think it is a usefull technology, once you find the tricks to make the best out of it. 

I hope this is helpful.

Hello Monica

Thanks for your answer, it's very helpful.

Kinds regards,

Félix

Hello Ricardo,

Could you share your tips about how you overcome the calibration problems_

Thanks!

Hi Monica,

Some tips examples taken from our experimental routines:

1. Subject-specific measurements:

- To avoid unnecessary drain of the batteries we register on a text file the Body Measurements (body height, shoe size, arm span, hip height, knee height, ankle height, hip width, shoulder width, shoe sole) and Data Fusion (distance between the MTx and anatomical landmarks) and only introduce them afterwards (now with the system connected). Also, the information on this text file can be use if the system crashes avoiding extra measurements.

2. Calibration procedures:

- Select a place where there isn’t a magnetic field distortion and apply N-Pose static calibration;

- When obtaining an incorrect alignment of the hands or knees, we do the dynamic calibration (Hand touch and Squat). Also for a gait trial we do the Scene Calibration (NosePointInit);

- If we are not able to find a good place (no magnetic field disturbance) then we use the KIC without magnetometers solution;

- After calibrating and whenever possible we select a distortion free area where we ask the subject to walk/move for ~1min.

3. Troubleshooting:

- If suspecting for a magnetic field disturbance of one sensor, then use the MagField Mapper to calibrate the sensor.

These are very simple and straightforward procedures - I hope they can somehow help you.

Hi Ricardo,

thank you, that is very helpful.

Hi Monica,

Please keep us posted on your workaround solutions and tips. I forgot to mention; we also notice that the system becomes less robust when the battery is 

Hi everybody,

has someone used the Mtw-Awinda and relative MT- Manager for the same purpose? I am interested especially in running analysis.

Thanks a lot!

Hi Ricardo! 

Can you elaborate on the use of the dynamic squat calibration? We are experiencing quite a lot of drift when calibrated with N- and T-Pose options. 

Best regards

Alex

Hi. Anyone has been able to export C3D files from Xsens including joint angles? It seems that only via MVNX files we can access joint angles. Is this correct?

Thanks,

Rodrigo

Hi everyone, 

Recently Xsens introduced an online support platform: 

https://base.xsens.com/

It includes a community forum and a knowledge base which can be very useful. 

Kind regards,

Angelos

Dear Dr. Felix

I with agree Dr. Monica

Best regards

Thanks for the new knowledge

agree with @ Monica Daniela Gomez

regards

Good luck.

Interesting question.

Following

Interesting question. I agree with Dr. Monica's answer.

Thank you for your question. I would recommend to use the latest version, now known as Xsens MVN Analyze. It is both immune to magnetic disturbances and already validated in several studies. To find the latest updates, go to:

https://www.xsens.com/products/xsens-mvn-analyze/