ahrs filter 'response time' mis-syncing between MIMUs

Hi All,

I am just wondering if anyone else has experienced any sort of problem with 'lag'/'response time'/'mis-syncing' of orientation estimations between two MIMUs?

To provide further explaination and an example of what I am trying to do please see the plots below.

IMAGE - The sensors are fixed on a goniometer and moved as per the sketch below. The red blocks correspond to the following plots titled 'distal', while the blue blocks correspond to the 'proximal' plots.

Figure(11) and Figure(12) - as you can see the two MIMUs appear to be properly synced based on the peak acceleration at approx. 12.9s (difference of 0.02s seems to be a reasonable data sync to me).

Figure(4) (relative) and Figure(5) (individual) - Once the raw data is passed through either the IMU or ahrs filter, there appears to be mis-synicing between the orientation estimations, which I can only put down to some kind of response time difference between the sensor orientation estimations. I am assuming that this is a mis-syncing problem due to the initial dip below 0deg and additional peak above 90deg when looking at the relative rotations of Figure(4). Rotations estimated by each sensor do not appear to signigicantly pass 90deg (proximal) or 180deg (distal) based on the individual plots of Figure(5), therefore making the 120deg peak relative roation unlikely. Note: I am only really interested in the rotation about the y-axis (blue trace)

I would love to hear if anyone has any thoughts on this problem or if anyone else has encountered the same problem?

Many thanks!

Ben