I need to calculate the relative orientation between two IMU sensors. The Imu sensors provide me with the orientation relative to a global coordinate system (the same). I place the 1 imu on the forearm and 1 on the upperarm. I stand in a static position where I know the relative position of the two segments relative to the global frame.
The imu's can be placed randomly on each segment and therefore I need to transform the imu orientation to the orientation of the segment. My problem is to 'subtract' the start orientation during the static position from all data frames from the imu. I have tried to do:
I use the following formula:
where m1 is a 3x3 rotation matrix and m1.0 is the start frame and m1.i is all the following frames.
How do I correctly 'subtract' the start rotation from all other rotations from the imu?
Next I need to transform the transformed rotation to the segment orientation. However I need to make the first step to work first.