IMU plugin linear acceleration weird frame/direction

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Dear Gazebo community,

I am currently working on a school assignment about indoor mapping in gazebo and I want to see if I can use an IMU to improve results in featureless environments. I wanted to try this with the IMU plugin in Gazebo, but I noticed the following with the linear acceleration in the output of the sensor:

• When I move the robot over the world's X axis the output on the linear acceleration is straight forward with a value of 0 on the linear_acceleration.y and the value of the measured acceleration on the linear_acceleration.x
• But when I start rotating over 45 degrees, the output of the acceleration is completely on the Y axis with linear_acceleration.y being the value of the measured acceleration and linear_acceleration.x being 0. This is weird to me since I would expect this to happen when I rotate over 90 degrees when the orientation of the robot is aligned with the world's frame Y-axis.
• Then when I rotate for 45 degrees in the same direction again (so 90 degrees in total) and the robot is aligned with the world's Y-axis, the output is like as if I had turned the robot for 180 degrees. With the linear acceleration value being over the X axis instead of the Y axis.

I have tried looking for a solution on different forums for a long time now but I can not seem to find anyone who experiences similar problems. Maybe I am doing something wrong with the implementation of the plugin?

I hope to find a solution as soon as possible as this would help me succeed with my school assignment a lot!

Many thanks in advance!