I want to get the difference between the orientation of my robot and a target point. The orientation is expressed as an angle as shown in the pictue below. The point is expressed as
(x, z) in a cartesian space that has origin in the robot position. The x and z axis are always fixed.
This image explains how the angle and the axis are intended.
I need the angle between the orientation and the target, and I need it to be positive/negative when the target is left/right.