compute_pitch_frame_in_parent()

double compute_pitch_frame_in_parent ( const Eigen::Matrix3d &  orientation_frame_in_parent )

inline

Get pitch angle of a given frame relative to the parent vertical.

Figure:

parent z
  ^    frame z
  |     /
  |    /
  |   /
  |  /
  | /
  |/
 (x)-----------> heading vector
   \\  )
    \\+  positive pitch
     \\
      \\
       \\
      frame x

Parameters

orientation_frame_in_parent

Rotation matrix from the target frame to the parent frame.

Returns

Angle from the parent z-axis (gravity) to the frame z-axis. Equivalently, angle from the heading vector to the sagittal vector of the frame.

Note

Angle is positive in the trigonometric sense (CCW positive, CW negative) in the heading-vertical plane directed by the lateral vector, which is (x) in the above schematic (pointing away) and not (.) (pointing from screen to the reader).