novaphy.ik.rotation_error_axis_angle¶

Compute the world-frame axis-angle error vector that rotates R_current into R_target. Robust at 180° via a quaternion-derived path.

def rotation_error_axis_angle(
    R_current: np.ndarray,
    R_target: np.ndarray,
) -> np.ndarray

Parameters¶

Parameter	Description
`R_current`	Current rotation matrix `(3, 3)`.
`R_target`	Target rotation matrix `(3, 3)`.

(3,) axis-angle vector (rotation axis scaled by angle in radians) such that exp(skew(error)) · R_current ≈ R_target.

Used by solve_ik_pose() to form the orientation residual. Pair with the angular-velocity Jacobian (compute_jacobian_angular_velocity()) in the LM normal-equation form.