from_angles

Quaternion.from_angles(angles: ndarray) → ndarray

Synonym to method from_rpy()

Parameters:

angles (numpy.ndarray) – 3 cardanian angles in following order: roll -> pitch -> yaw.

Returns:

q – Quaternion from roll-pitch-yaw angles.

Return type:

numpy.ndarray

Examples

>>> from ahrs import DEG2RAD    # Helper variable to convert angles to radians
>>> q = Quaternion()
>>> q.from_angles(np.array([10.0, 20.0, 30.0])*DEG2RAD)    # Give roll-pitch-yaw angles as radians.
array([0.95154852, 0.23929834, 0.18930786, 0.03813458])

It can be corroborated with the class DCM, which represents a Direction Cosine Matrix, and can also be built with roll-pitch-yaw angles.

>>> from ahrs import DCM
>>> R = DCM(rpy=[10.0, 20.0, 30.0])     # Here you give the angles as degrees
>>> R
DCM([[ 0.92541658,  0.01802831,  0.37852231],
     [ 0.16317591,  0.88256412, -0.44096961],
     [-0.34202014,  0.46984631,  0.81379768]])
>>> q.from_DCM(R)
array([0.95154852, 0.23929834, 0.18930786, 0.03813458])

With both approaches the same quaternion is obtained.