Create DCM from euler angles
        :param dcm: Matrix3
        :returns: array [roll, pitch, yaw] in rad

def _dcm_to_euler(self, dcm):
        """
        Create DCM from euler angles
        :param dcm: Matrix3
        :returns: array [roll, pitch, yaw] in rad
        """
        assert(isinstance(dcm, Matrix3))
        return np.array(dcm.to_euler())