rpy <-> quaternion

rpy-quat.md

#include <tf2/LinearMath/Quaternion.h>
#include <tf/transform_datatypes.h>
...
tf2::Quaternion myQuaternion;
myQuaternion.setRPY( 0, 0, 0 );  // Create this quaternion from roll/pitch/yaw (in radians)
ROS_INFO_STREAM(q);  // Print the quaternion components (0,0,0,1)
...
quaternionMsgToTF(quat_msg , quat_tf);

import tf
from geometry_msgs.msg import Quaternion
...
quat_msg = Quaternion(quat_tf[0], quat_tf[1], quat_tf[2], quat_tf[3])
quaternion = (
    pose.orientation.x,
    pose.orientation.y,
    pose.orientation.z,
    pose.orientation.w)
euler = tf.transformations.euler_from_quaternion(quaternion)
roll = euler[0]
pitch = euler[1]
yaw = euler[2]