ROS中四元素欧拉角变换

python版本

#my_pkg/msg/Eulers.msg类型
Header header
float64 roll
float64 pitch
float64 yaw

#my_pkg/quat_to_euler.py文件
#!/usr/bin/python
# -*- coding: utf-8 -*-

# Start up ROS pieces.
PKG = 'my_pkg'
import roslib; roslib.load_manifest(PKG)
import rospy
import tf

# ROS messages.
from nav_msgs.msg import Odometry
from sensor_msgs.msg import Imu
from my_pkg.msg import Eulers

class QuatToEuler():
    def __init__(self):
        self.got_new_msg = False
        self.euler_msg = Eulers()

        # Create subscribers and publishers.
        sub_imu   = rospy.Subscriber("imu", Imu, self.imu_callback)
        sub_odom  = rospy.Subscriber("odom", Odometry, self.odom_callback)
        pub_euler = rospy.Publisher("euler", Eulers)

        # Main while loop.
        while not rospy.is_shutdown():
            # Publish new data if we got a new message.
            if self.got_new_msg:
                pub_euler.publish(self.euler_msg)
                self.got_new_msg = False

    # Odometry callback function.
    def odom_callback(self, msg):
        # Convert quaternions to Euler angles.
        (r, p, y) = tf.transformations.euler_from_quaternion([msg.pose.pose.orientation.x, msg.pose.pose.orientation.y, msg.pose.pose.orientation.z, msg.pose.pose.orientation.w])
        self.fill_euler_msg(msg, r, p, y)

    # IMU callback function.
    def imu_callback(self, msg):
        # Convert quaternions to Euler angles.
        (r, p, y) = tf.transformations.euler_from_quaternion([msg.orientation.x, msg.orientation.y, msg.orientation.z, msg.orientation.w])
        self.fill_euler_msg(msg, r, p, y)

    # Fill in Euler angle message.
    def fill_euler_msg(self, msg, r, p, y):
        self.got_new_msg = True
        self.euler_msg.header.stamp = msg.header.stamp
        self.euler_msg.roll  = r
        self.euler_msg.pitch = p
        self.euler_msg.yaw   = y

# Main function.    
if __name__ == '__main__':
    # Initialize the node and name it.
    rospy.init_node('quat_to_euler')
    # Go to class functions that do all the heavy lifting. Do error checking.
    try:
        quat_to_euler = QuatToEuler()
    except rospy.ROSInterruptException: pass

#launch 文件
"my_pkg" type="quat_to_euler.py" name="imu_euler_angles">
    from="imu"   to="microstrain/data"/>
    from="euler" to="microstrain/euler"/>


"my_pkg" type="quat_to_euler.py" name="kf_euler_angles">
    from="odom"  to="kf/odom"/>
    from="euler" to="kf/euler"/>

#运行
rxplot /microstrain/euler/roll:/kf/euler/roll

---

C++版本

/****************************************************************************

Conversion from a quaternion to roll, pitch and yaw.

Nodes:
subscribed /rotation_quaternion (message of type geometry_msgs::Quaternion)
published /rpy_angles (message oftype geometry_msgs::Vector3.h)

****************************************************************************/

#include "ros/ros.h"
#include "geometry_msgs/Vector3.h"
#include "geometry_msgs/Quaternion.h"
#include "tf/transform_datatypes.h"
#include "LinearMath/btMatrix3x3.h"

// Here I use global publisher and subscriber, since I want to access the
// publisher in the function MsgCallback:
ros::Publisher rpy_publisher;
ros::Subscriber quat_subscriber;

// Function for conversion of quaternion to roll pitch and yaw. The angles
// are published here too.
void MsgCallback(const geometry_msgs::Quaternion msg)
{
    // the incoming geometry_msgs::Quaternion is transformed to a tf::Quaterion
    tf::Quaternion quat;
    tf::quaternionMsgToTF(msg, quat);

    // the tf::Quaternion has a method to acess roll pitch and yaw
    double roll, pitch, yaw;
    tf::Matrix3x3(quat).getRPY(roll, pitch, yaw);

    // the found angles are written in a geometry_msgs::Vector3
    geometry_msgs::Vector3 rpy;
    rpy.x = roll;
    rpy.y = pitch;
    rpy.z = yaw;

    // this Vector is then published:
    rpy_publisher.publish(rpy);
    ROS_INFO("published rpy angles: roll=%f pitch=%f yaw=%f", rpy.x, rpy.y, rpy.z);
}

int main(int argc, char **argv)
{
    ros::init(argc, argv, "talker");
    ros::NodeHandle n;
    rpy_publisher = n.advertise<geometry_msgs::Vector3>("rpy_angles", 1000);
    quat_subscriber = n.subscribe("rotation_quaternion", 1000, MsgCallback);

    // check for incoming quaternions untill ctrl+c is pressed
    ROS_INFO("waiting for quaternion");
    ros::spin();
    return 0;
}

---

参考文档：

ROS论坛