ROS入门篇

sudo sh -c 'echo "deb http://packages.ros.org/ros/ubuntu $(lsb_release -sc) main">/etc/apt/sources.list.d/ros-latest.list'

sudo apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654

sudo apt-get update
sudo apt install ros-noetic-desktop-full

sudo apt install ros-melodic-desktop-full

sudo vim /etc/profile

source /opt/ros/noetic/setup.bash
export ROS_PACKAGE_PATH=${ROS_PACKAGE_PATH}:~/ros_ws/src

source /opt/ros/melodic/setup.bash
export ROS_PACKAGE_PATH=${ROS_PACKAGE_PATH}:~/ros_ws/src

source /etc/profile
sudo apt-get install python3-rosdep2
sudo vim /etc/hosts

source /etc/profile
sudo apt-get install python3-rosdep
sudo vim /etc/hosts

199.232.28.133 raw.githubusercontent.com

sudo rm /etc/ros/rosdep/sources.list.d/20-default.list
sudo rosdep init
rosdep update

sudo rosdep init
rosdep update

sudo apt install python3-rosinstall python3-rosinstall-generator python3-wstool
sudo apt-get install ros-noetic-roslaunch

sudo apt install python3-catkin-pkg
sudo apt install python3-rosinstall python3-rosinstall-generator python3-wstool
sudo apt-get install ros-melodic-roslaunch

roscore

... logging to /home/guanjian/.ros/log/cb18d28e-35fe-11ee-b678-03d041231f43/roslaunch-guanjian-X99-38074.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://guanjian-X99:34311/
ros_comm version 1.16.0


SUMMARY
========

PARAMETERS
 * /rosdistro: noetic
 * /rosversion: 1.16.0

NODES

auto-starting new master
process[master]: started with pid [38083]
ROS_MASTER_URI=http://guanjian-X99:11311/

setting /run_id to cb18d28e-35fe-11ee-b678-03d041231f43
process[rosout-1]: started with pid [38093]
started core service [/rosout]

sudo apt install ros-noetic-rosbash
sudo apt install ros-noetic-catkin
sudo apt-get install ros-noetic-turtlesim

sudo apt install ros-melodic-rosbash
sudo apt install ros-melodic-catkin
sudo apt-get install ros-melodic-turtlesim

rosrun turtlesim turtlesim_node

rosrun turtlesim turtle_teleop_key

sudo apt-get install ros-noetic-rqt
sudo apt-get install ros-noetic-rqt-graph
sudo apt-get install ros-noetic-rqt-common-plugins

sudo apt-get install ros-melodic-rqt
sudo apt-get install ros-melodic-rqt-graph
sudo apt-get install ros-melodic-rqt-common-plugins

sudo apt-get install ros-noetic-cv-bridge
sudo apt-get install ros-noetic-image-transport

sudo apt-get install ros-melodic-cv-bridge
sudo apt-get install ros-melodic-image-transport

cd /opt/ros/melodic/share/cv_bridge/cmake/
sudo vim cv_bridgeConfig.cmake

roscore

rosrun turtlesim turtlesim_node

rosrun turtlesim turtle_teleop_key

rqt_graph

rosnode

rosnode is a command-line tool for printing information about ROS Nodes.

Commands:
	rosnode ping	test connectivity to node
	rosnode list	list active nodes
	rosnode info	print information about node
	rosnode machine	list nodes running on a particular machine or list machines
	rosnode kill	kill a running node
	rosnode cleanup	purge registration information of unreachable nodes

Type rosnode <command> -h for more detailed usage, e.g. 'rosnode ping -h'

rosnode list

/rosout
/teleop_turtle
/turtlesim

rosnode info /turtlesim

Node [/turtlesim]
Publications: 
 * /rosout [rosgraph_msgs/Log]
 * /turtle1/color_sensor [turtlesim/Color]
 * /turtle1/pose [turtlesim/Pose]

Subscriptions: 
 * /turtle1/cmd_vel [geometry_msgs/Twist]

Services: 
 * /clear
 * /kill
 * /reset
 * /spawn
 * /turtle1/set_pen
 * /turtle1/teleport_absolute
 * /turtle1/teleport_relative
 * /turtlesim/get_loggers
 * /turtlesim/set_logger_level


contacting node http://guanjian-X99:46261/ ...
Pid: 4769
Connections:
 * topic: /rosout
    * to: /rosout
    * direction: outbound (57873 - 127.0.0.1:56794) [27]
    * transport: TCPROS
 * topic: /turtle1/cmd_vel
    * to: /teleop_turtle (http://guanjian-X99:40209/)
    * direction: inbound (46338 - guanjian-X99:43423) [29]
    * transport: TCPROS

rostopic

rostopic is a command-line tool for printing information about ROS Topics.

Commands:
	rostopic bw	display bandwidth used by topic
	rostopic delay	display delay of topic from timestamp in header
	rostopic echo	print messages to screen
	rostopic find	find topics by type
	rostopic hz	display publishing rate of topic    
	rostopic info	print information about active topic
	rostopic list	list active topics
	rostopic pub	publish data to topic
	rostopic type	print topic or field type

Type rostopic <command> -h for more detailed usage, e.g. 'rostopic echo -h'

rostopic list

/rosout
/rosout_agg
/turtle1/cmd_vel
/turtle1/color_sensor
/turtle1/pose

rostopic pub /turtle1/cmd_vel geometry_msgs/Twist '[1.0,0.0,0.0]' '[0.0,0.0,0.0]'

rostopic pub -r 10 /turtle1/cmd_vel geometry_msgs/Twist '[1.0,0.0,0.0]' '[0.0,0.0,0.0]'

rosmsg show geometry_msgs/Twist

geometry_msgs/Vector3 linear
  float64 x
  float64 y
  float64 z
geometry_msgs/Vector3 angular
  float64 x
  float64 y
  float64 z

rosservice

Commands:
	rosservice args	print service arguments
	rosservice call	call the service with the provided args
	rosservice find	find services by service type
	rosservice info	print information about service
	rosservice list	list active services
	rosservice type	print service type
	rosservice uri	print service ROSRPC uri

Type rosservice <command> -h for more detailed usage, e.g. 'rosservice call -h'

rosservice list

/clear
/kill
/reset
/rosout/get_loggers
/rosout/set_logger_level
/spawn
/teleop_turtle/get_loggers
/teleop_turtle/set_logger_level
/turtle1/set_pen
/turtle1/teleport_absolute
/turtle1/teleport_relative
/turtlesim/get_loggers
/turtlesim/set_logger_level

rosservice call /spawn "x: 2.0
y: 2.0
theta: 0.0
name: 'turtle2'" 

rosbag record -a -O cmd_record

[ INFO] [1691623907.802537745]: Recording to 'cmd_record.bag'.
[ INFO] [1691623907.803795811]: Subscribing to /rosout_agg
[ INFO] [1691623907.806439843]: Subscribing to /rosout
[ INFO] [1691623907.809232127]: Subscribing to /turtle1/pose
[ INFO] [1691623907.811861515]: Subscribing to /turtle1/color_sensor
[ INFO] [1691623907.815194941]: Subscribing to /turtle1/cmd_vel

rosbag play cmd_record.bag

cd Documents/
mkdir -p catkin_ws/src
cd catkin_ws/src/
catkin_init_workspace

cd ..
catkin_make install

source devel/setup.bash

cd src
catkin_create_pkg test_pkg std_msgs rospy roscpp

CMakeLists.txt  include  package.xml  src

cd ..
catkin_make

source devel/setup.bash

echo $ROS_PACKAGE_PATH

/home/user/Documents/catkin_ws/src:/opt/ros/noetic/share

<?xml version="1.0"?>
<package format="2">
  <name>test_pkg</name>
  <version>0.0.0</version>
  <description>The test_pkg package</description>

  <!-- One maintainer tag required, multiple allowed, one person per tag -->
  <!-- Example:  -->
  <!-- <maintainer email="jane.doe@example.com">Jane Doe</maintainer> -->
  <maintainer email="guanjian@todo.todo">guanjian</maintainer>


  <!-- One license tag required, multiple allowed, one license per tag -->
  <!-- Commonly used license strings: -->
  <!--   BSD, MIT, Boost Software License, GPLv2, GPLv3, LGPLv2.1, LGPLv3 -->
  <license>TODO</license>


  <!-- Url tags are optional, but multiple are allowed, one per tag -->
  <!-- Optional attribute type can be: website, bugtracker, or repository -->
  <!-- Example: -->
  <!-- <url type="website">http://wiki.ros.org/test_pkg</url> -->


  <!-- Author tags are optional, multiple are allowed, one per tag -->
  <!-- Authors do not have to be maintainers, but could be -->
  <!-- Example: -->
  <!-- <author email="jane.doe@example.com">Jane Doe</author> -->


  <!-- The *depend tags are used to specify dependencies -->
  <!-- Dependencies can be catkin packages or system dependencies -->
  <!-- Examples: -->
  <!-- Use depend as a shortcut for packages that are both build and exec dependencies -->
  <!--   <depend>roscpp</depend> -->
  <!--   Note that this is equivalent to the following: -->
  <!--   <build_depend>roscpp</build_depend> -->
  <!--   <exec_depend>roscpp</exec_depend> -->
  <!-- Use build_depend for packages you need at compile time: -->
  <!--   <build_depend>message_generation</build_depend> -->
  <!-- Use build_export_depend for packages you need in order to build against this package: -->
  <!--   <build_export_depend>message_generation</build_export_depend> -->
  <!-- Use buildtool_depend for build tool packages: -->
  <!--   <buildtool_depend>catkin</buildtool_depend> -->
  <!-- Use exec_depend for packages you need at runtime: -->
  <!--   <exec_depend>message_runtime</exec_depend> -->
  <!-- Use test_depend for packages you need only for testing: -->
  <!--   <test_depend>gtest</test_depend> -->
  <!-- Use doc_depend for packages you need only for building documentation: -->
  <!--   <doc_depend>doxygen</doc_depend> -->
  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>roscpp</build_depend>
  <build_depend>rospy</build_depend>
  <build_depend>std_msgs</build_depend>
  <build_export_depend>roscpp</build_export_depend>
  <build_export_depend>rospy</build_export_depend>
  <build_export_depend>std_msgs</build_export_depend>
  <exec_depend>roscpp</exec_depend>
  <exec_depend>rospy</exec_depend>
  <exec_depend>std_msgs</exec_depend>


  <!-- The export tag contains other, unspecified, tags -->
  <export>
    <!-- Other tools can request additional information be placed here -->

  </export>
</package>

cmake_minimum_required(VERSION 3.0.2)
project(test_pkg)

## Compile as C++11, supported in ROS Kinetic and newer
# add_compile_options(-std=c++11)

## Find catkin macros and libraries
## if COMPONENTS list like find_package(catkin REQUIRED COMPONENTS xyz)
## is used, also find other catkin packages
find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  std_msgs
)

## System dependencies are found with CMake's conventions
# find_package(Boost REQUIRED COMPONENTS system)


## Uncomment this if the package has a setup.py. This macro ensures
## modules and global scripts declared therein get installed
## See http://ros.org/doc/api/catkin/html/user_guide/setup_dot_py.html
# catkin_python_setup()

################################################
## Declare ROS messages, services and actions ##
################################################

## To declare and build messages, services or actions from within this
## package, follow these steps:
## * Let MSG_DEP_SET be the set of packages whose message types you use in
##   your messages/services/actions (e.g. std_msgs, actionlib_msgs, ...).
## * In the file package.xml:
##   * add a build_depend tag for "message_generation"
##   * add a build_depend and a exec_depend tag for each package in MSG_DEP_SET
##   * If MSG_DEP_SET isn't empty the following dependency has been pulled in
##     but can be declared for certainty nonetheless:
##     * add a exec_depend tag for "message_runtime"
## * In this file (CMakeLists.txt):
##   * add "message_generation" and every package in MSG_DEP_SET to
##     find_package(catkin REQUIRED COMPONENTS ...)
##   * add "message_runtime" and every package in MSG_DEP_SET to
##     catkin_package(CATKIN_DEPENDS ...)
##   * uncomment the add_*_files sections below as needed
##     and list every .msg/.srv/.action file to be processed
##   * uncomment the generate_messages entry below
##   * add every package in MSG_DEP_SET to generate_messages(DEPENDENCIES ...)

## Generate messages in the 'msg' folder
# add_message_files(
#   FILES
#   Message1.msg
#   Message2.msg
# )

## Generate services in the 'srv' folder
# add_service_files(
#   FILES
#   Service1.srv
#   Service2.srv
# )

## Generate actions in the 'action' folder
# add_action_files(
#   FILES
#   Action1.action
#   Action2.action
# )

## Generate added messages and services with any dependencies listed here
# generate_messages(
#   DEPENDENCIES
#   std_msgs
# )

################################################
## Declare ROS dynamic reconfigure parameters ##
################################################

## To declare and build dynamic reconfigure parameters within this
## package, follow these steps:
## * In the file package.xml:
##   * add a build_depend and a exec_depend tag for "dynamic_reconfigure"
## * In this file (CMakeLists.txt):
##   * add "dynamic_reconfigure" to
##     find_package(catkin REQUIRED COMPONENTS ...)
##   * uncomment the "generate_dynamic_reconfigure_options" section below
##     and list every .cfg file to be processed

## Generate dynamic reconfigure parameters in the 'cfg' folder
# generate_dynamic_reconfigure_options(
#   cfg/DynReconf1.cfg
#   cfg/DynReconf2.cfg
# )

###################################
## catkin specific configuration ##
###################################
## The catkin_package macro generates cmake config files for your package
## Declare things to be passed to dependent projects
## INCLUDE_DIRS: uncomment this if your package contains header files
## LIBRARIES: libraries you create in this project that dependent projects also need
## CATKIN_DEPENDS: catkin_packages dependent projects also need
## DEPENDS: system dependencies of this project that dependent projects also need
catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES test_pkg
#  CATKIN_DEPENDS roscpp rospy std_msgs
#  DEPENDS system_lib
)

###########
## Build ##
###########

## Specify additional locations of header files
## Your package locations should be listed before other locations
include_directories(
# include
  ${catkin_INCLUDE_DIRS}
)

## Declare a C++ library
# add_library(${PROJECT_NAME}
#   src/${PROJECT_NAME}/test_pkg.cpp
# )

## Add cmake target dependencies of the library
## as an example, code may need to be generated before libraries
## either from message generation or dynamic reconfigure
# add_dependencies(${PROJECT_NAME} ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

## Declare a C++ executable
## With catkin_make all packages are built within a single CMake context
## The recommended prefix ensures that target names across packages don't collide
# add_executable(${PROJECT_NAME}_node src/test_pkg_node.cpp)

## Rename C++ executable without prefix
## The above recommended prefix causes long target names, the following renames the
## target back to the shorter version for ease of user use
## e.g. "rosrun someones_pkg node" instead of "rosrun someones_pkg someones_pkg_node"
# set_target_properties(${PROJECT_NAME}_node PROPERTIES OUTPUT_NAME node PREFIX "")

## Add cmake target dependencies of the executable
## same as for the library above
# add_dependencies(${PROJECT_NAME}_node ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})

## Specify libraries to link a library or executable target against
# target_link_libraries(${PROJECT_NAME}_node
#   ${catkin_LIBRARIES}
# )

#############
## Install ##
#############

# all install targets should use catkin DESTINATION variables
# See http://ros.org/doc/api/catkin/html/adv_user_guide/variables.html

## Mark executable scripts (Python etc.) for installation
## in contrast to setup.py, you can choose the destination
# catkin_install_python(PROGRAMS
#   scripts/my_python_script
#   DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )

## Mark executables for installation
## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_executables.html
# install(TARGETS ${PROJECT_NAME}_node
#   RUNTIME DESTINATION ${CATKIN_PACKAGE_BIN_DESTINATION}
# )

## Mark libraries for installation
## See http://docs.ros.org/melodic/api/catkin/html/howto/format1/building_libraries.html
# install(TARGETS ${PROJECT_NAME}
#   ARCHIVE DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
#   LIBRARY DESTINATION ${CATKIN_PACKAGE_LIB_DESTINATION}
#   RUNTIME DESTINATION ${CATKIN_GLOBAL_BIN_DESTINATION}
# )

## Mark cpp header files for installation
# install(DIRECTORY include/${PROJECT_NAME}/
#   DESTINATION ${CATKIN_PACKAGE_INCLUDE_DESTINATION}
#   FILES_MATCHING PATTERN "*.h"
#   PATTERN ".svn" EXCLUDE
# )

## Mark other files for installation (e.g. launch and bag files, etc.)
# install(FILES
#   # myfile1
#   # myfile2
#   DESTINATION ${CATKIN_PACKAGE_SHARE_DESTINATION}
# )

#############
## Testing ##
#############

## Add gtest based cpp test target and link libraries
# catkin_add_gtest(${PROJECT_NAME}-test test/test_test_pkg.cpp)
# if(TARGET ${PROJECT_NAME}-test)
#   target_link_libraries(${PROJECT_NAME}-test ${PROJECT_NAME})
# endif()

## Add folders to be run by python nosetests
# catkin_add_nosetests(test)

cd Documents/catkin_ws/src

catkin_create_pkg learning_topic roscpp rospy std_msgs geometry_msgs turtlesim

cd learning_topic/src

vim velocity_publisher.cpp

/*
 *  该程序将发布turtle1/cmd_vel话题，消息类型geometry_msgs::Twist
*/

#include <ros/ros.h>
#include <geometry_msgs/Twist.h>

using namespace ros;

int main(int argc, char **argv) {
    //ROS节点初始化
    init(argc, argv, "velocity_publisher");
    //创建节点句柄
    NodeHandle n;
    //创建一个Publisher，发布名为/turtle1/cmd_vel的topic，消息类型为geometry_msgs::Twist，队列长度10
    Publisher turtle_vel_pub = n.advertise<geometry_msgs::Twist>("/turtle1/cmd_vel", 10);
    //设置循环的频率
    Rate loop_rate(10);

    int count = 0;

    while(ok()) {
        //初始化geometry_msgs::Twist类型的消息
	geometry_msgs::Twist vel_msg;
        //设置小海龟的线动量
	vel_msg.linear.x = 0.5;
        //设置小海龟的角动量
	vel_msg.angular.z = 0.2;
        //发布消息
	turtle_vel_pub.publish(vel_msg);
	ROS_INFO("Publish turtle velocity command[%0.2f m/s, %0.2f rad/s]", vel_msg.linear.x, vel_msg.angular.z);
        //按照循环频率延时
	loop_rate.sleep();
    }

    return 0;
}

cd ..
vim CMakelists.txt

add_executable(velocity_publisher src/velocity_publisher.cpp)
target_link_libraries(velocity_publisher ${catkin_LIBRARIES})

cd ../..
catkin_make

source devel/setup.bash

sudo vim /etc/profile

source /home/user/Documents/catkin_ws/devel/setup.bash

source /etc/profile

roscore
rosrun turtlesim turtlesim_node
rosrun learning_topic velocity_publisher

cd Documents/catkin_ws/src/learning_topic

mkdir scripts
cd scripts

vim velocity_publisher.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该程序将发布turtle1/cmd_vel话题，消息类型geometry_msgs::Twist

import rospy
from geometry_msgs.msg import Twist

def velocity_publisher():
    # ROS节点初始化
    rospy.init_node('velocity_publisher', anonymous=True)
    # 创建一个Publisher，发布名为/turtle1/cmd_vel的topic，消息类型为geometry_msgs::Twist，队列长度10
    turtle_vel_pub = rospy.Publisher('/turtle1/cmd_vel', Twist, queue_size=10)
    # 设置循环的频率
    rate = rospy.Rate(10)

    while not rospy.is_shutdown():
        # 初始化geometry_msgs::Twist类型的消息
        vel_msg = Twist()
        # 设置小海龟的线动量
        vel_msg.linear.x = 0.5
        # 设置小海龟的角动量
        vel_msg.angular.z = 0.2
        # 发布消息
        turtle_vel_pub.publish(vel_msg)
        rospy.loginfo("Publish turtle velocity command[%0.2f m/s, %0.2f rad/s]", vel_msg.linear.x, vel_msg.angular.z)
        # 按照循环频率延时
        rate.sleep()

if __name__ == '__main__':

    try:
        velocity_publisher()
    except rospy.ROSInterruptException:
        pass

chmod 777 velocity_publisher.py

conda activate py39
pip install pyyaml
pip install rospkg

roscore
rosrun turtlesim turtlesim_node
rosrun learning_topic velocity_publisher.py

cd Documents/catkin_ws/src/learning_topic/src

vim pose_subscriber.cpp

/*
 *  该例程将订阅/turtle1/pose话题，消息类型turtlesim::Pose
*/

#include <ros/ros.h>
#include "turtlesim/Pose.h"

using namespace ros;

//接受到订阅的消息后，会进入消息回调函数
void poseCallback(const turtlesim::Pose::ConstPtr& msg) {
    //将接收的消息打印出来
    ROS_INFO("Turtle pose: x:%0.6f, y:%0.6f", msg->x, msg->y);
}

int main(int argc, char **argv) {
    //初始化ROS节点
    init(argc, argv, "pose_subscriber");
    //创建节点句柄
    NodeHandle n;
    //创建一个Subscriber，订阅名为/turtle1/pose的topic，注册回调函数poseCallback
    Subscriber pose_sub = n.subscribe("/turtle1/pose", 10, poseCallback);
    //循环等待回调函数
    spin();

    return 0;
}

cd ..
vim CMakelists.txt

add_executable(pose_subscriber src/pose_subscriber.cpp)
target_link_libraries(pose_subscriber ${catkin_LIBRARIES})

cd ../..
catkin_make

roscore
rosrun turtlesim turtlesim_node
rosrun turtlesim turtle_teleop_key
rosrun learning_topic pose_subscriber

[ INFO] [1691889920.721039829]: Turtle pose: x:7.258318, y:6.718236
[ INFO] [1691889920.736960560]: Turtle pose: x:7.226329, y:6.717391
[ INFO] [1691889920.752859056]: Turtle pose: x:7.194340, y:6.716546
[ INFO] [1691889920.768800015]: Turtle pose: x:7.162352, y:6.715701
[ INFO] [1691889920.784756857]: Turtle pose: x:7.130363, y:6.714856
[ INFO] [1691889920.800640019]: Turtle pose: x:7.098374, y:6.714011
[ INFO] [1691889920.816949030]: Turtle pose: x:7.066385, y:6.713166
[ INFO] [1691889920.832867584]: Turtle pose: x:7.034396, y:6.712321
[ INFO] [1691889920.848822764]: Turtle pose: x:7.002407, y:6.711476
[ INFO] [1691889920.864732401]: Turtle pose: x:6.970418, y:6.710631
[ INFO] [1691889920.880662398]: Turtle pose: x:6.938430, y:6.709786
[ INFO] [1691889920.896609434]: Turtle pose: x:6.906441, y:6.708941
[ INFO] [1691889920.912486155]: Turtle pose: x:6.874452, y:6.708097
[ INFO] [1691889920.928392700]: Turtle pose: x:6.842463, y:6.707252
[ INFO] [1691889920.944258964]: Turtle pose: x:6.810474, y:6.706407
[ INFO] [1691889920.961082117]: Turtle pose: x:6.778485, y:6.705562
[ INFO] [1691889920.976929758]: Turtle pose: x:6.746497, y:6.704717
[ INFO] [1691889920.992809891]: Turtle pose: x:6.714508, y:6.703872
[ INFO] [1691889921.008716570]: Turtle pose: x:6.682519, y:6.703027
[ INFO] [1691889921.024568443]: Turtle pose: x:6.650530, y:6.702182
[ INFO] [1691889921.040418382]: Turtle pose: x:6.618541, y:6.701337
[ INFO] [1691889921.056245800]: Turtle pose: x:6.586552, y:6.700492
[ INFO] [1691889921.072179865]: Turtle pose: x:6.554564, y:6.699647
[ INFO] [1691889921.088081910]: Turtle pose: x:6.522575, y:6.698802
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[ INFO] [1691889923.777058333]: Turtle pose: x:3.913240, y:4.874557
[ INFO] [1691889923.792188376]: Turtle pose: x:3.913240, y:4.874557

cd Documents/catkin_ws/src/learning_topic/scripts
vim pose_subscriber.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程将订阅/turtle1/pose话题，消息类型turtlesim::Pose

import rospy
from turtlesim.msg import Pose
# 接受到订阅的消息后，会进入消息回调函数
def poseCallback(msg):
    # 将接收的消息打印出来
    rospy.loginfo("Turtle pose: x:%0.6f, y:%0.6f", msg.x, msg.y)

def pose_subscriber():
    # 初始化ROS节点
    rospy.init_node('pose_subscriber', anonymous=True)
    # 创建一个Subscriber，订阅名为/turtle1/pose的topic，注册回调函数poseCallback
    rospy.Subscriber("/turtle1/pose", Pose, poseCallback)
    # 循环等待回调函数
    rospy.spin()

if __name__ == '__main__':

    pose_subscriber()

chmod 777 pose_subscriber.py

roscore
rosrun turtlesim turtlesim_node
rosrun turtlesim turtle_teleop_key
rosrun learning_topic pose_subscriber.py

cd Documents/catkin_ws/src

catkin_create_pkg learning_transfer_img sensor_msgs cv_bridge roscpp std_msgs image_transport

cd learning_transfer_img/src

vim img_publisher.cpp

#include <ros/ros.h>
#include <image_transport/image_transport.h>
#include <opencv2/highgui/highgui.hpp>
#include <cv_bridge/cv_bridge.h>

using namespace ros;
using namespace cv;
using namespace std;
using namespace sensor_msgs;
     
int main(int argc, char** argv){
    //ROS节点初始化
    init(argc, argv, "image_publisher");
    //创建节点句柄
    NodeHandle n;
    //创建一个图像传输发布者，发布名为/camera/image的topic
    image_transport::ImageTransport it(n);
    image_transport::Publisher pub = it.advertise("/camera/image", 1);
    VideoCapture cap(0);
    if(!cap.isOpened()) return 1;
    Mat frame;
    //初始化一个sensor_msgs::ImagePtr类型的消息
    ImagePtr msg;
    Rate loop_rate(1);
    while (ok()) {
        cap >> frame;
        if(!frame.empty()) {
            //将opencv的Mat转化成sensor_msgs::ImagePtr类型的消息
            msg = cv_bridge::CvImage(std_msgs::Header(), "bgr8", frame).toImageMsg();
            //发布消息
            pub.publish(msg);
        }
        //按照循环频率延时
        loop_rate.sleep();
    }
    return 0;
}

vim img_subscriber.cpp

#include <ros/ros.h>
#include <image_transport/image_transport.h>
#include <opencv2/highgui/highgui.hpp>
#include <cv_bridge/cv_bridge.h>

using namespace ros;
using namespace cv;
using namespace std;
using namespace sensor_msgs;
 
void imageCallback(const ImageConstPtr& msg) {
    try {
        //将sensor_msgs::ImagePtr类型的消息转化成opencv的Mat并显示出来
        imshow("view", cv_bridge::toCvShare(msg, "bgr8")->image);
        waitKey(1);
    } catch (cv_bridge::Exception& e) {
        ROS_ERROR("Could not convert from '%s' to 'bgr8'.", msg->encoding.c_str());
    }
}
 
int main(int argc, char **argv) {
    //ROS节点初始化
    init(argc, argv, "img_subscriber");
    //创建节点句柄
    NodeHandle n;
    namedWindow("view");
    startWindowThread();
    //创建一个image_transport::Subscriber，订阅名为/camera/image的topic，注册回调函数imageCallback
    image_transport::ImageTransport it(n);
    image_transport::Subscriber sub = it.subscribe("/camera/image", 1, imageCallback);
    //循环等待回调函数
    spin();
    destroyWindow("view");
    return 0;
}

cd ..
vim CMakelists.txt

find_package(OpenCV)
include_directories(${OpenCV_INCLUDE_DIRS})

add_executable(img_publisher src/img_publisher.cpp)
target_link_libraries(img_publisher ${catkin_LIBRARIES})
target_link_libraries(img_publisher ${OpenCV_LIBS})

add_executable(img_subscriber src/img_subscriber.cpp)
target_link_libraries(img_subscriber ${catkin_LIBRARIES})
target_link_libraries(img_subscriber ${OpenCV_LIBS})

cd ../..
catkin_make

roscore
rosrun learning_transfer_img img_subscriber
rosrun learning_transfer_img img_publisher

cd Documents/catkin_ws/src/learning_topic

mkdir msg
cd msg

vim Person.msg

string name
uint8 sex
uint8 age

uint8 unknown = 0
uint8 male    = 1
uint8 femal   = 2

cd ..
vim package.xml

<build_depend>message_generation</build_depend>
<exec_depend>message_runtime</exec_depend>

vim CMakeLists.txt

find_package(catkin REQUIRED COMPONENTS
  geometry_msgs
  roscpp
  rospy
  std_msgs
  turtlesim
  message_generation
)

add_message_files(FILES Person.msg)
generate_messages(DEPENDENCIES std_msgs)

catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES learning_topic
   CATKIN_DEPENDS geometry_msgs roscpp rospy std_msgs turtlesim message_runtime
#  DEPENDS system_lib
)

cd ../..
catkin_make

// Generated by gencpp from file learning_topic/Person.msg
// DO NOT EDIT!


#ifndef LEARNING_TOPIC_MESSAGE_PERSON_H
#define LEARNING_TOPIC_MESSAGE_PERSON_H


#include <string>
#include <vector>
#include <memory>

#include <ros/types.h>
#include <ros/serialization.h>
#include <ros/builtin_message_traits.h>
#include <ros/message_operations.h>


namespace learning_topic
{
template <class ContainerAllocator>
struct Person_
{
  typedef Person_<ContainerAllocator> Type;

  Person_()
    : name()
    , sex(0)
    , age(0)  {
    }
  Person_(const ContainerAllocator& _alloc)
    : name(_alloc)
    , sex(0)
    , age(0)  {
  (void)_alloc;
    }



   typedef std::basic_string<char, std::char_traits<char>, typename std::allocator_traits<ContainerAllocator>::template rebind_alloc<char>> _name_type;
  _name_type name;

   typedef uint8_t _sex_type;
  _sex_type sex;

   typedef uint8_t _age_type;
  _age_type age;



// reducing the odds to have name collisions with Windows.h 
#if defined(_WIN32) && defined(unknown)
  #undef unknown
#endif
#if defined(_WIN32) && defined(male)
  #undef male
#endif
#if defined(_WIN32) && defined(femal)
  #undef femal
#endif

  enum {
    unknown = 0u,
    male = 1u,
    femal = 2u,
  };


  typedef boost::shared_ptr< ::learning_topic::Person_<ContainerAllocator> > Ptr;
  typedef boost::shared_ptr< ::learning_topic::Person_<ContainerAllocator> const> ConstPtr;

}; // struct Person_

typedef ::learning_topic::Person_<std::allocator<void> > Person;

typedef boost::shared_ptr< ::learning_topic::Person > PersonPtr;
typedef boost::shared_ptr< ::learning_topic::Person const> PersonConstPtr;

// constants requiring out of line definition

   

   

   



template<typename ContainerAllocator>
std::ostream& operator<<(std::ostream& s, const ::learning_topic::Person_<ContainerAllocator> & v)
{
ros::message_operations::Printer< ::learning_topic::Person_<ContainerAllocator> >::stream(s, "", v);
return s;
}


template<typename ContainerAllocator1, typename ContainerAllocator2>
bool operator==(const ::learning_topic::Person_<ContainerAllocator1> & lhs, const ::learning_topic::Person_<ContainerAllocator2> & rhs)
{
  return lhs.name == rhs.name &&
    lhs.sex == rhs.sex &&
    lhs.age == rhs.age;
}

template<typename ContainerAllocator1, typename ContainerAllocator2>
bool operator!=(const ::learning_topic::Person_<ContainerAllocator1> & lhs, const ::learning_topic::Person_<ContainerAllocator2> & rhs)
{
  return !(lhs == rhs);
}


} // namespace learning_topic

namespace ros
{
namespace message_traits
{





template <class ContainerAllocator>
struct IsMessage< ::learning_topic::Person_<ContainerAllocator> >
  : TrueType
  { };

template <class ContainerAllocator>
struct IsMessage< ::learning_topic::Person_<ContainerAllocator> const>
  : TrueType
  { };

template <class ContainerAllocator>
struct IsFixedSize< ::learning_topic::Person_<ContainerAllocator> >
  : FalseType
  { };

template <class ContainerAllocator>
struct IsFixedSize< ::learning_topic::Person_<ContainerAllocator> const>
  : FalseType
  { };

template <class ContainerAllocator>
struct HasHeader< ::learning_topic::Person_<ContainerAllocator> >
  : FalseType
  { };

template <class ContainerAllocator>
struct HasHeader< ::learning_topic::Person_<ContainerAllocator> const>
  : FalseType
  { };


template<class ContainerAllocator>
struct MD5Sum< ::learning_topic::Person_<ContainerAllocator> >
{
  static const char* value()
  {
    return "2df326301c118b26e23f3606868068cc";
  }

  static const char* value(const ::learning_topic::Person_<ContainerAllocator>&) { return value(); }
  static const uint64_t static_value1 = 0x2df326301c118b26ULL;
  static const uint64_t static_value2 = 0xe23f3606868068ccULL;
};

template<class ContainerAllocator>
struct DataType< ::learning_topic::Person_<ContainerAllocator> >
{
  static const char* value()
  {
    return "learning_topic/Person";
  }

  static const char* value(const ::learning_topic::Person_<ContainerAllocator>&) { return value(); }
};

template<class ContainerAllocator>
struct Definition< ::learning_topic::Person_<ContainerAllocator> >
{
  static const char* value()
  {
    return "string name\n"
"uint8 sex\n"
"uint8 age\n"
"\n"
"uint8 unknown = 0\n"
"uint8 male    = 1\n"
"uint8 femal   = 2\n"
;
  }

  static const char* value(const ::learning_topic::Person_<ContainerAllocator>&) { return value(); }
};

} // namespace message_traits
} // namespace ros

namespace ros
{
namespace serialization
{

  template<class ContainerAllocator> struct Serializer< ::learning_topic::Person_<ContainerAllocator> >
  {
    template<typename Stream, typename T> inline static void allInOne(Stream& stream, T m)
    {
      stream.next(m.name);
      stream.next(m.sex);
      stream.next(m.age);
    }

    ROS_DECLARE_ALLINONE_SERIALIZER
  }; // struct Person_

} // namespace serialization
} // namespace ros

namespace ros
{
namespace message_operations
{

template<class ContainerAllocator>
struct Printer< ::learning_topic::Person_<ContainerAllocator> >
{
  template<typename Stream> static void stream(Stream& s, const std::string& indent, const ::learning_topic::Person_<ContainerAllocator>& v)
  {
    s << indent << "name: ";
    Printer<std::basic_string<char, std::char_traits<char>, typename std::allocator_traits<ContainerAllocator>::template rebind_alloc<char>>>::stream(s, indent + "  ", v.name);
    s << indent << "sex: ";
    Printer<uint8_t>::stream(s, indent + "  ", v.sex);
    s << indent << "age: ";
    Printer<uint8_t>::stream(s, indent + "  ", v.age);
  }
};

} // namespace message_operations
} // namespace ros

#endif // LEARNING_TOPIC_MESSAGE_PERSON_H

cd Documents/catkin_ws/src/learning_topic/src

vim person_publisher.cpp

/*
 * 该例程将发布/person_info话题，自定义消息类型learning_topic::Person
 */

#include <ros/ros.h>
#include "learning_topic/Person.h"

using namespace ros;

int main(int argc, char **argv) {
    //ROS节点初始化
    init(argc, argv, "person_publisher");
    //创建节点句柄
    NodeHandle n;
    //创建一个Publisher，发布名为/person_info的topic，消息类型为learning_topic::Person，队列长度为10
    Publisher person_info_pub = n.advertise<learning_topic::Person>("/person_info", 10);
    //设置循环的频率
    Rate loop_rate(1);

    int count = 0;
    while(ok()) {
        //初始化learning_topic::Person类型的消息
	learning_topic::Person person_msg;
	person_msg.name = "Tom";
	person_msg.age = 18;
	person_msg.sex = learning_topic::Person::male;
        //发布消息
	person_info_pub.publish(person_msg);

	ROS_INFO("Publish Person Info: name:%s age:%d sex:%d", person_msg.name.c_str(), person_msg.age, person_msg.sex);
        //按照循环频率延时
	loop_rate.sleep();
    }

    return 0;
}

vim person_subscriber.cpp

/*
 * 该例程将订阅/person_info话题，自定义消息类型learning_topic::Person
 */

#include <ros/ros.h>
#include "learning_topic/Person.h"

using namespace ros;

//接收到订阅消息后，会进入消息回调函数
void personInfoCallback(const learning_topic::Person::ConstPtr& msg) {
    //将接收到的消息打印出来
    ROS_INFO("Subcribe Person Info: name:%s age:%d sex:%d", msg->name.c_str(), msg->age, msg->sex);
}

int main(int argc, char **argv) {
    //初始化ROS节点
    init(argc, argv, "person_subscriber");
    //创建节点句柄
    NodeHandle n;
    //创建一个Subscriber，订阅名为/person_info的topic，注册回调函数personInfoCallback
    Subscriber person_info_sub = n.subscribe("/person_info", 10, personInfoCallback);
    //循环等待回调函数
    spin();

    return 0;
}

cd ..
vim CMakelists.txt

add_executable(person_publisher src/person_publisher.cpp)
target_link_libraries(person_publisher ${catkin_LIBRARIES})
add_dependencies(person_publisher ${PROJECT_NAME}_generate_messages_cpp)

add_executable(person_subscriber src/person_subscriber.cpp)
target_link_libraries(person_subscriber ${catkin_LIBRARIES})
add_dependencies(person_subscriber ${PROJECT_NAME}_generate_messages_cpp)

cd ../..
catkin_make

roscore
rosrun learning_topic person_subscriber
rosrun learning_topic person_publisher

[ INFO] [1692058319.598902884]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058320.599045308]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058321.599024124]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058322.599034397]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058323.599010303]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058324.599021551]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058325.599007207]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058326.598998586]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058327.598991095]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058328.599036958]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058329.599018178]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058330.599023816]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058331.599021355]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058332.599022894]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058333.599017425]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1692058334.599010853]: Publish Person Info: name:Tom age:18 sex:1

[ INFO] [1692058320.599351163]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058321.599261038]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058322.599291722]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058323.599267429]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058324.599267875]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058325.599275965]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058326.599178858]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058327.599225550]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058328.599308836]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058329.599291376]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058330.599301795]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058331.599281126]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058332.599277659]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058333.599294180]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1692058334.599276274]: Subcribe Person Info: name:Tom age:18 sex:1

cd Documents/catkin_ws/src/learning_topic/scripts

vim person_publisher.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程将发布/person_info话题，自定义消息类型learning_topic::Person

import rospy
from learning_topic.msg import Person

def velocity_publisher():
    # ROS节点初始化
    rospy.init_node('person_publisher', anonymous=True)
    # 创建一个Publisher，发布名为/person_info的topic，消息类型为learning_topic::Person，队列长度为10
    person_info_pub = rospy.Publisher('/person_info', Person, queue_size=10)
    # 设置循环的频率
    rate = rospy.Rate(10)

    while not rospy.is_shutdown():
        # 初始化learning_topic::Person类型的消息
        person_msg = Person()
        person_msg.name = "Tom"
        person_msg.age = 18
        person_msg.sex = Person.male
        # 发布消息
        person_info_pub.publish(person_msg)
        rospy.loginfo("Publish person message[%s, %d, %d]", person_msg.name, person_msg.age, person_msg.sex)
        # 按照循环频率延时
        rate.sleep()

if __name__ == '__main__':

    try:
        velocity_publisher()
    except rospy.ROSInterruptException:
        pass

vim person_subscriber.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程将订阅/person_info话题，自定义消息类型learning_topic::Person

import rospy
from learning_topic.msg import Person

# 接收到订阅消息后，会进入消息回调函数
def personInfoCallback(msg):
    rospy.loginfo("Subcribe Person info: name:%s age:%d sex:%d", msg.name, msg.age, msg.sex)
    
def person_subscriber():
    # 初始化ROS节点
    rospy.init_node('person_subscriber', anonymous=True)
    # 创建一个Subscriber，订阅名为/person_info的topic，注册回调函数personInfoCallback
    rospy.Subscriber('/person_info', Person, personInfoCallback)
    # 循环等待回调函数
    rospy.spin()
    
if __name__ == '__main__':
    
    person_subscriber()

chmod 777 person_publisher.py
chmod 777 person_subscriber.py

roscore
rosrun learning_topic person_subscriber.py
rosrun learning_topic person_publisher.py

cd Documents/catkin_ws/src

catkin_create_pkg learning_service roscpp rospy std_msgs geometry_msgs turtlesim

cd learning_service/src

vim turtle_spawn.cpp

/*
 * 该例程将请求/spawn服务，服务数据类型turtlesim::Spawn
 */

#include <ros/ros.h>
#include <turtlesim/Spawn.h>

using namespace ros;

int main(int argc, char** argv) {
    //初始化ROS节点
    init(argc, argv, "turtle_spawn");
    //创建节点句柄
    NodeHandle node;
    //发现/spawn服务后，创建一个服务客户端，连接名为/spawn的service
    service::waitForService("/spawn");
    ServiceClient add_turtle = node.serviceClient<turtlesim::Spawn>("/spawn");
    //初始化turtlesim::Spawn的请求数据
    turtlesim::Spawn srv;
    srv.request.x = 2.0;
    srv.request.y = 2.0;
    srv.request.name = "turtle2";
    //请求服务调用
    ROS_INFO("Call service to spwan turtle[x:%0.6f, y:%0.6f, name:%s]", srv.request.x, srv.request.y, srv.request.name.c_str());

    add_turtle.call(srv);
    //显示服务调用结果
    ROS_INFO("Spwan turtle successfully [name:%s]", srv.response.name.c_str());

    return 0;
}

cd ..
vim CMakelists.txt

add_executable(turtle_spawn src/turtle_spawn.cpp)
target_link_libraries(turtle_spawn ${catkin_LIBRARIES})

cd ../..
catkin_make

roscore
rosrun turtlesim turtlesim_node
rosrun learning_service turtle_spawn

[ INFO] [1692399646.686858318]: Call service to spwan turtle[x:2.000000, y:2.000000, name:turtle2]
[ INFO] [1692399646.697959476]: Spwan turtle successfully [name:turtle2]

[ INFO] [1692399646.697808644]: Spawning turtle [turtle2] at x=[2.000000], y=[2.000000], theta=[0.000000]

cd Documents/catkin_ws/src/learning_service

mkdir scripts
cd scripts

vim turtle_spawn.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程将请求/spawn服务，服务数据类型turtlesim::Spawn

import sys
import rospy
from turtlesim.srv import Spawn

def turtle_spawn():
    # 初始化ROS节点
    rospy.init_node('turtle_spawn')
    # 发现/spawn服务后，创建一个服务客户端，连接名为/spawn的service
    rospy.wait_for_service('/spawn')
    try:
        add_turtle = rospy.ServiceProxy('/spawn', Spawn)
        # 请求服务调用
        response = add_turtle(2.0, 2.0, 0.0, "turtle2")
        return response.name
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

if __name__ == "__main__":
    # 显示服务调用结果
    print("Spwan turtle successfully [name:%s]" %(turtle_spawn()))

chmod 777 turtle_spawn.py

roscore
rosrun turtlesim turtlesim_node
rosrun learning_service turtle_spawn.py

cd Documents/catkin_ws/src/learning_service/src

vim turtle_command_server.cpp

/*
 * 该例程将执行/turtle_command服务，服务数据类型std_srvs/Trigger
 */

#include <ros/ros.h>
#include <geometry_msgs/Twist.h>
#include <std_srvs/Trigger.h>

using namespace ros;

Publisher turtle_vel_pub;
bool pubCommand = false;
//service回调函数，输入参数req,输出参数res
bool commandCallback(std_srvs::Trigger::Request &req, std_srvs::Trigger:: Response &res) {
    pubCommand = !pubCommand;
    //显示请求数据
    ROS_INFO("Publish turtle velocity command [%s]", pubCommand==true?"Yes":"No");
    //设置反馈数据
    res.success = true;
    res.message = "Change turtle command state!";

    return true;
}

int main(int argc, char **argv) {
    //ROS节点初始化
    init(argc, argv, "turtle_command_server");
    //创建节点句柄
    NodeHandle n;
    //创建一个名为/turtle_command的server，注册回调函数commandCallback
    ServiceServer command_service = n.advertiseService("/turtle_command", commandCallback);
    //创建一个Publisher，发布名为/turtle1/cmd_vel的topic，消息类型为geometry_msgs::Twist，队列长度10
    turtle_vel_pub = n.advertise<geometry_msgs::Twist>("/turtle1/cmd_vel", 10);
    //循环等待回调函数
    ROS_INFO("Ready to receive turtle command.");
    //设置循环的频率
    Rate loop_rate(10);

    while(ok()) {
        //查看一次回调函数队列
	spinOnce();
        //如果标志为true，则发布速度指令
	if (pubCommand) {
	    geometry_msgs::Twist vel_msg;
	    vel_msg.linear.x = 0.5;
	    vel_msg.angular.z = 0.2;
	    turtle_vel_pub.publish(vel_msg);
	}
        //按照循环频率延时
	loop_rate.sleep();
    }

    return 0;
}

cd ..
vim CMakelists.txt

add_executable(turtle_command_server src/turtle_command_server.cpp)
target_link_libraries(turtle_command_server ${catkin_LIBRARIES})

cd ../..
catkin_make

roscore
rosrun turtlesim turtlesim_node
rosrun learning_service turtle_command_server
rosservice call /turtle_command "{}"

rosservice call /turtle_command "{}"

[ INFO] [1692495991.674337329]: Publish turtle velocity command [Yes]
[ INFO] [1692496732.674292008]: Publish turtle velocity command [No]

cd Documents/catkin_ws/src/learning_service/scripts

vim turtle_command_server.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程将执行/turtle_command服务，服务数据类型std_srvs/Trigger

import rospy
import _thread,time
from geometry_msgs.msg import Twist
from std_srvs.srv import Trigger,TriggerResponse

pubCommand = False
# 创建一个Publisher，发布名为/turtle1/cmd_vel的topic，消息类型为geometry_msgs::Twist，队列长度10
turtle_vel_pub = rospy.Publisher('/turtle1/cmd_vel', Twist, queue_size=10)

def command_thread():
    while True:
        if pubCommand:
            vel_msg = Twist()
            vel_msg.linear.x = 0.5
            vel_msg.angular.z = 0.2
            turtle_vel_pub.publish(vel_msg)

        time.sleep(0.1)

# service回调函数，输入参数req,输出参数res
def commandCallback(req):
    global pubCommand
    pubCommand = bool(1 - pubCommand)
    # 显示请求数据
    rospy.loginfo("Publish trutle velocity command![%d]", pubCommand)
    # 设置反馈数据
    return TriggerResponse(1, "Change turtle command state!")


def turtle_command_server():
    # ROS节点初始化
    rospy.init_node('turtle_command_server')
    # 创建一个名为/turtle_command的server，注册回调函数commandCallback
    s = rospy.Service('/turtle_command', Trigger, commandCallback)
    # 循环等待回调函数
    print("Ready to receive turtle command.")

    _thread.start_new_thread(command_thread, ())
    rospy.spin()

if __name__ == "__main__":

    turtle_command_server()

chmod 777 turtle_command_server.py

roscore
rosrun turtlesim turtlesim_node
rosrun learning_service turtle_command_server.py
rosservice call /turtle_command "{}"

rosservice call /turtle_command "{}"

[INFO] [1692498798.819324]: Publish trutle velocity command![1]
[INFO] [1692498830.254050]: Publish trutle velocity command![0]

cd Documents/catkin_ws/src/learning_service

mkdir srv
cd srv

vim Person.srv

string name
uint8 age
uint8 sex

uint8 unknown = 0
uint8 male    = 1
uint8 female  = 2
---
string result

cd ..
vim package.xml

<build_depend>message_generation</build_depend>
<exec_depend>message_runtime</exec_depend>

vim CMakeLists.txt

find_package(catkin REQUIRED COMPONENTS
  geometry_msgs
  roscpp
  rospy
  std_msgs
  turtlesim
  message_generation
)

add_service_files(FILES Person.srv)
generate_messages(DEPENDENCIES std_msgs)

catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES learning_service
   CATKIN_DEPENDS geometry_msgs roscpp rospy std_msge turtlesim message_runtime
#  DEPENDS system_lib
)

cd ../..
catkin_make

// Generated by gencpp from file learning_service/Person.msg
// DO NOT EDIT!


#ifndef LEARNING_SERVICE_MESSAGE_PERSON_H
#define LEARNING_SERVICE_MESSAGE_PERSON_H

#include <ros/service_traits.h>


#include <learning_service/PersonRequest.h>
#include <learning_service/PersonResponse.h>


namespace learning_service
{

struct Person
{

typedef PersonRequest Request;
typedef PersonResponse Response;
Request request;
Response response;

typedef Request RequestType;
typedef Response ResponseType;

}; // struct Person
} // namespace learning_service


namespace ros
{
namespace service_traits
{


template<>
struct MD5Sum< ::learning_service::Person > {
  static const char* value()
  {
    return "c198113e7dd9cc5c9fd5f271c8479b39";
  }

  static const char* value(const ::learning_service::Person&) { return value(); }
};

template<>
struct DataType< ::learning_service::Person > {
  static const char* value()
  {
    return "learning_service/Person";
  }

  static const char* value(const ::learning_service::Person&) { return value(); }
};


// service_traits::MD5Sum< ::learning_service::PersonRequest> should match
// service_traits::MD5Sum< ::learning_service::Person >
template<>
struct MD5Sum< ::learning_service::PersonRequest>
{
  static const char* value()
  {
    return MD5Sum< ::learning_service::Person >::value();
  }
  static const char* value(const ::learning_service::PersonRequest&)
  {
    return value();
  }
};

// service_traits::DataType< ::learning_service::PersonRequest> should match
// service_traits::DataType< ::learning_service::Person >
template<>
struct DataType< ::learning_service::PersonRequest>
{
  static const char* value()
  {
    return DataType< ::learning_service::Person >::value();
  }
  static const char* value(const ::learning_service::PersonRequest&)
  {
    return value();
  }
};

// service_traits::MD5Sum< ::learning_service::PersonResponse> should match
// service_traits::MD5Sum< ::learning_service::Person >
template<>
struct MD5Sum< ::learning_service::PersonResponse>
{
  static const char* value()
  {
    return MD5Sum< ::learning_service::Person >::value();
  }
  static const char* value(const ::learning_service::PersonResponse&)
  {
    return value();
  }
};

// service_traits::DataType< ::learning_service::PersonResponse> should match
// service_traits::DataType< ::learning_service::Person >
template<>
struct DataType< ::learning_service::PersonResponse>
{
  static const char* value()
  {
    return DataType< ::learning_service::Person >::value();
  }
  static const char* value(const ::learning_service::PersonResponse&)
  {
    return value();
  }
};

} // namespace service_traits
} // namespace ros

#endif // LEARNING_SERVICE_MESSAGE_PERSON_H

// Generated by gencpp from file learning_service/PersonRequest.msg
// DO NOT EDIT!


#ifndef LEARNING_SERVICE_MESSAGE_PERSONREQUEST_H
#define LEARNING_SERVICE_MESSAGE_PERSONREQUEST_H


#include <string>
#include <vector>
#include <memory>

#include <ros/types.h>
#include <ros/serialization.h>
#include <ros/builtin_message_traits.h>
#include <ros/message_operations.h>


namespace learning_service
{
template <class ContainerAllocator>
struct PersonRequest_
{
  typedef PersonRequest_<ContainerAllocator> Type;

  PersonRequest_()
    : name()
    , age(0)
    , sex(0)  {
    }
  PersonRequest_(const ContainerAllocator& _alloc)
    : name(_alloc)
    , age(0)
    , sex(0)  {
  (void)_alloc;
    }



   typedef std::basic_string<char, std::char_traits<char>, typename std::allocator_traits<ContainerAllocator>::template rebind_alloc<char>> _name_type;
  _name_type name;

   typedef uint8_t _age_type;
  _age_type age;

   typedef uint8_t _sex_type;
  _sex_type sex;



// reducing the odds to have name collisions with Windows.h 
#if defined(_WIN32) && defined(unknown)
  #undef unknown
#endif
#if defined(_WIN32) && defined(male)
  #undef male
#endif
#if defined(_WIN32) && defined(female)
  #undef female
#endif

  enum {
    unknown = 0u,
    male = 1u,
    female = 2u,
  };


  typedef boost::shared_ptr< ::learning_service::PersonRequest_<ContainerAllocator> > Ptr;
  typedef boost::shared_ptr< ::learning_service::PersonRequest_<ContainerAllocator> const> ConstPtr;

}; // struct PersonRequest_

typedef ::learning_service::PersonRequest_<std::allocator<void> > PersonRequest;

typedef boost::shared_ptr< ::learning_service::PersonRequest > PersonRequestPtr;
typedef boost::shared_ptr< ::learning_service::PersonRequest const> PersonRequestConstPtr;

// constants requiring out of line definition

   

   

   



template<typename ContainerAllocator>
std::ostream& operator<<(std::ostream& s, const ::learning_service::PersonRequest_<ContainerAllocator> & v)
{
ros::message_operations::Printer< ::learning_service::PersonRequest_<ContainerAllocator> >::stream(s, "", v);
return s;
}


template<typename ContainerAllocator1, typename ContainerAllocator2>
bool operator==(const ::learning_service::PersonRequest_<ContainerAllocator1> & lhs, const ::learning_service::PersonRequest_<ContainerAllocator2> & rhs)
{
  return lhs.name == rhs.name &&
    lhs.age == rhs.age &&
    lhs.sex == rhs.sex;
}

template<typename ContainerAllocator1, typename ContainerAllocator2>
bool operator!=(const ::learning_service::PersonRequest_<ContainerAllocator1> & lhs, const ::learning_service::PersonRequest_<ContainerAllocator2> & rhs)
{
  return !(lhs == rhs);
}


} // namespace learning_service

namespace ros
{
namespace message_traits
{





template <class ContainerAllocator>
struct IsMessage< ::learning_service::PersonRequest_<ContainerAllocator> >
  : TrueType
  { };

template <class ContainerAllocator>
struct IsMessage< ::learning_service::PersonRequest_<ContainerAllocator> const>
  : TrueType
  { };

template <class ContainerAllocator>
struct IsFixedSize< ::learning_service::PersonRequest_<ContainerAllocator> >
  : FalseType
  { };

template <class ContainerAllocator>
struct IsFixedSize< ::learning_service::PersonRequest_<ContainerAllocator> const>
  : FalseType
  { };

template <class ContainerAllocator>
struct HasHeader< ::learning_service::PersonRequest_<ContainerAllocator> >
  : FalseType
  { };

template <class ContainerAllocator>
struct HasHeader< ::learning_service::PersonRequest_<ContainerAllocator> const>
  : FalseType
  { };


template<class ContainerAllocator>
struct MD5Sum< ::learning_service::PersonRequest_<ContainerAllocator> >
{
  static const char* value()
  {
    return "b3f7ec37d11629ec3010e27635cf22a9";
  }

  static const char* value(const ::learning_service::PersonRequest_<ContainerAllocator>&) { return value(); }
  static const uint64_t static_value1 = 0xb3f7ec37d11629ecULL;
  static const uint64_t static_value2 = 0x3010e27635cf22a9ULL;
};

template<class ContainerAllocator>
struct DataType< ::learning_service::PersonRequest_<ContainerAllocator> >
{
  static const char* value()
  {
    return "learning_service/PersonRequest";
  }

  static const char* value(const ::learning_service::PersonRequest_<ContainerAllocator>&) { return value(); }
};

template<class ContainerAllocator>
struct Definition< ::learning_service::PersonRequest_<ContainerAllocator> >
{
  static const char* value()
  {
    return "string name\n"
"uint8 age\n"
"uint8 sex\n"
"\n"
"uint8 unknown = 0\n"
"uint8 male    = 1\n"
"uint8 female  = 2\n"
;
  }

  static const char* value(const ::learning_service::PersonRequest_<ContainerAllocator>&) { return value(); }
};

} // namespace message_traits
} // namespace ros

namespace ros
{
namespace serialization
{

  template<class ContainerAllocator> struct Serializer< ::learning_service::PersonRequest_<ContainerAllocator> >
  {
    template<typename Stream, typename T> inline static void allInOne(Stream& stream, T m)
    {
      stream.next(m.name);
      stream.next(m.age);
      stream.next(m.sex);
    }

    ROS_DECLARE_ALLINONE_SERIALIZER
  }; // struct PersonRequest_

} // namespace serialization
} // namespace ros

namespace ros
{
namespace message_operations
{

template<class ContainerAllocator>
struct Printer< ::learning_service::PersonRequest_<ContainerAllocator> >
{
  template<typename Stream> static void stream(Stream& s, const std::string& indent, const ::learning_service::PersonRequest_<ContainerAllocator>& v)
  {
    s << indent << "name: ";
    Printer<std::basic_string<char, std::char_traits<char>, typename std::allocator_traits<ContainerAllocator>::template rebind_alloc<char>>>::stream(s, indent + "  ", v.name);
    s << indent << "age: ";
    Printer<uint8_t>::stream(s, indent + "  ", v.age);
    s << indent << "sex: ";
    Printer<uint8_t>::stream(s, indent + "  ", v.sex);
  }
};

} // namespace message_operations
} // namespace ros

#endif // LEARNING_SERVICE_MESSAGE_PERSONREQUEST_H

// Generated by gencpp from file learning_service/PersonResponse.msg
// DO NOT EDIT!


#ifndef LEARNING_SERVICE_MESSAGE_PERSONRESPONSE_H
#define LEARNING_SERVICE_MESSAGE_PERSONRESPONSE_H


#include <string>
#include <vector>
#include <memory>

#include <ros/types.h>
#include <ros/serialization.h>
#include <ros/builtin_message_traits.h>
#include <ros/message_operations.h>


namespace learning_service
{
template <class ContainerAllocator>
struct PersonResponse_
{
  typedef PersonResponse_<ContainerAllocator> Type;

  PersonResponse_()
    : result()  {
    }
  PersonResponse_(const ContainerAllocator& _alloc)
    : result(_alloc)  {
  (void)_alloc;
    }



   typedef std::basic_string<char, std::char_traits<char>, typename std::allocator_traits<ContainerAllocator>::template rebind_alloc<char>> _result_type;
  _result_type result;





  typedef boost::shared_ptr< ::learning_service::PersonResponse_<ContainerAllocator> > Ptr;
  typedef boost::shared_ptr< ::learning_service::PersonResponse_<ContainerAllocator> const> ConstPtr;

}; // struct PersonResponse_

typedef ::learning_service::PersonResponse_<std::allocator<void> > PersonResponse;

typedef boost::shared_ptr< ::learning_service::PersonResponse > PersonResponsePtr;
typedef boost::shared_ptr< ::learning_service::PersonResponse const> PersonResponseConstPtr;

// constants requiring out of line definition



template<typename ContainerAllocator>
std::ostream& operator<<(std::ostream& s, const ::learning_service::PersonResponse_<ContainerAllocator> & v)
{
ros::message_operations::Printer< ::learning_service::PersonResponse_<ContainerAllocator> >::stream(s, "", v);
return s;
}


template<typename ContainerAllocator1, typename ContainerAllocator2>
bool operator==(const ::learning_service::PersonResponse_<ContainerAllocator1> & lhs, const ::learning_service::PersonResponse_<ContainerAllocator2> & rhs)
{
  return lhs.result == rhs.result;
}

template<typename ContainerAllocator1, typename ContainerAllocator2>
bool operator!=(const ::learning_service::PersonResponse_<ContainerAllocator1> & lhs, const ::learning_service::PersonResponse_<ContainerAllocator2> & rhs)
{
  return !(lhs == rhs);
}


} // namespace learning_service

namespace ros
{
namespace message_traits
{





template <class ContainerAllocator>
struct IsMessage< ::learning_service::PersonResponse_<ContainerAllocator> >
  : TrueType
  { };

template <class ContainerAllocator>
struct IsMessage< ::learning_service::PersonResponse_<ContainerAllocator> const>
  : TrueType
  { };

template <class ContainerAllocator>
struct IsFixedSize< ::learning_service::PersonResponse_<ContainerAllocator> >
  : FalseType
  { };

template <class ContainerAllocator>
struct IsFixedSize< ::learning_service::PersonResponse_<ContainerAllocator> const>
  : FalseType
  { };

template <class ContainerAllocator>
struct HasHeader< ::learning_service::PersonResponse_<ContainerAllocator> >
  : FalseType
  { };

template <class ContainerAllocator>
struct HasHeader< ::learning_service::PersonResponse_<ContainerAllocator> const>
  : FalseType
  { };


template<class ContainerAllocator>
struct MD5Sum< ::learning_service::PersonResponse_<ContainerAllocator> >
{
  static const char* value()
  {
    return "c22f2a1ed8654a0b365f1bb3f7ff2c0f";
  }

  static const char* value(const ::learning_service::PersonResponse_<ContainerAllocator>&) { return value(); }
  static const uint64_t static_value1 = 0xc22f2a1ed8654a0bULL;
  static const uint64_t static_value2 = 0x365f1bb3f7ff2c0fULL;
};

template<class ContainerAllocator>
struct DataType< ::learning_service::PersonResponse_<ContainerAllocator> >
{
  static const char* value()
  {
    return "learning_service/PersonResponse";
  }

  static const char* value(const ::learning_service::PersonResponse_<ContainerAllocator>&) { return value(); }
};

template<class ContainerAllocator>
struct Definition< ::learning_service::PersonResponse_<ContainerAllocator> >
{
  static const char* value()
  {
    return "string result\n"
"\n"
;
  }

  static const char* value(const ::learning_service::PersonResponse_<ContainerAllocator>&) { return value(); }
};

} // namespace message_traits
} // namespace ros

namespace ros
{
namespace serialization
{

  template<class ContainerAllocator> struct Serializer< ::learning_service::PersonResponse_<ContainerAllocator> >
  {
    template<typename Stream, typename T> inline static void allInOne(Stream& stream, T m)
    {
      stream.next(m.result);
    }

    ROS_DECLARE_ALLINONE_SERIALIZER
  }; // struct PersonResponse_

} // namespace serialization
} // namespace ros

namespace ros
{
namespace message_operations
{

template<class ContainerAllocator>
struct Printer< ::learning_service::PersonResponse_<ContainerAllocator> >
{
  template<typename Stream> static void stream(Stream& s, const std::string& indent, const ::learning_service::PersonResponse_<ContainerAllocator>& v)
  {
    s << indent << "result: ";
    Printer<std::basic_string<char, std::char_traits<char>, typename std::allocator_traits<ContainerAllocator>::template rebind_alloc<char>>>::stream(s, indent + "  ", v.result);
  }
};

} // namespace message_operations
} // namespace ros

#endif // LEARNING_SERVICE_MESSAGE_PERSONRESPONSE_H

cd Documents/catkin_ws/src/learning_service/src

vim person_server.cpp

/*
 * 该例程将执行/show_person服务，服务数据类型learning_service::Person
 */

#include <ros/ros.h>
#include "learning_service/Person.h"

using namespace ros;
//service回调函数，输入参数req，输出参数res
bool personCallback(learning_service::Person::Request &req, learning_service::Person::Response &res) {
    //显示请求数据
    ROS_INFO("Person: name:%s  age:%d  sex:%d", req.name.c_str(), req.age, req.sex);
    //设置反馈数据
    res.result = "OK";

    return true;
}

int main(int argc, char **argv) {
    //ROS节点初始化
    init(argc, argv, "person_server");
    //创建节点句柄
    NodeHandle n;
    //创建一个名为/show_person的server，注册回调函数personCallback
    ServiceServer person_service = n.advertiseService("/show_person", personCallback);
    //循环等待回调函数
    ROS_INFO("Ready to show person informtion");
    spin();

    return 0;
}

vim person_client.cpp

/*
 * 该例程将请求/show_person服务，服务数据类型learning_service::Person
 */

#include <ros/ros.h>
#include "learning_service/Person.h"

using namespace ros;

int main(int argc, char **argv) {
    //初始化ROS节点
    init(argc, argv, "person_client");
    //创建节点句柄
    NodeHandle node;
    //发现/show_person服务后，创建一个服务客户端，连接名为/show_person的service
    service::waitForService("/show_person");
    ServiceClient person_client = node.serviceClient<learning_service::Person>("/show_person");
    //初始化learning_service::Person的请求数据
    learning_service::Person srv;
    srv.request.name = "Tom";
    srv.request.age = 20;
    srv.request.sex = learning_service::Person::Request::male;
    //请求服务调用
    ROS_INFO("Call service to show person[name:%s, age:%d, sex:%d]", srv.request.name.c_str(), srv.request.age, srv.request.sex);

    person_client.call(srv);
    //显示服务调用结果
    ROS_INFO("Show person result: %s", srv.response.result.c_str());

    return 0;
}

cd ..
vim CMakelists.txt

add_executable(person_server src/person_server.cpp)
target_link_libraries(person_server ${catkin_LIBRARIES})
add_dependencies(person_server ${PROJECT_NAME}_gencpp)

add_executable(person_client src/person_client.cpp)
target_link_libraries(person_client ${catkin_LIBRARIES})
add_dependencies(person_client ${PROJECT_NAME}_gencpp)

cd ../..
catkin_make

roscore
rosrun learning_service person_client
rosrun learning_service person_server

[ INFO] [1692650896.468258699]: waitForService: Service [/show_person] has not been advertised, waiting...
[ INFO] [1692650916.053619203]: waitForService: Service [/show_person] is now available.
[ INFO] [1692650916.053701403]: Call service to show person[name:Tom, age:20, sex:1]
[ INFO] [1692650916.055466855]: Show person result: OK

[ INFO] [1692650916.045710322]: Ready to show person informtion
[ INFO] [1692650916.055297356]: Person: name:Tom  age:20  sex:1

cd Documents/catkin_ws/src/learning_service/scripts

vim person_server.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程将执行/show_person服务，服务数据类型learning_service::Person

import rospy
from learning_service.srv import Person, PersonResponse

# service回调函数，输入参数req，输出参数res
def personCallback(req):
    # 显示请求数据
    rospy.loginfo("Person: name:%s  age:%d   sex:%d", req.name, req.age, req.sex)
    # 设置反馈数据
    return PersonResponse("OK")

def person_server():
    # ROS节点初始化
    rospy.init_node('person_server')
    # 创建一个名为/show_person的server，注册回调函数personCallback
    s = rospy.Service('/show_person', Person, personCallback)
    # 循环等待回调函数
    print("Ready to show person informtion")
    rospy.spin()

if __name__ == "__main__":

    person_server()

vim person_client.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程将请求/show_person服务，服务数据类型learning_service::Person

import sys
import rospy
from learning_service.srv import Person, PersonRequest

def person_client():
    # 初始化ROS节点
    rospy.init_node('person_client')
    # 发现/show_person服务后，创建一个服务客户端，连接名为/show_person的service
    rospy.wait_for_service('/show_person')
    try:
        person_client = rospy.ServiceProxy('/show_person', Person)
        # 请求服务调用，输入请求数据
        response = person_client("Tom", 20, PersonRequest.male)
        return response.result
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

if __name__ == "__main__":
    # 显示服务调用结果
    print("Show person result : %s" %(person_client()))

chmod 777 person_server.py 
chmod 777 person_client.py

roscore
rosrun learning_service person_client.py
rosrun learning_service person_server.py

roscore
rosrun turtlesim turtlesim_node

rosparam

rosparam is a command-line tool for getting, setting, and deleting parameters from the ROS Parameter Server.

Commands:
	rosparam set	set parameter
	rosparam get	get parameter
	rosparam load	load parameters from file
	rosparam dump	dump parameters to file
	rosparam delete	delete parameter
	rosparam list	list parameter names

rosparam list

/rosdistro
/roslaunch/uris/host_guanjian_x99__40731
/rosversion
/run_id
/turtlesim/background_b
/turtlesim/background_g
/turtlesim/background_r

/turtlesim/background_b
/turtlesim/background_g
/turtlesim/background_r

/rosdistro
/roslaunch/uris/host_guanjian_x99__40731
/rosversion
/run_id

rosparam get /turtlesim/background_b

255

rosparam get /turtlesim/background_g

86

rosparam get /turtlesim/background_r

69

rosparam get /rosdistro

'noetic

  '

rosparam get /rosversion

'1.16.0

  '

rosparam set /turtlesim/background_b 100

rosservice call /clear "{}"

rosparam dump param.yaml

rosdistro: 'noetic

  '
roslaunch:
  uris:
    host_guanjian_x99__40731: http://guanjian-X99:40731/
rosversion: '1.16.0

  '
run_id: b1762296-4477-11ee-98d0-8defeaece2a0
turtlesim:
  background_b: 100
  background_g: 86
  background_r: 69

rosdistro: 'noetic

  '
roslaunch:
  uris:
    host_guanjian_x99__40731: http://guanjian-X99:40731/
rosversion: '1.16.0

  '
run_id: b1762296-4477-11ee-98d0-8defeaece2a0
turtlesim:
  background_b: 0
  background_g: 0
  background_r: 0

rosparam load param.yaml

rosservice call /clear "{}"

rosparam delete /turtlesim/background_g

rosparam list

/rosdistro
/roslaunch/uris/host_guanjian_x99__40731
/rosversion
/run_id
/turtlesim/background_b
/turtlesim/background_r

rosservice call /clear "{}"

cd Documents/catkin_ws/src

catkin_create_pkg learning_parameter roscpp rospy std_srvs

cd learning_parameter/src

vim parameter_config.cpp

/*
 * 该例程设置/读取小海龟例程中的参数
 */

#include <string>
#include <ros/ros.h>
#include <std_srvs/Empty.h>

using namespace ros;

int main(int argc, char **argv) {
    int red, green, blue;
    //ROS节点初始化
    init(argc, argv, "parameter_config");
    //创建节点句柄
    NodeHandle node;
    //读取背景颜色参数
    param::get("/turtlesim/background_r", red);
    param::get("/turtlesim/background_g", green);
    param::get("/turtlesim/background_b", blue);

    ROS_INFO("Get Background Color[%d, %d, %d]", red, green, blue);
    //设置背景颜色参数
    param::set("/turtlesim/background_r", 255);
    param::set("/turtlesim/background_g", 255);
    param::set("/turtlesim/background_b", 255);

    ROS_INFO("Set Background Color[255, 255, 255]");
    //读取背景颜色参数
    param::get("/turtlesim/background_r", red);
    param::get("/turtlesim/background_g", green);
    param::get("/turtlesim/background_b", blue);

    ROS_INFO("Re-get Background Color[%d, %d, %d]", red, green, blue);
    //调用服务，刷新背景颜色
    service::waitForService("/clear");
    ServiceClient clear_background = node.serviceClient<std_srvs::Empty>("/clear");
    std_srvs::Empty srv;
    clear_background.call(srv);

    sleep(1);

    return 0;
}

cd ..
vim CMakelists.txt

add_executable(parameter_config src/parameter_config.cpp)
target_link_libraries(parameter_config ${catkin_LIBRARIES})

cd ../..
catkin_make

roscore
rosrun turtlesim turtlesim_node
rosrun learning_parameter parameter_config

[ INFO] [1693175924.083145386]: Get Background Color[69, 86, 255]
[ INFO] [1693175924.086266645]: Set Background Color[255, 255, 255]
[ INFO] [1693175924.087441186]: Re-get Background Color[255, 255, 255]

cd Documents/catkin_ws/src/learning_parameter
mkdir scripts
cd scripts

vim parameter_config.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程设置/读取小海龟例程中的参数

import sys
import rospy
from std_srvs.srv import Empty

def parameter_config():
    # ROS节点初始化
    rospy.init_node('parameter_config', anonymous=True)
    # 读取背景颜色参数
    red = rospy.get_param('/turtlesim/background_r')
    green = rospy.get_param('/turtlesim/background_g')
    blue = rospy.get_param('/turtlesim/background_b')

    rospy.loginfo("Get Backgroud Color[%d, %d, %d]", red, green, blue)
    # 设置背景颜色参数
    rospy.set_param("/turtlesim/background_r", 255)
    rospy.set_param("/turtlesim/background_g", 255)
    rospy.set_param("/turtlesim/background_b", 255)
    # 读取背景颜色参数
    red = rospy.get_param('/turtlesim/background_r')
    green = rospy.get_param('/turtlesim/background_g')
    blue = rospy.get_param('/turtlesim/background_b')

    rospy.loginfo("Get Backgroud Color[%d, %d, %d]", red, green, blue)
    # 调用服务，刷新背景颜色
    rospy.wait_for_service('/clear')
    try:
        clear_background = rospy.ServiceProxy('/clear', Empty)

        response = clear_background()
        return response
    except rospy.ServiceException as e:
        print("Service call failed: %s"%e)

if __name__ == "__main__":

    parameter_config()

chmod 777 parameter_config.py

roscore
rosrun turtlesim turtlesim_node
rosrun learning_parameter parameter_config.py

sudo apt-get install ros-noetic-turtle-tf

sudo apt-get install ros-melodic-turtle-tf

conda activate py39
pip install numpy

roslaunch turtle_tf turtle_tf_demo.launch

rosrun turtlesim turtle_teleop_key

conda activate py39
rosrun tf view_frames

TypeError: cannot use a string pattern on a bytes-like object

sudo vim /opt/ros/noetic/lib/tf/view_frames

vstr = subprocess.Popen(args, stdout=subprocess.PIPE, stderr=subprocess.PIPE).communicate()[1]
vstr = str(vstr)

sudo chown user:user /opt/ros/noetic/lib/tf
sudo chown user:user /opt/ros/noetic/lib/tf/view_frames

rosrun tf view_frames

frames.gv
frames.pdf

rosrun tf tf_echo turtle1 turtle2

At time 1693616316.041
- Translation: [-0.909, 1.462, 0.000]
- Rotation: in Quaternion [0.000, 0.000, -0.548, 0.837]
            in RPY (radian) [0.000, -0.000, -1.160]
            in RPY (degree) [0.000, -0.000, -66.444]
At time 1693616317.049
- Translation: [-2.223, 0.791, 0.000]
- Rotation: in Quaternion [0.000, 0.000, -0.225, 0.974]
            in RPY (radian) [0.000, 0.000, -0.454]
            in RPY (degree) [0.000, 0.000, -25.995]
At time 1693616318.041
- Translation: [-1.314, 1.677, 0.000]
- Rotation: in Quaternion [0.000, 0.000, -0.496, 0.868]
            in RPY (radian) [0.000, 0.000, -1.038]
            in RPY (degree) [0.000, 0.000, -59.484]
At time 1693616319.049
- Translation: [-2.085, 0.923, 0.000]
- Rotation: in Quaternion [0.000, 0.000, -0.232, 0.973]
            in RPY (radian) [0.000, 0.000, -0.469]
            in RPY (degree) [0.000, 0.000, -26.852]
At time 1693616320.041
- Translation: [-1.256, 0.547, 0.000]
- Rotation: in Quaternion [0.000, 0.000, -0.204, 0.979]
            in RPY (radian) [0.000, 0.000, -0.412]
            in RPY (degree) [0.000, 0.000, -23.582]
At time 1693616321.049
- Translation: [-0.749, 0.326, 0.000]
- Rotation: in Quaternion [0.000, 0.000, -0.204, 0.979]
            in RPY (radian) [0.000, 0.000, -0.411]
            in RPY (degree) [0.000, 0.000, -23.544]

rosrun rviz rviz -d `rospack find turtle_tf`/rviz/turtle_rviz.rviz

cd Documents/catkin_ws/src

catkin_create_pkg learning_tf roscpp rospy tf turtlesim

cd learning_tf/src

vim turtle_tf_broadcaster.cpp

/*
 * 该例程产生tf数据，并计算、发布turtle2的速度指令
 */

#include <ros/ros.h>
#include <tf/transform_broadcaster.h>
#include <turtlesim/Pose.h>
#include <string>

using namespace ros;
using namespace std;

string turtle_name;

void poseCallback(const turtlesim::PoseConstPtr& msg) {
    //创建tf的广播器
    static tf::TransformBroadcaster br;
    //初始化tf数据
    //transform是坐标变换矩阵
    tf::Transform transform;
    //坐标平移，turtle1相对于world的，围绕x,y,z坐标轴的平移变换
    transform.setOrigin(tf::Vector3(msg->x, msg->y, 0.0));
    //四元数
    tf::Quaternion q;
    //坐标旋转，turtle1相对于world的，围绕x,y,z坐标轴的旋转变换
    q.setRPY(0, 0, msg->theta);
    transform.setRotation(q);
    //广播world与海龟坐标系turtle1之间的tf数据
    //后台的tf树会将广播的数据插入进去
    br.sendTransform(tf::StampedTransform(transform, Time::now(), "world", turtle_name));
}

int main(int argc, char** argv) {
    //初始化ROS节点
    init(argc, argv, "my_tf_broadcaster");
    //输入参数作为海龟的名字
    if (argc != 2) {
	ROS_ERROR("need turtle name as argument");
	return -1;
    }
    turtle_name = argv[1];
    //订阅海龟的位姿话题
    NodeHandle node;
    Subscriber sub = node.subscribe(turtle_name + "/pose", 10, &poseCallback);
    //循环等待回调函数
    spin();

    return 0;
}

vim turtle_tf_listener.cpp

/*
 * 该例程监听tf数据，并计算、发布turtle2的速度指令
 */

#include <ros/ros.h>
#include <tf/transform_listener.h>
#include <geometry_msgs/Twist.h>
#include <turtlesim/Spawn.h>

using namespace ros;

int main(int argc, char** argv) {
    //初始化ROS节点
    init(argc, argv, "my_tf_listener");
    //创建节点句柄
    NodeHandle node;
    //请求产生新海龟turtle2
    service::waitForService("/spawn");
    ServiceClient add_turtle = node.serviceClient<turtlesim::Spawn>("/spawn");
    turtlesim::Spawn srv;
    add_turtle.call(srv);
    //创建发布turtle2速度控制指令的发布者，让新海龟动起来
    Publisher turtle_vel = node.advertise<geometry_msgs::Twist>("/turtle2/cmd_vel", 10);
    //创建tf的监听器
    tf::TransformListener listener;

    Rate rate(10.0);
    while(node.ok()) {
        //获取turtle1与turtle2坐标系之间的tf数据
	tf::StampedTransform transform;
	try {
            //等待变换，系统中是否存在turtle1和turtle2两个坐标系，等待3秒
	    listener.waitForTransform("/turtle2", "/turtle1", Time(0), Duration(3.0));
            //查询变换，如果存在查询两个坐标系的关系，查询结果保存在transform中
	    listener.lookupTransform("/turtle2", "/turtle1", Time(0), transform);
	} catch (tf::TransformException &ex) {
	    ROS_ERROR("%s", ex.what());
	    Duration(1.0).sleep();
	    continue;
	}
        //根据turtle1与turtle2坐标系之间的位置关系，发布turtle2的速度控制指令，让海龟2向海龟1做移动
	geometry_msgs::Twist vel_msg;
        //角速度
	vel_msg.angular.z = 4.0 * atan2(transform.getOrigin().y(), transform.getOrigin().x());
        //线速度
	vel_msg.linear.x = 0.5 * sqrt(pow(transform.getOrigin().x(), 2) + pow(transform.getOrigin().y(), 2));
	turtle_vel.publish(vel_msg);

	rate.sleep();
    }
    return 0;
}

cd ..
vim CMakelists.txt

add_executable(turtle_tf_broadcaster src/turtle_tf_broadcaster.cpp)
target_link_libraries(turtle_tf_broadcaster ${catkin_LIBRARIES})

add_executable(turtle_tf_listener src/turtle_tf_listener.cpp)
target_link_libraries(turtle_tf_listener ${catkin_LIBRARIES})

cd ../..
catkin_make

roscore
rosrun turtlesim turtlesim_node
rosrun learning_tf turtle_tf_broadcaster __name:=turtle1_tf_broadcaster /turtle1
rosrun learning_tf turtle_tf_broadcaster __name:=turtle2_tf_broadcaster /turtle2
rosrun learning_tf turtle_tf_listener
rosrun turtlesim turtle_teleop_key

cd Documents/catkin_ws/src/learning_tf

mkdir scripts
cd scripts

vim turtle_tf_broadcaster.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程产生tf数据，并计算、发布turtle2的速度指令

import roslib
roslib.load_manifest('learning_tf')
import rospy
import tf
import turtlesim.msg
import sys

def handle_turtle_pose(msg, turtlename):
    # 创建tf的广播器
    br = tf.TransformBroadcaster()
    # 广播world与海龟坐标系turtle1之间的tf数据
    br.sendTransform((msg.x, msg.y, 0), tf.transformations.quaternion_from_euler(0, 0, msg.theta), rospy.Time.now(), turtlename, "world")

if __name__ == '__main__':
    # 初始化ROS节点
    rospy.init_node(sys.argv[1])
    # 输入参数作为海龟的名字
    turtlename = sys.argv[2]
    # 订阅海龟的位姿话题
    rospy.Subscriber('/%s/pose' % turtlename, turtlesim.msg.Pose, handle_turtle_pose, turtlename)
    # 循环等待回调函数
    rospy.spin()

vim turtle_tf_listener.py

#!/home/user/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-
# 该例程监听tf数据，并计算、发布turtle2的速度指令

import roslib
roslib.load_manifest('learning_tf')
import rospy
import math
import tf
import geometry_msgs.msg
import turtlesim.srv

if __name__ == '__main__':
    # 初始化ROS节点
    rospy.init_node('turtle_tf_listener')
    # 创建tf的监听器
    listener = tf.TransformListener()
    # 请求产生新海龟turtle2
    rospy.wait_for_service('/spawn')
    spawner = rospy.ServiceProxy('/spawn', turtlesim.srv.Spawn)
    spawner(4, 2, 0, 'turtle2')
    # 创建发布turtle2速度控制指令的发布者，让新海龟动起来
    turtle_vel = rospy.Publisher('turtle2/cmd_vel', geometry_msgs.msg.Twist, queue_size=1)

    rate = rospy.Rate(10.0)
    while not rospy.is_shutdown():
        try:
            # 查询变换，如果存在查询两个坐标系的关系，查询结果保存在trans中
            trans, rot = listener.lookupTransform('/turtle2', '/turtle1', rospy.Time(0))
        except (tf.LookupException, tf.ConnectivityException, tf.ExtrapolationException):
            continue
        # 根据turtle1与turtle2坐标系之间的位置关系，发布turtle2的速度控制指令，让海龟2向海龟1做移动
        angular = 4 * math.atan2(trans[1], trans[0])
        linear = 0.5 * math.sqrt(trans[0]**2 + trans[1]**2)
        cmd = geometry_msgs.msg.Twist()
        cmd.linear.x = linear
        cmd.angular.z = angular
        turtle_vel.publish(cmd)

        rate.sleep()

chmod 777 turtle_tf_broadcaster.py
chmod 777 turtle_tf_listener.py

roscore
rosrun turtlesim turtlesim_node
rosrun learning_tf turtle_tf_broadcaster.py turtle1_tf_broadcaster turtle1
rosrun learning_tf turtle_tf_broadcaster.py turtle2_tf_broadcaster turtle2
rosrun learning_tf turtle_tf_listener.py
rosrun turtlesim turtle_teleop_key

<launch>
    <node pkg="turtlesim" name="sim1" type="turtlesim_node" />
    <node pkg="turtlesim" name="sim2" type="turtlesim_node" />
</launch>

<param name="output_frame" value="odom" />

<rosparam file="params.yaml" command="load" ns="params" />

<arg name="arg-name" default="arg-value" />

<param name="foo" value="$(arg arg-name)" />
<node name="node" pkg="package" type="type" args="$(arg arg-name)" />

<remap from="/turtlebot/cmd_vel" to="/cmd_vel" />

<include file="$(dirname)/other.launch" />

cd Documents/catkin_ws/src

catkin_create_pkg learning_launch

cd learning_launch
mkdir launch
cd launch

vim simple.launch

<launch>
    <node pkg="learning_topic" type="person_subscriber" name="talker" output="screen" />
    <node pkg="learning_topic" type="person_publisher" name="listener" output="screen" />
</launch>

cd ../../..
catkin_make

roslaunch learning_launch simple.launch

... logging to /home/guanjian/.ros/log/8f043736-4a15-11ee-94ed-eb1c4a5ce82f/roslaunch-guanjian-X99-4414.log
Checking log directory for disk usage. This may take a while.
Press Ctrl-C to interrupt
Done checking log file disk usage. Usage is <1GB.

started roslaunch server http://guanjian-X99:43073/

SUMMARY
========

PARAMETERS
 * /rosdistro: noetic
 * /rosversion: 1.16.0

NODES
  /
    listener (learning_topic/person_publisher)
    talker (learning_topic/person_subscriber)

auto-starting new master
process[master]: started with pid [4426]
ROS_MASTER_URI=http://localhost:11311

setting /run_id to 8f043736-4a15-11ee-94ed-eb1c4a5ce82f
process[rosout-1]: started with pid [4436]
started core service [/rosout]
process[talker-2]: started with pid [4439]
process[listener-3]: started with pid [4440]
[ INFO] [1693716695.734350100]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1693716696.734435776]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1693716696.734844895]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1693716697.734414495]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1693716697.734667411]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1693716698.734408905]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1693716698.734658015]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1693716699.734416177]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1693716699.734658584]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1693716700.734417712]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1693716700.734663411]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1693716701.734412627]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1693716701.734663706]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1693716702.734420615]: Publish Person Info: name:Tom age:18 sex:1
[ INFO] [1693716702.734660215]: Subcribe Person Info: name:Tom age:18 sex:1
[ INFO] [1693716703.734366533]: Publish Person Info: name:Tom age:18 sex:1

cd src/learning_launch/launch
vim turtlesim_parameter_config.launch

<launch>
    <param name="/turtle_number" value="2" />

    <node pkg="turtlesim" type="turtlesim_node" name="turtlesim_node">
        <param name="turtle_name1" value="Tom" />
        <param name="trutle_name2" value="Jerry" />

        <rosparam file="$(find learning_launch)/config/param.yaml" command="load" />
    </node>

    <node pkg="turtlesim" type="turtle_teleop_key" name="turtle_teleop_key" output="screen" />
</launch>

cd ..
mkdir config
cd config
vim param.yaml

A: 123
B: "hello"

group:
        C: 456
        D: "hello"

roslaunch learning_launch turtlesim_parameter_config.launch

rosparam list

/rosdistro
/roslaunch/uris/host_guanjian_x99__37297
/rosversion
/run_id
/turtle_number
/turtlesim_node/A
/turtlesim_node/B
/turtlesim_node/background_b
/turtlesim_node/background_g
/turtlesim_node/background_r
/turtlesim_node/group/C
/turtlesim_node/group/D
/turtlesim_node/trutle_name2
/turtlesim_node/turtle_name1

rosparam get /turtle_number

2

rosparam get /turtlesim_node/turtle_name1

Tom

rosparam get /turtlesim_node/A

123

rosparam get /turtlesim_node/B

hello

rosparam get /turtlesim_node/group/C

456

vim start_tf_demo_c++.launch

<launch>
    <!-- Turlesim Node-->
    <node pkg="turtlesim" type="turtlesim_node" name="sim" />
    <node pkg="turtlesim" type="turtle_teleop_key" name="teleop" output="screen" />

    <node pkg="learning_tf" type="turtle_tf_broadcaster" args="/turtle1" name="turtle1_tf_broadcaster" />
    <node pkg="learning_tf" type="turtle_tf_broadcaster" args="/turtle2" name="turtle2_tf_broadcaster" />

    <node pkg="learning_tf" type="turtle_tf_listener" name="listener" />
</launch>

roslaunch learning_launch start_tf_demo_c++.launch

vim start_tf_demo_py.launch

<launch>
    <!-- Turtlesim Node-->
    <node pkg="turtlesim" type="turtlesim_node" name="sim" />
    <node pkg="turtlesim" type="turtle_teleop_key" name="teleop" output="screen" />

    <node name="turtle1_tf_broadcaster" pkg="learning_tf" type="turtle_tf_broadcaster.py">
        <param name="turtle" type="string" value="turtle1" />
    </node>
    <node name="turtle2_tf_broadcaster" pkg="learning_tf" type="turtle_tf_broadcaster.py">
        <param name="turtle" type="string" value="turtle2" />
    </node>

    <node pkg="learning_tf" type="turtle_tf_listener.py" name="listener" />
</launch>

cd Documents/catkin_ws/src/learning_tf/scripts
vim turtle_tf_broadcaster.py

#!/home/guanjian/anaconda3/envs/py39/bin/python
# -*- coding: utf-8 -*-

import roslib
roslib.load_manifest('learning_tf')
import rospy
import tf
import turtlesim.msg

def handle_turtle_pose(msg, turtlename):
    br = tf.TransformBroadcaster()
    br.sendTransform((msg.x, msg.y, 0), tf.transformations.quaternion_from_euler(0, 0, msg.theta), rospy.Time.now(), turtlename, "world")

if __name__ == '__main__':

    rospy.init_node('turtle_tf_broadcaster')
    turtlename = rospy.get_param('~turtle')
    rospy.Subscriber('/%s/pose' % turtlename, turtlesim.msg.Pose, handle_turtle_pose, turtlename)
    rospy.spin()

roslaunch learning_launch start_tf_demo_py.launch

roscore
rosrun turtlesim turtlesim_node
rosrun turtlesim turtle_teleop_key

rqt_console

[ WARN] [1693830491.863016173]: Oh no! I hit the wall! (Clamping from [x=5.655495, y=-0.030404])

rqt_plot

rqt_image_view

rqt

rosrun rviz rviz

sudo apt-get install ros-noetic-simulators

sudo apt-get install ros-melodic-simulators

roslaunch gazebo_ros willowgarage_world.launch