话题模型
发布者
实现发布者
初始化ROS节点
ros::init(argc,argv, 名称)
向ROS Master注册节点信息，包括发布的话题名和话题中消息类型
ros::Publisher publisher = n.advertise<消息类型>(话题名, 消息队列 10);
按照一定频率循环发布消息
xx.publish(消息)；
C++代码编辑编辑完成后
配置CMakeLists.txt
add_executable(可执行文件名 src/xxx.cpp) 设置编译的代码和生成可执行文件
target_link_libraries(可执行文件名 ${catkin_LIBRARIES}) 设置链接库
编译
catkin_make
设置环境变量
source devel/setup.bash
运行
roscore
rosrun turtlesim turtlesim_node
rosrun 功能包名 节点名(即上方可执行文件名)
C++实现发布者
注意：运行前需要先编译、设置环境变量和运行
***直接输入rosrun 功能包名 节点执行名方式
gedit ~/.bashrc
在.bashrc文件的最下方，输入source ~/catkin_ws/devel/setup.bash
重启终端，运行rosrun ...
velocity_publisher.cpp
// 构建发布者，发布话题turtle1/cmd_vel，消息类型为geometry_msgs::Twist#include <ros/ros.h>
#include <geometry_msgs/Twist.h>/*** 初始化ROS节点* 向ROS Master注册节点信息，包括发布的话题名和话题的消息类型* 创建消息数据* 按照一定频率循环发布消息
*/int main(int argc, char**argv)
{// ROS初始化节点ros::init(argc, argv, "velocity_publisher");// 创建节点句柄ros::NodeHandle n;// 创建Publisher，发布topic为/turtle1/cmd_vel，消息类型为geometry_msgs::Twist，队列长度为10ros::Publisher turtle_vel_pub = n.advertise<geometry_msgs::Twist>("/turtle1/cmd_vel", 10);// 设置循环频率ros::Rate loop_rate(10);int count = 0;while(ros::ok){// 初始化geometry_msgs::Twist类型的消息geometry_msgs::Twist vel_msg;// 线速度为0.5vel_msg.linear.x = 0.5;// 沿z轴的角速度为0.2vel_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;
}
python实现发布者
注意***：需要检查python文件属性是否是可执行
安装python3
sudo apt-get install python3
通过软连接，将python链接到python3，链接一次即可
sudo ln -s /usr/bin/python3 /usr/bin/python
chmod 更改或分配文件和目录的权限 +为增加权限
定位到workspace/src/功能包/scripts/
chmod +x xxx.py
python脚本上方添加
#!/usr/bin/env python3
# -*- coding:utf-8 -*-
velocity_publisher.py
#!/usr/bin/env python3
# -*- coding:utf-8 -*-import rospy
from geometry_msgs.msg import Twistdef velocity_publisher():print("查看是否启动")# ROS节点初始化rospy.init_node('velocity_publisher', anonymous=True)# 创建Publisher，发布topic /turtle1/cmd_vel，消息类型为geometry_msg::Twist，队列长度为10turtle_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(): // ***注意此有()# 初始化geometry_msgs::Twist类型的消息vel_msg = Twist()vel_msg.linear.x = 0.5vel_msg.angular.z = 0.3# 发布消息turtle_vel_pub.publish(vel_msg)rospy.loginfo("Publisher 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:print("发布出现问题，中断错误")
订阅者
初始化ROS节点
创建订阅者，订阅话题，注册回调函数
循环等待回调函数
回调函数在接收到订阅消息后执行
C++实现订阅者
pose_subscriber.cpp
/*
订阅/turtle1/pose话题，消息类型为turtlesim::pose
*/#include <ros/ros.h>
#include "turtlesim/Pose.h"// 接收到订阅消息，进入消息回调函数
void poseCallback(const turtlesim::Pose::ConstPtr & msg)
{// 打印消息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ros::init(argc, argv, "pose_subscriber");// 创建节点句柄ros::NodeHandle n;// 创建subscriber，订阅topic /turtle1/pose，注册回调函数ros::Subscriber pose_sub = n.subscribe("/turtle1/pose", 10, poseCallback);// 循环等待回调函数ros::spin();return 0;
}
python实现订阅者
pose_subscriber.py
#!/usr/bin/env python3
# -*- coding:utf-8 -*-import rospy
from turtlesim.msg import Posedef pose_Callback(msg):rospy.loginfo("Turtle pose: x: %0.6f, y: %0.6f", msg.x, msg.y)def pose_subscribe():# 初始化ROS节点rospy.init_node('pose_subscriber', anonymous=True)# 定义发布者rospy.Subscriber("/turtle1/pose", Pose, pose_Callback)# 循环等待回调函数rospy.spin()if __name__ == '__main__':pose_subscribe()自定义话题发布者和订阅者
步骤：
1、定义msg文件
2、package.xml中添加功能包依赖
3、在CMakeList.txt中添加编译选项
find_package(catkin REQUIRED roscpp rospy std_msgs geometry_msgs message_generation)
add_message_files(FILES Person.msg)
generate_message(DEPENDENCIES std_msgs geometry_msgs)
catkin_package(... CATKIN_DEPENDS message_runtime geometry_msgs roscpp rospy std_msgs)
include_directories(include ${catkin_INCLUDE_DIRS})
在package.xml中添加
<buildtool_depend>catkin</buildtool_depend>
<build_depend>geometry_msgs</build_depend>
<build_depend>roscpp</build_depend>
<build_depend>rospy</build_depend>
<build_depend>std_msgs</build_depend>
<build_depend>message_generation</build_depend>
<build_depend>message_runtime</build_depend><build_export_depend>geometry_msgs</build_export_depend>
<build_export_depend>roscpp</build_export_depend>
<build_export_depend>rospy</build_export_depend>
<build_export_depend>std_msgs</build_export_depend>
<build_export_depend>message_generation</build_export_depend>
<build_export_depend>message_runtime</build_export_depend><exec_depend>geometry_msgs</exec_depend>
<exec_depend>roscpp</exec_depend>
<exec_depend>rospy</exec_depend>
<exec_depend>std_msgs</exec_depend>
<exec_depend>message_generation</exec_depend>
<exec_depend>message_runtime</exec_depend>4、编译 catkin_make
5、创建自定义话题发布者、订阅者代码
CMakeList.txt中
add_execte(执行节点名 xxx.cpp)
target_link_liberaries(执行节点名 ${catkin_LIBRARIES})
add_dependencies(执行节点名 ${PROJECT_NAME}_generate_messages_cpp})
6、编译 catkin_make
创建msg文件
touch Person.msg
注意：如果没有引入Person.h头文件，则需要在VSCode的C/C++编辑中，增加xxx/catkin_ws/**
Person_Publisher.cpp
#include <ros/ros.h>
#include "learning_topic/Person.h"int main(int argc, char**argv)
{// 初始化节点ros::init(argc, argv, "person_publisher");// 创建节点句柄ros::NodeHandle n;// 创建发布者，发布topic名为person_info，类型为Person，队列长度为10ros::Publisher person_info_pub = n.advertise<learning_topic::Person>("/person_info", 10);// 设置循环频率ros::Rate loop_rate(10);int count = 0;while (ros::ok){// 初始化learning_topic::Person类型消息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;
}
Person_subscriber.cpp
#include <ros/ros.h>
#include "learning_topic/Person.h"void personInfoCallBack(const learning_topic::Person::ConstPtr& msg)
{// 接收订阅消息后进入回调函数，打印接收到的消息ROS_INFO("Subscribe 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ros::init(argc, argv, "person_subscriber");// 构建节点句柄ros::NodeHandle n;// 构建订阅者，订阅topic为/person_info，消息队列为10ros::Subscriber person_info_sub = n.subscribe("/person_info", 10, personInfoCallBack);// 循环等待回调函数ros::spin();return 0;
}
python代码
#!/usr/bin/env python3
# -*- coding:utf-8 -*-import rospy
from learning_topic.msg import Persondef info_publisher():# 初始化ROS节点rospy.init_node('person_publisher', anonymous=True)# 构建Publisher，topic为 /person_info，类型为Person，队列大小为10person_info_pub = rospy.Publisher("/person_info", Person, queue_size=10)# 设置循环频率rate = rospy.Rate(10)while not rospy.is_shutdown():# 初始化learning_topic功能包中Person类型消息person_msg = Person()person_msg.name = 'Tom'person_msg.age = 10person_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:info_publisher()except rospy.ROSInterruptException:print("执行错误，中断运行")
#!/usr/bin/env python3
# -*- coding:utf-8 -*-import rospy
from learning_topic.msg import Persondef personInfoCallBack(msg):# 收到消息，显示数据rospy.loginfo("Person subscribe get name:%s age:%d sex:%d]", msg.name, msg.age, msg.sex)def person_subscribe():# 初始化节点rospy.init_node('person_subscriber', anonymous=True)# 构建订阅者，订阅topic /person_info，消息类型为Personrospy.Subscriber("/person_info", Person, personInfoCallBack)# 循环等待回调函数rospy.spin()if __name__ == '__main__':person_subscribe()
)
的含义)
)
 】： 全面概述)
