ROS实践06 自定义消息类型

运行环境：

ubuntu20.04 noetic
宏基暗影骑士笔记本

思路：

定义.msg文件
修改package.xml和CMakeLists.txt文件

编译后修改includePath
创建功能包
在功能包src下新建.cpp文件

1.1 定义.msg文件

1)功能包下新建 msg 目录，添加文件 Person.msg

string name
uint16 age
float64 height

package.xml --功能包清单文件
CMakeLists.txt --CMake 配置文件

2)修改package.xml

# 编译依赖与执行依赖
 <build_depend>message_generation</build_depend>
 <exec_depend>message_runtime</exec_depend>

3)修改CMakeLists.txt

编译依赖、运行依赖、引入msg、依赖std_msg

# 编译依赖
find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  std_msgs
  message_generation
)

#运行依赖
catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES demo02_talker_listener
  CATKIN_DEPENDS roscpp rospy std_msgs message_runtime
#  DEPENDS system_lib
)

# 将.msg 引入功能包
add_message_files(
  FILES
  Person.msg
)

# generate_messages 依赖于 std_msgs
generate_messages(
  DEPENDENCIES
  std_msgs
)

2.1 自定义消息调用(C++)

1）编译后修改includePath

"/home/duduzai/demo01_ws/devel/include/**"

Person.msg编译后自动生成Person.h

2）发布方实现

在功能包src中新建person_pub.cpp文件

/*
    需求: 循环发布人的信息

*/

#include "ros/ros.h"
#include "demo01_pub/Person.h"


int main(int argc, char *argv[])
{
    setlocale(LC_ALL,"");

    //1.初始化 ROS 节点
    ros::init(argc,argv,"talker_person");

    //2.创建 ROS 句柄
    ros::NodeHandle nh;

    //3.创建发布者对象
    ros::Publisher pub = nh.advertise<demo01_pub::Person>("chatter_person",1000);

    //4.组织被发布的消息，编写发布逻辑并发布消息
    demo01_pub::Person p;
    p.name = "sunwukong";
    p.age = 2000;
    p.height = 1.45;

    ros::Rate r(1);
    while (ros::ok())
    {
        pub.publish(p);
        p.age += 1;
        ROS_INFO("我叫:%s,今年%d岁,高%.2f米", p.name.c_str(), p.age, p.height);

        r.sleep();
        ros::spinOnce();
    }



    return 0;
}

.msg编译后生成.h头文件，下面引入头文件
#include “demo01_pub/Person.h”

消息类型
<demo01_pub::Person>

2.1修改CMakeLists.txt

# 生成可执行文件
add_executable(person_pub.cpp src/person_pub.cpp)

# 链接可执行文件和消息类型
add_dependencies(person_pub.cpp ${PROJECT_NAME}_generate_messages_cpp)

# 链接可执行和编译库
target_link_libraries(person_pub.cpp
  ${catkin_LIBRARIES}
)

2.3运行节点

roscore
source ./devel/setup.bash
rosrun demo01_pub person_pub.cpp 

3）订阅方实现

在功能包src中新建person_sub.cpp文件

/*
    需求: 订阅人的信息

*/

#include "ros/ros.h"
#include "demo01_pub/Person.h"

void doPerson(const demo01_pub::Person::ConstPtr& person_p){
    ROS_INFO("订阅的人信息:%s, %d, %.2f", person_p->name.c_str(), person_p->age, person_p->height);
}

int main(int argc, char *argv[])
{   
    setlocale(LC_ALL,"");

    //1.初始化 ROS 节点
    ros::init(argc,argv,"listener_person");
    //2.创建 ROS 句柄
    ros::NodeHandle nh;
    //3.创建订阅对象
    ros::Subscriber sub = nh.subscribe<demo01_pub::Person>("chatter_person",10,doPerson);

    //4.回调函数中处理 person

    //5.ros::spin();
    ros::spin();    
    return 0;
}

3.1修改CMakeLists.txt

# 生成可执行文件
add_executable(person_sub.cpp src/person_sub.cpp)

# 链接可执行文件和消息类型
add_dependencies(person_sub.cpp ${PROJECT_NAME}_generate_messages_cpp)

# 链接可执行和编译库
target_link_libraries(person_sub.cpp
  ${catkin_LIBRARIES}
)

3.2运行节点

# 打开终端
cd /home/duduzai/demo01_ws
source ./devel/setup.bash
rosrun demo01_pub person_sub.cpp