学习资料主要源自http://wiki.ros.org/ROS/Tutorials/WritingPublisherSubscriber%28c%2B%2B%29
$ roscd beginner_tutorials/
$ mkdir -p src
$ cd src
$ gedit talker.cpp
- 编写发布器节点 talker
#include "ros/ros.h"
#include "std_msgs/String.h"
#include <sstream>
int main(int argc, char **argv)
{
//初始化ROS,名称重映射(唯一),必须为base name,不含/
ros::init(argc, argv, "talker");
// 为进程的节点创建一个句柄,第一个创建的NodeHandle初始化节点
ros::NodeHandle n;
// 告诉主机要在chatter topic上发布一个std_msgs消息
// 主机会订阅所有chatter topic节点,参数表示发布队列的大小(先进先出)
ros::Publisher chatter_pub = n.advertise<std_msgs::String>("chatter", 1000);
ros::Rate loop_rate(10); // 自循环频率
int count = 0;
while (ros::ok())
{
std_msgs::String msg;
std::stringstream ss;
ss << "hello world " << count;
msg.data = ss.str();
// 输出,用来替代prinf/cout
ROS_INFO("%s", msg.data.c_str());
chatter_pub.publish(msg);
ros::spinOnce();
// 休眠,来使发布频率为10Hz
loop_rate.sleep();
++count;
}
return 0;
}
实现功能:
(1) 初始化ROS系统
(2) 在chatter topic上发布std_msgs/String消息
(3) 以每秒10次频率发布消息
- 编写订阅器节点
#include "ros/ros.h"
#include "std_msgs/String.h"
// 回调函数
void chatterCallback(const std_msgs::String::ConstPtr& msg)
{
ROS_INFO("I heard: [%s]", msg->data.c_str());
}
int main(int argc, char **argv)
{
ros::init(argc, argv, "listener");
ros::NodeHandle n;
// 告诉master需要订阅chatter topic消息
ros::Subscriber sub = n.subscribe("chatter", 1000, chatterCallback);
ros::spin(); // 自循环
return 0;
}
实现功能:
(1) 初始化ROS系统
(2) 订阅chatter topic消息
(3) 进入自循环,等待消息到达
(4) 消息到达,调用chatterCallback()函数
- src/
/CMakeLists.txt
cmake_minimum_required(VERSION 2.8.3)
project(beginner_tutorials)
## Find catkin and any catkin packages
find_package(catkin REQUIRED COMPONENTS
roscpp
rospy
std_msgs
message_generation
)
## Declare ROS messages and services
add_message_files(
FILES
Num.msg
)
add_service_files(
FILES
AddTwoInts.srv
)
## Declare a catkin package
catkin_package(
CATKIN_DEPENDS message_runtime
)
## Build talker and listener
include_directories(include
${catkin_INCLUDE_DIRS}
)
add_executable(talker src/talker.cpp)
target_link_libraries(talker ${catkin_LIBRARIES})
add_dependencies(talker beginner_tutorials_generate_messages_cpp)
add_executable(listener src/listener.cpp)
target_link_libraries(listener ${catkin_LIBRARIES})
add_dependencies(listener beginner_tutorials_generate_messages_cpp)
$ rosrun rqt_graph rqt_graph 或直接rqt_graph
注:如果遇到Couldn't find executable named talker below */src/beginner_tutorials
很有可能是工作空间初始化的问题。
参考
http://wiki.ros.org/ROS/Tutorials
转载请注明http://www.cnblogs.com/lizhongpingchn/p/5543013.html
原文链接: https://www.cnblogs.com/dtyy/p/5543013.html
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