ROS系统目前主流语言为C++/Python , Python需要安装vscode, 所以本文使用C++ .编译使用catkin (catkin和rosbuild都能用)
首先创建工作空间(working space)
mkdir -p ~/catkin_ws/src
cd ~/catkin_ws/src
catkin_init_workspace
创建功能包pkg ,
catkin_create_pkg beginner_tutorials std_msgs rospy roscpp
创建源代码目录和源码cpp
mkdir -p ~/catkin_ws/src/beginner_tutorials/src
#include "ros/ros.h"
#include "std_msgs/String.h"
#include <sstream>
#include <string>
/**
* This tutorial demonstrates simple sending of messages over the ROS system.
*/
int main(int argc, char **argv)
{
/**
* The ros::init() function needs to see argc and argv so that it can perform
* any ROS arguments and name remapping that were provided at the command line. For programmatic
* remappings you can use a different version of init() which takes remappings
* directly, but for most command-line programs, passing argc and argv is the easiest
* way to do it. The third argument to init() is the name of the node.
*
* You must call one of the versions of ros::init() before using any other
* part of the ROS system.
*/
ros::init(argc, argv, "talker");
/**
* NodeHandle is the main access point to communications with the ROS system.
* The first NodeHandle constructed will fully initialize this node, and the last
* NodeHandle destructed will close down the node.
*/
ros::NodeHandle n;
/**
* The advertise() function is how you tell ROS that you want to
* publish on a given topic name. This invokes a call to the ROS
* master node, which keeps a registry of who is publishing and who
* is subscribing. After this advertise() call is made, the master
* node will notify anyone who is trying to subscribe to this topic name,
* and they will in turn negotiate a peer-to-peer connection with this
* node. advertise() returns a Publisher object which allows you to
* publish messages on that topic through a call to publish(). Once
* all copies of the returned Publisher object are destroyed, the topic
* will be automatically unadvertised.
*
* The second parameter to advertise() is the size of the message queue
* used for publishing messages. If messages are published more quickly
* than we can send them, the number here specifies how many messages to
* buffer up before throwing some away.
*/
ros::Publisher chatter_pub = n.advertise<std_msgs::String>("chatter", 1000);
ros::Rate loop_rate(10);
/**
* A count of how many messages we have sent. This is used to create
* a unique string for each message.
*/
int count = 1;
while (ros::ok())
{
/**
* This is a message object. You stuff it with data, and then publish it.
*/
std_msgs::String msg;
std::stringstream ss;
ss << "hello world from talker" << count;
msg.data = ss.str();
ROS_INFO("%s", msg.data.c_str());
/**
* The publish() function is how you send messages. The parameter
* is the message object. The type of this object must agree with the type
* given as a template parameter to the advertise<>() call, as was done
* in the constructor above.
*/
chatter_pub.publish(msg);
ros::spinOnce(); //监听一次消息 ,可不加
loop_rate.sleep();
++count;
}
return 0;
}
#include "ros/ros.h"
#include "std_msgs/String.h"
/**
* This tutorial demonstrates simple receipt of messages over the ROS system.
*/
void chatterCallback(const std_msgs::String::ConstPtr& msg)
{
ROS_INFO("I heard: [%s]", msg->data.c_str());
}
int main(int argc, char **argv)
{
/**
* The ros::init() function needs to see argc and argv so that it can perform
* any ROS arguments and name remapping that were provided at the command line. For programmatic
* remappings you can use a different version of init() which takes remappings
* directly, but for most command-line programs, passing argc and argv is the easiest
* way to do it. The third argument to init() is the name of the node.
*
* You must call one of the versions of ros::init() before using any other
* part of the ROS system.
*/
ros::init(argc, argv, "listener");
/**
* NodeHandle is the main access point to communications with the ROS system.
* The first NodeHandle constructed will fully initialize this node, and the last
* NodeHandle destructed will close down the node.
*/
ros::NodeHandle n;
/**
* The subscribe() call is how you tell ROS that you want to receive messages
* on a given topic. This invokes a call to the ROS
* master node, which keeps a registry of who is publishing and who
* is subscribing. Messages are passed to a callback function, here
* called chatterCallback. subscribe() returns a Subscriber object that you
* must hold on to until you want to unsubscribe. When all copies of the Subscriber
* object go out of scope, this callback will automatically be unsubscribed from
* this topic.
*
* The second parameter to the subscribe() function is the size of the message
* queue. If messages are arriving faster than they are being processed, this
* is the number of messages that will be buffered up before beginning to throw
* away the oldest ones.
*/
ros::Subscriber sub = n.subscribe("chatter", 1000, chatterCallback);
/**
* ros::spin() will enter a loop, pumping callbacks. With this version, all
* callbacks will be called from within this thread (the main one). ros::spin()
* will exit when Ctrl-C is pressed, or the node is shutdown by the master.
*/
ros::spin(); //阻塞监听
return 0;
}
程序包(~/catkin_ws/src/beginner_tutorials)的 CMakeLists.txt文件,修改如下(最后两行,要不要都行)
返回工作空间编译
catkin_make
编译之后测试,首先开启ROS系统,同样在工作空间分别开启两个控制台分别启动talker 和 listener
source ./devel/setup.bash
rosrun beginner_tutorials talker
source ./devel/setup.bash
rosrun beginner_tutorials listener
测试效果如下图,
特殊说明:
1. listener会丢失前面两次或者三次talker数据 ,具体原因未知,如果我系统性学习了ROS再来更新。使用ROS subscribe激光数据,丢失一丢丢貌似问题也不大。
2.ROS publish之后的数据,如果没有及时被subscribe走,会直接丢失,ROS应该无缓存。
3.代码部分看本文英文注释即可,没有注释的是特定框架。如果需了解更多,参考下面网ROS入门教程-目录 - 创客智造
ROS基础命令学习:
roscore :启动rosmaster
rosrun:启动节点
rosnode list:节点列表
rosnode info :查看具体节点信息
rostopic list:话题信息
rostopic info :查看具体话题信息
rostopic echo :监听话题信息
rpt_graph:可视化计算图
rqt_plot:可视化数据绘图
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更多推荐
ROS编程入门教程(全过程示例代码)
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