ROS 학습 노트 78(roscpp는 간단한 게시자와 구독자를 작성한다)
6907 단어 ROS 학습 노트
끊임없이 정보를 보내는'talker'노드를 만듭니다.
디렉토리 전환:
roscd beginner_tutorials
1.1 프로그램
src 디렉터리 만들기
mkdir -p src
예를 들어 초보자 강좌의:beginnertutorials 패키지는 이 디렉터리 아래에 있습니다.
#include "ros/ros.h"
#include "std_msgs/String.h"
#include
/**
* 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<:string>("chatter", 1000);
// 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 = 0;
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 " << 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();
loop_rate.sleep();
++count;
}
return 0;
}
절차는 매우 간단해서 더 이상 설명하지 않겠다. 전에 모두 상세하게 설명했다.
2 구독 노드 쓰기
2.1 절차
#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();
return 0;
}
프로그램은 매우 간단해서 더 이상 설명하지 않는다. 이전 강좌에는 모두 이런 것들이 있었다.
3 CMakeLists.txt 파일
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 genmsg)
## Declare ROS messages and services
## add_message_files(FILES Num.msg)
## add_service_files(FILES AddTwoInts.srv)
## Generate added messages and services
# generate_messages(DEPENDENCIES std_msgs)
## Declare a catkin package
catkin_package()
## 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)
4 실행
roscore
source ./devel/setup.bash
rosrun beginner_tutorials talker
rosrun beginner_tutorials listener
만약 이전에 모두 공부한 적이 있다면, 이 편은 그리 어려운 것이 없을 것이다...파라미터를 어떻게 사용하는지에 중점을 두다.
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ROS 학습 노트 82(roscpp 리 셋 함수)원본 링크:http://wiki.ros.org/roscpp_tutorials/Tutorials/UsingClassMethodsAsCallbacks 구독 자 만약 당신 에 게 간단 한 유형 이 있다 고 가정 하 세 요...
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