ROS常用代碼(C++)

ROS常用代碼(C++)

本部分僅包含ROS常用基礎代碼，不包含解釋，僅爲自己方便之用，如有敘述不明確請諒解;

目錄結構

.
├── CMakeLists.txt
├── include
│   └── learning_communication
├── launch
│   └── start_demo_with_listener.launch
├── msg
│   └── Person.msg
├── package.xml
├── src
│   ├── client.cpp
│   ├── listener.cpp
│   ├── server.cpp
│   ├── talker.cpp
│   ├── turtle_tf_broadcaster.cpp
│   └── turtle_tf_listener.cpp
└── srv
    └── AddTwoInts.srv

Topic

Publisher

#include <sstream>
#include "ros/ros.h"
#include "std_msgs/String.h"

int main(int argc, char **argv)
{
    ros::init(argc, argv, "talker");

    ros::NodeHandle n;

    ros::Publisher chatter_pub = n.advertise<std_msgs::String>("chatter", 1000);

    ros::Rate loop_rate(10);

    int count = 0;

    while(ros::ok())
    {
        std_msgs::String msg;
        std::stringstream ss;
        ss << "hello world  " << count;
        msg.data = ss.str();
        
        ROS_INFO("%s", msg.data.c_str() );
        chatter_pub.publish(msg);

        loop_rate.sleep();
        ++count;
    }
    return 0;
}

Subscriber

#include "ros/ros.h"
#include "std_msgs/String.h"

void chatterCallback(const std_msgs::String::ConstPtr& msg)
{
    ROS_INFO("[%s]", msg -> data.c_str());
}

int main(int argc, char **argv)
{
    ros::init(argc, argv, "listener");

    ros::NodeHandle n;

    ros::Subscriber sub = n.subscribe("chatter", 1000, chatterCallback);

    ros::spin();

    return 0;
}

msg

string name
uint8 sex
uint8 age

uint8 unknown = 0
uint8 male = 1
uint8 female = 2

Service

Server

#include "ros/ros.h"
#include "learning_communication/AddTwoInts.h"

bool add(learning_communication::AddTwoInts::Request &req,
        learning_communication::AddTwoInts::Response &res)
{
    res.sum = req.a + req.b;
    ROS_INFO("request: x = %ld, y = %ld", (long int)req.a, (long int)req.b);
    ROS_INFO("sending back response: [%ld]", (long int)res.sum);

    return true;
}

int main(int argc, char *argv[])
{
    ros::init(argc, argv, "add_two_int_server");

    ros::NodeHandle n;

    ros::ServiceServer service = n.advertiseService("add_two_ints", add);

    ROS_INFO("Ready to add two ints;");
    
    ros::spin();

    return 0;
}

Client

#include <cstdlib>
#include "ros/ros.h"
#include "learning_communication/AddTwoInts.h"

int main(int argc, char *argv[])
{
    ros::init(argc, argv, "add_two_ints_client");

    if( argc != 3)
    {
        ROS_INFO("usage: add_two_ints_client x y");
        return false;
    }

    ros::NodeHandle n;

    ros::ServiceClient client = n.serviceClient<learning_communication::AddTwoInts>("add_two_ints");

    learning_communication::AddTwoInts srv;

    srv.request.a = atoll(argv[1]);
    srv.request.b = atoll(argv[2]);

    if(client.call(srv))
    {
        ROS_INFO("SUM: %ld", (long int)srv.response.sum);
    }
    else
    {
        ROS_ERROR("Failed to call the service: ADDTWOINTS;");
        return 1;
    }
    
    return 0;
}

Service 的調用過程會發生阻塞;

srv

int64 a
int64 b
---
int64 sum

TF

turtle_tf_broadcaster

#include <ros/ros.h>
#include <tf/transform_broadcaster.h>
#include <turtlesim/Pose.h>

std::string turtle_name;

void poseCallback(const turtlesim::PoseConstPtr& msg)
{
    //static tf::TransformBroadcaster br;
    static tf::TransformBroadcaster br;
    tf::Transform transform;
    transform.setOrigin( tf::Vector3(msg->x, msg->y, 0.0));
    tf::Quaternion q;
    q.setRPY(0, 0, msg->theta);
    transform.setRotation( q );

    br.sendTransform(tf::StampedTransform(transform, ros::Time::now(), "world", turtle_name));

}

int main(int argc, char *argv[])
{
    ros::init(argc, argv, "my_tf_broadcaster");

    if(argc != 2)
    {
        ROS_ERROR("NEED TUETLE NAME AS ARGUMENT");
        return -1;
    }
    turtle_name = argv[1];
    ros::NodeHandle node;
    ros::Subscriber sub = node.subscribe(turtle_name+"/pose", 10, &poseCallback);

    ros::spin();

    return 0;
}

turtle_tf_listener

#include <ros/ros.h>
#include <tf/transform_listener.h>
#include <geometry_msgs/Twist.h>
#include <turtlesim/Spawn.h>

int main(int argc, char *argv[])
{
    ros::init(argc, argv, "my_tf_listener");

    ros::NodeHandle node;

    ros::service::waitForService("spawn");

    ros::ServiceClient add_turtle = node.serviceClient<turtlesim::Spawn>("spawn");
    turtlesim::Spawn srv;

    add_turtle.call(srv);

    ros::Publisher turtle_vel = node.advertise<geometry_msgs::Twist>("turtle2/cmd_vel", 10);

    tf::TransformListener listener;

    ros::Rate rate(10.0);

    while (node.ok())
    {
        tf::StampedTransform transform;

        try
        {
            listener.waitForTransform("/turtle2", "/turtle1", ros::Time(0), ros::Duration(3.0)); 
            // 該函數會阻塞程序的運行;

            listener.lookupTransform("/turtle2", "/turtle1", ros::Time(0), transform);

        }
        catch( tf::TransformException &ex)
        {
            ROS_ERROR("%s", ex.what());
            ros::Duration(1.0).sleep();
            continue;
        }

        geometry_msgs::Twist vel_msg;

        vel_msg.angular.z = 4.0 * atan2(transform.getOrigin().y(), transform.getOrigin().x());

        vel_msg.linear.x = 0.5 * sqrt( pow(transform.getOrigin().x(), 2) + pow(transform.getOrigin().y(), 2));
        
        turtle_vel.publish(vel_msg);

        rate.sleep();
    }
    return 0;
}

CMakeLists.txt

cmake_minimum_required(VERSION 2.8.3)
project(learning_communication)

find_package(catkin REQUIRED COMPONENTS
geometry_msgs
roscpp
rospy
std_msgs
turtlesim
tf
message_generation
)

add_message_files(
FILES
Person.msg
)

add_service_files(
FILES
AddTwoInts.srv
)

generate_messages(
DEPENDENCIES
std_msgs
)

catkin_package(
CATKIN_DEPENDS geometry_msgs roscpp rospy std_msgs message_runtime turtlesim tf
)

include_directories(
include
${catkin_INCLUDE_DIRS}
)

add_executable(talker src/talker.cpp)
target_link_libraries(talker ${catkin_LIBRARIES})
add_dependencies(talker ${PROJECT_NAME}_generate_messages_cpp)

add_executable(listener src/listener.cpp)
target_link_libraries(listener ${catkin_LIBRARIES})
add_dependencies(listener ${PROJECT_NAME}_generate_messages_cpp)

add_executable(server src/server.cpp)
target_link_libraries(server ${catkin_LIBRARIES})
add_dependencies(server ${PROJECT_NAME}_gencpp)

add_executable(client src/client.cpp)
target_link_libraries(client ${catkin_LIBRARIES})
add_dependencies(client ${PROJECT_NAME}_gencpp)

add_executable(turtle_tf_broadcaster src/turtle_tf_broadcaster)
target_link_libraries(turtle_tf_broadcaster ${catkin_LIBRARIES})

add_executable(turtle_tf_listener src/turtle_tf_listener)
target_link_libraries(turtle_tf_listener ${catkin_LIBRARIES})

Reference:

《ROS機器人開發實踐》