ROS教程第五步

编写一个简单的节点，用于发布消息和接收消息

1. 发布节点文件

#include"ros/ros.h"
#include"runcar/carinfo.h"
#include"geometry_msgs/Twist.h"
#include<string>
#include<vector>
#include<algorithm>
using namespace std;

int main(int argc,char **argv){

   ros::init(argc,argv,"theFirstCar");  // 当前节点的名字
   ros::NodeHandle n;

   ros::Publisher pub_pos_info = n.advertise<runcar::carinfo>("/car_pos",5);
   ros::Publisher pub_ctrl = n.advertise<geometry_msgs::Twist>("/turtle1/cmd_vel",5);
  
   ros::Rate delay(10);
   int count =0;
   float x1 = 0;
     float y1 = 0;
     float linear_x = 2;
     float angular_z = 2;
   while (ros::ok()){
     
     
     runcar::carinfo carpos;

     carpos.px = x1;
     carpos.py = y1;
     pub_pos_info.publish(carpos);  
     ROS_INFO("car1pos: px = %f py = %f [Count = %d]",carpos.px,carpos.py,count);

     
     geometry_msgs::Twist ctrl_msg;

     ctrl_msg.linear.x = linear_x;
     ctrl_msg.angular.z = angular_z;
     pub_ctrl.publish(ctrl_msg);
     ROS_INFO("car1ctrl: linear_x = %f angular_z = %f [Count = %d]",ctrl_msg.linear.x,ctrl_msg.angular.z,count);

     linear_x += 0.1;
     angular_z -= 0.1;
     x1  += 0.1;
     y1  += 0.1;
     count++;

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

2. 接收节点文件

#include"ros/ros.h"
#include"runcar/carinfo.h"
#include"geometry_msgs/Twist.h"
#include<string>
using namespace std;

void carpos_callback(const runcar::carinfo::ConstPtr& carpos){

  ROS_INFO("carpos_message: px =%f py = %f",carpos->px,carpos->py);
}

void carctrl_callback(const geometry_msgs::Twist::ConstPtr& carctrl){

  ROS_INFO("carctrl_message: linear_x = %f angular_z = %f",carctrl->linear.x,carctrl->angular.z);  
}


int main(int argc,char **argv){

   ros::init(argc,argv,"carReceive");   // 接收的节点名字
   ros::NodeHandle n;

   ros::Subscriber sub_chat1 = n.subscribe("/car_pos",5,carpos_callback);
   ros::Subscriber sub_chat2 = n.subscribe("/turtle1/cmd_vel",5,carctrl_callback);
   ros::Rate loop(1);

  /*while (ros::ok()){   /// 采取循环方式
   ros::spinOnce();
   loop.sleep();
  }*/

  ros::spin();   // 一直保留在这里等待
   return 0;
}

3. 消息文件

float64 px
float64 py
float64 vx
float64 vy
float64 ux
float64 uy
float64 u
float64 v

4. CmakeList.txt 编译文件

cmake_minimum_required(VERSION 2.8.3)
project(runcar)

find_package(catkin REQUIRED COMPONENTS
  roscpp
  rospy
  geometry_msgs
  message_generation
)

 add_message_files(
   FILES
#   Message1.msg
#   Message2.msg
   carinfo.msg
 )
 
 generate_messages(
   DEPENDENCIES
#   std_msgs  # Or other packages containing msgs
 )
catkin_package(
#  INCLUDE_DIRS include
#  LIBRARIES runcar
#  CATKIN_DEPENDS roscpp rospy
#  DEPENDS system_lib
)

include_directories(
 include
  ${catkin_INCLUDE_DIRS}
)

add_executable(exec_car1_du src/carrun.cpp)
add_dependencies(exec_car1_du ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
target_link_libraries(exec_car1_du ${catkin_LIBRARIES})

add_executable(exec_car1_re src/carreceive.cpp)
add_dependencies(exec_car1_re ${${PROJECT_NAME}_EXPORTED_TARGETS} ${catkin_EXPORTED_TARGETS})
target_link_libraries(exec_car1_re ${catkin_LIBRARIES})

5. package.xlm文件

<?xml version="1.0"?>
<package format="2">
  <name>runcar</name>
  <version>0.0.0</version>
  <description>The runcar package</description>
  <maintainer email="[email protected]">macl</maintainer>

  <license>TODO</license>

  <buildtool_depend>catkin</buildtool_depend>
  <build_depend>roscpp</build_depend>
  <build_depend>rospy</build_depend>
  <build_export_depend>roscpp</build_export_depend>
  <build_export_depend>rospy</build_export_depend>
  <exec_depend>roscpp</exec_depend>
  <exec_depend>rospy</exec_depend>

  <build_depend>message_generation</build_depend>
  <exec_depend>message_runtime</exec_depend>
  
  <!-- The export tag contains other, unspecified, tags -->
  <export>
    <!-- Other tools can request additional information be placed here -->

  </export>
</package>

6. launch文件

<launch>

  <node pkg = "turtlesim" name = "car1" type = "turtlesim_node"/>

  <node pkg = "runcar" name = "theFirstCar" type = "exec_car1_du"/>

  <node pkg = "runcar" name = "carReceive" type = "exec_car1_re" output = "screen"/>

</launch>