如何實現一個發佈者
1.初始化ROS節點;
2.向ROS Master 註冊節點信息,包括髮布的話題名和話題中的消息類型;
3.創建消息數據;
4.按照一定的頻率循環發佈消息
//來自古月居21講,自學做筆記用
/* 該例程將發佈turtle1/cmd_vel話題,消息類型geometry_msgs::Twist
*/
#include <ros/ros.h>
#include <geometry_msgs/Twist.h>
int main(int argc, char **argv)
{
// ROS節點初始化
ros::init(argc, argv, "velocity_publisher");
// 創建節點句柄
ros::NodeHandle n;
// 創建一個Publisher,發佈名爲/turtle1/cmd_vel的topic,消息類型爲geometry_msgs::Twist,隊列長度10
ros::Publisher turtle_vel_pub = n.advertise<geometry_msgs::Twist>("/turtle1/cmd_vel", 10);
// 設置循環的頻率
ros::Rate loop_rate(10);
int count = 0;
while (ros::ok())
{
// 初始化geometry_msgs::Twist類型的消息
geometry_msgs::Twist vel_msg;
vel_msg.linear.x = 0.5;
vel_msg.angular.z = 0.2;
// 發佈消息
turtle_vel_pub.publish(vel_msg);
ROS_INFO("Publsh turtle velocity command[%0.2f m/s, %0.2f rad/s]",
vel_msg.linear.x, vel_msg.angular.z);
// 按照循環頻率延時
loop_rate.sleep();
}
return 0;
}
如何配置CMakeList.txt中的編譯規則
1.設置需要編譯的代碼合生成可執行文件;
設置鏈接庫;
add_executable(velocity_publisher src/velocity_publisher.cpp)
target_link_libraries(velocity_publisher ${catkin_LIBRARIES})
編譯並運行發佈者
$ cd ~/catkin_ws
$ catkin_make
$ source devel/setup.bash
$ roscore
$ rosrun turtlesim turtlesim_node
$ rosrun learning_topic velocity_publisher