１.创建功能包

cd ~/testROS_ws/src

catkin_create_pkg　topic_publisher std_msgs rospy roscpp geometry_msgs turtlesim

cd ~/testROS_ws/src/topic_publisher/src

2.编辑代码

tourch test.cpp

/*** 该例程将发布turtle1/cmd_vel话题，消息类型geometry_msgs::Twist*/#include <ros/ros.h>
#include <geometry_msgs/Twist.h>int main(int argc, char **argv)
{// ROS节点初始化ros::init(argc, argv, "velocity_publisher");// 创建节点句柄ros::NodeHandle n;// 创建一个Publisher，发布名为/turtle1/cmd_vel的topic，消息类型为geometry_msgs::Twist，队列长度10ros::Publisher turtle_vel_pub = n.advertise<geometry_msgs::Twist>("/turtle1/cmd_vel", 10);// 设置循环的频率ros::Rate loop_rate(10);int count = 0;while (ros::ok()){// 初始化geometry_msgs::Twist类型的消息geometry_msgs::Twist vel_msg;vel_msg.linear.x = 0.5;vel_msg.angular.z = 0.2;// 发布消息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);// 按照循环频率延时loop_rate.sleep();}return 0;
}

３.编译代码

３.1修改cmakelists.txt

添加这两句：

add_executable(test src/test.cpp)
target_link_libraries(test ${catkin_LIBRARIES})

3.2 编译

catkin_make

3.3设置环境变量

source devel/setup.bash

为了避免每次设置在／home目录下

ctrl+h

编辑.bashrc

source /home/<user_name>/<worksapce_name>/devel/setup.bash

４运行节点

重新打开终端

roscore

运行海龟仿真器

rosrun turtlesim turtlesim_node

运行节点

rosrun <功能包名>　<节点名>

rosrun topic_publisher test

 

5.python脚本编写和运行

python代码

#!/usr/bin/env python
# -*- coding: utf-8 -*-
# 该例程将发布turtle1/cmd_vel话题，消息类型geometry_msgs::Twistimport rospy
from geometry_msgs.msg import Twistdef velocity_publisher():# ROS节点初始化rospy.init_node('velocity_publisher', anonymous=True)# 创建一个Publisher，发布名为/turtle1/cmd_vel的topic，消息类型为geometry_msgs::Twist，队列长度10turtle_vel_pub = rospy.Publisher('/turtle1/cmd_vel', Twist, queue_size=10)#设置循环的频率rate = rospy.Rate(10) while not rospy.is_shutdown():# 初始化geometry_msgs::Twist类型的消息vel_msg = Twist()vel_msg.linear.x = 0.5vel_msg.angular.z = 0.2# 发布消息turtle_vel_pub.publish(vel_msg)rospy.loginfo("Publsh turtle velocity command[%0.2f m/s, %0.2f rad/s]", vel_msg.linear.x, vel_msg.angular.z)# 按照循环频率延时rate.sleep()if __name__ == '__main__':try:velocity_publisher()except rospy.ROSInterruptException:pass

改变权限

sudo chmod 777 test.py

运行

python test.py