ROS主题发布订阅控制真实的机器人下位机

先模拟控制小乌龟

新建cmd_node.ccpp文件：

#include"ros/ros.h"
#include"geometry_msgs/Twist.h"                             //包含geometry_msgs::Twist消息头文件
#include <stdlib.h>
#include<stdlib.h>

int main(int argc, char **argv)
{
	ros::init(argc, argv, "cmd_node");
	ros::NodeHandle n;

    ros::Publisher cmd_pub = n.advertise<geometry_msgs::Twist>("turtle1/cmd_vel",1000);
    ros::Rate loop_rate(10);

    while(ros::ok())
    {
        geometry_msgs::Twist msg;
        msg.linear.x = (double)(rand()/(double(RAND_MAX)));                     //随机函数
        msg.angular.z = (double)(rand()/(double(RAND_MAX)));

        cmd_pub.publish(msg);
        ROS_INFO("msg.linear.x:%f ,  msg.angular.z: %f",msg.linear.x,msg.angular.z);
        loop_rate.sleep();
    }
	return 0;
}

编译成功产生

测试

roscore
rosrun turtlesim turtlesim_node
rosrun zxwtest_package hello_node

查看节点 框图：

rqt_graph

我们订阅/turtle1/cmd_vel话题上的turtlesim移动的角速度和线速度信息

#include"ros/ros.h"
#include"geometry_msgs/Twist.h"
#include <iostream>
#include <boost/asio.hpp>
#include <boost/bind.hpp>
#include <math.h>

void chatterCallback(const geometry_msgs::Twist& msg)
{
    ROS_INFO_STREAM(std::setprecision(2) << std::fixed << "linear.x=("<< msg.linear.x<<" msg.angular.z="<<msg.angular.z);

}

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

    ros::NodeHandle n;

    ros::Subscriber sub = n.subscribe("/turtle1/cmd_vel", 1000,&chatterCallback);
    ros::spin();

    return 0;
}

运行

roscore
rosrun odom_tf_package  listen_node
 rosrun turtlesim turtlesim_node
rosrun turtlesim turtle_teleop_key

修改回调函数，添加向下位机发送串口数据