C++類對象化編寫ROS的sub&pub

按照官方教程，寫一個簡單的ROS接收/發送是很容易的。但是C++倡導對象化，把ROS節點註冊、topic接收/發送寫到類裏，還是一個很好的做法。一方面工程大了之後，方便管理；另一方面個人看起來也更舒服。

1、C++ class

class_demo.cpp

#include <ros/ros.h>

#include <geometry_msgs/Twist.h>
#include <nav_msgs/Odometry.h>

class RobotMove {
 public:
  RobotMove();

 private:
  geometry_msgs::Twist cmd;
  nav_msgs::Odometry odom;

  ros::NodeHandle nh;   // declare nodehandle
  ros::Subscriber sub;  // declare sub
  ros::Publisher pub;   // declare pub

  void odomCallback(const nav_msgs::Odometry& msg);  // declare callback_func
  void loopCtl(void);
};

// difine sub&pub
RobotMove::RobotMove() {
  sub = nh.subscribe("odom", 1000, &RobotMove::odomCallback, this);  //
  pub = nh.advertise<geometry_msgs::Twist>("cmd_vel", 50);
  loopCtl();
}

// difine callback_func
void RobotMove::odomCallback(const nav_msgs::Odometry& msg) { odom = msg; }

// loop
void RobotMove::loopCtl() {
  ros::Rate rate(30);
  while (ros::ok()) {
    pub.publish(cmd);  // loop cmd
    ros::spinOnce();
    rate.sleep();
  }
}

int main(int argc, char** argv) {
  ros::init(argc, argv, "robotmove");
  RobotMove robotobj;
  ros::spin();
  return 0;
}

2、normal

normal_demo.cpp

#include <ros/ros.h>

#include <geometry_msgs/Twist.h>
#include <nav_msgs/Odometry.h>

geometry_msgs::Twist cmd;
nav_msgs::Odometry odom;

void odomCallback(const nav_msgs::Odometry& msg) { odom = msg; }

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

  ros::Subscriber sub = nh.subscribe("odom", 1000, odomCallback);
  ros::Publisher pub = nh.advertise<geometry_msgs::Twist>("cmd_vel", 50);

  ros::Rate r(30);
  while (ros::ok()) {
    pub.publish(cmd);
    ros::spinOnce();
    r.sleep();
  }
  return 0;
}

常規寫法代碼量比class寫法更少，但是class寫法更符合對象化思維吧。

other 帶 private_nh寫法

#include <ros/ros.h>

#include <geometry_msgs/Twist.h>
#include <nav_msgs/Odometry.h>
#include <iostream>

class RobotMove {
 public:
  RobotMove();

 private:
  geometry_msgs::Twist cmd;
  nav_msgs::Odometry odom;

  ros::NodeHandle nh;   // declare nodehandle
  ros::Subscriber sub;  // declare sub
  ros::Publisher pub;   // declare pub
  std::string odom_topic, cmd_vel_topic;

  void odomCallback(const nav_msgs::Odometry& msg);  // declare callback_func
  void loopCtl(void);
};

// difine sub&pub
RobotMove::RobotMove() {
  ros::NodeHandle private_nh("~");  // declare private nodehandle
  private_nh.param("odom_topic", odom_topic, std::string("odom"));
  private_nh.param("cmd_vel_topic", cmd_vel_topic, std::string("cmd_vel"));
  sub = nh.subscribe(odom_topic, 1000, &RobotMove::odomCallback, this);  //
  pub = nh.advertise<geometry_msgs::Twist>(cmd_vel_topic, 50);
  loopCtl();
}

// difine callback_func
void RobotMove::odomCallback(const nav_msgs::Odometry& msg) { odom = msg; }

// loop
void RobotMove::loopCtl() {
  ros::Rate rate(30);
  while (ros::ok()) {
    pub.publish(cmd);  // loop cmd
    ros::spinOnce();
    rate.sleep();
  }
}

int main(int argc, char** argv) {
  ros::init(argc, argv, "robotmove");
  RobotMove robotobj;
  ros::spin();
  return 0;
}