安装 ubuntu16.04 ROS2 超过5分钟你打我后带测试talker listener demo

ros2 初体验

0.先贴官方的网站的指导
1. 确保支持utf-8
2.安装源
3.安装ros2
4.配置环境
5.测试talker 和 listener
6. cpp 和python demo代码
7. ros1 和ros2 的区别，架构方面

0.先贴官方的网站的指导

我们通过 debian 包安装就是通过apt命令

传送门
网不好的话看看科学上网，或者换运营商试试

下面开始正文

1. 确保支持utf-8

安装的时候最好用英文环境吧

命令看下自己是不是utt-8

如果是就可以忽略下面的操作，不是请安心执行

sudo locale-gen en_US en_US.UTF-8
sudo update-locale LC_ALL=en_US.UTF-8 LANG=en_US.UTF-8
export LANG=en_US.UTF-8

2.安装源

安装需要用到的软件

sudo apt update && sudo apt install curl gnupg2 lsb-release

密钥认证GPG

curl -s https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -

添加分支到源列表文件里
清华大学得源，速度快

sudo sh -c 'echo "deb http://mirror.tuna.tsinghua.edu.cn/ros2/ubuntu `lsb_release -cs` main" > /etc/apt/sources.list.d/ros2-latest.list'

3.安装ros2

16.04 是xenial ，安装ardent版本

sudo apt-get update && sudo apt-get install ros-ardent-desktop

安装需要一定时间，这个包服务器是美国的，慢慢下载，失败就多试几次

4.配置环境

和ros1 类似，在.bashrc. 文件加一下

source /opt/ros/ardent/setup.bash

ros2 有个坑爹的地方就是自动补全有点不行，不想ros1 ，source 之后就会补全了

这里需要用到一个叫argcomplete 东东
安装：

sudo apt install python3-pip
sudo pip3 install argcomplete

激活：

sudo activate-global-python-argcomplet

这样就可以激活tab补全了，开心

5.测试talker 和 listener

ros2 run demo_nodes_cpp talker
ros2 run demo_nodes_py listener

不用起roscore，不用受制于master了，dds是个好东西

6. cpp 和python demo代码

ros2 可以用python3了，python2 马上EOX了

talker.cpp
官方写法

#include <chrono>
#include <memory>#include "rclcpp/rclcpp.hpp"
#include "std_msgs/msg/string.hpp"using namespace std::chrono_literals;/* This example creates a subclass of Node and uses std::bind() to register a
* member function as a callback from the timer. */class MinimalPublisher : public rclcpp::Node
{public:MinimalPublisher(): Node("minimal_publisher"), count_(0){publisher_ = this->create_publisher<std_msgs::msg::String>("chatter", 10);timer_ = this->create_wall_timer(500ms, std::bind(&MinimalPublisher::timer_callback, this));}private:void timer_callback(){auto message = std_msgs::msg::String();message.data = "Hello, world! " + std::to_string(count_++);RCLCPP_INFO(this->get_logger(), "Publishing: '%s'", message.data.c_str());publisher_->publish(message);}rclcpp::TimerBase::SharedPtr timer_;rclcpp::Publisher<std_msgs::msg::String>::SharedPtr publisher_;size_t count_;};int main(int argc, char * argv[]){rclcpp::init(argc, argv);rclcpp::spin(std::make_shared<MinimalPublisher>());rclcpp::shutdown();return 0;}

民间写法

#include <iostream>
#include <memory>#include "rclcpp/rclcpp.hpp"
#include "std_msgs/msg/string.hpp"int main(int argc, char * argv[])
{//ros::init(argc, argv, "talker");rclcpp::init(argc, argv);//ros::NodeHandle n;auto node = rclcpp::Node::make_shared("talker");// 配置质量服务原则，ROS2针对以下几种应用提供了默认的配置：// publishers and subscriptions (rmw_qos_profile_default).// Services (rmw_qos_profile_services_default).// Sensor data (rmw_qos_profile_sensor_data).rmw_qos_profile_t custom_qos_profile = rmw_qos_profile_default;// 配置QoS中历史数据的缓存深度custom_qos_profile.depth = 7;//ros::Publisher chatter_pub = n.advertise<std_msgs::String>("chatter", 1000);auto chatter_pub = node->create_publisher<std_msgs::msg::String>("chatter", custom_qos_profile);//ros::Rate loop_rate(10);rclcpp::WallRate loop_rate(2);auto msg = std::make_shared<std_msgs::msg::String>();auto i = 1;//while (ros::ok())while (rclcpp::ok()) {msg->data = "Hello World: " + std::to_string(i++);std::cout << "Publishing: '" << msg->data << "'" << std::endl;//chatter_pub.publish(msg);chatter_pub->publish(msg);//ros::spinOnce();rclcpp::spin_some(node);//loop_rate.sleep();loop_rate.sleep();}return 0;
}

主要是用了auto 和 make_shared

listener.py

# Copyright 2016 Open Source Robotics Foundation, Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.import sysimport rclpy
from rclpy.node import Nodefrom std_msgs.msg import Stringclass Listener(Node):def __init__(self):super().__init__('listener')self.sub = self.create_subscription(String, 'chatter', self.chatter_callback)def chatter_callback(self, msg):self.get_logger().info('I heard: [%s]' % msg.data)def main(args=None):if args is None:args = sys.argvrclpy.init(args=args)node = Listener()rclpy.spin(node)node.destroy_node()rclpy.shutdown()if __name__ == '__main__':main()

总结下，c++部分，库不一样了，不过思路一致，更c++化了用的c++14

接口文档在这里http://docs.ros2.org/ardent/api/rclcpp/index.html

python的差别不大，以前是rospy，现在是rclpy了

7. ros1 和ros2 的区别，架构方面

ros1 ------------------------------------------------------------------------------ros2

先到这，洗洗睡了