# ros2_tutorials

**Repository Path**: heguangchuan/ros2_tutorials

## Basic Information

- **Project Name**: ros2_tutorials
- **Description**: 《ROS2入门21讲 · 古月》课程代码
- **Primary Language**: Python
- **License**: Not specified
- **Default Branch**: master
- **Homepage**: https://class.guyuehome.com
- **GVP Project**: No

## Statistics

- **Stars**: 0
- **Forks**: 107
- **Created**: 2025-06-04
- **Last Updated**: 2025-06-09

## Categories & Tags

**Categories**: Uncategorized

**Tags**: None

## README

-

课程视频：[https://class.guyuehome.com/detail/p_628f4288e4b01c509ab5bc7a/6](https://class.guyuehome.com/detail/p_628f4288e4b01c509ab5bc7a/6)

- 图文教程：[https://book.guyuehome.com/](https://book.guyuehome.com/)
- 课程问答：[https://www.guyuehome.com/Bubble/circleDetail/id/90/](https://www.guyuehome.com/Bubble/circleDetail/id/90/)
- 博客泡圈：[https://www.guyuehome.com/](https://www.guyuehome.com/)

![课程大纲](docs/课程大纲.png)

### 终端设置

```shell
cmd.exe /k ""E:\miniconda\miniconda3\Scripts\activate.bat" "E:\miniconda\envs\ros2""
```

### 环境信息

```shell
ros2@ros2-virtual-machine:~$ cat /etc/os-release 
PRETTY_NAME="Ubuntu 22.04.5 LTS"
NAME="Ubuntu"
VERSION_ID="22.04"
VERSION="22.04.5 LTS (Jammy Jellyfish)"
VERSION_CODENAME=jammy
ID=ubuntu
ID_LIKE=debian
HOME_URL="https://www.ubuntu.com/"
SUPPORT_URL="https://help.ubuntu.com/"
BUG_REPORT_URL="https://bugs.launchpad.net/ubuntu/"
PRIVACY_POLICY_URL="https://www.ubuntu.com/legal/terms-and-policies/privacy-policy"
UBUNTU_CODENAME=jammy
```

```shell
ros2@ros2-virtual-machine:~$ uname  -a 
Linux ros2-virtual-machine 6.8.0-59-generic #61~22.04.1-Ubuntu SMP PREEMPT_DYNAMIC Tue Apr 15 17:03:15 UTC 2 x86_64 x86_64 x86_64 GNU/Linux
```

### 设置编码

```shell
sudo cp /etc/apt/sources.list /etc/apt/sources_default.list
sudo sed -i 's/security.ubuntu.com/mirrors.ustc.edu.cn/g' /etc/apt/sources.list
sudo apt update && sudo apt install locales
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
```

### 添加源

```shell
sudo apt update && sudo apt install curl gnupg2 lsb-release
sudo curl -sSL https://raw.githubusercontent.com/ros/rosdistro/master/ros.key  -o /usr/share/keyrings/ros-archive-keyring.gpg
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/ros-archive-keyring.gpg] http://packages.ros.org/ros2/ubuntu $(lsb_release -cs) main" | sudo tee /etc/apt/sources.list.d/ros2.list > /dev/null
```

如果遇到 https://raw.githubusercontent.com 访问不了，请使用 https://raw.gitmirror.com/ros/rosdistro/master/ros.key 替换

### 安装Ros2

```shell
sudo apt update
sudo apt upgrade
sudo apt install ros-humble-desktop
```

文件将会被安装到 /opt/ros/humble/ 目录

### 设置环境变量

```shell
source /opt/ros/humble/setup.bash
echo "source /opt/ros/humble/setup.bash" >> ~/.bashrc
```

### 测试Ros2

```shell
ros2 run demo_nodes_cpp talker
ros2 run demo_nodes_py listener

ros2 run turtlesim turtlesim_node
ros2 run turtlesim turtle_teleop_key

```

### 工作空间与功能包

工作空间是一个代码大本营，存放项目相关的开发文件夹，包含：

- src：存放功能包，是代码空间
- build：存放编译后的文件
- install：存放安装后的文件
- log：存放日志文件

```shell
sudo apt install python3-pip
sudo pip3 install rosdepc

heguangchuan@heguangchuan-virtual-machine:~/workspace/src$ cd ~/workspace/code/src/
heguangchuan@heguangchuan-virtual-machine:~/workspace/src$ sudo rosdepc init
heguangchuan@heguangchuan-virtual-machine:~/workspace/src$ sudo rosdepc update

heguangchuan@heguangchuan-virtual-machine:~/workspace/src$ cd ..
heguangchuan@heguangchuan-virtual-machine:~/workspace$ colcon build
```

如果没有安装 colcon 请使用 sudo apt install python3-colcon-common-extensions
安装,执行完成后在工作空间的根目录下会生成如下的结构:

```shell
heguangchuan@heguangchuan-virtual-machine:~/workspace/code$ tree
.
├── build
│   └── COLCON_IGNORE
├── install
│   ├── COLCON_IGNORE
│   ├── local_setup.bash
│   ├── local_setup.ps1
│   ├── local_setup.sh
│   ├── _local_setup_util_ps1.py
│   ├── _local_setup_util_sh.py
│   ├── local_setup.zsh
│   ├── setup.bash
│   ├── setup.ps1
│   ├── setup.sh
│   └── setup.zsh
├── log
│   ├── build_2025-06-04_09-30-23
│   │   ├── events.log
│   │   └── logger_all.log
│   ├── COLCON_IGNORE
│   ├── latest -> latest_build
│   └── latest_build -> build_2025-06-04_09-30-23
└── src
```

为了在执行 ros2 run 命令时方便的找到功能包，请将工作空间(通过 colcon build 命令生成的 install 目录)添加到环境变量中:

```shell
source /home/heguangchuan/workspace/code/install/local_setup.bash
echo "source /home/heguangchuan/workspace/code/install/local_setup.bash" >> ~/.bashrc
source ~/.bashrc
```

### 创建功能包

功能包是 ROS2 项目的基本单元，功能包的创建在工作空间下的 src 目录下进行，创建的语法如下：

```shell
ros2 pkg create --build-type ament_cmake my_package
ros2 pkg create --build-type ament_python my_package
```

ament_cmake 代表的是使用cmake进行编译，ament_python 代表的是使用python进行编译，my_package是功能包的名称，创建完成后会在工作空间下的，src
目录下生成如下结构：

```shell
heguangchuan@heguangchuan-virtual-machine:~/workspace/code$ cd src/
heguangchuan@heguangchuan-virtual-machine:~/workspace/code/src$ ros2 pkg create --build-type ament_python first_pkg
going to create a new package
package name: first_pkg
destination directory: /home/heguangchuan/workspace/code/src
package format: 3
version: 0.0.0
description: TODO: Package description
maintainer: ['heguangchuan <heguangchuan@todo.todo>']
licenses: ['TODO: License declaration']
build type: ament_python
dependencies: []
creating folder ./first_pkg
creating ./first_pkg/package.xml
creating source folder
creating folder ./first_pkg/first_pkg
creating ./first_pkg/setup.py
creating ./first_pkg/setup.cfg
creating folder ./first_pkg/resource
creating ./first_pkg/resource/first_pkg
creating ./first_pkg/first_pkg/__init__.py
creating folder ./first_pkg/test
creating ./first_pkg/test/test_copyright.py
creating ./first_pkg/test/test_flake8.py
creating ./first_pkg/test/test_pep257.py

[WARNING]: Unknown license 'TODO: License declaration'.  This has been set in the package.xml, but no LICENSE file has been created.
It is recommended to use one of the ament license identitifers:
Apache-2.0
BSL-1.0
BSD-2.0
BSD-2-Clause
BSD-3-Clause
GPL-3.0-only
LGPL-3.0-only
MIT
MIT-0
heguangchuan@heguangchuan-virtual-machine:~/workspace/code/src$ tree first_pkg/
first_pkg/
├── first_pkg
│   └── __init__.py
├── package.xml
├── resource
│   └── first_pkg
├── setup.cfg
├── setup.py
└── test
    ├── test_copyright.py
    ├── test_flake8.py
    └── test_pep257.py

3 directories, 8 files
```

### 节点

节点是机器人的工作细胞,节点具有以下的特点：

1. 执行具体任务的进程
2. 独立可运行的可执行文件
3. 可以使用不同的编程语言
4. 可以分布式的部署在不同的主机
5. 通过节点名称进行管理

### 执行节点

以本项目中 [node_helloworld.py](learning_node/learning_node/node_helloworld.py) 为例，需要先(colcon build)执行节点

```shell
heguangchuan@heguangchuan-virtual-machine:~/workspace/code/src/ros2_tutorials/learning_node$ ros2 run learning_node node_helloworld
[INFO] [1749006630.190521303] [node_helloworld]: Hello World
[INFO] [1749006630.693644108] [node_helloworld]: Hello World
[INFO] [1749006631.194889501] [node_helloworld]: Hello World
[INFO] [1749006631.697436672] [node_helloworld]: Hello World
[INFO] [1749006632.199129959] [node_helloworld]: Hello World
```

可以看到程序在每隔1秒打印一次Hello World，其代码具体如下：

```python
import rclpy  # ROS2 Python接口库
from rclpy.node import Node  # ROS2 节点类
import time


def main(args=None):  # ROS2节点主入口main函数
    rclpy.init(args=args)  # ROS2 Python接口初始化
    node = Node("node_helloworld")  # 创建ROS2节点对象并进行初始化

    while rclpy.ok():  # ROS2系统是否正常运行
        node.get_logger().info("Hello World")  # ROS2日志输出
        time.sleep(0.5)  # 休眠控制循环时间

    node.destroy_node()  # 销毁节点对象    
    rclpy.shutdown()  # 关闭ROS2 Python接口
```

对于更适合面向对象的开发习惯，代码改进如下：

```python

import rclpy  # ROS2 Python接口库
from rclpy.node import Node  # ROS2 节点类
import time

"""
创建一个HelloWorld节点, 初始化时输出“hello world”日志
"""


class HelloWorldNode(Node):
    def __init__(self, name):
        super().__init__(name)  # ROS2节点父类初始化
        while rclpy.ok():  # ROS2系统是否正常运行
            self.get_logger().info("Hello World")  # ROS2日志输出
            time.sleep(0.5)  # 休眠控制循环时间


def main(args=None):  # ROS2节点主入口main函数
    rclpy.init(args=args)  # ROS2 Python接口初始化
    node = HelloWorldNode("node_helloworld_class")  # 创建ROS2节点对象并进行初始化
    node.destroy_node()  # 销毁节点对象
    rclpy.shutdown()  # 关闭ROS2 Python接口
```

### 话题

话题是ROS2中用于数据传输的机制，ROS2中提供了很多话题，具体代码参考 [topic_helloworld_pub.py](learning_topic/learning_topic/topic_helloworld_pub.py)
和 [topic_helloworld_sub.py](learning_topic/learning_topic/topic_helloworld_sub.py)