以Ubuntu 18.04为例：
1.如果源没有切换到国内的建议切换
sudo cp /etc/apt/sources.list /etc/apt/sources.list.bak
sudo vi /etc/sources.list
删除原来的源切换到清华大学源
# 默认注释了源码镜像以提高 apt update 速度，如有需要可自行取消注释
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-updates main restricted universe multiverse
deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse
# deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-backports main restricted universe multiverse# 以下安全更新软件源包含了官方源与镜像站配置，如有需要可自行修改注释切换
deb http://security.ubuntu.com/ubuntu/ bionic-security main restricted universe multiverse
# deb-src http://security.ubuntu.com/ubuntu/ bionic-security main restricted universe multiverse# 预发布软件源，不建议启用
# deb https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
# # deb-src https://mirrors.tuna.tsinghua.edu.cn/ubuntu/ bionic-proposed main restricted universe multiverse
不同系统源获取方式参照：（注意一下源地址和密钥可能是变的，要根据清华大学网站复制）跳转到清华大学源
2.更新一下
sudo apt update
sudo apt upgrade
3.配置ros源仓库，还是以清华ros源为例 跳转到清华大学ros仓库地址
新建 /etc/apt/sources.list.d/ros-latest.list，内容为：（注意一下源地址和密钥可能是变的，要根据清华大学网站复制）
deb https://mirrors.tuna.tsinghua.edu.cn/ros/ubuntu/ focal main
然后再输入如下命令，信任 ROS 的 GPG Key，并更新索引：
apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654apt update
4.安装ros相关组件 此处安装desktop-full版本，其包含Gazebo、Rviz等常用组件
sudo apt install ros-melodic-desktop-full
5.再安装相关依赖
sudo apt install python-rosdep python-rosinstall python-rosinstall-generator python-wstool build-essential
6.安装rosdep
这里借助国内鱼香ros
sudo apt install python3-pip
sudo pip3 install 6-rosdep
sudo 6-rosdep
7.更新一下
sudo rosdep init
rosdep update
8.环境变量配置
echo "source /opt/ros/melodic/setup.bash" >> ~/.bashrc
source ~/.bashrc
9.测试
使用的经典的ros小乌龟测试
重新打开第一个终端，运行roscore
roscore
第二个终端，运行小乌龟ui节点
rosrun turtlesim turtlesim_node
第三个终端，通过键盘上下左右控制小乌龟运动
rosrun turtlesim turtle_teleop_key
