安装ROS（Ubuntu16.04）
本文简述ROS的安装过程，主要是给遇到的问题提供参考解决方案。
注意Ubuntu16对应ROS的Kinetic，且Ubuntu 16.04代号Xenial，参考其他Ubuntu版本时记得改代号。
基本步骤
基本和ROS官网一样：
# 走清华源
# 下面基本每个教程都是这么走的，随便找几个对比参考下即可
sudo sh -c '. /etc/lsb-release && echo "deb http://mirrors.tuna.tsinghua.edu.cn/ros/ubuntu/ `lsb_release -cs` main" > /etc/apt/sources.list.d/ros-latest.list'
sudo apt-key adv --keyserver 'hkp://keyserver.ubuntu.com:80' --recv-key C1CF6E31E6BADE8868B172B4F42ED6FBAB17C654
sudo apt-get update
sudo apt-get install ros-kinetic-desktop-full
sudo rosdep init
rosdep update
echo "source /opt/ros/kinetic/setup.bash" >> ~/.bashrc
source ~/.bashrc
遇到的问题
rosdep init（下载不下来）
直接从https://raw.githubusercontent.com/ros/rosdistro/master/rosdep/sources.list.d/20-default.list下载这个文件，放在/etc/ros/rosdep/sources.list.d/里（目录需要自己建），然后走下一步即可。
rosdep update（timeout错误）
直接去https://github.com/ros/rosdistro/tree/master/rosdep下载整个包，放在/etc/ros/rosdistro/master/下面
1、再改上面那个20-default.list文件，直接指定本地目录：
# os-specific listings first
yaml file:///etc/ros/rosdistro/master/rosdep/osx-homebrew.yaml osx
yaml file:///etc/ros/rosdistro/master/rosdep/base.yaml
yaml file:///etc/ros/rosdistro/master/rosdep/python.yaml
yaml file:///etc/ros/rosdistro/master/rosdep/ruby.yaml
gbpdistro file:///etc/ros/rosdistro/master/releases/fuerte.yaml fuerte
# newer distributions (Groovy, Hydro, ...) must not be listed anymore, they are being fetched from the rosdistro index.yaml instead
2、再改/usr/lib/python2.7/dist-packages/rosdistro/__init__.py文件：
#DEFAULT_INDEX_URL = 'https://raw.githubusercontent.com/ros/rosdistro/master/index-v4.yaml'
DEFAULT_INDEX_URL = 'file:///etc/ros/rosdistro/master/index-v4.yaml'
执行rosdep update即可。
其他问题
其他问题，参考以下几个：
https://zhuanlan.zhihu.com/p/77483614
https://blog.csdn.net/zhanghanningleaf/article/details/114710849?utm_medium=distribute.pc_relevant.none-task-blog-baidujs_baidulandingword-0&spm=1001.2101.3001.4242
https://blog.csdn.net/weixin_44221517/article/details/111189690?utm_medium=distribute.pc_relevant.none-task-blog-baidujs_baidulandingword-1&spm=1001.2101.3001.4242
