！！需要在ROS平台上安装 ROS见 https://www.cnblogs.com/haijian/p/8782560.html
cd ~/catkin_ws/src
下载usb_cam包
git clone https://github.com/bosch-ros-pkg/usb_cam.git usb_cam
编译
cd ..
catkin_make
启动节点测试
roslaunch usb_cam usb_cam-test.launch
安装错误
（1）v4l2-ctl: not found
sudo apt-get install v4l-utils
（2）[usb_cam-test.launch] is neither a launch file in package [usb_cam] nor is [usb_cam] a launch file name The traceback for the exception was written to the log file
source ~/catkin_ws/devel/setup.bash