$ mkdir ~/catkin_ws
$ mkdir ~/catkin_ws/src
$ cd ~/catkin_ws/src
$ git clone https://github.com/robopeak/rplidar_ros
$ cd ~/catkin_ws
$ ls -l /dev/ttyUSB0
$ sudo chmod 666 /dev/ttyUSB0
$ catkin_make rplidarNode
$ source ~/catkin_ws/devel/setup.bash
$ roslaunch rplidar_ros view_rplidar.launch
terminal1 : roscore
terminal2 : roslaunch rplidar_ros view_rplidar_a3.launch
terminal3 : rosrun rplidar_ros rplidarNode
in rviz
edit Global Options -> Fixed Frame = laser_frame
add LaserScan
edit Topic = /scan
terminal4 : rostopic list
rostopic echo /scan