1. remap的解释
For example, you are given a node that says it subscribes to the "chatter" topic, but you only have a node that publishes the "hello" topic. They are the same type, and you want to pipe your "hello" topic into the new node which wants "chatter" by simply:
<remap from="chatter" to="hello"/>
https://www.cnblogs.com/LiuQiang921202/p/7679943.html
http://wiki.ros.org/roslaunch/XML/remap
所以cartographer_ros中的remap应该是remap from=“scan” to=“scan”。因为目前hokuyo_node和LMS1XX中发布的都是sensor_msg::LaserScan消息类型。
2.urdf中的link的name要对应到sensor_msg::LaserScan消息的frame_id
目前hokuyo_node和LMS1XX中的消息的frame_id 都是设置为"laser"
3.点云的保存：http://google-cartographer-ros.readthedocs.io/en/latest/assets_writer.html
4.MOOC上仿真的命令
roslaunch robot_sim_demo robot_spawn.launch
rosrun robot_sim_demo robot_keyboard_teleop.py