ros

[david-gwa]

background

ros is helpful to connect differrent sensor nodes, analysis nodes together, which is used a lot in self-driving.

ros filesystem tools

first, check ROS_PACKAGE_PATH, where defines all ROS packages that are within the directories.

rospack find [package-name]

rospack list 

roscd [package-name]

take an example, how to locate rosbridge_websocket.launch:

rospack find rosbridge*    #rosbridge_server
roscd rosbridge_server
cd launch 

another tool to view ros-launch: roslaunch-logs

launch file

launch files, which uses XML format, usually make a directory named "launch" inside the workspace to organize all launch files, and it provides a convenient way to start up multiple nodes and master.

process in a depth-first tarversal order,

roslaunch package_name launch_file
#or 
roslaunch /path/to/launch_file

an sample launch file:

<launch> 
 
   <node pkg="package_name"  type=" "   name=" "  output=" " args=" " />
   
</launch>

args can define either env variables or a command.

[node/type](http://wiki.ros.org/roslaunch/XML/node) There must be a corresponding executable with the same name.

rviz

test run:

# terminal 1 
roscore 

# terminal 2 
rosrun rviz rviz 

rosbag

common commands:

rosbag record #use to write a bag file wit contents on the specified topics
rosbag info #display the contents of bag files 
rosbag play #play back bag file in a time-synchronized fashion

there are APIs to read/write ros bags.

kitti rosbag

official raw data

message_filter

ros filter

According to the loaded plugin descriptions the class jsk_rviz_plugin/BoundingBoxArray with base class type rviz::Display does not exist.

add launch to CmakeList build

if self defined node/type, it can be put in /package_name/scripts/type.py

ros package

mkdir -p ~/catkin_ws/src
cd ~/catkind_ws/src
catkin_create_pgk demo std_msgs rviz 
cd demo
mkdir launch
cat "<launch> <node  name="demo"  type="rviz" -d="ls `pwd`" /> </launch> " >  demo.launch
cd ~/catkin_ws
catkin_make --pkg demo

# add catkin_ws to 
cat "export ROS_PACKAGE_PATH=$ROS_PACKAGE_PATH:/path/to/catkin_ws/" >> ~/.bashrc

[ZJLi2013]

ros project with ADS

platbot

apollo perception ros