ROS Helpful Topic and Message Type Cheatsheet

Topics

Ex. topic_name (message_type_name) - Description of topic

Sensor Topics

  • /scan (sensor_msgs/LaserScan) - Topic that the Hokuyo LIDAR sends
  • /scan_processed - Topic that the processed Velodyne LIDAR sends
  • /imu/data (sensor_msgs/Imu) - Topic that the IMU sends
  • /tf (tf/tfMessage) - Topic that shows the various transformed coordinate systems
  • /odom (geometry_msgs/Point) - Topic that shows the Odometry data

Camera Topics

  • /zed/rgb/image_rect_color (sensor_msgs/Image) - Topic that gives the rectified image of the camera (in full color)
  • /zed/[right or left]/image_raw_color (sensor_msgs/Image) - Topic that gives the raw image of either of the right or left cameras (in full color)
  • /zed/depth/depth_registered (sensor_msgs/Image) - Topic that gives the depth data from the camera (black and white)

External Usage Topics

  • /vesc/high_level/ackermann_cmd_mux/input/nav_0 (ackermann_msgs/AckermannDriveStamped) - What to write to in order to run the car (without bypassing the safety controller)

Safety Controller Topics

  • /ackermann_cmd_input (ackermann_msgs/AckermannDriveStamped) - The input about to be published to run the RACECAR
  • /ackermann_cmd (ackermann_msgs/AckermannDriveStamped) - The output to actually drive the car (without anymore checking involved)

AR Topics

  • /visualization_marker (visualization_msgs/Marker) -
  • /ar_pose_marker (ar_track_alvar_msgs/AlvarMarkers) - Gives an array of the AlvarMarkers detected

Messages

Ex. from message_folder import message_type - What used for * important_sub_topic - what represents

Sensor Messages

  • from sensor_msgs.msg import LaserScan - The information coming from the LIDAR
    • LaserScan.ranges - An array of 1081 distances coming from the laser scan
  • from sensor_msgs.msg import Image - The image published by the camera

Ackermann Messages

  • from ackermann_msgs.msg import AckermannDriveStamped - The drive command that the Ackermann command mux takes in