Write your own Config

Pre-requisites

If you want to run your own data through nautilus you most likely will need to write a small config file with the parameters to use for you specific bag file.

Before you start you will need to have these things:

  1. A ROS Bag file, you can learn more about ROS Bag files here.
  2. Your bag should have Odometry and LiDAR Topics (If you are unsure, use the next section to see if they exist in your Bag file).

Finding topic names

First you will need to get the LiDAR and Odometry topic names from your bag. You can use the rosbag info command for this. Here is the output for the LGRC Bag used in the tutorial to get nautilus running, you can find the bag here.

> rosbag info data/00010_2019-05-16-03-59-04_0.bag
path: data/00010_2019-05-16-03-59-04_0.bag
version: 2.0
duration: 2:24s (144s)
start: Aug 07 2019 18:53:39.02 (1565218419.02)
end: Aug 07 2019 18:56:03.08 (1565218563.08)
size: 1.5 GB
messages: 88266
compression: none [1367/1367 chunks]
types: cobot_msgs/LocalizationMsg [d97acce230cd4cd8961fb0e1730022b9]
dynamic_reconfigure/Config [958f16a05573709014982821e6822580]
dynamic_reconfigure/ConfigDescription [757ce9d44ba8ddd801bb30bc456f946f]
geometry_msgs/Twist [9f195f881246fdfa2798d1d3eebca84a]
geometry_msgs/TwistStamped [98d34b0043a2093cf9d9345ab6eef12e]
geometry_msgs/Vector3Stamped [7b324c7325e683bf02a9b14b01090ec7]
jackal_msgs/Drive [601cf097cd47c174590c366c6ddd5fb3]
jackal_msgs/Feedback [3bdabb0ef46338ee5672d1b82220ab49]
multi_model_control_native/DriveStamped [3c1ca058b9dc17aff4cfac0c666ed6d1]
nav_msgs/Odometry [cd5e73d190d741a2f92e81eda573aca7]
nmea_msgs/Sentence [9f221efc5f4b3bac7ce4af102b32308b]
rosgraph_msgs/Log [acffd30cd6b6de30f120938c17c593fb]
sensor_msgs/CompressedImage [8f7a12909da2c9d3332d540a0977563f]
sensor_msgs/Imu [6a62c6daae103f4ff57a132d6f95cec2]
sensor_msgs/LaserScan [90c7ef2dc6895d81024acba2ac42f369]
sensor_msgs/NavSatFix [2d3a8cd499b9b4a0249fb98fd05cfa48]
sensor_msgs/PointCloud2 [1158d486dd51d683ce2f1be655c3c181]
sensor_msgs/TimeReference [fded64a0265108ba86c3d38fb11c0c16]
topics: /cmd_drive 6890 msgs : jackal_msgs/Drive
/cmd_drive_stamped 6890 msgs : multi_model_control_native/DriveStamped
/cmd_vel 6576 msgs : geometry_msgs/Twist
/cmd_vel_stamped 6573 msgs : geometry_msgs/TwistStamped
/feedback 2753 msgs : jackal_msgs/Feedback
/imu/data 9963 msgs : sensor_msgs/Imu
/imu/data_raw 9970 msgs : sensor_msgs/Imu
/imu/mag 9963 msgs : geometry_msgs/Vector3Stamped
/navsat/fix 1379 msgs : sensor_msgs/NavSatFix
/navsat/nmea_sentence 5214 msgs : nmea_msgs/Sentence
/navsat/time_reference 1379 msgs : sensor_msgs/TimeReference
/odometry/filtered 6889 msgs : nav_msgs/Odometry
/odometry/raw 2755 msgs : nav_msgs/Odometry
/rosout 29 msgs : rosgraph_msgs/Log (3 connections)
/rosout_agg 25 msgs : rosgraph_msgs/Log
/set_location 1 msg : cobot_msgs/LocalizationMsg
/stereo/left/image_raw/compressed 4140 msgs : sensor_msgs/CompressedImage
/stereo/left/image_raw/compressed/parameter_descriptions 1 msg : dynamic_reconfigure/ConfigDescription
/stereo/left/image_raw/compressed/parameter_updates 1 msg : dynamic_reconfigure/Config
/stereo/right/image_raw/compressed 4140 msgs : sensor_msgs/CompressedImage
/stereo/right/image_raw/compressed/parameter_descriptions 1 msg : dynamic_reconfigure/ConfigDescription
/stereo/right/image_raw/compressed/parameter_updates 1 msg : dynamic_reconfigure/Config
/velodyne_2dscan_high_beams 1367 msgs : sensor_msgs/LaserScan
/velodyne_points 1366 msgs : sensor_msgs/PointCloud2

There is a lot of output here, but all we care about is the final section named "topics". We then need an odometry message of the type nav_msgs/Odometry and a LiDAR message of type sensor_msgs/LaserScan. As long as you have two topics with both of these types of messages (listed after the colon on the right) you can run your data with nautilus!

The topics we need are "/odometry/raw" for odometry, and "/velodyne_2dscan_high_beams" for LiDAR.

info

If you are using CobotOdometry messages, they are differential odometry and need to set the differential_odom=true parameter to your config file. You can specify the path still using the lidar_path config parameter like below.

Now we will create a new config file in the config folder:

touch myconfig.lua

Inside Your new Config:

Now, we don't want to have to redefine all the different configuration parameters needed by nautilus, so we will add this line to the top of our config file so that the defaults will be loaded, and anything we don't overwrite will have it's default value.

dofile(debug.getinfo(1).source:match("@?(.*/)") .. '/default_config.lua')

Then we need to specify where our bag is:

bag_path="<path_to_bag_relative_to_nautilus_repository_root>"

Then we need to specify those topics that we found earlier:

lidar_topic="<lidar_topic_name_from_before>"
odom_topic="<odometry_topic_name_from_before>"

Finally, we should add the number of poses to process. The default is 30 poses, which is a very small number. I am going to guess for my bag file and say that there is 450 poses that I want to process. If you just want to process the entire bag file then set this parameter to a large number.

pose_number=450

Now you have written the config file you can run it through nautilus as follows:

./bin/nautilus --config_file config/myconfig.lua
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