FSM: Correspondenceless scan-matching of panoramic 2D range scans

fsm_lo is a ROS package written in C++ that provides LIDAR odometry from measurements of a single panoramic 2D LIDAR sensor, that is: a sensor whose field of view is 360 degrees. fsm_lo is the ROS wrapper of fsm.

Lidar odometry is achieved via scan-matching but without establishing correspondences between elements of the input scans or their properties, but by leveraging the range signal's periodicity. Hence FSM may exploit properties of the Discrete Fourier Transform, which it does. These two pillars support the robustness of FSM's pose error against (a) sensor noise and (b) distance between consecutive poses, as you can see in the figure that summarises key experiments below.

Why use FSM

Table of Contents

• Pre-installation
• Installation
• Run
  • Launch
  • Call
• Nodes
  • fsm_lo_node
    • Subscribed topics
    • Published topics
    • Services offered
    • Parameters
    • Transforms published
• Motivation and Under the hood
  • 1 min summary video
  • IROS 2022 paper

Pre-installation

fsm-lo is installed, launched, and called via Docker:

• if this is your first time running docker then I happen to find this docker installation guide very friendly and easy to follow
• if instead you wish to install and run the package natively then see the INSTALLATION_DEPRECATED.md guide.

Installation

Build the image with the most recent code of this repository using compose with

git clone git@github.com:li9i/fsm-lo.git
cd fsm-lo
docker compose build

or pull the docker image and run it with

docker pull li9i/fsm-lo:latest

docker run -it \
    --name=fsm_lo_container \
    --env="DISPLAY=$DISPLAY" \
    --net=host \
    --rm \
    li9i/fsm-lo:latest

Run

Launch

docker compose up

Call

Launching fsm simply makes it go into stand-by mode and does not actually execute anything. To do so simply call the provided service

docker exec -it fsm_lo_container sh -c "source ~/catkin_ws/devel/setup.bash; rosservice call /fsm_lo/start"

Nodes

fsm_lo_node

Subscribed topics

Topic	Type	Utility
scan_topic	sensor_msgs/LaserScan	2d panoramic scans are published here
initial_pose_topic	geometry_msgs/PoseWithCovarianceStamped	optional---for setting the very first pose estimate to something other than the origin

Published topics

Topic	Type	Utility
pose_estimate_topic	geometry_msgs/PoseStamped	the current pose estimate relative to the global frame is published here
path_estimate_topic	nav_msgs/Path	the total estimated trajectory relative to the global frame is published here
lo_topic	nav_msgs/Odometry	the odometry is published here

Services offered

Service	Type	Utility
fsm_lo/clear_estimated_trajectory	std_srvs/Empty	clears the vector of estimated poses
fsm_lo/set_initial_pose	std_srvs/Empty	calling this service means: node subscribes to initial_pose_topic, obtains the latest pose estimate, sets fsm's initial pose, and unsubscribes
fsm_lo/start	std_srvs/Empty	commences node functionality
fsm_lo/stop	std_srvs/Empty	halts node functionality (node remains alive)

Parameters

Found in config/params.yaml:

IO Topics	Description
scan_topic	2d panoramic scans are published here
initial_pose_topic	(optional) the topic where an initial pose estimate may be provided
pose_estimate_topic	fsm_lo's pose estimates are published here
path_estimate_topic	fsm_lo's total trajectory estimate is published here
lo_topic	fsm_lo's odometry estimate is published here

Frame ids	Description
global_frame_id	the global frame id (e.g. /map)
base_frame_id	the lidar sensor's reference frame id (e.g. /base_laser_link)
lo_frame_id	the (lidar) odometry's frame id

FSM-specific parameters	Description	Default value
size_scan	the size of scans that are matched (execution time is proportional to scan size, hence subsampling may be needed)	360
min_magnification_size	base angular oversampling	0
max_magnification_size	maximum angular oversampling	3
num_iterations	Greater sensor velocity requires higher values	2
xy_bound	Axis-wise radius for randomly generating a new initial position estimate in case of recovery	0.2
t_bound	Angular-wise radius for randomly generating a new initial orientation estimate in case of recovery	π/4
max_counter	Lower values decrease execution time	200
max_recoveries	Ditto	10

Transforms published

lo_frame_id <- base_frame_id

in other words fsm_lo_node publishes the transform from /base_laser_link (or equivalent) to the equivalent of /odom (in this case lo_frame_id)

Motivation and Under the hood

1 min summary video

IROS 2022 paper

@INPROCEEDINGS{9981228,
  author={Filotheou, Alexandros and Sergiadis, Georgios D. and Dimitriou, Antonis G.},
  booktitle={2022 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS)},
  title={FSM: Correspondenceless scan-matching of panoramic 2D range scans},
  year={2022},
  pages={6968-6975},
  doi={10.1109/IROS47612.2022.9981228}}