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beluga_amcl

Beluga AMCL

Beluga AMCL is a ROS node based on the Beluga library that aims to be fully compatible with both Navigation 2 AMCL and Navigation AMCL nodes.
The compatibility between beluga_amcl and its longstanding counterparts in the ROS ecosystem provides a simple migration path for projects that want to be able to integrate the power and modularity of the Beluga library in an existing nav2_amcl-based (or amcl-based) project.

Table of Contents

ROS 2 Interface

Parameters

Beluga AMCL currently supports the majority of ROS parameters used in Navigation 2 AMCL.
See Beluga AMCL documentation for further reference.

Subscribed Topics

The subscribed topic names can be changed with the parameters map_topic, scan_topic and initial_pose_topic.

Topic Type Description
map nav_msgs/OccupancyGrid Input topic for map updates.
scan sensor_msgs/LaserScan Input topic for laser scan updates.
initial_pose geometry_msgs/PoseWithCovarianceStamped Input topic for pose mean and covariance to initialize the particle filter.

Published Topics

Topic Type Description
particle_cloud geometry_msgs/PoseArray Output topic for particle cloud published at a fixed frequency.
pose geometry_msgs/PoseWithCovarianceStamped Output topic for estimated pose mean and covariance in map frame.

Published Transforms

The frame names can be changed with the parameters global_frame_id, odom_frame_id and base_frame_id. Defaults are map, odom and base.

Transform Description
odom to base Input transform used by motion models and resampling policies.
base to laser Input transform used to convert laser scan points to base frame.
map to odom Output transform calculated from the estimated pose mean and the current odom-to-base transform.

Advertised Services

Topic Type Description
reinitialize_global_localization std_srvs/Empty Request to reinitialize global localization without an initial pose estimate.
request_nomotion_update std_srvs/Empty Trigger a forced update of the filter estimates.

ROS 1 Interface

Parameters

Beluga AMCL currently supports the majority of ROS parameters used in AMCL.
See Beluga AMCL parameter reference for detailed information.

Subscribed Topics

The subscribed topic names can be changed with the parameters map_topic, scan_topic and initial_pose_topic.

Topic Type Description
map nav_msgs/OccupancyGrid Input topic for map updates.
scan sensor_msgs/LaserScan Input topic for laser scan updates.
initialpose geometry_msgs/PoseWithCovarianceStamped Input topic for pose mean and covariance to initialize the particle filter.

Published Topics

Topic Type Description
particlecloud geometry_msgs/PoseArray Output topic for particle cloud published at a fixed frequency.
amcl_pose geometry_msgs/PoseWithCovarianceStamped Output topic for estimated pose mean and covariance in map frame.
diagnostics diagnostic_msgs/DiagnosticArray Output topic for node diagnostics.

Published Transforms

The frame names can be changed with the parameters global_frame_id, odom_frame_id and base_frame_id. Defaults are map, odom and base.

Transform Description
odom to base Input transform used by motion models and resampling policies.
base to laser Input transform used to convert laser scan points to base frame.
map to odom Output transform calculated from the estimated pose mean and the current odom-to-base transform.

Advertised Services

Topic Type Description
global_localization std_srvs/Empty Request to reinitialize global localization without an initial pose estimate.
request_nomotion_update std_srvs/Empty Trigger a forced update of the filter estimates.
set_map nav_msgs/SetMap Set a new map and initial pose estimate.

Called Services

Topic Type Description
static_map nav_msgs/GetMap To retrieve map on initialization, if use_map_topic parameter is false

Performance

Performance reports are periodically generated and uploaded to track performance improvements and regressions. These reports are generated using a set of scripts in the beluga_benchmark package which can be used to compare the performance of beluga_amcl against that of nav2_amcl using a synthetic dataset.

The following plot displays the RSS (Resident Set Size), CPU usage, APE (Absolute Pose Error) and processing latency statistics for both beluga_amcl and nav2_amcl, with particle sizes ranging between 250 and 200000 and sensor model likelihood field.

Beluga vs Nav2 AMCL

The following plot displays the RSS (Resident Set Size), CPU usage, APE (Absolute Pose Error) and processing latency statistics for both beluga_amcl and nav2_amcl, with particle sizes ranging between 250 and 200000 and sensor model beam.

Beluga vs Nav2 AMCL

Further details can be found in the reports folder here.

Next Steps