Overview

This package provides a ROS2 driver node for HOKUYO 2D LiDAR(SOKUIKI Sensor).

Feature

• Supports Ethernet and USB connections
• Scanning data output
• Multi-Echo Scanning data output (use laser_proc topic)
• Output hardware diagnostic information (use diagnostic_updater topic)
• Component Mounting
• Life cycle controlsupport

The interfaces and some of the processes are based on urg_node package, which is often used in ROS1.

urg_library ver.1.2.5 is used for communication with LiDAR.

Life cycle control

The operation in each state of the life cycle is as follows

• Unconfigured $~~~~$ Startup state
• Inactive $~~~~~~~~~~~~$ LiDAR connection state（not delivered scanning data and diagnostic information）
• Active $~~~~~~~~~~~~~~$ LiDAR data delivery state（delivered scanning data and diagnostic information）
• Finalize $~~~~~~~~~~~~$ End state

Supported models

Hokuyo's SCIP 2.2-compliant LiDAR Tested models: UTM-30LX-EW, UST-10LX, UTM-30LX, URG-04LX-UG01, UAM-05LP, UAM-05LPA

Tested Environments: foxy, galactic, humble

License

Apache License 2.0 The urg_libray C API is licensed under the Simplified BSD License.

Publish

Topic	Message	Description	depends on
/scan	sensor_msgs::msg::LaserScan	LiDAR scanning data	publish_multiecho=false
/echoes	sensor_msgs::msg::MultiEchoLaserScan	LiDAR multi-echo scanning data	publish_multiecho=true
/first	sensor_msgs::msg::LaserScan	Nearest scanning data	publish_multiecho=true
/last	sensor_msgs::msg::LaserScan	Farthest scanning data	publish_multiecho=true
/most_intense	sensor_msgs::msg::LaserScan	Most intense scanning data	publish_multiecho=true
/diagnostics	diagnostics_msgs::msg::DiagnosticArray	Diagnostic information

Parameters

Parameter	Type	Default	Description
ip_address	string	" "	IP address for Ethernet connection（Specify in the format "XX.XX.XX.XX.XX"), If the specified string is empty, a serial connection is selected
ip_port	int	10940	Port number for Ethernet connection
serial_port	string	/dev/ttyACM0	Serial device path to connect to
serial_baud	int	115200	Serial baud rate
frame_id	string	"laser"	Frame_id of scanning data. The parameter frame_id is set in the message header "frame_id" of the scan data.
calibrate_time	bool	false	Adjustment mode flags. If this flag is true, the discrepancy between the LiDAR time and the system time is measured at the start of the scan and added to the timestamp of the scan data as latency.
synchronize_time	bool	false	Synchronous mode flags. If this flag is true, the system time, which is the reference for the timestamp of the scan data, is dynamically corrected using the discrepancy from the LiDAR time.
publish_intensity	bool	false	Intensity output mode flag. If this flag is true, the intensity data of the scan data is output; if false, the intensity data is output empty. If LiDAR does not support intensity output, it works the same as the false setting.
publish_multiecho	bool	false	Multi-echo mode flag. If this flag is true, multi-echo scan data (/echoes, /first, /last, /most_intense) is output; if false, scan data (/scan) is output. If LiDAR does not support multi-echo, it works the same as the false setting.
error_limit	int	4 [count]	Number of errors to perform reconnection. Reconnects the connection with LiDAR when the number of errors that occurred during data acquisition becomes larger than error_limit.
error_reset_period	double	5.0 [sec]	Error reset cycle. Periodically resets the number of errors that occurred during data acquisition. To prevent reconnection in case of sporadic errors.
diagnostics_tolerance	double	0.05	Allowable percentage of diagnostic information on frequency of scan data delivery relative to target delivery frequency. For example, if diagnostics_tolerance is 0.05, the normal range is 105% to 95% of the target delivery frequency.
diagnostics_window_time	double	5.0 [sec]	Period to measure the frequency of output delivery of diagnostic information on the frequency of scan data delivery.
error_limit	int	4 [count]	Number of errors to perform reconnection. Reconnects the connection with LiDAR when the number of errors that occurred during data acquisition becomes larger than error_limit.
time_offset	double	0.0 [sec]	User latency to be added to timestamp of scan data
angle_min	double	-pi [rad], range：-pi~pi	Minimum angle of scan data output range
angle_max	double	pi [rad], range：-pi~pi	Maximum angle of scan data output range
skip	int	0 [count], range: 0~9	Output thinning setting for scanned data. The frequency of scanned data delivery is multiplied by 1/(skip+1).
cluster	int	1 [count], range: 1~99	Scan data grouping settings. The number of data in the scan data is multiplied by 1/cluster.

Build

Obtaining Source Code

mkdir -p workspace/src
cd workspace/src
git clone --recursive https://github.com/AIResearchLab/urg_node2.git

2. Installing Related Packages

cd workspace/
rosdep update
rosdep install -i --from-paths urg_node2

3. Build

workspace/
colcon build --symlink-install

Use

launch

1. Connect LiDAR via Ethernet or USB.

2. Set the connection destination (parameters). Edit config/params_ether.yaml (for Ethernet connections) or config/params_serial.yaml (for USB connections).

3. Execute one of the following commands to automatically transition to the Active state and begin distribution of scan data.

   # for ethernet connected LiDAR
   ros2 launch urg_node2 urg_node2_ether.launch.py
   
   # for serial connected LiDAR
   ros2 launch urg_node2 urg_node2_serial.launch.py

   If you do not want to automatically transition to the Active state, execute the following command. (After startup, it will enter the Unconfigured state.)

   # for ethernet connected LiDAR
   ros2 launch urg_node2 urg_node2_ether.launch.py auto_start:=false
   
   # for serial connected LiDAR
   ros2 launch urg_node2 urg_node2_serial.launch.py auto_start:=false
   

   In urg_node2.launch.py, urg_node2 is launched as a standalone lifecycle node (not as a component). This is because there is no lifecycle control interface in launch when launched as a component and lifecycle node (not implemented in ROS2 at this time).

4. LaserScan messages are published with the frame_id parameter (default laser). If visualizing laser scan data with Rviz2, run the following command in a new terminal to startup a temporary static_transform_publisher

ros2 run tf2_ros static_transform_publisher 0 0 0 0.0 0.0 0.0 map laser

Usage with Docker

Clone this reposiotory

git clone https://github.com/AIResearchLab/urg_node2.git && cd urg_node2/docker

Pull the Docker image and start compose (No need to run docker compose build)

docker compose pull
docker compose up

To clean the system,

docker compose down
docker volume rm docker_hakuyo