urg_node

LaserScan Visualization

Until the launch API is sorted out, there are two ways to view the laserscan in RViz:

1. use the static_transform_publisher tool from tf2_ros to publish a static transform for a fixed frame simultaneously with rviz and urg_node.

ros2 run tf2_ros static_transform_publisher 0 0 0 0 0 0 "world" "laser"

where "laser" is the frame id, which you can set in your urg_node yaml file

2. Run the robot_state_publisher along with a urdf file so that a fixed frame can be loaded in rviz

ros2 run robot_state_publisher robot_state_publisher <path to urdf file>

A urdf file is already included and if you have succesfully ran an colcon build, the path to urdf file will be:

<path to ros2_ws>/install/share/urg_node/launch/hokuyo_laser.urdf

Parameters

A YAML file example is included in the launch folder, all the available parameters are listed in it. For example (note that the serial_port is commented because you can't set a param with an empty string):

urg_node:
  ros__parameters:
    ip_address: "192.168.0.10"
    ip_port: 10940
    #serial_port: ""
    serial_baud: 115200
    laser_frame_id: laser
    angle_max: 3.14
    angle_min: -3.14
    publish_intensity: false
    publish_multiecho: false
    calibrate_time: false
    default_user_latency: 0
    diagnostics_tolerance: 0.05
    diagnostics_window_time: 5.0
    error_limit: 4
    get_detailed_status: false
    cluster: 0
    skip: 1

To give parameters to urg_node :

ros2 run urg_node urg_node_driver __params:=path/to/my/file.yaml

You can reconfigure parameters while the node is launched. For now, you can only reconfigure the following parameters:

laser_frame_id
error_limit
default_user_latency
angle_max
angle_min
cluster
skip

For example to reconfigure the cluster parameter using command line :

ros2 param set /urg_node cluster 1

How to use the ust-20lx (and other ethernet based laser)

To use ust-20lx, you need to be on the same subnet as the laser. The ust-20lx default ip is 192.168.0.10, so you might need to change your ip, for something on the same subnet.

On Ubuntu :

• go to the network settings
• settings of the wired connection
• under IPv4, change the IPv4 method from automatic to Manual and under Addresses, set the values:

    Address : 192.168.0.15
    Netmask : 255.255.255.0
    Gateway : 192.168.0.1

• Turn off and on the connection or wait a bit for the change to apply
• To check if it worked, open a terminal and type

ifconfig

• Under eth0 (or maybe something like enpxxxxx), your IP should be 192.168.0.15. You should now be able to ping the ust-20lx at its address (by default 192.168.0.10)

ping 192.168.0.10

If you don't receive any answer, you might have a connection problem or the IP of your laser might have been change, either find it and go on the same subnet or reset it.

• Once you can ping the laser, you can launch the urg_node_driver:

ros2 run urg_node urg_node_driver __params:=path/to/my/file.yaml

then the static publisher:

ros2 run tf2_ros static_transform_publisher 0 0 0 0 0 0 "world" "laser"

and rviz:

ros2 run rviz2 rviz2

Add the laserScan topic, change the frame on rviz from map to world and you should be able to see the laser.