ouster_ros

This package is a simpler ROS client implementation for the Ouster lidar sensors with firmware version >=1.14.0. It includes new functionalities that cannot be found in the original ouster_example (see Motivation)

Table of Contents

• Motivation / Features

• Requirements

• Instructions

  • Building
  • PTP Configuration
  • Usage

• Launch files

• Nodes

• License

• Help

Motivation / Features

The motivation for creating this package is:

• Unify the example libraries provided by Ouster in one place, making it easier to compile
• Avoid the overhead given in the official Ouster example
• Possibility to disable IMU message processing in case of non-use, freeing up CPU
• Possibility to inverse TF publication between /os_sensor and /os_lidar
• Code-level check of the synchronization of published messages when setting up PTP

If you are ok without these functionalities, feel free to use the original ouster_example from Ouster.

Requirements

• Tested with ROS Melodic on Ubuntu 18.04, but it may work with ROS Kinetic on Ubuntu 16.04 (untested) with some extra packages:
  • ros-melodic-pcl-ros
  • ros-melodic-tf2-geometry-msgs
• Ouster sensor, firmware [>= 1.14.0]. Tested with OS0-128 and OS1-64, but any other with the proper firmware should work

Instructions

Building

Just clone in your ROS workspace and do catkin_make -DCMAKE_BUILD_TYPE=Release

PTP Configuration

1. sudo apt install linuxptp chrony ethtool
2. Make sure the ethernet interface supports PTP with sudo ethtool -T YOUR_INTERFACE
3. Modify /etc/linuxptp/ptp4l.conf with:
   • clockClass 128
   • boundary_clock_jbod 1
   • [YOUR_INTERFACE] <- append this to the end of the file
4. Create folder sudo mkdir -p /etc/systemd/system/ptp4l.service.d
5. Create file /etc/systemd/system/ptp4l.service.d/override.conf with:

   [Service]
   ExecStart=
   ExecStart=/usr/sbin/ptp4l -f /etc/linuxptp/ptp4l.conf
   

6. Create folder: sudo mkdir -p /etc/systemd/system/phc2sys.service.d
7. Create file /etc/systemd/system/phc2sys.service.d/override.conf with:

   [Service]
   ExecStart=
   ExecStart=/usr/sbin/phc2sys -w -s CLOCK_REALTIME -c YOUR_INTERFACE
   

8. Modify /etc/systemd/system/phc2shm.service:

   [Unit]
   Description=Synchronize PTP hardware clock (PHC) to NTP SHM
   Documentation=man:phc2sys
   After=ntpdate.service
   Requires=ptp4l.service
   After=ptp4l.service
   [Service]
   Type=simple
   ExecStart=/usr/sbin/phc2sys -s YOUR_INTERFACE -E ntpshm -w 
   [Install]
   WantedBy=multi-user.target
   

NOTE: Change YOUR_INTERFACE to the ethernet interface used (ex: eno1)

Usage

1. Start PTP services with rosrun ouster_ros lidar_ptp.sh
2. In case lidar is in DHCP mode: sudo dnsmasq -C /dev/null -kd -F MIN_IP,MAX_IP -i YOUR_INTERFACE --bind-dynamic (ex: MIN_IP=10.5.0.1, MAX_IP=10.5.0.255, YOUR_INTERFACE=eno1)
3. roslaunch ouster_ros ouster.launch

Launch files

• ouster.launch:

  Arguments:

  • sensor_hostname (string) - Lidar IP or ID (ex: 10.5.0.10)
  • udp_dest (string) - Local PC IP (ex: 10.5.0.1)
  • lidar_port (int) - Port to which the sensor should send lidar data (default 7502)
  • imu_port (int) - Port to which the sensor should send imu data (default 7503). If 0, IMU is disabled.
  • lidar_mode (string) - Lidar resolution and rate [512x10, 512x20, 1024x10, 1024x20, 2048x10]
  • timestamp_mode (string) - Method used to timestamp measurements [TIME_FROM_INTERNAL_OSC, TIME_FROM_SYNC_PULSE_IN, TIME_FROM_PTP_1588]
  • tf_prefix (string) - Namespace for tf transform (default = "")
  • tf_inverse (bool) - Inverse tf os_sensor <-> os_lidar.
  • stamp_offset (float) - Seconds to be added to the stamp header before publishing it
  • max_sync_diff (float) - Max admissible delay in the stamp header
  • enable_img_node (bool) - Whether or not enable the image node
  • metadata (string) - Path to metadata file for image node

Nodes

• os_node

  Advertised topics:

  • ~/points (sensor_msgs/PointCloud2) - Pointcloud from lidar
  • ~/imu (sensor_msgs/Imu) - Imu topic from sensor
  • ~/lidar_status (std_msgs/Header) - Publish one message for each pointcloud. In case lidar sensor fails (ex: overheating), it stops publishing.

• os_img_node

  Advertised topics:

  • ~/range_image (sensor_msgs/Image)
  • ~/noise_image (sensor_msgs/Image)
  • ~/intensity_image (sensor_msgs/Image)

License

See License

This code is distributed with the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of merchantability or fitness for a particular purpose.

All the credits go to the Ouster team and their original repo ouster_example for establishing the basis of this project.

Help / Contribution

• Contact: Rafael Caballero (rcaballero@catec.aero)

  

• Found a bug? Create an ISSUE!

• Do you want to contribute? Create a PULL-REQUEST!