Sensor Drivers Setup

This guide covers the installation and configuration of ZED camera and Ouster LiDAR drivers for Clearpath robots.

Prerequisites

• ROS 2 Humble installed
• Clearpath robot system configured
• Appropriate permissions to edit systemd services

1. ZED Camera ROS Driver

1.1 Installation

1. Create or navigate to your ROS 2 workspace:

   mkdir -p ~/ros2_ws/src
   cd ~/ros2_ws/src
   

2. Clone the ZED ROS 2 wrapper repository:

   git clone https://github.com/stereolabs/zed-ros2-wrapper.git
   

3. Build the package:

   cd ~/ros2_ws
   colcon build --packages-select zed_wrapper zed_components zed_interfaces
   

4. Source the workspace:

   source ~/ros2_ws/install/setup.bash
   

1.2 Testing

Launch the ZED camera with the following command:

ros2 launch zed_wrapper zed_camera.launch.py \
    camera_model:=zed2 \
    namespace:=<robot_namespace>

Note: Replace <robot_namespace> with your robot's namespace (e.g., j100_0893).

1.3 Additional Resources

• Official ZED camera ROS 2 documentation: https://www.stereolabs.com/docs/ros2

2. Ouster ROS Driver

2.1 Installation

1. Navigate to your ROS 2 workspace source directory:

   cd ~/ros2_ws/src
   

2. Clone the Ouster ROS repository (Humble branch):

   git clone -b humble-devel https://github.com/ouster-lidar/ouster-ros.git
   

3. Build the package:

   cd ~/ros2_ws
   colcon build --packages-select ouster_ros
   

4. Source the workspace:

   source ~/ros2_ws/install/setup.bash
   

2.2 Testing

Launch the Ouster LiDAR driver:

ros2 launch ouster_ros driver.launch.py \
    sensor_hostname:=<sensor_ip> \
    lidar_port:=7502 \
    imu_port:=7503 \
    namespace:=<robot_namespace>

Note: - Replace <sensor_ip> with your LiDAR's IP address - Replace <robot_namespace> with your robot's namespace

2.3 Additional Resources

• Ouster ROS repository: https://github.com/ouster-lidar/ouster-ros/tree/ros2

3. Integrating with Clearpath Services

To ensure the sensor drivers are properly sourced when Clearpath services start, you need to override the systemd service configurations.

3.1 Override Robot Service

1. Edit the robot service:

   sudo systemctl edit clearpath-robot.service
   

2. Add the following configuration:

   [Service]
   Environment="CLEARPATH_ROBOT_NAMESPACE=<robot_namespace>"
   ExecStart=
   ExecStart=/bin/bash -lc ' \
       source /opt/ros/humble/setup.bash && \
       source /home/administrator/clearpath_ws/install/setup.bash && \
       source ~/ros2_ws/install/setup.bash && \
       exec /usr/sbin/clearpath-robot-start \
   '
   

Note: Replace <robot_namespace> with your robot's namespace.

3.2 Override Platform Service

1. Edit the platform service:

   sudo systemctl edit clearpath-platform.service
   

2. Add the following configuration:

   [Service]
   ExecStart=
   ExecStart=/bin/bash -lc ' \
       source /opt/ros/humble/setup.bash && \
       source /home/administrator/clearpath_ws/install/setup.bash && \
       source ~/ros2_ws/install/setup.bash && \
       exec /usr/sbin/clearpath-platform-start \
   '
   

3.3 Override Sensors Service

1. Edit the sensors service:

   sudo systemctl edit clearpath-sensors.service
   

2. Add the following configuration:

   [Service]
   ExecStart=
   ExecStart=/bin/bash -lc ' \
       source /opt/ros/humble/setup.bash && \
       source /home/administrator/clearpath_ws/install/setup.bash && \
       source ~/ros2_ws/install/setup.bash && \
       exec /usr/sbin/clearpath-sensors-start \
   '
   

3.4 Restart Services

After making these changes, restart the services:

sudo systemctl daemon-reload
sudo systemctl restart clearpath-robot.service
sudo systemctl restart clearpath-platform.service
sudo systemctl restart clearpath-sensors.service

4. Verification

1. Check that services are running:

   sudo systemctl status clearpath-robot.service
   sudo systemctl status clearpath-platform.service
   sudo systemctl status clearpath-sensors.service
   

2. Verify sensor topics are published:

   ros2 topic list | grep -E "(zed|ouster)"
   

3. Check TF frames:

   ros2 run tf2_ros tf2_echo /map /<robot_namespace>/base_link
   

5. Troubleshooting

Services fail to start

• Verify all workspace paths are correct
• Check that all packages built successfully
• Review service logs: sudo journalctl -u clearpath-robot.service -n 50

Sensor topics not appearing

• Ensure sensors are physically connected
• Verify sensor IP addresses and ports
• Check that launch files are being called correctly

Namespace issues

• Confirm namespace is consistent across all configurations
• Verify environment variables are set correctly