Environment Setup - Raspberry Pi

This section describes the steps to prepare the development environment for the UGV project on the Raspberry Pi, which is the base board of the robot platform, including the installation of the operating system, ROS 2 Humble, and the configuration of the Raspberry Pi for control.

Operating System Installation

1. Download Ubuntu Server Image:

   • Go to the official Ubuntu Server website and download the latest image.

   • Use software like Raspberry Pi Imager to save the image to the SD card.

2. Initial Setup:

   • Insert the SD card into the Raspberry Pi and turn on the device.

   • Configure Wi-Fi network and other basic preferences during startup.

   • Update the operating system:

     sudo apt update
     sudo apt upgrade
     

Configuring Raspberry Pi as Server and SSH Communication

1. Server Mode:

   • Server configuration allows Raspberry Pi to be accessed remotely.

   • Connect to the server using SSH:

     ssh embrapa@10.42.0.1
     

ROS Humble Installation

1. Add ROS Repository Key:

   sudo apt install software-properties-common
   sudo add-apt-repository universe
   sudo apt update
   sudo apt install curl
   curl -sSL https://raw.githubusercontent.com/ros/rosdistro/master/ros.asc | sudo apt-key add -
   

2. Add ROS Repository:

   sudo sh -c 'echo "deb http://packages.ros.org/ros2/ubuntu $(lsb_release -cs) main" > /etc/apt/sources.list.d/ros2-latest.list'
   sudo apt update
   sudo apt install ros-humble-desktop
   

3. Configure ROS Environment:

   Add the following lines to the ~/.bashrc file:

   source /opt/ros/humble/setup.bash
   

Manual Rover Bringup

To manually start the rover, run the following commands in the terminal:

1. Make sure the program is not already running:

   sudo systemctl stop osr_startup
   

2. Execute the bringup command:

   ros2 launch osr_bringup osr_launch.py
   

Automatic Bringup with Launch Script

To automate the bringup and eliminate the need for SSH access, configure the Raspberry Pi to launch the rover code automatically:

1. Navigate to the init_scripts folder:

   cd ~/osr_ws/src/osr-rover-code/init_scripts
   

2. Create symbolic links:

   sudo ln -s $(pwd)/launch_osr.sh /usr/local/bin/launch_osr.sh
   sudo ln -s $(pwd)/osr_paths.sh /usr/local/bin/osr_paths.sh
   

3. Copy the service file to the systemd services directory:

   sudo cp osr_startup.service /etc/systemd/system/osr_startup.service
   

4. Adjust service file permissions:

   sudo chmod 644 /etc/systemd/system/osr_startup.service
   

Image Acquisition Setup

1. Installation of Required Libraries:

   sudo apt install ros-humble-cv-bridge
   sudo apt install ros-humble-image-transport
   

2. Camera Configuration:

   • Connect Intel RealSense D435i and Logitech C920 HD PRO cameras to Raspberry Pi.

   • Use the following commands to check and adjust settings:

     rs-enumerate-devices
     v4l2-ctl --list-devices
     

3. Publishing and Viewing Images:

   • Run ROS nodes to capture and publish images:

     ros2 run realsense2_camera realsense2_camera_node
     ros2 run image_transport republish raw in:=/camera/color/image_raw out:=/image_raw
     

   • Another way to start capturing images:

     systemctl restart start_turtle.service
     

   • To view images use Rviz2 or rqt_image_view:

     ros2 run rqt_image_view rqt_image_view
     # or
     rviz2