Internship Progress Week 5 (July 30 ~ August 05)

This week, my progress focused on developing a Nav2-based path planning and tracking solution for the Global Navigation exercise in RoboticsAcademy, utilizing standard global navigation algorithms already included in Nav2 instead of the custom GPP algorithm.

Here is the progress detailing how we implemented Nav2 and the current blockages encountered:

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1. Implementing Nav2-based Solution for Global Navigation

Instead of implementing a custom GPP path-planning algorithm, we worked on utilizing standard ROS 2 Humble Navigation Stack (Nav2) packages:

• Static Map Configuration: Created cityLargenBin.yaml to map the $500\text{m} \times 500\text{m}$ Gazebo city world coordinates to standard ROS 2 occupancy grid metrics (at 1.25 meters per pixel). This enables standard Nav2 map servers to feed the costmap.
• Costmap and Nav2 Parameters: Configured planner_server (using standard NavfnPlanner global path planner) and controller_server (using RegulatedPurePursuitController local tracker) inside nav2_params.yaml. Static costmaps were tuned to run without LiDAR sensor dependencies.
• Bridge Interface (nav2_bridge.py): Developed a ROS 2 bridge node to translate JdeRobot’s WebGUI mouse click coordinates to standard /goal_pose topics and publish the resulting Nav2 planned paths back to the user GUI canvas.
• Unified Launch Integration: Combined the Gazebo world server, robot spawner, static transforms, map server, Nav2 planners, and the GUI bridge into a single executable launch file global_navigation_nav2.launch.py linked natively to the database.

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2. Current Blockages & Unresolved Issues

We are currently blocked by the following errors, preventing final verification of the Nav2 navigation loops:

• VNC Black Screen (UNRESOLVED): The VNC desktop screen (displays :1 and :2) remains completely black. The Gazebo GUI client fails to create its main rendering window, caused by Mesa software OpenGL emulation rendering bugs under Rosetta 2 translator on ARM64 macOS host.
• Costmap TF Timeout Warnings: The costmap server throws continuous warnings: Timed out waiting for transform from base_link to map to become available... because odometry is not published while the simulation physics is paused or the vehicle description joints are disconnected.
• Verification Blocked: Because the simulation frontend and window manager rendering is black, we cannot visually verify if the Nav2 planner successfully drives the taxi vehicle to the selected target.

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3. Visual Verification

Below is the static city occupancy grid map used for costmap planning:

Figure: The binary occupancy grid map loaded into nav2_map_server.