nav_visualization

Overview

This repository provides tools for visualizing robot navigation on a grid-based costmap. It includes ROS2 launch files and utility scripts that allow you to create, simulate, and visualize both path and local planning demos.

Launch Files

server-demo-pp.py

• Purpose: Launches the path planning visualizer with the planner server.
• Parameters:
  • costmap_file (default: costmap.txt)
  • window_width (default: 800)
  • window_height (default: 800)
• Usage Example:

  ros2 launch nav_visualization server-demo-pp.py costmap_file:=your_costmap.txt window_width:=800 window_height:=600
  

dummy-demo-pp.py

• Purpose: Runs the path planning visualizer with a dummy position publisher to simulate robot positions.
• Parameter:
  • costmap_file (default: costmap.txt)
• Usage Example:

  ros2 launch nav_visualization dummy-demo-pp.py costmap_file:=your_costmap.txt
  

dummy-demo-lp.py

• Purpose: Launches the local planning visualizer with a dummy twist publisher to simulate real-time motion.
• Parameters:
  • costmap_file (default: costmap.txt)
  • window_width (default: 800)
  • window_height (default: 800)
  • topic (default: /robot_twist)
• Usage Example:

  ros2 launch nav_visualization dummy-demo-lp.py costmap_file:=your_costmap.txt window_width:=800 window_height:=600 topic:=/your_twist_topic
  

Utility Scripts

draw_costmap.py

Launches a pygame interface to create/edit costmaps. Follow the prompts to set grid dimensions, designate start/goal positions, and add or remove obstacles. The map is saved upon closing the window.

pp_visualization.py

Visualizes the robot’s planned trajectory by reading a costmap and sending navigation goals using an action client. Window dimensions and costmap file can be modified via command line arguments.

lp_visualization.py

Subscribes to a ROS2 Twist topic and renders the costmap along with real-time robot movement and direction. Includes adjustable parameters for file name, window size, and topic name.

dummy_position_publisher.py

Simulates robot positions by reading the costmap file to determine the grid and publishing random, constrained positions based on the map’s boundaries.

dummy_twist_publisher.py

Publishes simulated Twist messages at a fixed rate to mimic smooth, realistic robot motion. Parameters include the destination topic and update rate.

Costmap File Format

• Line 1: Starting position coordinates (e.g., 1 1).
• Line 2: Goal position coordinates (e.g., 7 7).
• Remaining Lines: Rows of space-separated integers representing cell costs:
  • 0: Free cell.
  • Negative numbers (e.g., -1) or high positive numbers (e.g., 100) indicate obstacles or high-cost areas.

Usage Instructions

1. Creating a Costmap:

   • Navigate to the repository directory:

     cd ws/src/nav_visualization
     python3 draw_costmap.py
     

   • Follow the on-screen instructions to define grid dimensions, start/goal positions, and obstacles. The costmap is saved after closing the interface.

2. Integrating a Custom Costmap:

   • Update the file name in either pp_visualization.py or lp_visualization.py by passing the new costmap file name as a parameter.
   • Optionally, add the new file in your configuration (e.g., in setup.py).

3. Launching a Demo:

   • Build Packages:

     colcon build --packages-select nav_visualization nav_infrastructure
     

   • Source Setup File:

     source install/setup.bash   # or source install/setup.zsh
     

   • Launch Examples:
     • Path Planning Demo:

       ros2 launch nav_visualization server-demo-pp.py costmap_file:=your_costmap.txt window_width:=800 window_height:=600
       

     • Dummy Position Demo:

       ros2 launch nav_visualization dummy-demo-pp.py costmap_file:=your_costmap.txt
       

     • Local Planning Demo:

       ros2 launch nav_visualization dummy-demo-lp.py costmap_file:=your_costmap.txt window_width:=800 window_height:=600 topic:=/your_twist_topic