🧭 Multi-Map Navigation with Wormholes in ROS 1

Overview

This ROS package demonstrates a modular, action-based multi-map navigation system for a mobile robot that seamlessly transitions between independently mapped rooms (maps) using a mechanism called wormholes.

Key features:

• Dynamic room-to-room navigation
• SQL database to store wormhole data
• Gazebo simulation and move_base navigation
• Custom action server for multi-map goal handling
• Automatic launch and shutdown of Gazebo + Nav Stack nodes

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📌 Problem Statement

Design and implement a system where:

• Each room is mapped separately.
• A robot can navigate to any location across rooms.
• A wormhole connects overlapping areas between rooms.
• Robot autonomously:
  • Navigates to the wormhole,
  • Switches map and Gazebo world,
  • Continues navigation in the new room.

---

🗂️ Project Structure

multi_map_navigator/
├── action/
│ └── NavigateBetweenMaps.action
├── maps/
│ ├── room_a.yaml
│ └── room_b.yaml
├── world/
│ ├── room_a.world
│ └── room_b.world
├── launch/
│ ├── amcl.launch
│ ├── move_base.launch
│ ├── my_world_loader.launch
│ └── my_navigation.launch
├── src/
│ ├── action_server.cpp
│ ├── action_client.cpp
│ ├── nav_controller.cpp
│ ├── map_manager.cpp
│ └── db_interface.cpp
├── include/
│ └── multi_map_navigator/
│ ├── nav_controller.hpp
│ ├── map_manager.hpp
│ └── db_interface.hpp
├── param/
│ ├── base_local_planner_params.yaml
│ ├── costmap_common_params_burger.yaml
│ ├── dwa_local_planner_params_burger.yaml
│ ├── global_costmap_params.yaml
│ ├── local_costmap_params.yaml
│ └── move_base_params.yaml
├── rviz/
│ └── turtlebot3_navigation.rviz
├── my_wormholes.db
├── CMakeLists.txt
└── package.xml

---

🧠 Architecture

Core Components:

• action_server.cpp: Receives goal with pose + map ID, dispatches to NavController.
• NavController: Handles logic to either:
  • Navigate directly if in the same map.
  • Go to wormhole, shutdown current world, launch new one, continue navigation.
• db_interface: SQLite wrapper for reading wormhole positions.
• map_manager: Publishes initial pose after map switch.

Inter-process Coordination:

• Launch files for spawning Gazebo + navigation stack per map.
• Wormholes act as bridges between maps.
• Modular launch separation ensures extendability.

---

🚀 Execution Flow

1. Client Node:

   • Starts my_world_loader.launch and my_navigation.launch.
   • Sends a NavigateBetweenMapsGoal to the server.

2. Server (Action):

   • Checks if target map is same.
   • If not:
     • Moves to wormhole using move_base.
     • Kills current Gazebo and Nav stack.
     • Launches new world_file and map_file.
     • Sets initial pose via map_manager.
     • Sends final goal to move_base.

3. Navigation is visualized in RViz.

---

⚙️ How to Run

cd ~/multi_map_nav_ws
catkin_make
source devel/setup.bash
rosrun multi_map_navigator navigate_between_maps_server
rosrun multi_map_navigator navigate_between_maps_client

📡 Wormhole DB Schema

my_wormholes.db contains:

CREATE TABLE wormholes (
  source_map TEXT,
  target_map TEXT,
  source_x REAL,
  source_y REAL,
  source_yaw REAL,
  target_x REAL,
  target_y REAL,
  target_yaw REAL
);

📋 Pseudocode (C++ Style)

handleNavigation(...)

if (target_map == current_map) {
    // Already in the desired map, send goal directly
    return sendGoal(target_pose);
}

// Step 1: Fetch wormhole details from SQLite DB
Wormhole wh = db.getWormhole(current_map, target_map);

// Step 2: Navigate to the wormhole pose in current map
sendGoal(wh.source_pose);

// Step 3: Kill old Gazebo and Navigation nodes
killGazeboAndNavStack();

// Step 4: Launch new world and map
launchNewWorld(target_map);
launchNavStack(target_map);

// Step 5: Set initial pose in new map using wormhole target
map_mgr.setInitialPose(wh.target_x, wh.target_y, wh.target_yaw);

// Step 6: Wait for new move_base to come up
waitForMoveBase();

// Step 7: Send final goal in the new map
return sendGoal(target_pose);

📋 Pseudocode – sendGoal(...)

// Connect to move_base action server
wait for move_base;

// Send the goal
send goal;

// Wait for result
wait for result;

// Return outcome
if (success)
    return true;
else
    return false;

📊 Trajectory Handling

Collection:

Trajectories generated by move_base can be recorded using:

rosbag record /odom /move_base/TrajectoryPlannerROS/global_plan /tf

Storage

• Navigation is dynamic and reactive.
• Paths are computed live by move_base.
• No pre-defined or statically stored trajectories are used.

Visualization (RViz)

• View real-time robot movement
• Set initial pose (/initialpose)
• Send navigation goals (2D Nav Goal)
• Track coordinate frames (/tf)
• Observe global and local planned paths in RViz

✅ Modularity & OOP Principles

• All core functionality is modular and separated into:
  • NavController: Handles decision flow and control logic.
  • DBInterface: Interfaces with the SQLite wormhole database.
  • MapManager: Publishes initial pose after map switch.
• ROS parameters, file paths, and topic names are externally configurable.
• To add new maps:
  • Just create new .yaml, .world, and a DB entry — no code change needed.

📦 Dependencies

• ROS Noetic
• move_base, amcl, map_server
• gazebo_ros, turtlebot3_description
• SQLite3 (system library)

sudo apt-get install libsqlite3-dev sqlite3