SLAM Navigation Stack — UCR Robotics Project

Full SLAM and navigation stack on TurtleBot3 in Gazebo simulation and real-world testbed — covering mapping, localization, path planning, and Nav2 integration.

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Key Results

• 15% map accuracy improvement via Nav2 frontier exploration parameter tuning
• 10Hz real-time mapping performance
• Stable localization over 10m trajectories
• Successful autonomous exploration of unknown indoor environments

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Stack Overview

Component	Implementation
Mapping	SLAM Toolbox, Gmapping, Cartographer
Localization	AMCL with adaptive resampling
Global Planning	A*
Local Planning	DWB, TEB
Navigation	Nav2
Sensor	LiDAR (LaserScan)
Platform	TurtleBot3 Burger

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Repo Layout

slam_nav_tb3/
├── src/          # ROS2 packages and nodes
├── launch/       # Bringup and Nav2 launch files
├── config/       # Costmap, planner, controller parameters
├── maps/         # Saved maps (YAML + PGM)
├── scripts/      # Helper scripts (bag-to-map, teleop logging)
├── media/        # GIF and MP4 demos
└── docs/         # Project report and diagrams

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Quick Start

# Launch simulation
ros2 launch slam_nav_tb3 slam_sim.launch.py

# Run Nav2 with saved map
ros2 launch slam_nav_tb3 nav2.launch.py map:=maps/ucr_lab.yaml

# Build workspace
cd ~/slam_ws
colcon build
source install/setup.bash

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Key Components

SLAM Mapping

• SLAM Toolbox for real-time occupancy grid mapping
• Frontier-based autonomous exploration via Nav2
• Parameter tuning achieved 15% accuracy improvement over baseline

Localization

• AMCL particle filter for pose estimation
• Adaptive resampling for dynamic environments
• Validated over 10m trajectories in UCR lab

Path Planning

• Global: A* for optimal path generation
• Local: DWB for real-time obstacle avoidance
• Velocity constraints tuned for safe indoor navigation

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Configuration

Key parameter files in config/:

• costmap_params.yaml — Obstacle inflation, footprint
• planner_params.yaml — A* and DWB tuning
• controller_params.yaml — Velocity limits and constraints
• slam_params.yaml — SLAM Toolbox configuration

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Troubleshooting

Map not building:

ros2 topic echo /scan        # Verify LiDAR data
ros2 topic echo /odom        # Verify odometry
ros2 run tf2_tools view_frames  # Check TF tree

Nav2 not navigating:

ros2 topic list | grep nav   # Check Nav2 topics active
ros2 node list               # Verify all nodes running

Localization drift:

• Increase AMCL particle count in config
• Verify map matches environment
• Check odometry calibration

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Notes

• Test in simulation before real hardware deployment
• Save maps after successful exploration runs
• Tune local planner parameters for different environments
• Source workspace before running any ROS2 commands