TDLE

[The corresponding paper TDLE: 2D Lidar Exploration with Hierarchical Planning Using Regional Division has been accepted by IEEE CASE 2023.]

Introduction

Demonstration Video:

Frontier Detection

The frontier detection module is adapted from Hasauino's rrt_exploration (sincere thanks for his work), with series of improvements, including:

• Refactored the entire code for clearer logic and efficient implementation;

• Set sampling boundary automatically;

• Dynamically adjust the number of nodes in the global tree.

Hierarchical Planning

The hierarchical exploration planning module is the core component of this framework.

In the first phase, the planning space is divided into several subregions. After that, subregions with frontier points inside or mostly unknown are selected. The selected subregions are then sorted to provide global guidance for exploration.

In the second phase, the subregions are visited one by one in the order determined in the first phase. In each subregion, various indicators, including global compatibility, information gain, and motion consistency, are calculated. Robot selects the exploration target with the highest comprehensive revenue.

Quick Start

Prerequisites

We tried to minimize the unnecessary use of third-party libraries (like OpenCV, tf, etc). Simple external functions were implemented manually.

• ROS Environment

  Make sure you have ROS environment properly installed. This project has been tested on several devices under ROS-Melodic and ROS-Noetic. (Desktop-Full version is recommended)

• Local Planner

  Currently, TDLE uses TEB as its local planner by default. Install it with:

  sudo apt install ros-noetic-navigation
  sudo apt install ros-noetic-teb-local-planner
  

  At the same time, DWA, which is already included in ros-noetic-navigation, can also be used as the local planner. You can change the planner_name parameter in tdle_sim.launch.

• Cartographer_ROS

  TDLE uses cartographer as its mapping module, with a few adaptions that make it suitable for exploration. Using this fork instead of the original repository.

  In fact, TDLE supports any method that can generate an occupancy grid map with the message type nav_msgs/OccupancyGrid.

• Gazebo Models (optional)

  The model files required by robot(turtlebot3-waffle) and simulation scene(museum) can be found in gz_sim_models, which is organized as a catkin package. You can clone it into your workspace and build it with catkin_make.

  If you want to use the simulation scene(library), please download extra models, put them in your Gazebo model folder (usually ~/.gazebo/models), and change the world_name parameter in tdle_sim.launch.

Run TDLE

• For Gazebo Simulation

  roslaunch tdle tdle_sim.launch
  

• For Field Test

  roslaunch tdle tdle_real.launch
  

Known Issues