Navigation Stack Overview

This section explains the core components of our robot's navigation system. It covers how we localize, plan paths, avoid obstacles, and control movement.

Localization

Mapping

Planning

Control

Obstacle Avoidance

GPS

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Localization

What it does:
Determines the robot's position in the environment using sensor data.

What we use:

• Sensor inputs: [ZED Camera / IMU / Realsense] /EXPAND ON THIS

Key files / nodes:

• /TO BE COMPLETED

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Mapping

Overview

Generates a 3D occupancy map of the environment using incoming sensor data. This enables elevation-aware navigation and obstacle detection in complex terrains.

Primary Launch File: octomap.launch

Basic Usage

roslaunch rover octomap.launch

Core Components

1. OctoMap
   Probabilistic 3D mapping system that builds occupancy maps from PointCloud2 data

   • Captures multi-height obstacles
   • Handles dynamic environments
   • Official Documentation

2. octomap_server Node
   Real-time map builder that publishes:

   • Binary octomaps (/octomap_binary)
   • Full-resolution maps (/octomap_full)
   • Visualization markers (/occupied_cells_vis_array)
   • Node Documentation

3. octomap_rviz Node - Visualization

   • Visualizes 3D occupancy grid in RViz
   • octomap_rviz_file

4. Input Topic

<remap from="cloud_in" to="/zed_node/point_cloud/cloud_registered"/>

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Planning

Overview

Provides real-time navigation and collision avoidance using sensor data. Implements Dynamic Window Approach (DWA) for local path planning in dynamic environments.

Primary Launch File: dwa_planner.launch

Basic Usage

roslaunch rover dwa_planner.launch

Core Components

1. DWA (Dynamic Window Approach)
   Real-time local planner that:

   • Evaluates feasible velocity windows
   • Optimizes for obstacle clearance and path alignment
   • Dynamically adjusts to new obstacles

2. dwa_planner Node
   Custom implementation that:

   • Processes occupancy maps and localization data
   • Generates collision-free trajectories
   • Publishes velocity commands

3. 'dwa_rviz' Node

• Visualization interface for planning
• dwa_rviz_file

4. Core Topics

<param name="odom_topic" value="/rtabmap/odom" />
<param name="octomap_topic" value="/octomap_full"/>
<param name="map_topic" value="/map" />

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Control

What it does:
Translates the planned path into actual robot movement.

Key files / nodes:

• /TO BE COMPLETED

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Obstacle Avoidance

What it does:
Uses real-time sensor data to update the robot's local costmap and avoid collisions.

Key files / nodes:

• /TO BE COMPLETED

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GPS

What it does:
Provides global positioning data, primarily used for outdoor navigation. Fused with IMU and odometry through the EKF to improve localization accuracy.

Key files / nodes:

• /TO BE COMPLETED