breadcrumb

An A* path planner for grid-based navigation

Download & Compile

cd ~/catkin_ws/src
git clone https://github.com/qutas/breadcrumb
cd ~/catkin_ws
catkin_make
source ~/catkin_ws/devel/setup.bash

Updating

roscd breadcrumb
git pull
cd ~/catkin_ws
catkin_make
source ~/catkin_ws/devel/setup.bash

Usage

This node listens for an OccupancyGrid and will advertise a service which can be called to do path planning within this grid space.

Running Breadcrumb

First, copy the launch file and open it to edit:

mkdir -p ~/catkin_ws/launch
cd ~/catkin_ws/launch
roscp breadcrumb breadcrumb.launch ./
nano breadcrumb.launch

At this point, you will have to uncomment the grid remap command to tell breadcrumb which occupancy grid to connect to:

<remap from="~grid" to="/grid" />

You can now run breadcrumb:

roslaunch ~/catkin_ws/breadcrumb.launch

If breadcrumb stops with the message [Breadcrumb] Waiting for occupancy grid, then it is waiting to recieve the grid. You will recieve the message [Breadcrumb] Received a new occupancy grid, path planning service started! when breadcrumb has successfully received the occupancy grid and is ready for operation.

Provided Services

• Request Path
  • Topic: ~request_path
  • Type: breadcrumb/RequestPath
  • Description: This is a service server that allows a service client to query breadcrumb for a path from point A to point B. This interface only becomes available after breadcrumb has received a valid occupancy grid. The response message may return an empty path (size of 0), which represents that no solution could be found.

Subscribed Topics

• Occupancy Grid
  • Topic: grid
  • Type: nav_msgs/OccupancyGrid
  • Description: This input sets the grid that is used by breadcrumb to perform the path planning steps. This should be connected to a pre-determined occupancy grid.

Published Topics

The breadcrumb path planner does not publish to any topics.

Credit

This package utilizes source code developed by github user daancode.