ROS 1 Multimaster Packages

This page will introduce the multimaster packages we looked into over the course of our research.

Overview

Multimaster packages are a useful way to achieve the ROS2 communication style when working with a ROS 1 system. This can be preferable in systems such as multi-agent mapping, where we do not necessarily want to exchange all topics, and instead only want a few topics (such as the global map, and local costmaps) to be visible outside of each robot's namespace. Additionally, while it is possible to use the ros1_bridge to convert ROS 1 messages into ROS 2 messages (and vice versa), there may be some circumstances where it may be preferable to stick with ROS 2 so that we do not have to install two meta-operating-systems onto the same device.

Multimaster-FKIE

This package provides a multimaster approach by rebroadcasting topics onto other ROS masters on the same network. This package comes with two nodes:

Node	Description
master_discovery	This node is responsible for discovering other ROS masters on the same network. It will relay the IP addresses of these devices, as well as pass them on to any running master_sync nodes.
master_sync	This node is responsible to syncing the topics that are present on the current ROS master to other ROS masters that have been reported by master_discovery nodes.

Installation Instructions

To install the multimaster-fkie package, simply run the command in any bash terminal:

sudo apt-get install ros-melodic-multimaster-fkie

Execution Instructions

To run the multimaster-fkie package on your machine(s), run these commands on both devices. Make sure that they are connected to the same network before attempting to run these commands.

# Terminal A
roscore

# Terminal B
rosrun master_discovery_fkie master_discovery

# Terminal C
rosrun master_sync_fkie master_sync

Pound

Pound is a UDP-based communications node that is meant to serve as an improvement upon RT-WMP. The main difference between this node and the multimaster-fkie package is that Pound introduces priorities into managing topics.