Implementation of a routing protocol for ad hoc networks in search and rescue robotics

As robotics evolves, we expect to see increasing numbers of search and rescue teams (SARTs) of humans and autonomous mobile robots, especially in hazardous scenarios. Under these conditions, a third party infrastructure network might be unavailable, forcing the agents´ mobile devices to self-organize in a wireless ad hoc network. Search and rescue actions pose specific challenges to these networks, as they need large communication bandwidths, and, at the same time, a very tight connection to the Command Center (CC). Hence, SART ad hoc networks are neither typical mobile ad hoc networks (MANETs), nor wireless sensor networks with firm energy restrictions. To respond to these requirements, we propose a routing protocol, called CHOPIN, that defines a tree rooted at the CC, while also allowing flooding within teams of nodes. We conceived, implemented and integrated this protocol in the Robot Operating System (ROS), using simple but proven methods, and open standards for messages. The field benchmarking we did against the Optimized Link State Routing Protocol (OLSR) shows the ability of CHOPIN to assist SART agents in their communication.