Communication Aware Mobile Robot Teams

The type of scenarios that could benefit from a team of robots that are able to self configure into an ad-hoc multi-hop mobile communication network while completing a task in an unknown environment, range from search and rescue in a partially collapsed building to providing a security perimeter around a region of interest. In this thesis, we present a hybrid system that enables a team of robots to maintain a prescribed end-to-end data rate while moving through a complex unknown environment, in a distributed manner, to complete a specific task. This is achieved by a systematic decomposition of the real-time situational awareness problem into subproblems that can be efficiently solved by distributed optimization. The validity of this approach is demonstrated through multiple simulations and experiments in which the a team of robots is able to accurately map an unknown environment and then transition to complete a traditional situational awareness task. We also present MCTP, a lightweight communication protocol that is specifically designed for use in ad-hoc multi-hop wireless networks composed of low-cost low-power transceivers. This protocol leverages the spatial diversity found in mobile robot teams as well as recently developed robust routing systems designed to minimize the variance of the end-to-end communication link. The combination of the hybrid system and MCTP results in a system that is able to complete a task, with minimal global coordination, while providing near loss-less communication over an ad-hoc multi-hop network created by the members of the team in unknown environments

Navigation problems for autonomous robots in distributed environments

This thesis studies algorithms for Distributed Computing. More specifically however the project aimed to carry out research on the performance analysis of mobile robots in a variety of different settings. In a range of different network and geometric settings we investigate efficient algorithms for the robots to perform given tasks. We looked at a variety of different models when completing this work but focused mainly on cases where the robots have limited communication mechanisms. Within this framework we investigated cases where the robots were numerous to cases where they were few in number. Also we looked at scenarios where the robots involved had different limitations on the maximal speeds they could travel. When conducting this work we explored two main tasks carried out by the robots that became the primary theme of the study. These two main tasks are Robot Location Discovery and Robot Evacuation. To accomplish these tasks we constructed algorithms that made use of both randomised and deterministic approaches in their solutions