Path Planning and Communication Strategies to Enable Connectivity in Robotic Systems

There has been considerable interest in the area of communication-aware robotics in recent years, where the sensing, communication and motion objectives of robotic systems are jointly optimized. One particular open problem in this area is that of exploiting the mobility of unmanned vehicles in order to improve or satisfy communication objectives in realistic communication environments. Progress in this field could not only affect robust networked operation of unmanned vehicles but also would improve communication systems of the future (e.g. 5G), thus contributing to both areas of robotics and communications. This mobility-enabled connectivity and communication is the main area of interest in this dissertation.This dissertation is focused on path planning and communication strategies for robotic systems seeking to satisfy certain communication objectives in realistic communication environments experiencing path loss, shadowing and multipath fading. We consider realistic communication environments by leveraging and incorporating a probabilistic channel prediction framework that allows the robots to predict the channel quality at unvisited locations. This thesis then contributes to the area of mobility and connectivity through three main topics 1) energy-optimal distributed beamforming, 2) finding the statistics of the distance traveled until connectivity, and 3) path planning for connectivity. First, in energy-optimal distributed beamforming, we utilize the motion of a group of initially unconnected mobile robots to enable new forms of connectivity. More specifically, we co-optimize their locations and transmission powers to cooperatively enable connectivity through distributed beamforming. We further bring a foundational theoretical understanding to robotic distributed beamforming. Next, in finding the statistics of the distance traveled until connectivity, we analytically characterize the probability density function of the distance traveled by an initially unconnected robot until it gets connected to a remote node as it moves along a given path. We utilize tools from the stochastic differential equation literature to develop this characterization. Finally, in path planning for connectivity, we actively plan the path of a mobile robot such that it finds a connected spot with a minimum expected traveled distance (i.e., energy). The scenario considered in this part is in fact a more general one, and tackles the problem of path planning on a graph to minimize the expected cost incurred until the successful completion of a task. This framework has applications beyond path planning for connectivity, in areas such as celestial body imaging, human-robot collaboration, and search scenarios. We bring a foundational understanding to this problem. We show how this problem is inherently hard to solve (NP-complete) and also propose a path planner, based on a game-theoretic framework, that provides an asymptotic optimality guarantee.Overall, this thesis proposes novel strategies for utilizing the mobility of unmanned vehicles and enabling connectivity while considering the underlying energy constraints. We also provide a rigorous theoretical analysis of the aforementioned problems using a wide range of tools from communications theory, game theory, optimal control and time series literature. Moreover, through extensive realistic numerical studies using real channel parameters/data, we show the efficiency and performance of our proposed approaches

A Novel Communications Protocol Using Geographic Routing for Swarming UAVs Performing a Search Mission

This research develops the UAV Search Mission Protocol (USMP) for swarming UAVs and determines the protocol\u27s effect on search mission performance. It is hypothesized that geographically routing USMP messages improves search performance by providing geography-dependent data to locations where it impacts search decisions. It is also proposed that the swarm can use data collected by the geographic routing protocol to accurately determine UAV locations and avoid sending explicit location updates. The hypothesis is tested by developing several USMP designs that are combined with the Greedy Perimeter Stateless Routing (GPSR) protocol and a search mission swarm logic into a single network simulation. The test designs use various transmission power levels, sensor types and swarm sizes. The simulation collects performance metrics for each scenario, including measures of distance traveled, UAV direction changes, number of searches and search concentration. USMP significantly improves mission performance over scenarios without inter-UAV communication. However, protocol designs that simply broadcast messages improve search performance by 83% in total searches and 20% in distance traveled compared to geographic routing candidates. Additionally, sending explicit location updates generates 3%-6% better performance per metric versus harvesting GPSR\u27s location information

An Examination of Latency and Degradation Issues in Unmanned Combat Aerial Vehicle Environments

Since the multidimensional knapsack problems are NP-hard problems, the exact solutions of knapsack problems often need excessive computing time and storage space. Thus, heuristic approaches are more practical for multidimensional knapsack problems as problems get large. This thesis presents the results of an empirical study of the performance of heuristic solution procedures based on the coefficients correlation structures and constraint slackness settings. In this thesis, the three representative greedy heuristics, Toyoda, Senju and Toyoda, and Loulou and Michaelides methods, are studied. The purpose of this thesis is to explore which heuristic of the three representative greedy heuristics perform best under certain combination of conditions between constraint slackness and correlation structures. This thesis examines three heuristics over 1120 problems which are all 2KPs with 100 variables created by four constraint slackness settings and 45 feasible correlation structures. Then we analyze why the best heuristic behaves as it does as a function of problem characteristic. The last chapter presents two new heuristics using knowledge gained in the study. When these new heuristics are competitively tested against the three original heuristics, the results show their better performances

The Case of Medicine Supply in Aveiro, Portugal

The evolution of the urban environment has changed significantly in the last 50 years, and we see considerable investments in urban logistics in order to make urban processes more efficient. This investigation intends to study the situation of urban logistics with the objective to study the current state of this system and analyze what lies ahead in the near future. The unmanned aerial vehicle (UAV) has been under investigation in the world of logistics, having been pointed has the next logistic technology. For that reason, we set as an objective, analyze the working process of this aircraft, its capabilities, and its limitations. Based on this information, we intend to implement a scenario of deliveries in an urban environment. This scenario will be in the city of Aveiro and consists on the delivery of medicines into pharmacies located in an urban environment. With this study, we pretend to find the best current and future solution to operate in an urban environment. The study is divided into several studies, starting with an analysis of the literature, and then we carry out the SWOT analysis. Then we implement a delivery route to pharmacies, both for daily delivery and emergency medicines. The analysis is divided into two phases, one where the vehicles would initially start from the current logistical base and another phase, where the logistical base is proposed for a new location, that has been optimized to the delivery route to be carried out. From the various analyzes carried out, we obtain very conclusive results. For routes of significant payload and distance, the UAV is still not able to have great performances, being still preferential the use of a van. However, we verified that for emergency deliveries, the UAV from the new logistics base (L2) would have the best performance, as well as it would be a low cost of implementation. In some results, the performance was close to the van or even better, although it would not be cost effective. For that reason, we foresee a robust competition from the UAV as an emerging technology. It will soon have better capabilities and more competitive prices. The cost reduction of this type of deliveries may soon be possible with the use of UAVs.O meio urbano tem evoluído durante os últimos 50 anos, onde se verificou uma enorme aposta na logística urbana, por forma a tornar as tarefas urbanas mais eficientes e económicas. Esta investigação tem como objeto o estudo da logística urbana e tem como objetivo, aprofundar e estudar a estrutura atual dos sistemas de logística e analisar o que poderá ser o futuro próximo. Atualmente, a maior aposta tecnológica no mundo da logística é a aeronave não tripulada (UAV). Posto isto, tem-se também como objetivo analisar o funcionamento destas aeronaves, nomeadamente, as suas capacidades e limitações. Partindo de um cenário de logística urbana com recurso a UAV’s, pretendemos estudar e comparar o processo de entregas nesse mesmo meio urbano. A implementação do teatro de operações será na cidade de Aveiro e consiste na entrega de medicamentos às farmácias localizadas no meio urbano. Com este estudo tencionasse encontrar a melhor solução atual e prever uma futura que se adeque à operação apresentada. O estudo está dividido em várias partes. Primeiramente, começamos por uma análise da literatura e seguido uma análise SWOT. Por fim, no caso de estudo são implementadas várias rotas de entregas a farmácias, quer para medicamentos de entrega diária, quer de emergência. O sistema de entregas está dividido em duas fases, uma onde inicialmente a partida dos veículos seria feita na atual base de logística e outra onde o veículo parte de uma base logística proposta, que estará otimizada ao percurso de entrega que se pretende realizar. Das várias análises realizadas obtivemos resultados muito conclusivos. Para rotas de grande carga e distância, o UAV não consegue ter grandes desempenhos, sendo ainda preferencial a utilização da uma carrinha. Contudo, verificamos que para entregas de emergência, o UAV teria um melhor desempenho a partir da nova base de logística, e para além disso, o sistema de implementação seria mais barato. Numa análise futura, prevemos uma concorrência muito forte por parte do UAV, visto que em alguns resultados a performance deste é próxima ou melhor do que a carrinha. Sendo uma tecnologia emergente, em breve terá melhores capacidades e preços mais concorrentes. As reduções de custos deste tipo de entregas poderão em breve ser possíveis com a utilização de um UAV

Enabling connectivity for tactical networks in mountainous areas by aerial relays

The dimension of the Meiac as a diffuser of Latin American art has been key in Spain in the late twentieth century. The genesis of the museum, its cultural policy of debate and diffusion, and the creation of a Latin American collection, which until then did not exist in Spain, forced Spanish art criticism to look at and reconsider work from Latin America. At present the Meiac has developed the new technological platforms, as a new perspective of identity and common imaginaries between Spain and Latin America.La dimensión del Meiac como difusor del arte latinoamericano ha sido clave en España a finales del siglo XX. La génesis del museo, su política cultural de debate y difusión y la creación de una colección latinoamericana, hasta entonces inexistente en España, obligó a la crítica artística española a mirar y a reconsiderar la obra procedente de Latinoamérica. En la actualidad el Meiac ha desarrollado las nuevas plataformas tecnológicas, como una nueva perspectiva de identidad e imaginarios comunes entre España y América Latina

Multi-Robot Auction Based Coordination

This dissertation studied the coordination problem for a Task Initiator (TI) with multiple ground stations (GSs). Each GS has a team of unmanned aerial vehicles (UAVs) that frequently collected data from a set of unattended ground sensors (UGSs) and delivered it to the source ground station (GS)

Enabling connectivity for tactical networks in mountainous areas by aerial relays

A general modeling framework for realistic performance evaluations of tactical mobile ad-hoc networks deployed in mountainous areas is presented. The framework is easily extensible, and can be eventually automated. It can be also used to generate data for other network simulators. The framework utilizes the freely downloadable high resolution 3D terrain data to define time dependent trajectories of network nodes. The node speeds and directions are linked to the terrain profile which extends the previously proposed mobility models. The path-loss analysis along the node trajectories revealed the need for aerial relays to enable full network connectivity at all times. The network consisting of 5 cluster heads and a single stationary relay is considered as a case study. The relay location and its antenna height are optimized to achieve the line-of-sight connectivity over the whole mission duration. The antenna radiation pattern at the relay is incorporated in the analysis. The resulting star network topology is used by the cluster heads to broadcast their packets to all other cluster heads. Several relaying schemes including the amplify-and-forward and the decode-and-forward relaying are studied together with the go-back-N retransmissions to achieve the reliable data transfer

System Integration and Intelligence Improvements for WPI’s UGV - Prometheus

This project focuses on realizing a series of operational improvements for WPI\u27s unmanned ground vehicle Prometheus with the end goal of a prize winning entry to the Intelligent Ground Vehicle Challenge. Operational improvements include a practical implementation of stereo vision on an NVIDIA GPU, a more reliable implementation of line detection, a better approach to mapping and path planning, and a modified system architecture realized by an easier to work with GPIO implementation. The end result of these improvements is better autonomy, accessibility, robustness, reliability, and usability for Prometheus