A game theoretic approach to coordinating unmanned aerial vehicles with communications payloads

This thesis considers the placement of two or more Unmanned Aerial Vehicles (UAVs) to provide communications to a community of ground mobiles. The locations for the UAVs are decided by the outcome of a non-cooperative game in which the UAVs compete to maximize their coverage of the mobiles. The game allows navigation decisions to be made onboard the UAVs with the effect of increasing coverage, reducing the need for a central planning function, and increasing the autonomy of the UAVs. A non-cooperative game that includes the key system elements is defined and simulated. The thesis compares methods for solving the game to evaluate their performance. A conflict between the quality of the solution and the time required to obtain that solution is identified and explored. It considers how the payload calculations could be used to modify the behaviour of the UAVs, and the sensitivity of the game to resource limitations such as RF power and radio spectrum. It finishes by addressing how the game could be scaled from two UAVs to many UAVs, and the constraints imposed by current methods for solving games

Preclinical evaluation of the Versius surgical system: A next‐generation surgical robot for use in minimal access prostate surgery

© 2023 The Authors. BJUI Compass published by John Wiley & Sons Ltd on behalf of BJU International Company. This is an open access article under the terms of the Creative Commons Attribution License, https://creativecommons.org/licenses/by/4.0/Objectives: To evaluate the Versius surgical system for robot‐assisted prostatectomy in a preclinical cadaveric model using varying system setups and collect surgeon feedback on the performance of the system and instruments, in line with IDEAL‐D recommendations. Materials and methods: Procedures were performed in cadaveric specimens by consultant urological surgeons to evaluate system performance in completing the surgical steps required for a prostatectomy. Procedures were conducted using either a 3‐arm or 4‐arm bedside unit (BSU) setup. Optimal port placements and BSU layouts were determined and surgeon feedback collected. Procedure success was defined as the satisfactory completion of all steps of the procedure, according to the operating surgeon. Results: All four prostatectomies were successfully completed; two were completed with a 3‐arm BSU setup and two using a 4‐arm BSU setup. Small adjustments were made to the port and BSU positioning, according to surgeon preference, in order to complete the surgical steps. The surgeons noted some instrument difficulties with the Monopolar Curved Scissor tip and the Needle Holders, which were subsequently refined between the first and second sessions of the study, in line with surgeon feedback. Three cystectomies were also successfully completed, demonstrating the capability of the system to perform additional urological procedures. Conclusions: This study provides a preclinical assessment of a next‐generation surgical robot for prostatectomies. All procedures were completed successfully, and port and BSU positions were validated, thus supporting the progression of the system to further clinical development according to the IDEAL‐D framework.Peer reviewe

UAV flight coordination for communication networks:Genetic algorithms versus game theory

The autonomous coordinated flying for groups of unmanned aerial vehicles that maximise network coverage to mobile ground-based units by efficiently utilising the available on-board power is a complex problem. Their coordination involves the fulfilment of multiple objectives that are directly dependent on dynamic, unpredictable and uncontrollable phenomena. In this paper, two systems are presented and compared based on their ability to reposition fixed-wing unmanned aerial vehicles to maintain a useful airborne wireless network topology. Genetic algorithms and non-cooperative games are employed for the generation of optimal flying solutions. The two methods consider realistic kinematics for hydrocarbon-powered medium-altitude, long-endurance aircrafts. Coupled with a communication model that addresses environmental conditions, they optimise flying to maximising the number of supported ground-based units. Results of large-scale scenarios highlight the ability of genetic algorithms to evolve flexible sets of manoeuvres that keep the flying vehicles separated and provide optimal solutions over shorter settling times. In comparison, game theory is found to identify strategies of predefined manoeuvres that maximise coverage but require more time to converge

A scoping study on measuring and monitoring tools and technology for precision irrigation

This scoping study is designed to advance high standards of precision in management of water and develop efficient methods of irrigation prescription to reduce losses and improve water use efficiency. All aspects of irrigation process are considered in this study to include various components of farm water storage and distribution systems to facilitate accurate accounting of water. In this study, we will attempt to: * Identify key attributes and specifications for various tools (sensors and control systems) for precision irrigation management; * Develop strategies to fill current gaps in the functionality of various tools and technology available for irrigation and * Prioritise opportunities to refine and/or develop new tools and technology to increase on-farm precision and meet off-farm hydrology needs

Implementing Solar-Powered HAPS for Rural broadband Connectivity: Concepts, Challenges & Mitigation

This paper examines the implementation of solar-powered High Altitude Platform Stations(HAPS) for rural broadband connectivity. It outlines some technical considerations and concepts associated with implementing HAPS as a communications infrastructure. To realise the potentials of solar HAPS for rural broadband connectivity, some key technology, business and policy questions must be addressed. For instance, to meet service demands, the solar-HAPS platform must remain aloft for long periods without running out of power (endurance), which is a technology challenge. Also relevant are non-technology issues like fitness-for-purpose and business viability, which are often overshadowed by technology problems but yet consequential. An aggregation and analysis of these implementation concepts may be helpful for both technology and policy decisions in the bid to address rural connectivity gaps

Situation Awareness and Routing Challenges in Unmanned HAPS/UAV based Communications Networks

This paper examines Situation Awareness (SA) as a factor in addressing routing challenges in HAPS/UAV based networks especially in multi-HAPS/UAV implementations. Routing in UAV based networks is a critical element for successful transmission of data from source to destination node. However, in UAV based networks the concept of routing assumes a more challenging dimension mainly due to the mobility of the vehicles or platforms. This paper highlights how situation awareness can impact routing decisions and consequently improve network throughput. It is suggested that SA should be considered a factor in mitigating routing challenges in UAV based networks

Antenna Implementations for High Altitude Platform Stations (HAPS) and Considerations for Future Designs

This paper examines antenna implementations for the different communication links in a HAPS network i.e. service, inter-HAPS and feeder links. In this context, antenna implementation covers form-factor, size, steering and platform mounting templates. Antenna implementations vary significantly from one HAPS platform to another including proprietary and regulatory induced variations. Achieving the levels of link stability and performance demanded by current digital trends involves a steep technology and cost curve. This work proposes standardisation of HAPS antenna implementation to harmonise how antennas are implemented from design to installation. Accelerating the adoption of HAPS will require innovation at all levels of the HAPS technology value chain and antenna implementation is high up this chain

Integrating Routing Schemes and Platform Autonomy Algorithms for UAV Ad-hoc & Infrastructure based networks

This paper highlights the considerations for implementing autonomous or self-organising unmanned aerial vehicles (UAVs) for communications area coverage with particular emphasis on the impact of aerial vehicle autonomy algorithms on routing techniques for such networks. UAV networks can be deployed either as ad-hoc or infrastructure based solutions. The mobility of UAVs introduce periodic topology changes, impacting link availability and routing paths. This work examines the implications of autonomous coordination of multiple UAVs on routing techniques and network architecture stability. The paper proposes a solution where routing techniques and UAV autonomy algorithms are integrated for improved global network efficiency for both ad-hoc and infrastructure-based scenarios. Integrating UAV autonomy algorithms with routing schemes may be an efficient method to mitigate link/topology stability issues and improve inter-UAV communication and network throughput, a key requirement for UAV networks. The implementation of interUAV links using optical, microwave or mmWave transmission was examined as a critical element in the context of this work. The proposed integration may be crucial for communications coverage, where UAVs provide communications area coverage to community of mobile or fixed users in either ad-hoc or infrastructure based modes

Autonomously Coordinated Multi-HAPS Communications Network: Failure Mitigation in Volcanic Incidence Area Coverage.

This paper investigates the coordination of multiple autonomous High Altitude Platform Stations (HAPS) in a volcanic cloud emergency scenario for aerial communications coverage. Deploying unmanned(pilot-less) HAPS over areas impacted by volcanic ash clouds is proposed in this work. Volcanic ash clouds stretching over distances can be challenging and requires resilient wireless communications infrastructure. In this work a self-organising solar-powered HAPS network is presented and its resilience tested in the event of the failure of a participating HAPS in the swarm. The future of implementing swarm of unmanned HAPS for communications services requires autonomous capabilities as demonstrated in this paper. A swarm intelligence based algorithm developed for this work is applied to coordinate a swarm of HAPS for communications coverage. The paper highlights the demands of such self-organising infrastructure and how failure may impact communications coverage, especially in emergency scenarios where high availability and reliability of the supporting communications infrastructure is critical

Comparative Study for Coordinating Multiple Unmanned HAPS for Communications Area Coverage.

This work compares the application of Reinforcement Learning (RL) and Swarm Intelligence (SI) based methods for resolving the problem of coordinating multiple High Altitude Platform Stations (HAPS) for communications area coverage. Swarm coordination techniques are essential for developing autonomous capabilities for multiple HAPS/UAS control and management. This paper examines the performance of artificial intelligence (AI) capabilities of RL and SI for autonomous swarm coordination. In this work, it was observed that the RL approach showed superior overall peak user coverage with unpredictable coverage dips; while the SI based approach demonstrated lower coverage peaks but better coverage stability and faster convergence rates