ArduSim: Accurate and real-time multicopter simulation

[EN] As the popularity and the number of Unmanned Aerial Vehicles (UAVs) increases, new protocols are needed to coordinate UAVs when flying autonomously, and to avoid that these UAVs collide with each other. Directly testing such novel protocols on real UAVs is a complex procedure that requires investing much time, money and research effort. Hence, it becomes necessary to have the possibility to first test different solutions using simulation. Unfortunately, existing tools present significant limitations: some of them only simulate accurately the flight behavior of one UAV, while some other simulators can manage several UAVs simultaneously, but not in real-time, thus loosing accuracy regarding the mobility pattern of the UAV. In this work we address such problem by introducing ArduSim, a novel simulator that allows controlling in soft real-time the flight and communications of multiple UAVs, being the developed protocols directly portable to real devices. The contributions of this work include: (i) the ArduSim simulation platform, which allows realistic simulation and control of multiple UAVs simultaneously, offering functionalities not provided by existing alternatives; (ii) a model for the WiFi communications link between UAVs, based on real experiments, and that is integrated into ArduSim itself; and (iii) a thorough study of the scalability performance of our simulator.This work was supported by the Ministerio de Economia y Competitividad for the "Programa Estatal de Investigacion, Desarrollo e Innovacion Orientada a Retos de la Sociedad, Proyecto I+D+I SMART@CARPHONE: Integracion del smartphone y el vehiculo para conectar conductores, sensores y entorno a traves de una arquitectura de servicios funcionales" (grant number TEC2014-52690-R), and the Universitat Politecnica de Valencia (UPV) under program "Contratos Pre-doctorales para la Formacion de Personal Investigador (FPI)" (grant number 0060100000).Fabra Collado, FJ.; Tavares De Araujo Cesariny Calafate, CM.; Cano, J.; Manzoni, P. (2018). ArduSim: Accurate and real-time multicopter simulation. Simulation Modelling Practice and Theory. 87:170-190. https://doi.org/10.1016/j.simpat.2018.06.009S1701908

Flight coordination solutions for multirotor unmanned aerial vehicles

[EN] As the popularity and the number of Unmanned Aerial Vehicles (UAVs) increases, new protocols are needed to coordinate them when flying without direct human control, and to avoid that these UAVs collide with each other. Testing such novel protocols on real UAVs is a complex procedure that requires investing much time, money and research efforts. Hence, it becomes necessary to first test the developed solutions using simulation. Unfortunately, existing tools present significant limitations: some of them only simulate accurately the flight behavior of a single UAV, while some other simulators can manage several UAVs simultaneously, but not in real time, thus losing accuracy regarding the mobility pattern of the UAV. In this work we address such problem by introducing Arducopter Simulator (ArduSim), a novel simulation platform that allows controlling in soft real-time the flight and communications of multiple UAVs, being the developed protocols directly portable to real devices. Moreover, ArduSim includes a realistic model for the WiFi communications link between UAVs, which was proposed based on real experiments. The chances that two UAVs get close to each other during their flights is increasing as more and more of them populate our skies, causing concerns regarding potential collisions. Therefore, this thesis also proposes the Mission Based Collision Avoidance Protocol (MBCAP), a novel UAV collision avoidance protocol applicable to all types of multicopters flying autonomously. It relies on wireless communications in order to detect nearby UAVs, and to negotiate the procedure to avoid any potential collision. Experimental and simulation results demonstrate the validity and effectiveness of the proposed solution, which typically introduces a small overhead in the range of 15 to 42 seconds for each risky situation successfully handled. The previous solution aims at UAVs performing independent flights, but they can also form a swarm, where more constraints have to be met to avoid collisions among them, and to allow them to complete their task efficiently. Deploying an UAV swarm instead of a single UAV can provide additional benefits when, for example, cargo carrying requirements exceed the lifting power of a single UAV, or when the deployment of several UAVs simultaneously can accelerate the accomplishment of the mission, and broaden the covered area. To this aim, in this work we present the Mission-based UAV Swarm Coordination Protocol (MUSCOP), a solution that allows multiple UAVs to perfectly coordinate their flight when performing planned missions. Experimental results show that the proposed protocol is able to achieve a high degree of swarm cohesion independently of the flight formation adopted, and even in the presence of very lossy channels, achieving minimal synchronization delays and very low position offsets with regard to the ideal case. Currently, there are some other scenarios, such as search and rescue operations, where the deployment of manually guided swarms of UAVs can be necessary. In such cases, the pilot's commands are unknown a priori (unpredictable), meaning that the UAVs must respond in near real-time to the movements of the leader UAV in order to maintain swarm consistency. Hence, in this thesis we also propose the FollowMe protocol for the coordination of UAVs in a swarm where the swarm leader is controlled by a real pilot, and the other UAVs must follow it in real-time to maintain swarm cohesion. Simulation results show the validity of the proposed swarm coordination protocol, detailing the responsiveness limits of our solution, and finding the minimum distances between UAVs to avoid collisions.[ES] A medida que la popularidad de los Vehículos Aéreos No Tripulados (VANTs) se incrementa, también se hacen necesarios nuevos protocolos para coordinarlos en vuelos sin control humano directo, y para evitar que colisionen entre sí. Probar estos nuevos protocolos en VANTs reales es un proceso complejo que requiere invertir mucho tiempo, dinero y esfuerzo investigador. Por lo tanto, es necesario probar en simulación las soluciones previamente implementadas. Lamentablemente, las herramientas actuales tienen importantes limitaciones: algunas simulan con precisión el vuelo de un único VANT, mientras que otros simuladores pueden gestionar varios VANTs simultáneamente aunque no en tiempo real, perdiendo por lo tanto precisión en el patrón de movilidad del VANT. En este trabajo abordamos este problema introduciendo Arducopter Simulator (ArduSim), una nueva plataforma de simulación que permite controlar en tiempo real el vuelo y la comunicación entre múltiples VANTs, permitiendo llevar los protocolos desarrollados a dispositivos reales con facilidad. Además, ArduSim incluye un modelo realista de un enlace de comunicaciones WiFi entre VANTs, el cual está basado en el resultado obtenido de experimentos con VANTs reales. La posibilidad de que dos VANTs se aproximen entre sí durante el vuelo se incrementa a medida que hay más aeronaves de este tipo surcando los cielos, introduciendo peligro por posibles colisiones. Por ello, esta tesis propone Mission Based Collision Avoidance Protocol (MBCAP), un nuevo protocolo de evitación de colisiones para VANTs aplicable a todo tipo de multicópteros mientras vuelan autónomamente. MBCAP utiliza comunicaciones inalámbricas para detectar VANTs cercanos y para negociar el proceso de evitación de la colisión. Los resultados de simulaciones y experimentos reales demuestran la validez y efectividad de la solución propuesta, que introduce un pequeño aumento del tiempo de vuelo de entre 15 y 42 segundos por cada situación de riesgo correctamente resuelta. La solución anterior está orientada a VANTs que realizan vuelos independientes, pero también pueden formar un enjambre, donde hay que cumplir más restricciones para evitar que colisionen entre sí, y para que completen la tarea de forma eficiente. Desplegar un enjambre de VANTs en vez de uno solo proporciona beneficios adicionales cuando, por ejemplo, la necesidad de carga excede la capacidad de elevación de un único VANT, o cuando al desplegar varios VANTs simultáneamente se acelera la misión y se cubre un área mayor. Con esta finalidad, en este trabajo presentamos el protocolo Mission-based UAV Swarm Coordination Protocol (MUSCOP), una solución que permite a varios VANTs coordinar perfectamente el vuelo mientras realizan misiones planificadas. Los resultados experimentales muestran que el protocolo propuesto permite al enjambre alcanzar un grado de cohesión elevado independientemente de la formación de vuelo adoptada, e incluso en presencia de un canal de comunicación con muchas pérdidas, consiguiendo retardos en la sincronización insignificantes y desfases mínimos en la posición con respecto al caso ideal. Actualmente hay otros escenarios, como las operaciones de búsqueda y rescate, donde el despliegue de enjambres de VANTs guiados manualmente puede ser necesario. En estos casos, las órdenes del piloto son desconocidas a priori (impredecibles), lo que significa que los VANTs deben responder prácticamente en tiempo real a los movimientos del VANT líder para mantener la consistencia del enjambre. Por ello, en esta tesis proponemos el protocolo FollowMe para la coordinación de VANTs en un enjambre donde el líder es controlado por un piloto, y el resto de VANTs lo siguen en tiempo real para mantener la cohesión del enjambre. Las simulaciones muestran la validez del protocolo de coordinación de enjambres propuesto, detallando los límites de la solución, y definiendo la distancia mínima entre VANTs para evita[CA] A mesura que la popularitat dels Vehicles Aeris No Tripulats (VANTs) s'incrementa, també es fan necessaris nous protocols per a coordinar-los en vols sense control humà directe, i per a evitar que col·lisionen entre si. Provar aquests nous protocols en VANTs reals és un procés complex que requereix invertir molt de temps, diners i esforç investigador. Per tant, és necessari provar en simulació les solucions prèviament implementades. Lamentablement, les eines actuals tenen importants limitacions: algunes simulen amb precisió el vol d'un únic VANT, mentre que altres simuladors poden gestionar diversos VANTs simultàniament encara que no en temps real, perdent per tant precisió en el patró de mobilitat del VANT. En aquest treball abordem aquest problema introduint Arducopter Simulator (ArduSim), una nova plataforma de simulació que permet controlar en temps real el vol i la comunicació entre múltiples VANTs, permetent portar els protocols desenvolupats a dispositius reals amb facilitat. A més, ArduSim inclou un model realista d'un enllaç de comunicacions WiFi entre VANTs, que està basat en el resultat obtingut d'experiments amb VANTs reals. La possibilitat que dues VANTs s'aproximen entre si durant el vol s'incrementa a mesura que hi ha més aeronaus d'aquest tipus solcant els cels, introduint perill per possibles col·lisions. Per això, aquesta tesi proposa Mission Based Collision Avoidance Protocol (MBCAP), un nou protocol d'evitació de col·lisions per a VANTs aplicable a tota mena de multicòpters mentre volen autònomament. MBCAP utilitza comunicacions sense fils per a detectar VANTs pròxims i per a negociar el procés d'evitació de la col·lisió. Els resultats de simulacions i experiments reals demostren la validesa i efectivitat de la solució proposada, que introdueix un xicotet augment del temps de vol de entre 15 i 42 segons per cada situació de risc correctament resolta. La solució anterior està orientada a VANTs que realitzen vols independents, però també poden formar un eixam, on cal complir més restriccions per a evitar que col·lisionen entre si, i perquè completen la tasca de forma eficient. Desplegar un eixam de VANTs en comptes d'un només proporciona beneficis addicionals quan, per exemple, la necessitat de càrrega excedeix la capacitat d'elevació d'un únic VANT, o quan en desplegar diversos VANTs simultàniament s'accelera la missió i es cobreix una àrea major. Amb aquesta finalitat, en aquest treball presentem el protocol Mission-based UAV Swarm Coordination Protocol (MUSCOP), una solució que permet a diversos VANTs coordinar perfectament el vol mentre realitzen missions planificades. Els resultats experimentals mostren que el protocol proposat permet a l'eixam aconseguir un grau de cohesió elevat independentment de la formació de vol adoptada, i fins i tot en presència d'un canal de comunicació amb moltes pèrdues, aconseguint retards en la sincronització insignificants i desfasaments mínims en la posició respecte al cas ideal. Actualment hi ha altres escenaris, com les operacions de cerca i rescat, on el desplegament d'eixams de VANTs guiats manualment pot ser necessari. En aquests casos, les ordres del pilot són desconegudes a priori (impredictibles), el que significa que els VANTs han de respondre pràcticament en temps real als moviments del VANT líder per a mantindre la consistència de l'eixam. Per això, en aquesta tesi proposem el protocol FollowMe per a la coordinació de VANTs en un eixam on el líder és controlat per un pilot, i la resta de VANTs ho segueixen en temps real per a mantindre la cohesió de l'eixam. Les simulacions mostren la validesa del protocol de coordinació d'eixams proposat, detallant els límits de la solució, i definint la distància mínima entre VANTs per a evitar col·lisions.Fabra Collado, FJ. (2020). Flight coordination solutions for multirotor unmanned aerial vehicles [Tesis doctoral no publicada]. Universitat Politècnica de València. https://doi.org/10.4995/Thesis/10251/147857TESI

Proceedings of the 5th MIT/ONR Workshop on C[3] Systems, held at Naval Postgraduate School, Monterey, California, August 23 to 27, 1982

"December 1982."Includes bibliographies and index.Office of Naval Research Contract no. ONR/N00014-77-C-0532 NR041-519edited by Michael Athans ... [et al.]

The use of ICT to support urban heritage appraisal : the case of medieval Tripoli, Lebanon

Conservation officers are faced with many problems when dealing with applications for intervention in urban heritage areas. The process involves reviewing different categories of heritage resources and legislation; understanding and relating together different heritage values; applying different kinds and levels of analysis; contacting the various stakeholders and accessing diverse digital and paper based documents. Such processes are largely tedious, time consuming and are generally inefficient (Morton, 1996a; Angelides, 2000). Despite the intention of many heritage organizations to identify models that can be used for managing decision-making in urban heritage areas, as yet no information model exists that is capable of properly and dynamically appraising such areas. The lack of such a model has exacerbated the difficulties and conflict in the selection and assessment of alternative intervention strategies in urban heritage areas. The diverse range of heritage categories, values, stakeholders and types of data related to the conservation of urban heritage resources provide a challenge in developing an adequate information model for informing the management of intervention. ICT based on a combination of Geographical information system (GIS), surveying, visualization and database packages can help in urban heritage appraisal process. However, efforts to apply the recently developed ICT to urban heritage recording and appraising have not yet fully come to fruition (Ford et al, 1999). Generally, efforts have only been concentrated on the use of ICT as a records database, (Sahib, 1993) rather than making more use of their analytical capabilities. This study develops a theoretical framework to help the full understanding of the categories of urban heritage resources, values and the identification of the constraints for using ICT in the urban heritage appraisal process. The aim is to develop a decision support system for intervention in Lebanese urban conservation areas. The effects of war, negligence and conservation plans have been the main factors causing destruction of the urban heritage in Lebanon. Appraisal is a necessary step to define the major components which contribute to the character of urban heritage. It is a first step towards the future development of heritage policies with regard to heritage management, conservation and enhancement (English Heritage, 1997a-b). This study creates, according to a developed theoretical framework, a prototype model for the appraisal of urban heritage areas. The study takes the medieval centre of the city of Tripoli as a case study. This centre is the unique sole depository of Mamluk art and architectural treasures in Lebanon.EThOS - Electronic Theses Online ServiceGBUnited Kingdo

LIPIcs, Volume 248, ISAAC 2022, Complete Volume

LIPIcs, Volume 248, ISAAC 2022, Complete Volum

LIPIcs, Volume 274, ESA 2023, Complete Volume

LIPIcs, Volume 274, ESA 2023, Complete Volum

NASA's University Program active projects. Fiscal year 1980

Data on projects active during fiscal year 1980 are organized alphabetically by state. The appendix includes a cross-reference indexed by field of science and engineering