MRS Drone: A Modular Platform for Real-World Deployment of Aerial Multi-Robot Systems

This paper presents a modular autonomous Unmanned Aerial Vehicle (UAV) platform called the Multi-robot Systems (MRS) Drone that can be used in a large range of indoor and outdoor applications. The MRS Drone features unique modularity with respect to changes in actuators, frames, and sensory configuration. As the name suggests, the platform is specially tailored for deployment within a MRS group. The MRS Drone contributes to the state-of-the-art of UAV platforms by allowing smooth real-world deployment of multiple aerial robots, as well as by outperforming other platforms with its modularity. For real-world multi-robot deployment in various applications, the platform is easy to both assemble and modify. Moreover, it is accompanied by a realistic simulator to enable safe pre-flight testing and a smooth transition to complex real-world experiments. In this manuscript, we present mechanical and electrical designs, software architecture, and technical specifications to build a fully autonomous multi UAV system. Finally, we demonstrate the full capabilities and the unique modularity of the MRS Drone in various real-world applications that required a diverse range of platform configurations.Comment: 49 pages, 39 figures, accepted for publication to the Journal of Intelligent & Robotic System

Safe Autonomous Aerial Surveys of Historical Building Interiors

Cílem této práce je vývoj systému pro bezpečný autonomní průzkum interiérů historických budov za pomocí vícerotorových autonomních bezpilotních helikoptér. Navržené řešení zahrnuje metodu pro sledování požadované trajektorie založené na přístupu lídr-následovník a prediktivním řízení, detekci potenciálních chyb a systému pro řízení mise, který zprostředkovává spolupráci mezi jednotlivými členy formace a korektní reakci na nastalé chyby jednotlivých podsystémů. Návrh celého systému je ovlivněn jeho plánovaným nasazením v rámci skenování interiérů historických budov. Funkčnost navrženého systému je nejprve otestována v rámci početných simulací a následně během experimentu s reálnými bezpilotními helikoptérami.This thesis is aimed at development of the system for safe autonomous survey of historical building interiors by the cooperative formation of multi-rotor unmanned aerial vehicles (UAVs). The proposed solution involves the method for safe trajectory tracking based on the leader-follower scheme and model predictive control, detection of potential faults and failures, and the mission controller which ensures the control of cooperation of particular UAVs and proper reaction on occurrence of faults and failures. The proposition of the whole system is influenced by the aim at its deployment in real world scenarios motivated by the documentation of historical monuments. The developed system is firstly evaluated in simulations. After that, it is tested in a real world scenario with the real UAVs

The MRS UAV System: Pushing the Frontiers of Reproducible Research, Real-world Deployment, and Education with Autonomous Unmanned Aerial Vehicles

We present a multirotor Unmanned Aerial Vehicle control (UAV) and estimation system for supporting replicable research through realistic simulations and real-world experiments. We propose a unique multi-frame localization paradigm for estimating the states of a UAV in various frames of reference using multiple sensors simultaneously. The system enables complex missions in GNSS and GNSS-denied environments, including outdoor-indoor transitions and the execution of redundant estimators for backing up unreliable localization sources. Two feedback control designs are presented: one for precise and aggressive maneuvers, and the other for stable and smooth flight with a noisy state estimate. The proposed control and estimation pipeline are constructed without using the Euler/Tait-Bryan angle representation of orientation in 3D. Instead, we rely on rotation matrices and a novel heading-based convention to represent the one free rotational degree-of-freedom in 3D of a standard multirotor helicopter. We provide an actively maintained and well-documented open-source implementation, including realistic simulation of UAV, sensors, and localization systems. The proposed system is the product of years of applied research on multi-robot systems, aerial swarms, aerial manipulation, motion planning, and remote sensing. All our results have been supported by real-world system deployment that shaped the system into the form presented here. In addition, the system was utilized during the participation of our team from the CTU in Prague in the prestigious MBZIRC 2017 and 2020 robotics competitions, and also in the DARPA SubT challenge. Each time, our team was able to secure top places among the best competitors from all over the world. On each occasion, the challenges has motivated the team to improve the system and to gain a great amount of high-quality experience within tight deadlines.Comment: 28 pages, 20 figures, submitted to Journal of Intelligent & Robotic Systems (JINT), for the provided open-source software see http://github.com/ctu-mr

Optimal Multi-UAV Trajectory Planning for Filming Applications

Teams of multiple Unmanned Aerial Vehicles (UAVs) can be used to record large-scale outdoor scenarios and complementary views of several action points as a promising system for cinematic video recording. Generating the trajectories of the UAVs plays a key role, as it should be ensured that they comply with requirements for system dynamics, smoothness, and safety. The rise of numerical methods for nonlinear optimization is finding a ourishing field in optimization-based approaches to multi- UAV trajectory planning. In particular, these methods are rather promising for video recording applications, as they enable multiple constraints and objectives to be formulated, such as trajectory smoothness, compliance with UAV and camera dynamics, avoidance of obstacles and inter-UAV con icts, and mutual UAV visibility. The main objective of this thesis is to plan online trajectories for multi-UAV teams in video applications, formulating novel optimization problems and solving them in real time. The thesis begins by presenting a framework for carrying out autonomous cinematography missions with a team of UAVs. This framework enables media directors to design missions involving different types of shots with one or multiple cameras, running sequentially or concurrently. Second, the thesis proposes a novel non-linear formulation for the challenging problem of computing optimal multi-UAV trajectories for cinematography, integrating UAV dynamics and collision avoidance constraints, together with cinematographic aspects such as smoothness, gimbal mechanical limits, and mutual camera visibility. Lastly, the thesis describes a method for autonomous aerial recording with distributed lighting by a team of UAVs. The multi-UAV trajectory optimization problem is decoupled into two steps in order to tackle non-linear cinematographic aspects and obstacle avoidance at separate stages. This allows the trajectory planner to perform in real time and to react online to changes in dynamic environments. It is important to note that all the methods in the thesis have been validated by means of extensive simulations and field experiments. Moreover, all the software components have been developed as open source.Los equipos de vehículos aéreos no tripulados (UAV) son sistemas prometedores para grabar eventos cinematográficos, en escenarios exteriores de grandes dimensiones difíciles de cubrir o para tomar vistas complementarias de diferentes puntos de acción. La generación de trayectorias para este tipo de vehículos desempeña un papel fundamental, ya que debe garantizarse que se cumplan requisitos dinámicos, de suavidad y de seguridad. Los enfoques basados en la optimización para la planificación de trayectorias de múltiples UAVs se pueden ver beneficiados por el auge de los métodos numéricos para la resolución de problemas de optimización no lineales. En particular, estos métodos son bastante prometedores para las aplicaciones de grabación de vídeo, ya que permiten formular múltiples restricciones y objetivos, como la suavidad de la trayectoria, el cumplimiento de la dinámica del UAV y de la cámara, la evitación de obstáculos y de conflictos entre UAVs, y la visibilidad mutua. El objetivo principal de esta tesis es planificar trayectorias para equipos multi-UAV en aplicaciones de vídeo, formulando novedosos problemas de optimización y resolviéndolos en tiempo real. La tesis comienza presentando un marco de trabajo para la realización de misiones cinematográficas autónomas con un equipo de UAVs. Este marco permite a los directores de medios de comunicación diseñar misiones que incluyan diferentes tipos de tomas con una o varias cámaras, ejecutadas de forma secuencial o concurrente. En segundo lugar, la tesis propone una novedosa formulación no lineal para el difícil problema de calcular las trayectorias óptimas de los vehículos aéreos no tripulados en cinematografía, integrando en el problema la dinámica de los UAVs y las restricciones para evitar colisiones, junto con aspectos cinematográficos como la suavidad, los límites mecánicos del cardán y la visibilidad mutua de las cámaras. Por último, la tesis describe un método de grabación aérea autónoma con iluminación distribuida por un equipo de UAVs. El problema de optimización de trayectorias se desacopla en dos pasos para abordar los aspectos cinematográficos no lineales y la evitación de obstáculos en etapas separadas. Esto permite al planificador de trayectorias actuar en tiempo real y reaccionar en línea a los cambios en los entornos dinámicos. Es importante señalar que todos los métodos de la tesis han sido validados mediante extensas simulaciones y experimentos de campo. Además, todos los componentes del software se han desarrollado como código abierto

Verbesserte Dokumentation des kulturellen Erbes mithilfe digitaler Photogrammetrie mit sichtbaren und thermischen Bildern von unbemannten Luftfahrzeugen (UAV)

There is always need for reliable and accurate data for documentation of cultural heritage including archaeological areas. The development in 3D data acquisition has let some technologies use for getting a complete documentation. Close range photogrammetry and terrestrial laser scanning are among the most common used techniques which help to get 3D data acquisition, with high level of detail, accuracy and effective results. However, these techniques are not always the most suitable ones for large archaeological areas, yet aerial images may help to provide a general overview of the area which is fundamental for interpretation and documentation of archaeological sites. Because of the limitations in aerial photogrammetry, UAVs (Unmanned Aerial Vehicles) has become an optimal solution for archaeological areas documentation with its potentials in the context of costs and abilities. To cover large areas at different altitudes, to be able to fly at different altitudes, under different weather conditions, to acquire image with high resolution are among the main advantages of this technology which make it usable and preferable for archaeological documentation. Since UAVs have been rapidly improving in sophistication and reliability, its possibilities aid in archaeological research have recently generated much interest, particularly for documenting sites, monuments and excavations. In this case study several aerial surveys will be conducted with a UAV mounted thermal camera on an archaeological area. After acquiring aerial images, they will be processed for producing both color and thermal-imagery in related software. Next step will be the alignment of the images in order to build an accurate and georeferenced 3D and mesh model of surveyed area. Then colored and thermal orthophoto mosaics as well as digital surface model (DSM) will be obtained for the documentation. The datasets of thermal images and color images will be collected and compared in order to detect archaeological remains on and under the ground.Es besteht immer Bedarf an zuverlässigen und genauen Daten für die Dokumentation des kulturellen Erbes, einschließlich archäologischer Gebiete. Die technischen Entwicklungen in der 3D-Datenerfassung haben erst die vollständige Dokumentation ermöglicht. Nahbereichsphotogrammetrie und terrestrisches Laserscanning gehören zu den am häufigsten verwendeten Techniken, die 3D-Datenerfassung mit hohem Detaillierungsgrad, Genauigkeit und effektive Ergebnissen ermöglichen. Diese Techniken sind jedoch nicht immer die am besten geeigneten für große archäologische Gebiete, dennoch können Luftbilder helfen, einen allgemeinen Überblick über das Gebiet zu geben, was für die Interpretation und Dokumentation archäologischer Stätten von grundlegender Bedeutung ist. Aufgrund der Einschränkungen in der Luftbildvermessung sind UAVs (Unmanned Aerial Vehicles) zu einer optimalen Lösung für die archäologische Geländedokumentation mit ihren Potenzialen im Kontext von Kosten und Fähigkeiten geworden. Hauptvorteile dieser Technologie sind u.a. große Gebiete in verschiedenen Höhen abzudecken und unter verschiedenen Wetterbedingungen fliegen zu können, Bilder mit hoher Auflösung aufzunehmen, die dann auch für die archäologische Dokumentation nutzbar und damit auch anderen Verfahren vorzuziehen sind. Da sich die UAVs in Bezug auf Entwicklungsgrad und Zuverlässigkeit rasant verbessert haben, haben ihre Möglichkeiten zur Unterstützung der archäologischen Forschung in jüngster Zeit großes Interesse geweckt, insbesondere bei der Dokumentation von Stätten, Denkmälern und Ausgrabungen. In dieser Fallstudie werden mehrere Kampagnen von Luftaufnahmen mit einer UAV-Wärmebildkamera auf einem archäologischen Gebiet durchgeführt. Nach der Bildaufufnahme die Farb- und Wärmebilder in einer entsprechenden Software verarbeitet. Der nächste Schritt wird die Verknüpfung der Bilder sein, um ein genaues und georeferenziertes 3D- und Netzmodell des vermessenden Bereichs zu erstellen. Anschließend werden farbige und thermische Orthophoto-Mosaike sowie digitale Oberflächenmodelle (DSM) für die Dokumentation abgeleitet. Die Datensätze von Wärme- und Farbbildern werden gesammelt und verglichen, um archäologische Überreste auf und unter dem Boden zu erkennen

Autonomous Execution of Cinematographic Shots with Multiple Drones

This paper presents a system for the execution of autonomous cinematography missions with a team of drones. The system allows media directors to design missions involving different types of shots with one or multiple cameras, running sequentially or concurrently. We introduce the complete architecture, which includes components for mission design, planning and execution. Then, we focus on the components related to autonomous mission execution. First, we propose a novel parametric description for shots, considering different types of camera motion and tracked targets; and we use it to implement a set of canonical shots. Second, for multi-drone shot execution, we propose distributed schedulers that activate different shot controllers on board the drones. Moreover, an event-based mechanism is used to synchronize shot execution among the drones and to account for inaccuracies during shot planning. Finally, we showcase the system with field experiments filming sport activities, including a real regatta event. We report on system integration and lessons learnt during our experimental campaigns

UAVs for the Environmental Sciences

This book gives an overview of the usage of UAVs in environmental sciences covering technical basics, data acquisition with different sensors, data processing schemes and illustrating various examples of application

Aerial Vehicles

This book contains 35 chapters written by experts in developing techniques for making aerial vehicles more intelligent, more reliable, more flexible in use, and safer in operation.It will also serve as an inspiration for further improvement of the design and application of aeral vehicles. The advanced techniques and research described here may also be applicable to other high-tech areas such as robotics, avionics, vetronics, and space