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

Decentralized Visual-Inertial-UWB Fusion for Relative State Estimation of Aerial Swarm

The collaboration of unmanned aerial vehicles (UAVs) has become a popular research topic for its practicability in multiple scenarios. The collaboration of multiple UAVs, which is also known as aerial swarm is a highly complex system, which still lacks a state-of-art decentralized relative state estimation method. In this paper, we present a novel fully decentralized visual-inertial-UWB fusion framework for relative state estimation and demonstrate the practicability by performing extensive aerial swarm flight experiments. The comparison result with ground truth data from the motion capture system shows the centimeter-level precision which outperforms all the Ultra-WideBand (UWB) and even vision based method. The system is not limited by the field of view (FoV) of the camera or Global Positioning System (GPS), meanwhile on account of its estimation consistency, we believe that the proposed relative state estimation framework has the potential to be prevalently adopted by aerial swarm applications in different scenarios in multiple scales.Comment: Accepted ICRA 202

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

Swarming of Unmanned Aerial Vehicles Using Indirect Information Exchange by Observation of the Workspace

Tato práce se soustředí na návrh, implementaci a ověření řídícího systému a systému pro relativní lokalizaci roje bezpilotních autonomních helikoptér v lesním prostředí. Základem lokalizačního systému je ICP algoritmus. Rojový řídící systém je inspirován Boidy a modifikován pro lepší interakci s reálným prostředím. Implementace byla ověřena v realistickém simulátoru Gazebo a pomocí Matlabu. Přístup, který je uveden v této práci, byl následně porovnán se současným systémem pro relativní lokalizaci a navigaci v lese, které používá skupina Multirobotických systémů na ČVUT v Praze.This thesis focuses on the design, implementation, and verification of a control system and relative localization approach for a swarm consisting of unmanned aerial vehicles in a forest environment. The core of the localization system is the ICP algorithm. The control system is based on Boids with modifications to adapt to the forest environment better. Implementation was verified in the realistic Gazebo simulator as well as in Matlab. The approach introduced in this thesis was also compared with the existing system for relative localization and navigation used in the Multi-Robot Systems group at Czech Technical University in Prague

Safe navigation and motion coordination control strategies for unmanned aerial vehicles

Unmanned aerial vehicles (UAVs) have become very popular for many military and civilian applications including in agriculture, construction, mining, environmental monitoring, etc. A desirable feature for UAVs is the ability to navigate and perform tasks autonomously with least human interaction. This is a very challenging problem due to several factors such as the high complexity of UAV applications, operation in harsh environments, limited payload and onboard computing power and highly nonlinear dynamics. Therefore, more research is still needed towards developing advanced reliable control strategies for UAVs to enable safe navigation in unknown and dynamic environments. This problem is even more challenging for multi-UAV systems where it is more efficient to utilize information shared among the networked vehicles. Therefore, the work presented in this thesis contributes towards the state-of-the-art in UAV control for safe autonomous navigation and motion coordination of multi-UAV systems. The first part of this thesis deals with single-UAV systems. Initially, a hybrid navigation framework is developed for autonomous mobile robots using a general 2D nonholonomic unicycle model that can be applied to different types of UAVs, ground vehicles and underwater vehicles considering only lateral motion. Then, the more complex problem of three-dimensional (3D) collision-free navigation in unknown/dynamic environments is addressed. To that end, advanced 3D reactive control strategies are developed adopting the sense-and-avoid paradigm to produce quick reactions around obstacles. A special case of navigation in 3D unknown confined environments (i.e. tunnel-like) is also addressed. General 3D kinematic models are considered in the design which makes these methods applicable to different UAV types in addition to underwater vehicles. Moreover, different implementation methods for these strategies with quadrotor-type UAVs are also investigated considering UAV dynamics in the control design. Practical experiments and simulations were carried out to analyze the performance of the developed methods. The second part of this thesis addresses safe navigation for multi-UAV systems. Distributed motion coordination methods of multi-UAV systems for flocking and 3D area coverage are developed. These methods offer good computational cost for large-scale systems. Simulations were performed to verify the performance of these methods considering systems with different sizes

UVDAR System for Visual Relative Localization with application to Leader-Follower Formations of Multirotor UAVs

International audienceA novel onboard relative localization method, based on ultraviolet light, used for real-time control of a leader-follower formation of multirotor UAVs is presented in this paper. A new smart sensor, UVDAR, is employed in an innovative way, which does not require communication and is extremely reliable in real-world conditions. This innovative sensing system exploits UV spectrum and provides relative position and yaw measurements independently of environment conditions such as changing illumination and presence of undesirable light sources and their reflections. The proposed approach exploits this retrieved information to steer the follower to a given 3D position and orientation relative to the leader, which may be considered as the main building block of any multi-UAV system operating with small mutual distances among team-members. The proposed solution was verified in demanding outdoor conditions, validating usage of UVDAR in real flight scenario and paving the way for further usage of UVDAR for practical multi-UAV formation deployments