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This paper introduces the reasoning and concepts behind a generic and modular approach to obstacle avoidance based on geofencing. The issue of UAV safety is tackled from a practical point of view and a collision avoidance system based on practical usage and safety considerations is presented. Before doing so, the need for a reference model of geographic geometry is discussed, looking at global positioning...
The design and testing of unmanned aerial vehicles is a difficult task due to the high risk of damage to property during testing, to prevent accidents from happening it is indeed necessary to perform extensive simulation of controllers to ensure good stability and performance. We have been working to solve this problem by developing a realistic simulator by using a complete mathematical model of the...
In this paper, we investigate the problem of fault tolerant for a group of multiple autonomous cooperative unmanned aerial vehicles (UAVs) during execution their mission in a desired geometrical pattern. A decentralized linear model predictive control (LMPC) is designed and implemented on a team of cooperative UAVs to achieve the desired formation in the absence of faults (normal/fault-free cases)...
An estimation framework is presented that improves the robustness of GPS-denied state estimation to changing environmental conditions by fusing updates from multiple view-based odometry algorithms. This allows the vehicle to utilize a suite of complementary exteroceptive sensors or sensing modalities. By estimating the vehicle states relative to a local coordinate frame collocated with an odometry...
This article presents an image-based visual servoing system for indoor visual tracking of 3D moving objects by an Unmanned Aerial Vehicle. This system autonomously follows a 3D moving target object, maintaining it with a fixed distance and centered on its image plane. The initial setup is tested in a detailed simulation environment. The system is then validated on flights in indoor scenarios using...
This paper presents an Unmanned Aerial System (UAS) for precision forestry applications. The UAS is capable of performing fully autonomous flights under the canopies of an unknown plantation forest by avoiding obstacles without the use of GPS navigation. The navigation framework of this system consists of a velocity estimator and an obstacle avoidance controller. In particular, the velocity estimator...
In a search and rescue scenario, an expeditious response is critical since the radius of the search area increases by roughly 3 km per hour while the life expectancy of the lost individual decreases. To find the object of the search as quickly as possible, the incident commander creates an overlay probability map identifying high priority search areas and develops a search plan that allocates search...
In recent years, the availability of low-cost and autonomous unmanned aerial vehicles (UAVs) results in the use of them for different types of military and commercial applications. The crucial part of the autonomous UAVs is their online or offline path planning algorithms. In the literature, there are many types of solutions, which use evolutionary and/or swarm intelligence approaches. Ant colony...
Personal drones are becoming part of every day life. To fully integrate them into society, it is crucial to design safe and intuitive ways to interact with these aerial systems. The recent advances on User-Centered Design (UCD) applied to Natural User Interfaces (NUIs) intend to make use of human innate features, such as speech, gestures and vision to interact with technology in the way humans would...
Unmanned stratospheric aircraft capable of staying aloft for long periods of time have become a topic of interest in the past years. Several problems are still to be solved to allow for a profitable commercial use of such aircraft. The inherent lightweight design leads to fragile structures with low payload capacities and a high wind sensitivity. The weather dependence significantly reduces the system's...
Payload sensory information is critical to improve the degree of realism and context awareness in multi-UAV simulators. This paper describes a simulator for multi-payload cooperative UAS missions. It adopts an open Software-In-The-Loop (SITL) approach where the simulation of payload sensors and UAV navigation systems are distributed providing high degree of realism. The proposed simulation tool imposes...
A mission restoration control system in an integrated automatic flight controller for aircraft Loss-of-Control Prevention and Recovery is presented, in which the two-phase Loss-of-Control recovery includes a LOC arrest mode and a mission restoration mode. For a trajectory tracking mission, a complete mission restoration mode is achieved by i) a close-in sub-mode of guiding the vehicle to catch up...
In this paper, the system requirements for the integration of Remotely Piloted Aircraft Systems (RPAS) in controlled airspace regions are discussed. The specificities in terms of Air Traffic Management (ATM) level of service, jurisdiction for deconfliction duties and prevalent traffic characteristics are analysed to support the identification of operational and equipage requirements for RPAS developers...
In this paper a scalable and flexible Architecture for real-time mission planning and dynamic agent-to-task assignment for a swarm of Unmanned Aerial Vehicles (UAV) is presented. The proposed mission planning architecture consists of a Global Mission Planner (GMP) which is responsible of assigning and monitoring different high-level missions through an Agent Mission Planner (AMP), which is in charge...
Given the proliferation of Unmanned Aerial Systems (UASs) for military and commercial purposes, there is a fast-approaching need for comprehensive and robust systems which secure the UAS for public safety and assurance of military goals. This paper puts forth a comprehensive system of protecting UASs against hardware and software attacks, at the lowest and highest semantic levels. This approach monitors...
This paper presents the combination of Potential Flow Field (PFF) and Virtual Force Field (VFF) methods to construct a viable means for UAS's to autonomously navigate and avoid collisions with obstacles. A validated flight dynamics model of a fixed-wing UAS was integrated with a heading hold autopilot that receives commanded heading angles from the selected output of the PFF and VFF methods. PFF primarily...
As part of the aviation regulations in the Netherlands, third party risk models have been developed and are applied in the determination of risks to the people on ground (third parties) due to aircraft departures and arrivals. In the derivation of these models, accident data are required. Such risk model has yet to be developed for unmanned aerial vehicles (UAVs). As foreseen in the future, accidents...
The small unmanned aircraft systems (SUAS) threat is not emerging. It is real. It is international. It is varied. A quadcopter landed on the White House lawn.1 A SUAS hovered in front of German Chancellor Angela Merkel while she stood on a public podium.2 Numerous unidentified SUAS' have conducted surveillance of French nuclear facilities.3 A man recently crashed his SUAS into the Empire State Building,...
This article presents a structural analysis of the Unmanned Aerial System UAS-S4 ETHECATL. The mass and the center of gravity position are numerically determined and further experimentally verified using the “pendulum method”. The numerical estimations are computed through Raymer statistical-empirical method coupled with mechanical calculations. The mass of the UAS-S4 component are estimated according...
Conventional quadrotor UAVs have crucial underactuation limitations. This appears in the coupling between the roll angle and the movement in y-direction, and between the pitch angle and the movement in x-direction. The quadrotor capability of hovering with either roll or pitch angle is restricted due to these limitations. In this paper, a novel design modification is proposed in order to increase...
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