Download or read book Obstacle Detection and Avoidance for UAVs in Nap of the Earth Flight written by Roger Fusté Mollà and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: A vision-based obstacle detection and avoidance algorithm for Unmanned Aerial Vehicles (UAVs) in fast and low flights ('Nap of the Earth' flights) has been developed. First, a literature review has been performed for both obstacle detection methods and obstacle avoidance methods. Two main categories have been recognised amongst the approaches used for each of them: the use of either a monocular camera or a stereo camera for the obstacle detection; and either reactive or anticipative methods for the obstacle avoidance. The implemented algorithm uses a stereo camera and an anticipative approach, as they have been identified as the most suitable techniques for fast flights. The stereo pairs of images are used to construct a 3D global occupancy map with a novel cell tagging method. This map is then used to calculate a set of waypoints which can lead the vehicle safely towards its goal. Finally, a novel optimisation algorithm is used to compute the fastest feasible polynomial trajectory along this set of waypoints to bring the vehicle to the target in the minimum achievable amount of time.

Download or read book Concepts for Pilot Interaction with an Automated NOE Obstacle avoidance System written by and published by . This book was released on 1992 with total page 22 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Embedded Platforms for UAS Landing Path and Obstacle Detection written by Umberto Papa and published by Springer. This book was released on 2018-01-05 with total page 115 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book reports on the design and development of a system that assists remote pilots during the landing procedure. In particular, it covers a previously neglected topic, namely the search for the best pathway and landing site. It describes the system’s components, such as the ultrasonic sensor, infrared sensor and optical sensor, in detail, and discusses the experimental tests carried out in both controlled laboratory and real-world environments. Providing a fascinating survey of the state of the art in the field of unmanned aircraft system electronics design and development, the book also presents recent advances in and cutting-edge methodologies for the development of acquisition systems and inexpensive sensor design for navigation data.

Download or read book Embedded Platforms for UAS Landing Path and Obstacle Detection II written by Gennaro Ariante and published by Springer Nature. This book was released on with total page 131 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Vision Based UAV Flight Control and Obstacle Avoidance written by and published by . This book was released on 2006 with total page 12 pages. Available in PDF, EPUB and Kindle. Book excerpt: In this work, we explore various ideas and approaches to deal with the inherent uncertainty and image noise in motion analysis, and develop a low-complexity, accurate and reliable scheme to estimate the motion fields from UAV navigation videos. The motion field information allows us to accurately estimate ego-motion parameters of the UAV and refine (or correct) the motion measurements from other sensors. Based on the motion field information, we also compute the range map for objects in the scene. Once we have accurate knowledge about the vehicle motion and its navigation environment (range map), control and guidance laws can be designed to navigate the UAV between way points and avoid obstacles.

Download or read book Moving Obstacle Avoidance for Unmanned Aerial Vehicles written by Yucong Lin and published by . This book was released on 2015 with total page 113 pages. Available in PDF, EPUB and Kindle. Book excerpt: There has been a vast increase in applications of Unmanned Aerial Vehicles (UAVs) in civilian domains. To operate in the civilian airspace, a UAV must be able to sense and avoid both static and moving obstacles for flight safety. While indoor and low-altitude environments are mainly occupied by static obstacles, risks in space of higher altitude primarily come from moving obstacles such as other aircraft or flying vehicles in the airspace. Therefore, the ability to avoid moving obstacles becomes a necessityfor Unmanned Aerial Vehicles. Towards enabling a UAV to autonomously sense and avoid moving obstacles, this thesis makes the following contributions. Initially, an image-based reactive motion planner is developed for a quadrotor to avoid a fast approaching obstacle. Furthermore, A Dubins curve based geometry method is developed as a global path planner for a fixed-wing UAV to avoid collisions with aircraft. The image-based method is unable to produce an optimal path and the geometry method uses a simplified UAV model. To compensatethese two disadvantages, a series of algorithms built upon the Closed-Loop Rapid Exploratory Random Tree are developed as global path planners to generate collision avoidance paths in real time. The algorithms are validated in Software-In-the-Loop (SITL) and Hardware-In-the-Loop (HIL) simulations using a fixed-wing UAV model and in real flight experiments using quadrotors. It is observed that the algorithm enables a UAV to avoid moving obstacles approaching to it with different directions and speeds.

Download or read book UAV or Drones for Remote Sensing Applications written by Felipe Gonzalez Toro and published by MDPI. This book was released on 2018-11-23 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book is a printed edition of the Special Issue "UAV or Drones for Remote Sensing Applications" that was published in Sensors

Download or read book Online Optimal Obstacle Avoidance for Rotary wing Autonomous Unmanned Aerial Vehicles written by Keeryun Kang and published by . This book was released on 2012 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This thesis presents an integrated framework for online obstacle avoidance of rotary-wing unmanned aerial vehicles (UAVs), which can provide UAVs an obstacle field navigation capability in a partially or completely unknown obstacle-rich environment. The framework is composed of a LIDAR interface, a local obstacle grid generation, a receding horizon (RH) trajectory optimizer, a global shortest path search algorithm, and a climb rate limit detection logic. The key feature of the framework is the use of an optimization-based trajectory generation in which the obstacle avoidance problem is formulated as a nonlinear trajectory optimization problem with state and input constraints over the finite range of the sensor. This local trajectory optimization is combined with a global path search algorithm which provides a useful initial guess to the nonlinear optimization solver. Optimization is the natural process of finding the best trajectory that is dynamically feasible, safe within the vehicle's flight envelope, and collision-free at the same time. The optimal trajectory is continuously updated in real time by the numerical optimization solver, Nonlinear Trajectory Generation (NTG), which is a direct solver based on the spline approximation of trajectory for dynamically flat systems. In fact, the overall approach of this thesis to finding the optimal trajectory is similar to the model predictive control (MPC) or the receding horizon control (RHC), except that this thesis followed a two-layer design; thus, the optimal solution works as a guidance command to be followed by the controller of the vehicle. The framework is implemented in a real-time simulation environment, the Georgia Tech UAV Simulation Tool (GUST), and integrated in the onboard software of the rotary-wing UAV test-bed at Georgia Tech. Initially, the 2D vertical avoidance capability of real obstacles was tested in flight. Then the flight test evaluations were extended to the benchmark tests for 3D avoidance capability over the virtual obstacles, and finally it was demonstrated on real obstacles located at the McKenna MOUT site in Fort Benning, Georgia. Simulations and flight test evaluations demonstrate the feasibility of the developed framework for UAV applications involving low-altitude flight in an urban area.

Download or read book Stereoscopic Imaging for Obstacle Detection Onboard Low flying Unmanned Aerial Vehicles written by Emad Hanna and published by . This book was released on 2010 with total page 194 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Sense and Avoid in UAS written by Plamen Angelov and published by John Wiley & Sons. This book was released on 2012-04-30 with total page 381 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is increasing interest in the potential of UAV (Unmanned Aerial Vehicle) and MAV (Micro Air Vehicle) technology and their wide ranging applications including defence missions, reconnaissance and surveillance, border patrol, disaster zone assessment and atmospheric research. High investment levels from the military sector globally is driving research and development and increasing the viability of autonomous platforms as replacements for the remotely piloted vehicles more commonly in use. UAV/UAS pose a number of new challenges, with the autonomy and in particular collision avoidance, detect and avoid, or sense and avoid, as the most challenging one, involving both regulatory and technical issues. Sense and Avoid in UAS: Research and Applications covers the problem of detect, sense and avoid in UAS (Unmanned Aircraft Systems) in depth and combines the theoretical and application results by leading academics and researchers from industry and academia. Key features: Presents a holistic view of the sense and avoid problem in the wider application of autonomous systems Includes information on human factors, regulatory issues and navigation, control, aerodynamics and physics aspects of the sense and avoid problem in UAS Provides professional, scientific and reliable content that is easy to understand, and Includes contributions from leading engineers and researchers in the field Sense and Avoid in UAS: Research and Applications is an invaluable source of original and specialised information. It acts as a reference manual for practising engineers and advanced theoretical researchers and also forms a useful resource for younger engineers and postgraduate students. With its credible sources and thorough review process, Sense and Avoid in UAS: Research and Applications provides a reliable source of information in an area that is fast expanding but scarcely covered.

Download or read book Concepts for Pilot Interaction with an Automated Noe Obstacle Avoidance System written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-08-16 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: The problem of providing an appropriate method by which a human pilot interacts with an automated nap-of-the-Earth rotorcraft guidance and control system is addressed. This problem is closely related to the broader question of what level and degree of automation is effective at reducing pilot workload during low-altitude flight missions requiring obstacle avoidance. A systematic approach for establishing the possible combinations of manual versus automatic authority over relevant guidance and control functions is first presented. From these possibilities, three candidate concepts are selected; selection is based upon their potential for practical implementation and reduction in pilot workload. This paper describes the selection of these three pilot-interaction concepts and the mathematical models for their implementation. Coppenbarger, R. A. and Cheng, V. H. L. Ames Research Center NASA-TM-103960, A-92157, NAS 1.15:103960 RTOP 505-64-36...

Download or read book Control and Obstacle Avoidance for Agile Fixed wing Aircraft written by Eitan Bulka and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: "Unmanned aerial vehicles (UAVs) have been increasingly proposed for aerial surveillance, mapping, and delivery tasks. Historically these vehicles fall into two categories: conventional fixed-wing aircraft, which are capable of efficient flight over long distances but lack maneuverability, and rotorcraft, which are capable of agile and maneuverable flight but lack efficiency and endurance. Recent advancements in aerial vehicle design aim to incorporate characteristics from both rotorcraft and conventional fixed-wing aircraft, ultimately creating aircraft that are capable of both maneuverable and efficient long distance flight. These type of platforms are ideal for tasks that require both the ability to maneuver through cluttered environments, and the ability to fly long distances efficiently. An aircraft of this type, the agile fixed-wing aircraft, is a fixed-wing aircraft characterized by a high thrust-to-weight ratio (> 1), and large control surfaces capable of large deflections.The objective of this thesis is to further the autonomous capabilities of agile fixed-wing aircraft; specifically in the context of control systems and real-time collision avoidance. The thesis begins with a discussion of a previously developed flight dynamics model, and presents a method for validating a flight dynamics model in flight regimes that rely on feedback control. Subsequently, a single control architecture is developed that can track trajectories within both conventional and aerobatic flight regimes. This architecture is then extended to be applicable to many other types of vehicles, specifically vehicles which can generate a torque in an arbitrary direction, and can apply a single body-fixed force. We demonstrate autonomous aerobatic trajectories with an agile fixed-wing aircraft, specifically knife-edge, rolling harrier, aggressive turnaround and hovering maneuvers within conventional simulations, hardware-in-the-loop simulations, indoor flight tests and outdoor flight tests. We also validate the extension to other platforms by demonstrating flips with a quadrotor in both simulation and outdoor flight tests. All flights were performed with on-board sensing and computation.We then present a reactive obstacle avoidance algorithm that utilizes the maneuvering capabilities of agile fixed-wing aircraft and can be run in real-time with on-board sensing and computation. At each time step, trajectories are selected in real-time from a pre-computed library that lead to various positions on the edge of the obstacle sensor's field-of-view. A cost is assigned to each collision-free trajectory based on its heading toward the goal and minimum distance to obstacles, and the lowest cost trajectory is tracked. If all of the potential trajectories leading to the various positions at the edge of the obstacle sensor's field-of-view result in a collision, the aircraft has enough space to hover and come to a stop, which theoretically guarantees collision-free flight in unknown static environments. Autonomous flight in unknown and unstructured environments using only on-board sensing (stereo camera, IMU, and GPS) and computation is demonstrated with an agile fixed-wing aircraft in both simulation and outdoor flight tests. During the flight testing campaign, the aircraft autonomously flew 4.4 km in a tree-filled environment with an average speed of 8.1 m/s and a top speed of 14.4 m/s"--

Download or read book Commercial and General Aircraft Avoidance Using Multi spectral Wave Detection written by Nathan Michael Paczan and published by . This book was released on 2020-11-26 with total page 26 pages. Available in PDF, EPUB and Kindle. Book excerpt: This disclosure is directed to a detection and avoidance apparatus for an unmanned aerial vehicle ("UAV") and systems, devices, and techniques pertaining to automated object detection and avoidance during UAV flight. The system may detect objects within the UAV's airspace through acoustic, visual, infrared, multispectral, hyperspectral, or object detectable signal emitted or reflected from an object. The system may identify the source of the object detectable signal by comparing features of the received signal with known sources signals in a database. The features may include, for example, a multispectral signature emitted or reflected by the object. Furthermore, a trajectory envelope for the object may be determined based on characteristic performance parameters for the object such as cursing speed, maneuverability, etc. The UAV may determine an optimized flight plan based on the trajectory envelopes of detected objects within the UAV's airspace.

Download or read book Autonomous Monocular Obstacle Detection for Avoidance in Quadrotor UAVs written by Panos Valavanis and published by . This book was released on 2019 with total page 54 pages. Available in PDF, EPUB and Kindle. Book excerpt: Obtained results contribute to: i.) a thorough understanding of advantages, disadvan- tages and applicability limitations of using only monocular vision for obstacle detection and avoidance; ii.) real-time applicability, and, iii.) applicability restrictions due to limita- tions of existing support technologies, i.e., ROS, Gazebo and the TUM Simulator package. A major contribution of the developed system is that it may be used as an open-source ed- ucational tool for students, practitioners and end users who are interested in unmanned aviation.

Download or read book Obstacle Detection and Avoidance Algorithm in Drones written by Vikas Vasudevan and published by . This book was released on 2021 with total page 32 pages. Available in PDF, EPUB and Kindle. Book excerpt: This project is realization of Obstacle Detection and Avoidance algorithm in Drones. The proposed project is a simulation in Airsim with hardware-in-loop (HIL). This report begins with setting up the necessary environments for simulation and review of the algorithm. In this project, the simulation is carried out in Unreal Engine with a preferred simulation environment. The hardware used is a PX4 based Pixhawk 2.4.8. It is configured with a ground control center application called QGroundControl. Unreal Engine was chosen over other game development engines since Airsim libraries are better built for the former and provides a good platform to various testing scenarios. The Drone used in the simulation is a generic quadcopter enabled with three sensors. The three sensors are lidar, stereo depth sensor and a camera sensor. The environment data is logged through these sensors into a csv file which is then used in the algorithm. The algorithm chosen for this purpose is deep Q-network or DQN, a reinforcement learning algorithm. The algorithm is scripted in Python to use cameras to capture the data from the environment in the simulation. The captured data is collected from the moving drone and the data is trained. This algorithm trains the drone to detect and avoid obstacles in its planned path

Download or read book Passive Long Range Detection of Aircraft Towards a Field Deployable Sense and Avoid System written by and published by . This book was released on 2009 with total page 11 pages. Available in PDF, EPUB and Kindle. Book excerpt: Unmanned Aerial Vehicles (UAVs) typically fly blind with operators in distant locations. Most UAVs are too small to carry a traffic collision avoidance system (TCAS) payload or transponder. Collision avoidance is currently done by flight planning, use of ground or air based human observers and segregated air spaces. US lawmakers propose commercial unmanned aerial systems access to national airspace (NAS) by 30th September 2013. UAVs must not degrade the existing safety of the NAS, but the metrics that determine this have to be fully determined yet. It is still possible to state functional requirements and determine some performance minimums. For both manned and unmanned aircraft to fly safely in the same airspace UAVs will need to detect other aircraft and follow the same rules as human pilots. Key specifications of the international committee F38 on UAS systems standard F2411-04 (1) proposed requirements which include a field of regard of 220 degrees (horizontal) x 30 degrees (vertical), minimum detection range of 3 statute miles under visual flight rules and a required miss distance of 500 feet. Without this capability, widespread utilization of UAVs will not be possible.

Download or read book Cooperative Path Planning of Unmanned Aerial Vehicles written by Antonios Tsourdos and published by Progress in Astronautics and A. This book was released on 2011 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: An invaluable addition to the literature on UAV guidance and cooperative control, Cooperative Path Planning of Unmanned Aerial Vehicles is a dedicated, practical guide to computational path planning for UAVs. One of the key issues facing future development of UAVs is path planning: it is vital that swarm UAVs/ MAVs can cooperate together in a coordinated manner, obeying a pre-planned course but able to react to their environment by communicating and cooperating. An optimized path is necessary in order to ensure a UAV completes its mission efficiently, safely, and successfully. Focussing on the path planning of multiple UAVs for simultaneous arrival on target, Cooperative Path Planning of Unmanned Aerial Vehicles also offers coverage of path planners that are applicable to land, sea, or space-borne vehicles. Cooperative Path Planning of Unmanned Aerial Vehicles is authored by leading researchers from Cranfield University and provides an authoritative resource for researchers, academics and engineers working in the area of cooperative systems, cooperative control and optimization particularly in the aerospace industry.Include chapters on path planning, 3-D path planning, cooperative path planning, path planning in complex environments as well as guidance for accurate path following and sense and avoid algorithms to deal with collision avoidanceApproaches the solution to UAV path planning via two phases: producing paths to meet curvature constraints - the flyable paths, and then tuning the flyable paths to meet the mission demandsDescribes flyable path approaches using composite curves using Dubins and Clothoid principles, and continuous curves using Pythagorean Hodograph principles; and extends these approaches to cater for the complex problem of obstacle avoidance.?