Download or read book Autonomous Control Modes and Optimized Path Guidance for Shipboard Landing in High Sea States written by Junfeng Yang and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Rotorcraft, due to their unique vertical take-off and landing capability, are well-suited for maritime applications. The capability of shipboard launch and recovery of a rotorcraft allows extension of the operational envelope of a single ship as well as the whole fleet. However, due to the cross-axes coupling, inherent instability and sluggish response, accurate and soft landing of rotorcraft is a challenging task, especially when the flight deck is moving in high sea states and in the presence of adverse factors such as the gusty airwake and limited space. In low to medium sea state, an experienced pilot can designate a window of quiescent ship motion to perform the landing while also using an intuitive predictive strategy. In very high sea states, the workload and control precision become unacceptable, and therefore motivate the development of an automated landing system. This thesis contributes both theoretical investigations and technical solutions to the guidance, navigation and control for an autonomous shipboard recovery mode in high states. Using the high-fidelity modeling software FLIGHTLAB together with ship airwake and motion models, the specific aspects of rotorcraft flight dynamics and the characteristics of the shipboard landing environment were studied and provided guidelines for the formulation of design requirements. The Dynamic Inversion method was applied to design an inner-loop attitude control system and then an outer-loop trajectory following system, and the associated design problems such as control parameter optimization, robustness testing are discussed. In order to provide a fully autonomous capability, a parameterization and optimization algorithm was developed for approach path generation. The resulting path geometry and velocity profile can ensure fundamental flight safety but also provide enough flexibility for console operators to specify approach azimuth and steepness. A landing path generator incorporating predictive deck state has been developed to complete the last stage of shipboard recovery, both forecasting and instantaneous measurement of deck state are used to construct the commanded descent trajectory through a hybrid implementation. The technical adequacy of high-grade vehicle location and motion detection has been proven by an integrated navigation system incorporating information from GPS, inertial measurement unit and shipboard tracking system. Stand-alone testing of system components, as well as comprehensive testing of the entire system from approach entry to touchdown have been carried out using FLIGHTLAB simulations. As justified by the simulation results: the scientific concept and engineering approach developed in this thesis show great potential to an overall solution to the challenging problems of shipboard recovery of rotorcraft in high sea states in a fully autonomous mode.
Download or read book Model Scale Evaluation of Autonomous Ship Landing Guidance and Control Modes for Rotorcraft written by Christopher Hendrick and published by . This book was released on 2024 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: Ship landing in high sea states is a challenge for both manned and unmanned rotorcraft. A system that provides reliable autonomous recovery of ship-based rotorcraft could reduce mishap rates and reduce costs associated with training and certification testing. Such a system might also increase operational capability by allowing operations in more severe wave and wind conditions. These potential benefits have motivated a significant amount of public domain research on autonomous ship landing algorithms for rotorcraft. Existing works have primarily been simulation based, however, and the rigorous experimental evaluation of advanced landing algorithms is lacking in the public-domain literature. This is due in part to the inaccessibility of full-scale testing. Model-scale testing, on the other hand, offers a more accessible test bed for vetting autonomous landing solutions and has therefore been utilized in all existing openly available experimental studies. These studies have not considered the scaling of either the closed-loop aircraft dynamics or ship motions, however, meaning key aspects of the full-scale landing scenario may not be realistically represented at model-scale. The objective of this research was to develop a methodology for performing dynamically scaled autonomous ship landing experiments, and then to use the proposed scaling method to perform a rigorous experimental analysis of advanced autonomous landing guidance and control modes. Toward this end, Froude scaling is proposed for relating aircraft closed-loop dynamics and ship motions across test scales and the validity of this method is then analyzed. Two representative landing guidance algorithms were then developed and experimentally evaluated using the proposed scaling methodology. The first is an advanced landing strategy that uses quadratic programming (QP) optimization to plan the landing path to a forecasted deck state. The second is a simpler ``baseline'' guidance method that tracks deck motions while closing the distance between the aircraft and deck at a constant rate. Both guidance algorithms command position and heading to an explicit model following (EMF) control law. The guidance algorithms were first evaluated in experiments conducted in the Maneuvering and Seakeeping Basin (MASK) located at the Naval Surface Warfare Center Carderock Division. During these experiments, control law parameters were modified to impose artificial constraints on the maneuverability of the aircraft, providing insight into how well both guidance methods can cope with a less agile airframe. The results showed that the predictive landing strategy allowed for more direct landing paths to be planned when compared to the baseline algorithm and can also allow for landings to be performed with lower control bandwidth. The baseline guidance algorithm, on the other hand, proved to be both simple and reliable when the UAV was in high bandwidth configurations, but may not be feasible for aircraft with limited control authority that must land in moderate to high sea states. The experimental setup in the MASK did not include aerodynamic disturbances. Additional flight tests were therefore performed in the Penn State Indoor Flight Facility to determine if the QP guidance algorithm offers any advantage over the baseline method when operating in the presence of a significant aerodynamic disturbance. The experimental results obtained at Penn State did not indicate that the QP algorithm provides a definitive advantage over the baseline algorithm in terms of matching deck position, velocity, and attitude at landing while operating in a gusty environment. The QP algorithm did allow for landings with a shorter duration, however, resulting in lower total control usage due to less time operating in aerodynamic disturbances.
Download or read book Shipboard UAS Operations with Optimized Landing Trajectories written by Jintasit Pravitra and published by . This book was released on 2021 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: Unmanned Aircraft Systems (UASs) have become increasingly important assets for naval and maritime law enforcement operations. In response to the ever-increasing demand for safe autonomous systems, this dissertation presents a development of an unmanned rotorcraft system capable of operating with a ship. The dissertation presents several software components, including ship motion simulation, ship motion prediction, and a practical integration between model predictive controllers and an autopilot. The UAS was flight validated by operating off the US Naval Academy's yard patrol craft as the craft was underway in the Chesapeake Bay. Autonomous capabilities including takeoff, landing, station-keeping, and maneuvering relative to the ship were successfully demonstrated. The key element for the success of the test was the RTK relative positioning solution between the helicopter and the moving ship. Since landing a helicopter on a moving ship is an extremely difficult task, this dissertation also proposes a new trajectory generation algorithm that can land on an aggressively moving target. Because a similar issue also occurs with manned helicopters, this algorithm is not only beneficial for UAS operations but can also be applied to help reduce pilot workload in manned operations. The algorithm utilizes the recent availability of small form factor graphics processing units (GPUs). Multiple optimal control problems will be solved online and in parallel. Each optimal control problem corresponds to different time horizons and different target states. Iterative Linear Quadratic Regulator (iLQR) is selected due to its convergence property. Similar to Differential Dynamic Programming (DDP), iLQR solves an optimal control problem through a back-and-forth scheme where the optimal control law is updated during the backward pass, and the trajectory is updated during the forward pass. The novel algorithm is termed Ensemble iLQR (EiLQR), and it includes several notable properties. 1) Analytical expression of the target dynamics is not required, and only the state sequence of the target is needed. 2) Multiple solutions are available, and the autopilot has the liberty to select the best trajectory to fly. 3) Because iLQR is a nonlinear optimal control algorithm, relative attitude minimization can be formulated directly. Relative attitude minimization is essential for soft touchdown, especially when the deck is pitching and rolling with substantial magnitude. EiLQR is validated in simulation and is shown to work well against moderate sea states. EiLQR outperforms a purely reactive landing guidance on both touchdown position dispersion and impact velocity. To demonstrate the practicality of the algorithm, EiLQR was also flight tested against a static ground. The computational performance of the GPU is also included.
Download or read book Receding Horizon Control for Autonomous UAS Shipboard Landing with Tau Guidance and Polynomial Trajectory Planning written by Emma Jaques and published by . This book was released on 2023 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: It can be very difficult to autonomously land a small UAS (Unmanned Aerial System) on a ship deck that is in motion on the water in the presence of sea and air disturbance conditions. In this thesis, a technique was developed to perform receding horizon control using fast closed form path planning. This technique involves the use of second order tau guidance to determine an initial landing path and subsequent path re-plans at fixed intervals using fifth order Chebyshev polynomial path planning that enables matching of position, velocity, and acceleration at both the start and end of the path. The path is represented in non-dimensional form with position normalized by distance to goal and time normalized by the desired time-to-touchdown. Certain state-based criteria were chosen that would necessitate a go-around maneuver and path adjustments were made within each re-plan to determine if the criteria could be bypassed or if a go-around was needed. A simulation was built in MATLAB to test the receding horizon control system in a variety of light wind environments. This simulation was used to generate single-flight tests to view the calculated optimal flight paths in different disturbance environments. It was also used to generate Monte Carlo data sets to determine the best UAS beginning positional locations and the limits of disturbance tolerance to increase the odds of a successful shipboard landing.
Download or read book VTOL Control for Shipboard Landing in High Sea States written by Christopher Graham McMuldroch and published by . This book was released on 1979 with total page 8 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of a Novel Method for Autonomous Navigation and Landing of Unmanned Aerial Vehicles written by David J. Grymin and published by . This book was released on 2009 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt: "In this work, control techniques for the autonomous navigation and landing of an Unmanned Aerial Vehicle (UAV) are developed and compared. Controllers were developed and implemented on two different aircraft models: the Lockheed-Martin F-16 and AAI Corporation/Israel Aircraft Industries RQ-2 Pioneer. Due to the expense of modifying the pre-existing F-16 flight control system, the controller is implemented outside of the closed loop. Proportional-integral-derivative and proportional-integral controllers are developed for holding the aircraft at a desired velocity and altitude. The aircraft are approximated as Dubins vehicles constrained to travel on a two-dimensional surface for decreased simulation time. Using the simplified model two control techniques are developed and then compared. the first uses a proportional feedback controller based on the Rhumb-line that the aircraft is traveling along. The second control technique uses a trajectory determined from an algorithm using the Dubins path determination for the shortest travel distance between the two points. A sliding mode controller is developed to guide the simplified model along the Dubins path trajectory. The advantage of the Dubins path trajectory is that it allows for a closed-form time estimate to reach the desired way-point. Comparison between the two navigation techniques using the simplified system shows a significant decrease in time to way-point for the Dubins curve trajectory controller. The Rhumb-line controller and a hybrid Rhumb-line/Dubins path controller are implemented on nonlinear models of both aircraft. Simulation of both controllers on the nonlinear model shows acceptable performance in guiding the aircraft between way-points. Also, the time to way-point for the nonlinear aircraft model guided by the hybrid controller is within 5% of the closed-form Dubins trajectory estimate. Autonomous landing is accomplished utilizing the path guidance and altitude controllers. The nonlinear simulated aircraft successfully followed the glideslope from way-point to runway."--Abstract.
Download or read book Scientific and Technical Aerospace Reports written by and published by . This book was released on 1994 with total page 328 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Autonomous Horizons written by Greg Zacharias and published by Independently Published. This book was released on 2019-04-05 with total page 420 pages. Available in PDF, EPUB and Kindle. Book excerpt: Dr. Greg Zacharias, former Chief Scientist of the United States Air Force (2015-18), explores next steps in autonomous systems (AS) development, fielding, and training. Rapid advances in AS development and artificial intelligence (AI) research will change how we think about machines, whether they are individual vehicle platforms or networked enterprises. The payoff will be considerable, affording the US military significant protection for aviators, greater effectiveness in employment, and unlimited opportunities for novel and disruptive concepts of operations. Autonomous Horizons: The Way Forward identifies issues and makes recommendations for the Air Force to take full advantage of this transformational technology.
Download or read book Shipboard Operations written by H I Lavery and published by Routledge. This book was released on 2013-10-11 with total page 315 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book covers the knowledge of shipboard operations required by candidates for professional qualification as Chief Officer and Master Mariner. It deals with the basic routines and procedures, and the many regulations governing their use, for the safe and efficient operation of merchant ships. The book is also designated a fundamental text for the Maritime Transport paper of the Chartered Institute of Transport's membership examinations. The second edition takes into account recent developments in technology and regulation, and in particular covers major international legislation on Safety of Life at Sea and on Maritime Pollution as well as recent UK regulations on occupational health and safety and on operation of ro-ro ferries.
Download or read book Advancing Autonomous Systems written by Bradley Martin and published by . This book was released on 2018-12 with total page 120 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Naval Aviation Maintenance Program NAMP Maintenance data systems written by United States. Office of the Chief of Naval Operations and published by . This book was released on 1990 with total page 828 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Ocean Law and Policy written by Carlos Espósito and published by BRILL. This book was released on 2016-10-11 with total page 483 pages. Available in PDF, EPUB and Kindle. Book excerpt: In the years since 1994, when the UN Convention on the Law of the Sea (UNCLOS) entered into force, the ocean law regime has been profoundly affected by an interplay of new forces in global ocean affairs. Numbered among them are innovations in technology and science, the emergence of intensified piracy and other challenges to maritime security, national, and regional programs. In Ocean Law and Policy: Twenty Years of Development under the UNCLOS Regime, experts from fourteen countries present nineteen papers that provide insightful analyses of these wide-ranging issues that form the emerging new context of UNCLOS as a keystone to a working regime system. Accessible as well as authoritative, this volume offers to general readers as well as academics, policy officials, and legal experts a set of important analyses and provocative insights, forming a major contribution to the literature of ocean studies.
Download or read book Handbook of Marine Craft Hydrodynamics and Motion Control written by Thor I. Fossen and published by John Wiley & Sons. This book was released on 2021-04-16 with total page 96 pages. Available in PDF, EPUB and Kindle. Book excerpt: Handbook of MARINE CRAFT HYDRODYNAMICS AND MOTION CONTROL The latest tools for analysis and design of advanced GNC systems Handbook of Marine Craft Hydrodynamics and Motion Control is an extensive study of the latest research in hydrodynamics, guidance, navigation, and control systems for marine craft. The text establishes how the implementation of mathematical models and modern control theory can be used for simulation and verification of control systems, decision-support systems, and situational awareness systems. Coverage includes hydrodynamic models for marine craft, models for wind, waves and ocean currents, dynamics and stability of marine craft, advanced guidance principles, sensor fusion, and inertial navigation. This important book includes the latest tools for analysis and design of advanced GNC systems and presents new material on unmanned underwater vehicles, surface craft, and autonomous vehicles. References and examples are included to enable engineers to analyze existing projects before making their own designs, as well as MATLAB scripts for hands-on software development and testing. Highlights of this Second Edition include: Topical case studies and worked examples demonstrating how you can apply modeling and control design techniques to your own designs A Github repository with MATLAB scripts (MSS toolbox) compatible with the latest software releases from Mathworks New content on mathematical modeling, including models for ships and underwater vehicles, hydrostatics, and control forces and moments New methods for guidance and navigation, including line-of-sight (LOS) guidance laws for path following, sensory systems, model-based navigation systems, and inertial navigation systems This fully revised Second Edition includes innovative research in hydrodynamics and GNC systems for marine craft, from ships to autonomous vehicles operating on the surface and under water. Handbook of Marine Craft Hydrodynamics and Motion Control is a must-have for students and engineers working with unmanned systems, field robots, autonomous vehicles, and ships. MSS toolbox: https://github.com/cybergalactic/mss Lecture notes: https://www.fossen.biz/wiley Author’s home page: https://www.fossen.biz
Download or read book U S Navy Program Guide 2017 written by Department Of the Navy and published by Independently Published. This book was released on 2019-03-12 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Navy is ready to execute the Nation's tasks at sea, from prompt and sustained combat operations to every-day forward-presence, diplomacy and relief efforts. We operate worldwide, in space, cyberspace, and throughout the maritime domain. The United States is and will remain a maritime nation, and our security and prosperity are inextricably linked to our ability to operate naval forces on, under and above the seas and oceans of the world. To that end, the Navy executes programs that enable our Sailors, Marines, civilians, and forces to meet existing and emerging challenges at sea with confidence. Six priorities guide today's planning, programming, and budgeting decisions: (1) maintain a credible, modern, and survivable sea based strategic deterrent; (2) sustain forward presence, distributed globally in places that matter; (3) develop the capability and capacity to win decisively; (4) focus on critical afloat and ashore readiness to ensure the Navy is adequately funded and ready; (5) enhance the Navy's asymmetric capabilities in the physical domains as well as in cyberspace and the electromagnetic spectrum; and (6) sustain a relevant industrial base, particularly in shipbuilding.
Download or read book Perception as Information Detection written by Jeffrey B. Wagman and published by Routledge. This book was released on 2019-07-31 with total page 355 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a chapter-by-chapter update to and reflection on of the landmark volume by J.J. Gibson on the Ecological Approach to Visual Perception (1979). Gibson’s book was presented a pioneering approach in experimental psychology; it was his most complete and mature description of the ecological approach to visual perception. Perception as Information Detection commemorates, develops, and updates each of the sixteen chapters from Gibson’s volume. The book brings together some of the foremost perceptual scientists in the field, from the United States, Europe, and Asia, to reflect on Gibson’s original chapters, expand on the key concepts discussed and relate this to their own cutting-edge research. This connects Gibson’s classic with the current state of the field, as well as providing a new generation of students with a contemporary overview of the ecological approach to visual perception. Perception as Information Detection is an important resource for perceptual scientists as well as both undergraduates and graduates studying sensation and perception, vision, cognitive science, ecological psychology, and philosophy of mind.
Download or read book Smart Autonomous Aircraft written by Yasmina Bestaoui Sebbane and published by CRC Press. This book was released on 2015-11-18 with total page 434 pages. Available in PDF, EPUB and Kindle. Book excerpt: With the extraordinary growth of Unmanned Aerial Vehicles (UAV) in research, military, and commercial contexts, there has been a need for a reference that provides a comprehensive look at the latest research in the area. Filling this void, Smart Autonomous Aircraft: Flight Control and Planning for UAV introduces the advanced methods of flight contr
Download or read book Robust Control Design Using H 8 Methods written by Ian R. Petersen and published by Springer Science & Business Media. This book was released on 2000-09-22 with total page 478 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a unified collection of important, recent results for the design of robust controllers for uncertain systems. Most of the results presented are based on H? control theory, or its stochastic counterpart, risk sensitive control theory.Central to the philosophy of the book is the notion of an uncertain system. Uncertain systems are considered using several different uncertainty modeling schemes. These include norm bounded uncertainty, integral quadratic constraint (IQC) uncertainty and a number of stochastic uncertainty descriptions. In particular, the authors examine stochastic uncertain systems in which the uncertainty is outlined by a stochastic version of the IQC uncertainty description.For each class of uncertain systems covered in the book, corresponding robust control problems are defined and solutions discussed.
