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 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 Advances in Aerospace Guidance Navigation and Control written by Bogusław Dołęga and published by Springer. This book was released on 2017-12-15 with total page 735 pages. Available in PDF, EPUB and Kindle. Book excerpt: The first three CEAS (Counsil of European Aerospace Societies) Specialist Conferences on Guidance, Navigation and Control (CEAS EuroGNC) were held in Munich, Germany in 2011, in Delft, Netherlands in 2013 and in Toulouse, France in 2017. The Warsaw University of Technology (WUT) and the Rzeszow University of Technology (RzUT) accepted the challenge of jointly organizing the 4th edition. The conference aims to promote scientific and technical excellence in the fields of Guidance, Navigation and Control (GNC) in aerospace and other fields of technology. The Conference joins together the industry with the academia research. This book covers four main topics: Guidance and Control, Control Theory Application, Navigation, UAV Control and Dynamic. The papers included focus on the most advanced and actual topics in guidance, navigation and control research areas: · Control theory, analysis, and design · ; Novel navigation, estimation, and tracking methods · Aircraft, spacecraft, missile and UAV guidance, navigation, and control · Flight testing and experimental results · Intelligent control in aerospace applications · Aerospace robotics and unmanned/autonomous systems · Sensor systems for guidance, navigation and control · Guidance, navigation, and control concepts in air traffic control systems For the 4th CEAS Specialist Conference on Guidance, Navigation and Control the International Technical Committee established a formal review process. Each paper was reviewed in compliance with good journal practices by independent and anonymous reviewers. At the end of the review process papers were selected for publication in this book.

Download or read book Autonomous Guidance of Agile Small Scale Rotorcraft written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-06-21 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt: This report describes a guidance system for agile vehicles based on a hybrid closed-loop model of the vehicle dynamics. The hybrid model represents the vehicle dynamics through a combination of linear-time-invariant control modes and pre-programmed, finite-duration maneuvers. This particular hybrid structure can be realized through a control system that combines trim controllers and a maneuvering control logic. The former enable precise trajectory tracking, and the latter enables trajectories at the edge of the vehicle capabilities. The closed-loop model is much simpler than the full vehicle equations of motion, yet it can capture a broad range of dynamic behaviors. It also supports a consistent link between the physical layer and the decision-making layer. The trajectory generation was formulated as an optimization problem using mixed-integer-linear-programming. The optimization is solved in a receding horizon fashion. Several techniques to improve the computational tractability were investigate. Simulation experiments using NASA Ames 'R-50 model show that this approach fully exploits the vehicle's agility. Mettler, Bernard and Feron, Eric Ames Research Center

Download or read book Advances in Aerospace Guidance Navigation and Control written by Florian Holzapfel and published by Springer Science & Business Media. This book was released on 2011-03-15 with total page 465 pages. Available in PDF, EPUB and Kindle. Book excerpt: Over the last few decades, both the aeronautics and space disciplines have greatly influenced advances in controls, sensors, data fusion and navigation. Many of those achievements that made the word “aerospace” synonymous with “high–tech” were enabled by innovations in guidance, navigation and control. Europe has seen a strong trans-national consolidation process in aerospace over the last few decades. Most of the visible products, like commercial aircraft, fighters, helicopters, satellites, launchers or missiles, are not made by a single country – they are the fruits of cooperation. No European country by itself hosts a specialized guidance, navigation and controls community large enough to cover the whole spectrum of disciplines. However, on a European scale, mutual exchange of ideas, concepts and solutions is enriching for all. The 1st CEAS Specialist Conference on Guidance, Navigation and Control is an attempt to bring this community together. This book is a selection of papers presented at the conference. All submitted papers have gone through a formal review process in compliance with good journal practices. The best papers have been recommended by the reviewers to be published in this book.

Download or read book Fully Automatic Guidance and Control for Rotorcraft Nap Of The Earth Flight Following Planned Profiles Volume 1 written by National Aeronautics and Space Administration (NASA) and published by Createspace Independent Publishing Platform. This book was released on 2018-07-17 with total page 158 pages. Available in PDF, EPUB and Kindle. Book excerpt: Developing a single-pilot, all-weather nap-of-the-earth (NOE) capability requires fully automatic NOE (ANOE) navigation and flight control. Innovative guidance and control concepts are investigated in a four-fold research effort that: (1) organizes the on-board computer-based storage and real-time updating of NOE terrain profiles and obstacles in course-oriented coordinates indexed to the mission flight plan; (2) defines a class of automatic anticipative pursuit guidance algorithms and necessary data preview requirements to follow the vertical, lateral, and longitudinal guidance commands dictated by the updated flight profiles; (3) automates a decision-making process for unexpected obstacle avoidance; and (4) provides several rapid response maneuvers. Acquired knowledge from the sensed environment is correlated with the forehand knowledge of the recorded environment (terrain, cultural features, threats, and targets), which is then used to determine an appropriate evasive maneuver if a nonconformity of the sensed and recorded environments is observed. This four-fold research effort was evaluated in both fixed-based and moving-based real-time piloted simulations, thereby, providing a practical demonstration for evaluating pilot acceptance of the automated concepts, supervisory override, manual operation, and re-engagement of the automatic system. Volume one describes the major components of the guidance and control laws as well as the results of the piloted simulations. Volume two describes the complete mathematical model of the fully automatic guidance system for rotorcraft NOE flight following planned flight profiles. Clement, Warren F. and Gorder, Peter J. and Jewell, Wayne F. Unspecified Center AIRCRAFT GUIDANCE; AUTOMATIC FLIGHT CONTROL; AUTOMATIC PILOTS; AUTONOMOUS NAVIGATION; NAP-OF-THE-EARTH NAVIGATION; OBSTACLE AVOIDANCE; REAL TIME OPERATION; ROTARY WING AIRCRAFT; ALGORITHMS; COMPUTERIZED SIMULATION; CONTROL THEORY; FLIGHT SIMULATION; PILOT PERFORMANCE...

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 Flight Control Design for an Autonomous Rotorcraft Using Pseudo sliding Mode Control and Waypoint Navigation written by Nicolas Joseph Mallory and published by . This book was released on 2013 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The design of robust automated flight control systems for aircraft of varying size and complexity is a topic of continuing interest for both military and civilian industries. By merging the benefits of robustness from sliding mode control (SMC) with the familiarity and transparency of design tradeoff offered by frequency domain approaches, this thesis presents pseudo-sliding mode control as a viable option for designing automated flight control systems for complex six degree-of-freedom aircraft. The infinite frequency control switching of SMC is replaced, by necessity, with control inputs that are continuous in nature. An introduction to SMC theory is presented, followed by a detailed design of a pseudo-sliding mode control and automated flight control system for a six degree-of-freedom model of a Hughes OH6 helicopter. This model is then controlled through three different waypoint missions that demonstrate the stability of the system and the aircraft's ability to follow certain maneuvers despite time delays, large changes in model parameters and vehicle dynamics, actuator dynamics, sensor noise, and atmospheric disturbances.

Download or read book Linear and Nonlinear Control of Unmanned Rotorcraft written by Ioannis A. Raptis and published by . This book was released on 2010 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: ABSTRACT: The main characteristic attribute of the rotorcraft is the use of rotary wings to produce the thrust force necessary for motion. Therefore, rotorcraft have an advantage relative to fixed wing aircraft because they do not require any relative velocity to produce aerodynamic forces. Rotorcraft have been used in a wide range of missions of civilian and military applications. Particular interest has been concentrated in applications related to search and rescue in environments that impose restrictions to human presence and interference. The main representative of the rotorcraft family is the helicopter. Small scale helicopters retain all the flight characteristics and physical principles of their full scale counterpart. In addition, they are naturally more agile and dexterous compared to full scale helicopters. Their flight capabilities, reduced size and cost have monopolized the attention of the Unmanned Aerial Vehicles research community for the development of low cost and efficient autonomous flight platforms. Helicopters are highly nonlinear systems with significant dynamic coupling. In general, they are considered to be much more unstable than fixed wing aircraft and constant control must be sustained at all times. The goal of this dissertation is to investigate the challenging design problem of autonomous flight controllers for small scale helicopters. A typical flight control system is composed of a mathematical algorithm that produces the appropriate command signals required to perform autonomous flight. Modern control techniques are model based, since the controller architecture depends on the dynamic description of the system to be controlled. This principle applies to the helicopter as well, therefore, the flight control problem is tightly connected with the helicopter modeling. The helicopter dynamics can be represented by both linear and nonlinear models of ordinary differential equations. Theoretically, the validity of the linear models is restricted in a certain region around a specific operating point. Contrary, nonlinear models provide a global description of the helicopter dynamics. This work proposes several detailed control designs based on both dynamic representations of small scale helicopters. The controller objective is for the helicopter to autonomously track predefined position (or velocity) and heading reference trajectories. The controllers performance is evaluated using X-Plane, a realistic and commercially available flight simulator.

Download or read book Flight Control System Design for Autonomous UAV Carrier Landing written by and published by . This book was released on 2004 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The challenge of integrating the UAV fleet into the carrier landing operational structure with respect to navigation and control strategies is addressed. A simulation model was developed which includes an aircraft model, an atmosphere model and an aircraft carrier motion model. The six degree of freedom non-linear aircraft model is based on the aerodynamic characteristics of the Mk 4a Jindivik extended to include rudder, spoiler and thrust vectoring controls, and an undercarriage model. The atmosphere model includes a carrier landing atmospheric disturbance model. The six degree of freedom aircraft carrier motion model is based on the ship motion simulation program SEAWAY. A Navigation System was developed which conforms to current operational procedures and future military navigation goals. This Navigation System continuously predicts the position in space where touchdown on the carrier deck will take place, based on aircraft position, the relative velocity between the aircraft and carrier, and the motion time history of the carrier. A reference flight path to the predicted touchdown point is continuously defined. The aircraft deviation from this flight path is determined and input to the autoland control system. For the purposes of this study perfection prediction is assumed. Automatic flight control systems were developed to assess three control strategies for suitability to the carrier landing task. The focus of this assessment was on vertical glide path deviation control. Direct Lift Control was compared to conventional control and was found to have superior performance, especially in turbulence. As UAV planforms tend to be tailless, and therefore lateral and pitch control are generated by a common aerodynamic surface, thrust vectoring was investigated as a means of alleviating aerodynamic pitch control requirements in the carrier landing task. An Adaptive Approach Speed Controller was developed as an extension of the Navigation System. This system synchronises.

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 Modeling Small scale Unmanned Rotorcraft for Advanced Flight Control Design written by Bernard Mettler and published by . This book was released on 2001 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book NASA SP written by and published by . This book was released on 1992 with total page 332 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book The History of the XV 15 Tilt Rotor Research Aircraft written by Martin D. Maisel and published by . This book was released on 2000 with total page 222 pages. Available in PDF, EPUB and Kindle. Book excerpt:

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 International Aerospace Abstracts written by and published by . This book was released on 1999 with total page 1042 pages. Available in PDF, EPUB and Kindle. Book excerpt:

Download or read book Aeronautical Engineering written by and published by . This book was released on 1992 with total page 204 pages. Available in PDF, EPUB and Kindle. Book excerpt: A selection of annotated references to unclassified reports and journal articles that were introduced into the NASA scientific and technical information system and announced in Scientific and technical aerospace reports (STAR) and International aerospace abstracts (IAA).