Download or read book Handling Qualities Requirements and Control Design for High Speed Rotorcraft written by Tom Berger and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The U.S. Department of Defense has established the Future Vertical Lift initiative to develop a family of next-generation vertical lift aircraft that will fly farther, faster, and more efficiently than the current fleet of rotorcraft. To accomplish these goals, advanced rotorcraft configurations beyond the single main rotor/tail rotor design must be considered. Two advanced configurations currently being flight tested in a technology demonstrator program are a lift offset coaxial rotorcraft with a pusher propeller and a tiltrotor. The U.S. Army Aviation Development Directorate has developed generic, high-fidelity flight-dynamics models of these two configurations to provide the government with independent control-system design, handling-qualities analysis, and simulation research capabilities for these types of aircraft in support of the Future Vertical Lift initiative.In an effort to begin defining high-speed handling qualities requirements for these types of advanced rotorcraft configurations, full flight envelope inner-loop explicit model following control systems were designed for both configurations using a multi-objective optimization approach to meet a comprehensive set of stability, handling qualities, and performance requirements. The requirements were chosen from both helicopter and fixed-wing criteria. The control laws for both aircraft were evaluated in a piloted simulation experiment at the NASA Ames Vertical Motion Simulator using a series of high-speed handling qualities demonstration maneuvers. The results from the simulation experiment show overall assigned Level 1 handling qualities for both aircraft which correlates well with the predicted Level 1 handling qualities they were designed to, thus supporting the choice of handling qualities requirements selected during the design process.In addition, outer-loop control laws were also developed for both aircraft in an effort to improve handling qualities and reduce pilot workload. A dynamic inversion control law architecture was used for the outer loops, and again a comprehensive set of stability, handling qualities, and performance requirements was used to optimize the parameters of the control laws. The outer-loop control laws for both aircraft were evaluated in a piloted simulation experiment at the Pennsylvania State University Flight Simulator facility using a subset of the high-speed handling qualities demonstration maneuvers used in the first evaluation. Overall, the outer-loop control laws provided Level 1 handling qualities for the Break Turn and High-Speed Acceleration/Deceleration maneuvers, with improvements seen over the inner-loop control laws. In addition, the outer-loop control laws improved performance and reduced workload during a formation flying task that was developed for this project. However, for pitch attitude capture and tracking tasks, the outer-loop control laws degraded handling qualities as compared to the inner-loop control laws. This was due to the pitch attitude dropback behavior of the outer-loops, even though they were tuned to meet the dropback specification. The results suggest that the amount of allowable dropback should be decreased for high-speed rotorcraft and the outer-loop functionality might be provided as a selectable mode. The set of handling qualities criteria used to optimize the inner- and outer-loop control systems presented here are proposed as a set of requirements to tune high-speed rotorcraft control systems to achieve Level 1 handling qualities.
Download or read book Incorporating Handling Qualities Assessment Into the Design of Compound Rotorcraft written by Angelina Conti and published by . This book was released on 2018 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The next fleet of rotorcraft will need to achieve higher forward flight speeds to meet the demanding requirements of military operation. One potential solution is to offload the main rotor by compounding with a lifting wing and auxiliary propulsion system. Compound rotorcraft also feature additional control effectors (flaperons, elevators, propeller thrust, etc.), which can be used to augment control response of the aircraft. To leverage the benefits of fly-by-wire flight controls and meet flight handling qualities requirements, it is essential that controller design be incorporated early in the development process.Modern handling qualities design standards, such as ADS-33E-PRF, provide specifications that can be implemented in early design phases. Predictive strategies relate signal response characteristics to desired flight handling qualities specifications, and piloted simulation verifies the results for various maneuvers called Mission Task Elements. This thesis incorporates predictive and experimental handling qualities analysis into the design of a future high-speed compound rotorcraft and its fly-by-wire flight control system. The simulated rotorcraft features a compounded wing and pusher propeller to offload the main rotor, various drag clean-ups and larger installed power to reach high forward flight speeds, and a full-authority dynamic inversion controller to optimize handling qualities.This study focuses on the combined effect of controller and design parameter variations on handling qualities. Initial results revealed that the controller command filter parameter impacts the bandwidth of the aircraft, where increasing this parameter generally improved handling qualities for all cyclic pitch deflections. The addition of redundant controls improved handling qualities by relieving control saturation, and trends from variation of flapping hinge offset and wing/tail size were generally unclear. Future research studies should apply alternative predictive and piloted simulation methods in order to identify and verify trends.
Download or read book Advances In Aircraft Flight Control written by MB Tischler and published by Routledge. This book was released on 2018-04-24 with total page 450 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a single comprehensive resource that reviews many of the current aircraft flight control programmes from the perspective of experienced practitioners directly involved in the projects. Each chapter discusses a specific aircraft flight programme covering the control system design considerations, control law architecture, simulation and analysis, flight test optimization and handling qualities evaluations. The programmes described have widely exploited modern interdisciplinary tools and techniques and the discussions include extensive flight test results. Many important `lessons learned' are included from the experience gained when design methods and requirements were tested and optimized in actual flight demonstration.
Download or read book An Examination of Handling Qualities Criteria for V STOL Aircraft written by Seth B. Anderson and published by . This book was released on 1960 with total page 56 pages. Available in PDF, EPUB and Kindle. Book excerpt: A study has been undertaken to define hand-ling qualities criteria for V/STOL aircraft. With the current military requirements for helicopters and airplanes as a framework, modifications and additions were made for conversion to a preliminary set of V/STOL requirements using a broad background of flight experience and pilots' comments from VTOL and STOL aircraft, BLC (boundary-layer-control) equipped aircraft, variable stability aircraft, flight simulators and landing approach studies. The report contains a discussion of the reasoning behind and the sources of information leading to suggested requirements. The results of the study indicate that the majority of V/STOL requirements can be defined by modifications to the helicopter and/or airplane requirements by appropriate definition of reference speeds. Areas where a requirement is included but where the information is felt to be inadequate to establish a firm quantitative requirement include the following: Control power and damping relationships about all axes for various sizes and types of aircraft; control power, sensitivity, d-amping and response for height control; dynamic longitudinal and dynamic lateral- directional stability in the transition region, including emergency operation; hovering steadiness; acceleration and deceleration in transition; descent rates and flight-path angles in steep approaches, and thrust margin for approach.
Download or read book The Definition Understanding and Design of Aircraft Handling Qualities written by J. C. Gibson and published by . This book was released on 1997 with total page 180 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Applications of Flight Control System Methods to an Advanced Combat Rotorcraft written by and published by . This book was released on 1989 with total page 66 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced flight control system design, analysis, and testing methods are applied in an analytical and flight test evaluation of the Advanced Digital Optical Control System (ADOCS) demonstrator. This paper describes the knowledge gained about the implications of digital flight control system design for rotorcraft, and illustrates. The analysis of the resulting handling-qualities in the context of the proposed new handling-qualities specification for rotorcraft. Topics included are digital flight control design and analysis methods, flight testing techniques, ADOCS handling-qualities evaluation results, and correlation of flight test results with analytical models and the proposed handling- qualities specification. Evaluation of the ADOCS demonstrator indicated desirable response characteristics based on equivalent damping and frequency, but undesirably large effective time-delays. Piloted handling-qualities are desirable or adequate for all low, medium, and high pilot gain tasks; but handling-qualities are inadequate for ultra-high gain tasks such as slope and running landings. Correlation of these results with the proposed handling- qualities specification indicates good agreement for the bandwidth boundaries, but suggests the need for more stringent limits on allowable phase-delay. Analytical models based on emulation (s-plane) techniques compare favorably with flight extracted frequency-domain characteristics of the overall (end-to-end) ADOCS responses. Direct digital analysis procedures are necessary to characterize the intersample behavior of the actuator rate response.
Download or read book Criteria for Low Speed Longitudinal Handling Qualities written by H.A. Mooij and published by Springer Science & Business Media. This book was released on 2013-04-18 with total page 151 pages. Available in PDF, EPUB and Kindle. Book excerpt: In-fl ight simulation experiments performed in 1967 with a variable-stabil ity aircraft during the author's stay at Princeton University, motivated the study of handl ing characteristics of future transport aircraft with closed-loop fl ight control systems. In 1972, the first experiment took place at the National Aerospace Laboratory NLR, using one of its research aircraft. In anticipation of expected developments in (digital) fl ight control technology, the research programme following the first experiments was aimed at the establ ishment of quantitative handl ing qual ities criteria. An appreciable part of that programme has been sponsored by the Netherlands Agency for Aerospace Programs (Nederlands Instituut voor VI iegtuigontwikkel ing en Ruimtevaart) and the Department of Civil Aviation of the Netherlands (Rijksluchtvaartdienst). In 1981, a thorough review of the extensive and valuable data gathered was started. The result, presented in this book, was also included in the author's thesis for a Ph.D. degree of the Delft University of Technology. To introduce the reader to the multi-discipl inary field of handl ing qual ities research, introductory chapters are presented on longitudinal aircraft dynamics, closed-loop fl ight control systems using non-mechanical signal transmission, human pilot dynamics, hand I ing qual ities assessment techniques, and the present status of handl ing qual ity criteria.
Download or read book Flight Control Design for Rotorcraft with Variable Rotor Speed written by Wei Guo and published by . This book was released on 2009 with total page 121 pages. Available in PDF, EPUB and Kindle. Book excerpt: Flight control design issues for rotorcraft with variable rotor speed are investigated, and new design methodologies are developed to deal with the challenges of variable rotor speed. The benefits of using variable rotor speed for rotorcraft are explored with a rotor speed optimization study using a modified GENHEL model of UH-60A Blackhawk. The optimization results recommend to use the optimal rotor speed in each flight condition to improve the helicopter performance. The efforts are made to accommodate the optimal rotor speed schedule into the flight control system design and also address the stability issues due to the rotor speed variation. The rotor speed optimization results show significant performance improvements can be achieved with moderate reductions in rotor speed. The objective of the control design is to accommodate these rotor speed variations, while achieving desired flying qualities and maneuver performance. A gain scheduled model following/model inversion controller is used to control the roll, pitch, yaw, heave, and rotor speed degrees of freedom. Rotor speed is treated as a redundant control effector for the heave axis, and different control allocation schemes are investigated. The controllers are evaluated based on step responses and the ADS-33E height response requirement. Results show that dynamic variation in rotor speed can improve maximum climb rate and flying qualities for moderate to large commands in vertical speed, but that non-linear effects present significant challenges when integrating control of the aircraft and the engine. The effects of reduced rotor speeds on stability margins, torque required, and stability issues are also studied. A power command system in the vertical axis is designed to incorporate variable rotor speed while handling torque limits and other constraints. The vertical axis controller uses a fixed nonlinear mapping to find the combination of collective pitch and rotor speed to optimize performance in level flight, climbing/descending flight, and steady turns. In this scheme, the controller is open-loop, making it an inexpensive and reliable solution. The mapping is designed to produce a desired power level for a given pilot input. Thus the mapping can take into account the performance limits associated with the vertical axis such as power limits, torque limits, and maximum rate of descent. A model following controller is implemented for the pitch, roll, and yaw axes. The piloted simulation was performed to evaluate the controller. The impact of variable rotor speed on closed loop stability of rotorcraft is discussed. The model following controller can provide high bandwidth control and improve performance using variable rotor speed. However, reduction of rotor speed can result in rotor body coupling and even instability. A rotor state feedback control law can be designed independently and easily integrated into the baseline model following control architecture. Simulations were performed to verify the effectiveness of RSF control to stabilize the rotorcraft dynamics or improve the command tracking performance in the presence of reduced rotor RPM.
Download or read book Digital Control of Highly Augmented Combat Rotorcraft written by and published by . This book was released on 1987 with total page 178 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proposed concepts for the next generation of combat (scout/attack) helicopters are to be embodied in a complex, highly maneuverable, multiroled vehicle with avionics systems which are as important to mission success as the airframe itself. Single pilot and nap-of-the-Earth operations require handling qualities which minimize the involvement of the pilot in basic stabilization tasks. To meet these requirements will demand a full authority, high-gain, multimode, multiply-redundant, digital flight-control system. The gap between these requirements and current low-authority, low-bandwidth operational rotorcraft flight-control technology is considerable. this research aims at smoothing the transition between current technology and advanced concept requirements. The report: (a) extensively reviews the state of the art of high-bandwidth digital flight-control systems; (b) illustrates the important concepts in design and analysis of high-gain, digital systems with a detailed case study involving a current rotorcraft system. Frequency-domain methods for design and analysis are stressed in this report as essential for the practical implementation of high-gain control systems for rotorcraft. Approximate and exact methods are explained and illustrated for treating the important concerns which are unique to digital systems. Proposed specifications and flight-test data concerning the handling qualities of scout/attack rotorcraft imply restrictions on the maximum effective time delay which must be carefully considered in the design process.
Download or read book Aeronautical Design Standard Performance Specification Handling Qualities Requirements For Military Rotorcraft written by and published by . This book was released on 2000 with total page 103 pages. Available in PDF, EPUB and Kindle. Book excerpt: This specification contains the requirements for the flying and ground handling qualities of rotorcraft. It is intended that the specification should cover land based rotorcraft which have primary missions ranging from scout and attack to utility and cargo. Additional requirements or modified standards may be required for rotorcraft that have to operate from small ships in sea states resulting in more than small ship motion. Intended use is described in 6.1. The requirements of this specification are intended to assure that no limitations on flight safety or on the capability to perform intended missions will result from deficiencies in flying qualities. Flying qualities for the rotorcraft shall be in accordance with the provisions of this specification unless specific deviations are authorized by the Government. Additional or alternate special requirements may be specified by the procuring activity. For example, if the form of a requirement should not fit a particular vehicle configuration or control mechanization, the Government may, at its discretion, agree to a modified requirement that will maintain an equivalent degree of acceptability.
Download or read book Aircraft Handling Qualities written by MS. John Hodgkinson and published by Wiley-Blackwell. This book was released on 1999 with total page 246 pages. Available in PDF, EPUB and Kindle. Book excerpt: This book provides a readable introduction to handling qualities, the combination of pilot acceptability and piloted performance with stability and control. It adopts the analytical and qualitative standpoints needed for handling qualities analysis and design of fixed-wing aircraft. Although there are several texts on stability and control, until now none has provided insight into the piloting concerns that have affected the success of recent fly-by-wire aircraft developments.
Download or read book Performance Specification written by Aeronautical design standard and published by . This book was released on 2000 with total page 90 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Development of Handling Qualities Criteria for Rotorcraft with Externally Slung Loads written by and published by . This book was released on 2006 with total page 174 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Helicopter Flight Dynamics written by Gareth D. Padfield and published by John Wiley & Sons. This book was released on 2008-04-15 with total page 681 pages. Available in PDF, EPUB and Kindle. Book excerpt: The behaviour of helicopters is so complex that understanding the physical mechanisms at work in trim, stability and response, and thus the prediction of Flying Qualities, requires a framework of analytical and numerical modelling and simulation. Good Flying Qualities are vital for ensuring that mission performance is achievable with safety and, in the first edition of Helicopter Flight Dynamics, a comprehensive treatment of design criteria was presented. In this second edition, the author complements this with a new Chapter on Degraded Flying Qualities, drawing examples from flight in poor visibility, failure of control functions and encounters with severe atmospheric disturbances. Fully embracing the consequences of Degraded Flying Qualities during the design phase will contribute positively to safety. The accurate prediction and assessment of Flying Qualities draws on the modelling and simulation discipline on the one hand and testing methodologies on the other. Checking predictions in flight requires clearly defined ‘mission-task-elements’, derived from missions with realistic performance requirements. High fidelity simulations also form the basis for the design of stability and control augmentation systems, essential for conferring Level 1 Flying Qualities. The integrated description of flight dynamic modelling, simulation and flying qualities forms the subject of this book, which will be of interest to engineers in research laboratories and manufacturing industry, test pilots and flight test engineers, and as a reference for graduate and postgraduate students in aerospace engineering. The Author Gareth Padfield, a Fellow of the Royal Aeronautical Society, is the Bibby Professor of Aerospace Engineering at the University of Liverpool. He is an aeronautical engineer by training and has spent his career to date researching the theory and practice of flight for both fixed-wing aeroplanes and rotorcraft. During his years with the UK’s Royal Aircraft Establishment and Defence Evaluation and Research Agency, he conducted research into rotorcraft dynamics, handling qualities and flight control. His work has involved a mix of flight testing, creating and testing simulation models and developing analytic approximations to describe flight behaviour and handling qualities. Much of his research has been conducted in the context of international collaboration – with the Technical Co-operation Programme, AGARD and GARTEUR as well as more informal collaborations with industry, universities and research centres worldwide. He is very aware that many accomplishments, including this book, could not have been achieved without the global networking that aerospace research affords. During the last 8 years as an academic, the author has continued to develop his knowledge and understanding in flight dynamics, not only through research, but also through teaching the subject at undergraduate level; an experience that affords a new and deeper kind of learning that, hopefully, readers of this book will benefit from.
Download or read book Rotorcraft Flight propulsion Control Integration written by James R. Mihaloew and published by . This book was released on 1988 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Rotorcraft Flight propulsion Control Integration written by James R. Mihaloew and published by . This book was released on 1988 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book Aviation Safety and Pilot Control written by National Research Council and published by National Academies Press. This book was released on 1997-03-28 with total page 221 pages. Available in PDF, EPUB and Kindle. Book excerpt: Adverse aircraft-pilot coupling (APC) events include a broad set of undesirable and sometimes hazardous phenomena that originate in anomalous interactions between pilots and aircraft. As civil and military aircraft technologies advance, interactions between pilots and aircraft are becoming more complex. Recent accidents and other incidents have been attributed to adverse APC in military aircraft. In addition, APC has been implicated in some civilian incidents. This book evaluates the current state of knowledge about adverse APC and processes that may be used to eliminate it from military and commercial aircraft. It was written for technical, government, and administrative decisionmakers and their technical and administrative support staffs; key technical managers in the aircraft manufacturing and operational industries; stability and control engineers; aircraft flight control system designers; research specialists in flight control, flying qualities, human factors; and technically knowledgeable lay readers.
