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 Assessment of Control Allocation Optimization on Performance and Dynamic Response Enhancement of a Compound Rotorcraft written by Adam Thorsen and published by . This book was released on 2014 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: This research investigates control allocation for a compound rotorcraft to minimize power required in acceleration, pull-up, and turning maneuvers and examines the transient response characteristics of a compound rotorcraft in order to establish methods of control that enhance handling qualities via the use of redundant control surfaces. Simulations of a hypothetical compound rotorcraft based on an H-60 airframe and rotor compounded with a wing and pusher propeller are used. Background is provided on the simulated compound rotorcraft's performance in trim and the trim methodology employed, the simulated compound rotorcraft model, and the behavior of redundant controls in minimum power quasi-steady maneuvering flight; then the focus shifts to the transient response characteristics of the aircraft in various maneuvers. In addition to the four traditional controls, this research will examine the use of five redundant control effectors: rotor speed, propeller pitch, symmetric stabilator deflection, symmetric wing flap deflection, and differential wing flap deflection, which can be optimized for performance in trim and maneuvering flight along with handling qualities. The results of the minimum power quasi-steady maneuver optimization are incorporated into a g-command dynamic inversion controller that regulates longitudinal and vertical load factor in minimum power flight. This g-command controller is used to achieve optimal control allocation with regards to the propulsive force distribution between the main rotor and propeller, and the lift force distribution between the main rotor and wing. Pull-up and turning maneuvers are simulated to analyze predicted handling qualities both with and without redundant controls. Quickness metrics (agility, roll attitude, and turn quickness) are also investigated for pull-up and turning maneuvers to understand how the deployment of redundant controls might be used to enhance transient response and handling qualities.
Download or read book Rotorcraft Flight Control Design with Alleviation of Unsteady Rotor Loads written by Umberto Saetti and published by . This book was released on 2019 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: The objective of this research effort is to develop rotorcraft flight control laws that minimize unsteady rotor loads by acting solely through the primary flight controls (first harmonic swashplate control). As opposed to Higher-Harmonic Control, this strategy does not affect stationary (periodic trim) loads, and is therefore effective only in maneuvering flight. However, such system could be readily integrated with existing or future Automatic Flight Control Systems (AFCS). The study considers control designs for both conventional and compound configurations.Starting from a non-linear simulation model of the rotorcraft developed in FLIGHTLAB, which includes sufficient fidelity to simulate rotor loads and vibrations, Linear Time-Periodic models (LTP) are derived via linearization. Next, the Harmonic Decomposition methodology is used to approximate the LTP systems with higher-order Linear Time-Invariant (LTI) systems. Reduced-order systems are subsequently obtained by using singular perturbation theory. By retaining the higher-harmonics of the rotor loads in the output, the reduced-order models are shown to accurately predicted the influence of the zeroth harmonics of the rigid-body and rotor flapping states on the higher-harmonics of the rotor loads. This way, previous limitations such as the reliance on non-physics-based models and curve fits to approximate rotor loads are lifted. Next, model following flight control laws are developed based on the reduced-order models. Parametric studies are performed to provide insights on how both the feed-forward and feedback paths of the model following control laws can be used to alleviate the rotor loads. Also, the impact of load alleviation on handling qualities is studied. It is shown that, for a standard helicopter configuration, load alleviation comes at the cost of a degradation in handling qualities. However, for the case of a compound rotorcraft, allocation of the control signal to the redundant control surfaces provides load alleviation without degradation in the handling qualities. The flight control laws are subsequently optimized using CONDUIT to meet a comprehensive set of stability, handling qualities, and performance specifications for specific mission task elements while minimizing the unsteady rotor loads. Finally, since industry will not only rely on LTP systems obtained from simulation models, a novel methodology is developed to identify LTP systems from flight test data. The methodology is successfully applied to JUH-60A Black Hawk flight test data using CIFER. The identified LTP systems capture the Nb/rev component of the rotorcraft dynamics. Further, it is shown how the higher-harmonics of the rotor states contribute to the overall rotorcraft dynamics for up to a 7%. On the other hand, the rigid-body states contribute to the overall rotorcraft dynamics almost entirely through their zeroth harmonic. Flight control design based on LTP systems identified from flight-test data could benefit the Future Vertical Lift (FVL) program. FVL is a plan to develop a new generation of military helicopters for the U.S. Army with increased capabilities in speed, range, and payload, and reduced maintenance and operational cost. Because these rotorcraft would operate at significantly higher speeds than the current helicopters, alleviation of the higher harmonic rotor loads and flight envelope protection are key elements to reduced maintenance cost. These rotorcraft are also likely to employ redundant control surfaces which, in connection with LTP-based flight control design, demonstrated outstanding effectiveness towards the alleviation of unsteady rotor loads.
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 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 Probabilistic Assessment of Handling Qualities Characteristics in Preliminary Aircraft Design written by Dimitri N. Mavris and published by . This book was released on 1998 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt:
Download or read book The Handling Qualities Assessment of Novel Personal Air Vehicle Systems written by Oliver-James Grant and published by . This book was released on 2018 with total page 308 pages. Available in PDF, EPUB and Kindle. Book excerpt: There is a requirement for rigorous analytical tools that can be used to analyse the flying and handling qualities deficiencies of novel personal-air-vehicles (PAV), prior to experimental flight testing. In more recent years, ground-based simulation has become a critical component of aircraft-level design and a core requirement of the procuring activity. For small footprint, personal, air-vehicle systems the analysis of pilot workload has often relied, exclusively, on pilot-in-the-loop flight test and full immersion simulation experiments. In order to facilitate the preliminary stages of aircraft design there is need for an off-line, quantitative, rating method that can be brought to bear in the absence of an adequate pilot representation. The prediction of aircraft handling qualities is complicated, however, by the need to accurately assess pilot effort. This thesis provides a comprehensive analysis of the control design and handling qualities of a manually controlled, novel, PAV. The handling qualities of the vehicle are assessed, first by reference to the Rotorcraft Aeronautical Design Standard (ADS33-E-PRF), then by pilot/vehicle analysis using models of pursuit, compensatory, and regressive human pilot behaviour. In the latter case, handling qualities levels, pilot-induced oscillation rating levels, and tracking performance are predicted. Consideration is given to both linear and nonlinear pilot/vehicle behaviour. Approximate bounds on the off-nominal linear vehicle model stability derivatives are explored and the expected operational and service flights envelope, temporal and corridor constraints examined. Finally, validation of the proposed pilot modelling techniques and rating criterion are presented, and the use of traditional rotary and fixed-wing HQ rating boundaries are examined with application to a prototype, rotary-wing PAV system. The research work presented in this dissertation provides a means of (1) identifying the feasible design space of a unique aircraft based upon predicted and expected levels of handling qualities and performance, and (2) determining compliance with both civil and (where required) military requirements for manned operation of PAV systems. 2 The research presented may provide a useful template for assessing the handling qualities of more novel, personal air-vehicle concepts prior to pilot-in-the-loop simulation or flight testing.
Download or read book Design Criteria for the Future of Flight Controls written by S. G. Fuller and published by . This book was released on 1982 with total page 726 pages. Available in PDF, EPUB and Kindle. Book excerpt: Proceedings are reported of a symposium held in Dayton, sponsored by the Flight Dynamics Laboratory during 2-5 March 1982. The symposium was planned and ran by the Flight Control Division, specifically the Flying Qualities Group and the Control Techniques Group as part of an ongoing effort to revise and upgrade both MIL-F-8785C, Military Specification, Flying Qualities of Piloted Airplanes, and MIL-F-9490D, Flight Control System-Design, Installation and Test of Piloted Aircraft, General Specification For. Specialists from both the flying qualities and flight control system disciplines were gathered in Dayton from both industry and government agencies. Formal and informal presentations, plus workshop discussions, were structured around proposed draft versions of the new Flying Qualities MIL-Standard and Handbook and the new Flight Control Systems MIL-Specification and Handbook. This report contains a record of the presentations and discussions as submitted by the individual authors.
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 Army R D A written by and published by . This book was released on 1980-05 with total page 36 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Army RD A written by and published by . This book was released on 1979 with total page 696 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 National Aeronautics and Space Adm Nasa and published by . This book was released on 2018-11-03 with total page 64 pages. Available in PDF, EPUB and Kindle. Book excerpt: Advanced flight control system design, analysis, and testing methodologies developed at the Ames Research Center are applied in an analytical and flight test evaluation of the Advanced Digital Optical Control System (ADOCS) demonstrator. The primary objectives are to describe the knowledge gained about the implications of digital flight control system design for rotorcraft, and to illustrate the analysis of the resulting handling-qualities in the context of the proposed new handling-qualities specification for rotorcraft. Topics covered in-depth 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. The evaluation of the ADOCS demonstrator indicates desirable response characteristics based on equivalent damping and frequency, but undersirably large effective time-delays (exceeding 240 m sec in all axes). Piloted handling-qualities are found to be 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. Tischler, Mark B. and Fletcher, Jay W. and Morris, Patrick M. and Tucker, George T. Ames Research Center...
Download or read book Army RD A Bulletin written by and published by . This book was released on 1980 with total page 254 pages. Available in PDF, EPUB and Kindle. Book excerpt:
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 Performance and Handling Qualities Requirements for Rotorcraft Us Federal Aviation Administration Regulation Faa 2018 Edition written by The Law The Law Library and published by Createspace Independent Publishing Platform. This book was released on 2018-09-22 with total page 40 pages. Available in PDF, EPUB and Kindle. Book excerpt: Performance and Handling Qualities Requirements for Rotorcraft (US Federal Aviation Administration Regulation) (FAA) (2018 Edition) The Law Library presents the complete text of the Performance and Handling Qualities Requirements for Rotorcraft (US Federal Aviation Administration Regulation) (FAA) (2018 Edition). Updated as of May 29, 2018 This final rule provides new and revised airworthiness standards for normal and transport category rotorcraft due to technological advances in design and operational trends in normal and transport rotorcraft performance and handling qualities. The changes enhance the safety standards for performance and handling qualities to reflect the evolution of rotorcraft capabilities. This rule harmonizes U.S. and European airworthiness standards for rotorcraft performance and handling qualities. This book contains: - The complete text of the Performance and Handling Qualities Requirements for Rotorcraft (US Federal Aviation Administration Regulation) (FAA) (2018 Edition) - A table of contents with the page number of each section
