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Results for “Maneuver Design”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 505 records · Page 28
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Vortex generator design for aircraft inlet distortion as a numerical optimization problem

Aerodynamic compatibility of aircraft/inlet/engine systems is a difficult design problem for aircraft that must operate in many different flight regimes. Takeoff, subsonic cruise, supersonic cruise, transonic maneuvering, and high altitude loiter each place different constraints on inlet design. Vortex generators, small wing like sections mounted on the inside surfaces of the inlet duct, are used to control flow separation and engine face distortion. The design of vortex generator installations in an inlet is defined as a problem addressable by numerical optimization techniques. A performance parameter is suggested to account for both inlet distortion and total pressure loss at a series of design flight conditions. The resulting optimization problem is difficult since some of the design parameters take on integer values. If numerical procedures could be used to reduce multimillion dollar development test programs to a small set of verification tests, numerical optimization could have a significant impact on both cost and elapsed time to design new aircraft.

Anderson, Bernhard H.↗
DOE OSTI2025

Automated Construction of Artificial Lattice Structures with Designer Electronic States

Manipulating matter with a scanning tunneling microscope (STM) enables the creation of atomically defined artificial structures that host designer quantum states. However, the time-consuming nature of the manipulation process, coupled with the sensitivity of the STM tip, constrains the exploration of diverse configurations and limits the size of the designed features. In this study, we present a reinforcement learning (RL)-based framework for creating artificial structures by spatially manipulating carbon monoxide (CO) molecules on a copper substrate by using the STM tip. The automated workflow combines molecule detection and manipulation, employing deep-learning-based object detection to locate CO molecules and linear assignment algorithms to allocate these molecules to designated target sites. We initially perform molecule maneuvering based on randomized parameter sampling for sample bias, tunneling current set point, and manipulation speed. This data set is then structured into an action trajectory used to train an RL agent. The model is subsequently deployed on the STM for real-time fine-tuning of the manipulation parameters during structure construction. Our approach incorporates path-planning protocols coupled with active drift compensation to enable atomically precise fabrication of structures with significantly reduced human input while realizing larger-scale artificial lattices with the desired electronic properties. Furthermore, using our approach, we demonstrate the automated construction of an extended artificial graphene lattice and confirm the existence of a characteristic Dirac point in its electronic structure. Further challenges regarding the RL-based structural assembly scalability are discussed.

Algorithms↗
NASA NTRSDate not supplied

A perceptual evaluation of the efficacy of Sound Exposure Level in the rating of annoyance to helicopter noise

A psychoacoustic test was performed that aimed to test how well Sound Exposure Level (SEL) is at indicating changes in annoyance to helicopter noise for simple changes in design as well as for realistic changes found from flight tests. In particular, SEL was evaluated for auralizations of optimized designs of rotor geometries when compared to a baseline design and for recordings that compare different helicopters and maneuvers. Paired comparisons consisted of the 10dB-down portion of flyovers, which is the same portion used to calculate SEL. When played at the same SEL, annoyance responses showed in which cases SEL is a good indicator as well as when other aspects not included in the calculation of SEL may be important. Annoyance responses for relative differences in SEL allowed the calculation of an Equal Annoyance Point, giving further insight to the performance of SEL. Confidence intervals calculated with Monte Carlo simulations showed when responses are statistically different from the equal SEL comparison and also gave an indication of the necessary reduction for designers to be confident that a low noise design is impactful or that a difference in rotorcraft or maneuver is perceptually favorable.

psychoacoustics↗
NASA NTRSDate not supplied

A Perceptual Evaluation of the Efficacy of Sound Exposure Level in the Rating of Annoyance to Helicopter Noise

A psychoacoustic test was performed that aimed to test how well Sound Exposure Level (LAE) is at indicating changes in annoyance to helicopter noise for simple changes in design as well as for realistic changes found from flight tests. In particular, LAE was evaluated for auralizations of optimized designs of rotor geometries when compared to a baseline design and for recordings that compare different helicopters and maneuvers. Paired comparisons consisted of the 10dBA-down portion of flyovers, which is the same portion used to calculate LAE. When played at the same LAE, annoyance responses showed in which cases LAE is a good indicator as well as when other aspects not included in the calculation of LAE may be important. Annoyance responses for relative differences in LAE allowed the calculation of an Equal Annoyance Point, giving further insight to the performance of LAE. Confidence intervals calculated with Monte Carlo simulations showed when responses are statistically different from the equal LAE comparison and also gave an indication of the necessary reduction for designers to be confident that a low noise design is impactful or that a difference in rotorcraft or maneuver is perceptually favorable.

Matthew Alban Boucher↗
NASA NTRS1976

Space shuttle prototype check valve development

Contaminant-resistant seal designs and a dynamically stable prototype check valve for the orbital maneuvering and reaction control helium pressurization systems of the space shuttle were developed. Polymer and carbide seal models were designed and tested. Perfluoroelastomers compatible with N2O4 and N2H4 types were evaluated and compared with Teflon in flat and captive seal models. Low load sealing and contamination resistance tests demonstrated cutter seal superiority over polymer seals. Ceramic and carbide materials were evaluated for N2O4 service using exposure to RFNA as a worst case screen; chemically vapor deposited tungsten carbide was shown to be impervious to the acid after 6 months immersion. A unique carbide shell poppet/cutter seat check valve was designed and tested to demonstrate low cracking pressure ( 2.0 psid), dynamic stability under all test bench flow conditions, contamination resistance (0.001 inch CRES wires cut with 1.5 pound seat load) and long life of 100,000 cycles (leakage 1.0 scc/hr helium from 0.1 to 400 psig).

Tellier, G. F.↗
NASA NTRS1990

Airbus windshear warning and guidance system

From its first designed airplane, Airbus considered mandatory a help in the crew's decision-making process to initiate an escape maneuver and help to successfully realize it. All the Airbus airplanes designed since 1975 included an alpha-floor function and a speed reference control law imbedded in the speed reference system (SRS) box for A 300 and FAC and FCC for A 310, A300/600 and the A 320. Alpha-Floor function takes into account the airplane energy situation considering angle of attack and observed longitudinal situation in order to apply immediately the full power without any pilot action. Speed reference managers control airspeed and/or ground speed in order to survive a maximum in shear situation. In order to comply with the new FAA regulation: Aerospatiale and Airbus developed more efficient systems. A comparison between 1975 and a newly developed system is given. It is explained how the new system improves the situation.

Bonafe, J. L.↗
NASA NTRS1982

Supercritical maneuvering fighter configuration. Wind-tunnel investigation at Mach numbers of 0.60 to 0.95

A wind tunnel investigation was conducted to study the application of supercritical technology to highly maneuverable combat aircraft. The configuration studied has a leading-edge sweep of 45 deg and an aspect ratio of 3.28. Two supercritical-wing shapes were tested at Mach numbers from 0.60 to 0.95 with angles of attack from -2 deg to 17 deg. On supercritical wing was designed to achieve a high level of transonic maneuver performance at a Mach number of 0.90; however, excessive flow separation developed on this wing at a Mach number of 0.85. A second supercritical wing was tested which had significantly reduced flow separation and improved drag characteristics at a Mach number of 0.85 and maintained the performance of the original wing at the higher Mach numbers. Leading-edge vortex generators did not improve the performance of the second wing; however, a sharp leading-edge flap produced sizable drag reductions at Mach numbers from 0.60 to 0.90.

Mann, M. J.↗
NASA NTRS1995

Design and development of an F/A-18 inlet distortion rake: A cost and time saving solution

An innovative inlet total pressure distortion measurement rake has been designed and developed for the F/A-18 A/B/C/D aircraft inlet. The design was conceived by NASA and General Electric Aircraft Engines personnel. This rake has been flight qualified and flown in the F/A-18 High Alpha Research Vehicle at NASA Dryden Flight Research Center, Edwards, California. The eight-legged, one-piece, wagon wheel design of the rake was developed at a reduced cost and offered reduced installation time compared to traditional designs. The rake features 40 dual-measurement ports for low- and high-frequency pressure measurements with the high-frequency transducer mounted at the port. This high-frequency transducer offers direct absolute pressure measurements from low to high frequencies of interest, thereby allowing the rake to be used during highly dynamic aircraft maneuvers. Outstanding structural characteristics are inherent to the design through its construction and use of lightweight materials.

Yuhas, Andrew J.↗
DOE OSTI2025

Optimizing Non-Terrestrial Hybrid RF/FSO Links With Reinforcement Learning: Navigating Through Clouds

In the pursuit of ubiquitous broadband connectivity, there has been a significant shift towards the vertical expansion of communication networks into space, particularly through the exploitation of low Earth orbit (LEO) satellite constellations, which are favored for their relatively low latency. However, this approach faces many challenges that need to be addressed, including atmospheric turbulence, high path loss, and dynamic cloud formations. High-altitude pseudo-satellites (HAPS) have emerged as promising relaying layers between LEO satellites and ground stations, enhancing coverage, latency, and direct terrestrial user connectivity. While radio frequency (RF) bands suffer from congestion and limited bandwidth, free space optical (FSO) communications offer higher data rates, but are susceptible to misalignment and weather-induced signal degradation. To address these challenges, a hybrid RF/FSO approach has been proposed to take advantage of both technologies by dynamic switching between RF and FSO based on propagation channel conditions. This paper introduces a reinforcement learning-based algorithm designed to optimize the trajectory of HAPS, maneuver around cloudy areas, and seamlessly switch between the RF and FSO communication modes to maximize the achievable capacity. The proposed approach aims to maximize system performance by intelligently adapting to environmental conditions and offering a promising solution for next-generation space communication networks.

actor-critic algorithm↗
NASA NTRS1976

Applications Study of Aero-Maneuvering Orbit-to-Orbit Shuttle (AMOOS), Executive Summary

Preliminary designs and the supporting analysis for both the Aeromaneuvering Orbit-to-Orbit Shuttle (AMOOS) and the Aeromaneuvering Recovery System (AMRS) are presented. The AMOOS design is shown to yield from twice to almost three times the high energy, round-trip payloads as a purely propulsive vehicle of the same weight. Typically AMOOS can perform a crew rotation mission to equatorial geosynchronous orbit in one space shuttle launch. The flight test program analysis modeled parameters such as maximum dynamic pressure, heating rates, guidance, stability and recovery. Two model flight schedules were developed, one consisting of four flights and the other of two flights. The former is considered a very low risk, high information return program whereas the latter is a minimal cost program consistent with reasonable data returns and chance of success. The AMOOS and AMRS guidance scheme developed using linear regulator theory proved a precise and accurate guidance scheme. Both it and a classical linear system's based scheme were evaluated using 65 simulated trajectories in which the position in the entry corridor and the atmospheric density were varied randomly.

White, J.↗
NASA NTRS1977

Airborne navigation system performance during RNAV/MLS transition

Aircraft position error sensitivity to sensor errors and flight path geometry is analyzed during RNAV/MLS transition using a digital computer simulation. The avionics sensitivity data provides information necessary to establish requirements for additional guidance law design and to establish airspace requirements for maneuvering to null out any residual RNAV errors upon MLS transition. The data base is also beneficial as planning information for subsequent flight testing. The parameters varied during the generation of the data base include flight profile, error source content and magnitude, ground facility location, runway/flight path orientation and navigation mode. The avionics, autopilots and aircraft dynamics correspond to the existing NASA Terminal Configured Vehicle. Significant transients were observed during MLS transition, primarily in the vertical channel. These transients have a significant impact on airspace requirements and operational procedures in the RNAV/MLS environment.

Heine, W.↗
NASA NTRS1979

The design of supercritical wings by the use of three-dimensional transonic theory

A procedure was developed for the design of transonic wings by the iterative use of three dimensional, inviscid, transonic analysis methods. The procedure was based on simple principles of supersonic flow and provided the designer with a set of guidelines for the systematic alteration of wing profile shapes to achieve some desired pressure distribution. The method was generally applicable to wing design at conditions involving a large region of supercriterical flow. To illustrate the method, it was applied to the design of a wing for a supercritical maneuvering fighter that operates at high lift and transonic Mach number. The wing profiles were altered to produce a large region of supercritical flow which was terminated by a weak shock wave. The spanwise variation of drag of this wing and some principles for selecting the streamwise pressure distribution are also discussed.

Mann, M. J.↗
NASA NTRS1985

Remotely Operated Gripper Tracks Applied Force

Operator "feel" incorporated into new design. Remotely controlled gripper grasps holds, and maneuvers items not equipped with grapple fixture and no preplanned interface with gripper.

Burns, G. C.↗
NASA NTRS1987

Orbital transfer vehicle concept definition and system analysis study. Volume 2: OTV concept definition and evaluation. Book 1: Mission and system requirements

The mission and system requirements for the concept definition and system analysis of the Orbital Transfer Vehicle (OTV) are established. The requirements set forth constitute the single authority for the selection, evaluation, and optimization of the technical performance and design of the OTV. This requirements document forms the basis for the Ground and Space Based OTV concept definition analyses and establishes the physical, functional, performance and design relationships to STS, Space Station, Orbital Maneuvering Vehicle (OMV), and payloads.

Kofal, Allen E.↗
NASA NTRS1990

Lateral-directional stability and control characteristics of the Quiet Short-Haul Research Aircraft (QSRA)

The results are presented of flight experiments to determine the lateral-directional stability and control characteristics of the Quiet Short-Haul Research Aircraft (QSRA), an experimental aircraft designed to furnish information on various aerodynamic characteristics of a transport type of airplane that makes use of the upper-surface blown (USB) flap technology to achieve short takeoff and landing (STOL) performance. The flight program designed to acquire the data consisted of maneuvers produced by rudder and control-wheel inputs with the airplane in several configurations that had been proposed for landing approach and takeoff operation. The normal stability augmentation system was not engaged during these maneuvers. Time-history records from the maneuvers were analyzed with a parameter estimation procedure to extract lateral-directional stability and control derivatives. For one aircraft configuration in which the USB flaps were deflected 50 deg, several maneuvers were performed to determine the effects of varying the average angle of attack, varying the thrust coefficient, and setting the airplane's upper surface spoilers at a 13 deg symmetrical bias angle . The effects on the lateral characteristics of deflecting the spoilers were rather small and generally favorable. The data indicate that for one test, conducted at low thrust (a thrust coefficient of 0.38), compared with results from tests at thrust coefficients of 0.77 and larger, there was a significant decrease in the lateral control effectiveness, in the yaw damping and in the directional derivative. The directional derivative was also decreased (by about 30 percent) when the average angle of attack of the test was increased from 3 to 16 deg.

Stephenson, Jack D.↗
NASA NTRS1991

Shuttle performance enhancements using an OMS payload bay kit

The study focuses on the use of an orbital maneuvering system (OMS) payload bay kit (PBK) designed to utilize OMS tanks identical to those currently employed in the Orbiter OMS pods. Emphasis is placed on payload deployment capability and payload servicing/reboost capability augmentation from the point of view of payload mass, maximum deployment altitudes, and initial retrieval and final deployment altitudes. The deployment, servicing, and reboost requirements of the Hubble Space Telescope and Advanced X-ray and Astrophysics Facility are analyzed in order to show the benefits an OMS PBK can provide for these missions. It is shown that OMS PBKs can provide the required capability enhancement necessary to support deployment, reboost, and servicing of payloads requiring altitudes greater than 325 nautical miles.

Templin, Kevin C.↗
NASA NTRS1992

Preliminary assessment of the robustness of dynamic inversion based flight control laws

Dynamic-inversion-based flight control laws present an attractive alternative to conventional gain-scheduled designs for high angle-of-attack maneuvering, where nonlinearities dominate the dynamics. Dynamic inversion is easily applied to the aircraft dynamics requiring a knowledge of the nonlinear equations of motion alone, rather than an extensive set of linearizations. However, the robustness properties of the dynamic inversion are questionable especially when considering the uncertainties involved with the aerodynamic database during post-stall flight. This paper presents a simple analysis and some preliminary results of simulations with a perturbed database. It is shown that incorporating integrators into the control loops helps to improve the performance in the presence of these perturbations.

Snell, S. A.↗