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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 73 records · Page 4
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Accomplishments in ride quality research: Present and near future

Areas of research in the field of ride quality were categorized into generic subdivisions. The following generic areas were identified: single degree of freedom simulations, multiple degrees of freedom simulations, field simulations, field experiments, surveys/reviews, and modeling techniques. From this review a consensus was reached on the projection of needs for future research efforts, including a prioritization, as well as time and cost estimates of ride quality studies.

Source record↗
NASA NTRS1977

Ride quality research techniques: Section on general techniques

Information is gathered about the methods currently used for the study of ride quality in a variety of transportation modes by a variety of research organizations, including universities, Federal agencies, contracting firms, and private industries. Detailed descriptions of these techniques and their strengths and weaknesses, and identifying the organizations using such methods are presented. The specific efforts of the Group's participants, as well as a variety of feasible approaches not currently in use, are presented as methodological alternatives under the three basic factors which must be considered in ride quality studies: research techniques, research environments, and choice of subjects.

Source record↗
NASA NTRS1978

Analytical study of ride smoothing benefits of control system configurations optimized for pilot handling qualities

An analytical study was conducted to evaluate the relative improvements in aircraft ride qualities that resulted from utilizing several control law configurations that were optimized for pilot handling qualities only. The airplane configuration used was an executive jet transport in the approach configuration. The control law configurations included the basic system, a rate feedback system, three command augmentation systems (rate command, attitude command, and rate command/attitude hold), and a control wheel steering system. Both the longitudinal and lateral directional axes were evaluated. A representative example of each control law configuration was optimized for pilot handling qualities on a fixed base simulator. The root mean square airplane responses to turbulence were calculated, and predictions of ride quality ratings were computed by using three models available in the literature.

Powers, B. G.↗
NASA NTRS1983

Ride-Quality Meter

Single- and combined-Axis discomfort are corrected by effects of noise and vibration to yield measure of total discomfort experienced by rider. Three modules transform mathematically-weighted rms accelerations, which represent physical vibration characteristics, into subjective discomfort units. Portable "ride-quality" meter measures passenger discomfort and acceptability of vehicle interior noise and vibration. Meter especially suited for determining vehicle comfort and design tradeoffs and for comparing ride quality of vehicles.

Leatherwood, J. D.↗
NASA NTRS1983

Ride quality systems for commuter aircraft

The state-of-the-art in Active Ride Augmentation, specifically in terms of its feasibility for commuter aircraft applications. A literature survey was done, and the principal results are presented here through discussion of different Ride Quality Augmentation System (RQAS) designs and advances in related technologies. Recommended follow-on research areas are discussed, and a preliminary RQAS configuration for detailed design and development is proposed.

Downing, D. R.↗
NASA NTRS1983

Operational military helicopter interior noise and vibration measurements with comparisons to ride quality criteria

Balka (1981) has identified the attainment of a 'jet-smooth' ride as a primary goal of the helicopter industry for commercial and certain military helicopters. It was noted that criteria accounting for both multiple axis vibration and interior noise are needed. The present investigation has the objective to present a vibration and interior noise data base in a format suitable for direct evaluation of aircraft ride quality. The investigation is also concerned with an assessment of the measured environment against available criteria as an indication of the state-of-the-art for current machines. Interior noise and vibration measurements were obtained on eight military helicopters during routine operational flights. The data are presented in the form of a number of parameters.

Clevenson, S. A.↗
NASA NTRS1986

Simplified Ride-Comfort Program

Vibration and noise contributions to discomfort quantified. RIDEQUL estimates passenger ride comfort within air- and surface-transportion systems. Provides engineers with reliable method of objectively predicting and evaluating vehicle ride quality. Transforms individual elements of noise and vibration characteristics of vehicle into subjective units and combines these units to produce single discomfort index. Program written in FORTRAN 77 for interactive or batch execution.

Leatherwood, J. D.↗
NASA NTRS1989

Detailed design of a Ride Quality Augmentation System for commuter aircraft

The design of a Ride Quality Augmentation System (RQAS) for commuter aircraft is documented. The RQAS is designed for a Cessna 402B, an 8 passenger prop twin representative to this class of aircraft. The purpose of the RQAS is the reduction of vertical and lateral accelerations of the aircraft due to atmospheric turbulence by the application of active control. The detailed design of the hardware (the aircraft modifications, the Ride Quality Instrumentation System (RQIS), and the required computer software) is examined. The aircraft modifications, consisting of the dedicated control surfaces and the hydraulic actuation system, were designed at Cessna Aircraft by Kansas University-Flight Research Laboratory. The instrumentation system, which consist of the sensor package, the flight computer, a Data Acquisition System, and the pilot and test engineer control panels, was designed by NASA-Langley. The overall system design and the design of the software, both for flight control algorithms and ground system checkout are detailed. The system performance is predicted from linear simulation results and from power spectral densities of the aircraft response to a Dryden gust. The results indicate that both accelerations are possible.

Suikat, Reiner↗
NASA NTRS1999

Quick Ride: Acquisition Overview

Quick Ride is an outgrowth of rapid spacecraft acquisition. It provides a variety of low-cost, short lead time satellite rides for science instruments. Task order contracts with commercial firms will permit placing a order within 30 days. Secondary objectives include a demonstration of a FAR Part 12 commercial acquisition and the exploration of the use of on-ramps.

Adams, W. James↗
NASA NTRS2004

The Geo Quick Ride (GQR) Program: Providing Inexpensive and Frequent Access to Space

This paper examines piggybacking NASA, university, and industry payloads on commercial geosynchronous satellites. NASA's RSDO Office awarded Geo Quick Ride (GQR) study contracts in 1998 to spacecraft manufactures to examine the issues with flying secondary payloads. The study results were very promising. Commercial communication satellites have frequent flights and significant unused resources that could be used to fly secondary payloads. However, manifesting secondary payloads on a commercial revenue-generating satellite is a complex problem to solve. The solution requires multiple simultaneous approaches in order to be successful. There are business, economic, technical, schedule, and organizational issues to be resolved. This paper examines the Geo Quick Ride (GQR) concept, discusses the development issues, and describes how this concept solves many of these issues.

Caffrey, Robert↗
NASA NTRS2013

Sally Ride EarthKAM - Automated Image Geo-Referencing Using Google Earth Web Plug-In

Sally Ride EarthKAM is an educational program funded by NASA that aims to provide the public the ability to picture Earth from the perspective of the International Space Station (ISS). A computer-controlled camera is mounted on the ISS in a nadir-pointing window; however, timing limitations in the system cause inaccurate positional metadata. Manually correcting images within an orbit allows the positional metadata to be improved using mathematical regressions. The manual correction process is time-consuming and thus, unfeasible for a large number of images. The standard Google Earth program allows for the importing of KML (keyhole markup language) files that previously were created. These KML file-based overlays could then be manually manipulated as image overlays, saved, and then uploaded to the project server where they are parsed and the metadata in the database is updated. The new interface eliminates the need to save, download, open, re-save, and upload the KML files. Everything is processed on the Web, and all manipulations go directly into the database. Administrators also have the control to discard any single correction that was made and validate a correction. This program streamlines a process that previously required several critical steps and was probably too complex for the average user to complete successfully. The new process is theoretically simple enough for members of the public to make use of and contribute to the success of the Sally Ride EarthKAM project. Using the Google Earth Web plug-in, EarthKAM images, and associated metadata, this software allows users to interactively manipulate an EarthKAM image overlay, and update and improve the associated metadata. The Web interface uses the Google Earth JavaScript API along with PHP-PostgreSQL to present the user the same interface capabilities without leaving the Web. The simpler graphical user interface will allow the public to participate directly and meaningfully with EarthKAM. The use of similar techniques is being investigated to place ground-based observations in a Google Mars environment, allowing the MSL (Mars Science Laboratory) Science Team a means to visualize the rover and its environment.

Andres, Paul M.↗
NASA NTRS1972

Symposium on Vehicle Ride Quality

A review of ride-quality technology in the United States is given in the thirteen papers presented at the symposium. Although emphasis is directed toward criteria for passenger air travel, information on ground and water modes of transportation is also presented. The papers include an overview of the present state of knowledge, results of various recent studies involving people, vehicles, and simulators, discussion of mechanisms underlying motion discomfort, and description of ongoing activities.

Ride Quality↗
NASA NTRS1972

Riding and handling qualities of light aircraft: A review and analysis

Design procedures and supporting data necessary for configuring light aircraft to obtain desired responses to pilot commands and gusts are presented. The procedures employ specializations of modern military and jet transport practice where these provide an improvement over earlier practice. General criteria for riding and handling qualities are discussed in terms of the airframe dynamics. Methods available in the literature for calculating the coefficients required for a linearized analysis of the airframe dynamics are reviewed in detail. The review also treats the relation of spin and stall to airframe geometry. Root locus analysis is used to indicate the sensitivity of airframe dynamics to variations in individual stability derivatives and to variations in geometric parameters. Computer programs are given for finding the frequencies, damping ratios, and time constants of all rigid body modes and for generating time histories of aircraft motions in response to control inputs. Appendices are included presenting the derivation of the linearized equations of motion; the stability derivatives; the transfer functions; approximate solutions for the frequency, damping ratio, and time constants; an indication of methods to be used when linear analysis is inadequate; sample calculations; and an explanation of the use of root locus diagrams and Bode plots.

Smetana, F. O.↗
NASA NTRS1972

STOL ride quality criteria - Passenger acceptance.

The ability to mathematically model human reaction to variables involved in transportation systems offers a very desirable tool both for the prediction of passenger acceptance of proposed systems, and for establishing acceptance criteria for the system designer. As a first step in the development of a general model for STOL systems, a mathematical formulation is presented which accepts as inputs nine variables felt to be important in flight under STOL-type conditions and presents an index of human response as the output. The variables used are three linear motions, three angular motions, pressure, temperature and noise level. The results are used to establish specifications for stability augmentation systems to improve the ride quality of existing STOL aircraft.

Jacobson, I. D.↗
NASA NTRS1972

Ride Quality Criteria for Large Commercial Helicopters

A review of major ride-quality criteria used in the design of commercial helicopters, some of the limitations of these criteria, research programs conducted to better define these criteria, and some recommended research programs is presented. Primary emphasis is given to the question of noise and vibration criteria for passenger acceptance and comfort.

Schlegel, R. G.↗
NASA NTRS1972

Analytical and experimental evaluation of proposed ride comfort criteria

An exploratory study was conducted to evaluate the effectiveness of indices proposed by different investigators to relate vehicle vibrations to passenger comfort. The indices considered included criteria for sinusoidal vibrations, unweighted and weighted amplitude exceedance counts, the integral of the unweighted and weighted power spectral density and absorbed power. These functions were initially examined analytically to determine the manner in which they each weighed vibration amplitude and frequency. Similarities among them are noted. Index values were then computed from measured vibrations and compared with the associated comfort ratings. The data for these comparisons were obtained from ride comfort evaluations of passenger trains.

Vinje, E. W.↗