3,889 research outputs found

    Space Station RT and E Utilization Study

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    Descriptive information on a set of 241 mission concepts was reviewed to establish preliminary Space Station outfitting needs for technology development missions. The missions studied covered the full range of in-space technology development activities envisioned for early Space Station operations and included both pressurized volume and attached payload requirements. Equipment needs were compared with outfitting plans for the life sciences and microgravity user communities, and a number of potential outfitting additions were identified. Outfitting implementation was addressed by selecting a strawman mission complement for each of seven technical themes, by organizing the missions into flight scenarios, and by assessing the associated outfitting buildup for planning impacts

    Estimation of automobile-driver describing function from highway tests using the double steering wheel

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    The automobile-driver describing function for lateral position control was estimated for three subjects from frequency response analysis of straight road test results. The measurement procedure employed an instrumented full size sedan with known steering response characteristics, and equipped with a lateral lane position measuring device based on video detection of white stripe lane markings. Forcing functions were inserted through a servo driven double steering wheel coupling the driver to the steering system proper. Random appearing, Gaussian, and transient time functions were used. The quasi-linear models fitted to the random appearing input frequency response characterized the driver as compensating for lateral position error in a proportional, derivative, and integral manner. Similar parameters were fitted to the Gabor transformed frequency response of the driver to transient functions. A fourth term corresponding to response to lateral acceleration was determined by matching the time response histories of the model to the experimental results. The time histories show evidence of pulse-like nonlinear behavior during extended response to step transients which appear as high frequency remnant power

    A Recording and Analysis System of Bioptic Driving Behaviors

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    Millions of visually impaired people do not drive because they fail to meet the general vision requirements. There is a legal option in 38 US states where people with moderate central vision loss (e.g. visual acuity better than 20/200) may be permitted to drive while wearing spectacle-mounted bioptic telescopes. However, the safety of bioptic driving is still highly controversial, because bioptic use in driving is not well understood. Whether and how bioptic telescopes are actually used in driving, how they should be used appropriately, and whether their use results in better or worse driving performance has never been scientifically established. We are developing an in-car camera system that can be installed in bioptic drivers’ own vehicles to record their daily driving activities over long periods of time. Videos of the driver and traffic, GPS coordinates, XYZ acceleration, and vehicle black box data are recorded. We are also developing computer-aided reviewing techniques to automatically identify the most informative driving segments from the vast amount of data and, reconstruct the selected driving maneuvers on an interactive interface, so that these representative segments can be assessed off-line by driver evaluation and training specialists

    Contributions to the 10th International Cycling Safety Conference 2022 (ICSC2022)

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    This publication contains all contributions (extended abstracts) to the 10th International Cycling Safety Conference, which was held in Dresden, Germany, Nov. 08-10, 2022

    Development of a heavy-duty vehicle chassis dynamometer test route

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    A heavy duty vehicle chassis dynamometer driving route, titled City-Suburban Heavy Vehicle Route (CSHVR) was developed. Data for designing the CSHVR were collected using a Campbell Scientific 21x. Procedures were developed to reduce statistically the speed and time data into representative speed vs. time cycles. Criteria for producing the speed vs. time cycles included average vehicle speed, standard deviation of vehicle speed and total cruise time. The speed vs. time cycle was converted into a speed vs. distance route with free acceleration ramps. Using this method, the CSHVR was developed. Testing of the CSHVR was completed using the West Virginia University transportable heavy duty vehicle emissions testing laboratory. CSHVR results showed that average emissions values in grams/mile were at levels of 23.3 (NOX), 2563 (CO2), 1.98 (HC), 0.78 (PM) and 6.03 (CO) while driving the CSHVR

    Evaluation of event data recorders in real world crashes and full-scale crash tests

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    With the advent of advanced safety systems in U.S. passenger vehicles, there has been increased interest shown by automakers in recording crash related parameters that ultimately lead to the deployment of these safety systems in what are known as Event Data Recorders (EDRs). Since the only other record of these parameters, specifically crash pulse, comes from staged crash tests in a controlled environment, the advent of the EDR has become increasingly important to crash researchers. The purpose of this study is to quantify the performance of EDRs in full-scale crash tests and real world crashes. Comparison of EDRs with staged crash tests included 6 General Motors vehicles. The EDRs performed well in staged crash tests reporting delta-V accurately in five of six tests. They were able to report other crash related parameters such as driver seat belt and airbag deployment status accurately in five of six tests as well. Comparison of EDRs with real world accident reconstructions was performed for 315 General Motors cases and 10 Ford cases from the National Automotive Sampling System Crashworthiness Data System (NASS / CDS) database. Computer generated (WinSmash) values for delta-V showed the tendency to underestimate delta-V for high-speed deployment events and overestimate delta-V for low-speed nondeployment events when compared to the GM EDR. The Ford EDR showed a lack of sufficient recording duration to draw any concrete conclusions on the accuracy of its delta-V value

    Biotelemetry of the triaxial ballistocardiogram and electrocardiogram in a weightless environment

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    Biotelemetry of triaxial ballistocardiogram and electrocardiogram in weightless environmen

    Expanded study of feasibility of measuring in-flight 747/JT9D loads, performance, clearance, and thermal data

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    The JT9D jet engine exhibits a TSFC loss of about 1 percent in the initial 50 flight cycles of a new engine. These early losses are caused by seal-wear induced opening of running clearances in the engine gas path. The causes of this seal wear have been identified as flight induced loads which deflect the engine cases and rotors, causing the rotating blades to rub against the seal surfaces, producing permanent clearance changes. The real level of flight loads encountered during airplane acceptance testing and revenue service and the engine's response in the dynamic flight environment were investigated. The feasibility of direct measurement of these flight loads and their effects by concurrent measurement of 747/JT9D propulsion system aerodynamic and inertia loads and the critical engine clearance and performance changes during 747 flight and ground operations was evaluated. A number of technical options were examined in relation to the total estimated program cost to facilitate selection of the most cost effective option. It is concluded that a flight test program meeting the overall objective of determining the levels of aerodynamic and inertia load levels to which the engine is exposed during the initial flight acceptance test and normal flight maneuvers is feasible and desirable. A specific recommended flight test program, based on the evaluation of cost effectiveness, is defined
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