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Toward a Framework for Highly Automated Vehicle Safety Validation

Carnegie Mellon Univ.-Philip Koopman
Edge Case Research LLC-Michael Wagner
Published 2018-04-03 by SAE International in United States
Validating the safety of Highly Automated Vehicles (HAVs) is a significant autonomy challenge. HAV safety validation strategies based solely on brute force on-road testing campaigns are unlikely to be viable. While simulations and exercising edge case scenarios can help reduce validation cost, those techniques alone are unlikely to provide a sufficient level of assurance for full-scale deployment without adopting a more nuanced view of validation data collection and safety analysis. Validation approaches can be improved by using higher fidelity testing to explicitly validate the assumptions and simplifications of lower fidelity testing rather than just obtaining sampled replication of lower fidelity results. Disentangling multiple testing goals can help by separating validation processes for requirements, environmental model sufficiency, autonomy correctness, autonomy robustness, and test scenario sufficiency. For autonomy approaches with implicit designs and requirements, such as machine learning training data sets, establishing observability points in the architecture can help ensure that vehicles pass the right tests for the right reason. These principles could improve both efficiency and effectiveness for demonstrating HAV safety as part of a phased…
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Autonomous Technologies: Applications That Matter

Carnegie Mellon Univ.-William C. Messner
  • Book
  • JPF-AUV-004
Published 2014-09-03 by AUVSI in United States
Over the years, the DARPA Challenges in the United States have galvanized interest in autonomous cars, making them a real possibility in the mind of the public, but autonomous and unmanned vehicles have been increasingly employed in many roles on land, in the water, and in the air. Military applications have received a great deal of attention, with weaponized unmanned aircraft (drones) being the most prominent. However, unmanned vehicles with varying degrees of autonomy already have many civilian applications. Some of these are quite familiar (such as the Roomba autonomous vacuum cleaner), while others remain largely out of the public eye (such as autonomous farm equipment). Additional applications and more capable vehicles are rapidly coming to the markets in the years ahead. This book examines a number of economically important areas in which unmanned and autonomous vehicles, also understood here as autonomous technologies, are already used or soon will be. Co-published by SAE International and AUVSI, Autonomous Technologies: Applications That Matter will assist the reader in identifying profitable opportunities and avoiding costly misconceptions with respect…
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V2V-Intersection Management at Roundabouts

SAE International Journal of Passenger Cars - Mechanical Systems

Carnegie Mellon Univ.-Reza Azimi, Gaurav Bhatia, Raj Rajkumar
GM Technical Center-Priyantha Mudalige
  • Journal Article
  • 2013-01-0722
Published 2013-04-08 by SAE International in United States
More than 44% of all automotive crashes occur in intersections. These incidents in intersections result in more than 8,500 fatalities and approximately 1 million injuries each year in USA. It is also established that roundabouts are safer than junctions. According to a USDOT study, when compared with the junctions they replaced, roundabouts have 40% fewer vehicle collisions, 80% fewer injuries and 90% fewer serious injuries and fatalities.In earlier work, we have proposed a family of vehicular network protocols, which use Dedicated Short Range Communications (DSRC) and Wireless Access in Vehicular Environment (WAVE) technologies to coordinate a vehicle's movement through intersections. We have shown that vehicle-to-vehicle (V2V) communications can be used to avoid collisions at the intersection and also significantly decrease the trip delays introduced by traffic lights and stop signs. In this paper, we investigate the use of our proposed V2V-intersection protocols for autonomous driving at roundabouts. We have extended our hybrid emulator-simulator called AutoSim to implement realistic map and mobility models to study traffic flow at roundabouts and have implemented our V2V-intersection protocols on…
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Numerical Investigation of NO2 Formation Mechanism in H2-Diesel Dual-Fuel Engine

Carnegie Mellon Univ.-Satbir Singh
West Virginia Univ-Shiyu Liu, Hailin Li
Published 2012-04-16 by SAE International in United States
The nitrogen dioxide (NO₂) emissions of compression ignition diesel engines are usually relatively small, especially when operated at medium and high loads. Recent experimental investigations have suggested that adding hydrogen (H₂) into the intake air of a diesel engine leads to a substantial increase in NO₂ emissions. The increase in NO₂ fraction in the total NOx is more pronounced at lower engine load than at medium- and high-load operation, especially when a small amount of H₂ is added. However, the chemistry causing the increased NO₂ formation in H₂-diesel dual-fuel engines has not been fully explored.In the present work, kinetics of NO and NO₂ formation in a H₂-diesel dual-fuel engine are investigated using a CFD model integrated with a reduced hydrocarbon oxidation chemistry and an oxides of nitrogen (NOx) formation mechanism. A low-load and a medium-load operating condition are selected for numerical simulations. The experimental trends of NOx emissions are reproduced with the numerical model. The effect of in-cylinder chemical and thermal conditions on the formation of nitric oxide (NO) and NO₂ is studied through a…
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Development of a Simulation Model to Analyze the Effect of Thermal Management on Battery Life

Carnegie Mellon Univ.-Tugce Yuksel, Jeremy Michalek
Published 2012-04-16 by SAE International in United States
Battery life and performance depend strongly on temperature; thus there exists a need for thermal conditioning in plug-in vehicle applications. The effectiveness of thermal management in extending battery life depends on the design of thermal management used as well as the specific battery chemistry, cell and pack design, vehicle system characteristics, and operating conditions. We examine the case of an air cooled plug-in hybrid electric vehicle battery pack with cylindrical LiFePO4/graphite cell design and address the question: How much improvement in battery life can be obtained with passive air cooling? To answer this question, a model is constructed consisting of a thermal model that calculates temperature change in the battery and a degradation model that estimates capacity loss. A driving and storage profile is constructed and simulated in two cities - Miami and Phoenix - which have different seasonal temperatures. The results suggest that air cooling may extend battery life by 5% in Miami, characterized by higher average temperatures, and by 23% in Phoenix, characterized by higher peak temperatures. Thus, thermal management appears to have…
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An AUTOSAR-Compliant Automotive Platform for Meeting Reliability and Timing Constraints

Carnegie Mellon Univ.-Junsung Kim, Gaurav Bhatia, Ragunathan (Raj) Rajkumar
General Motors Research-Markus Jochim
Published 2011-04-12 by SAE International in United States
High demands on advanced safety and driving functions, such as active safety and lane departure warnings, increase a vehicle's dependency on automotive electrical/electronic architectures. Hard real-time requirements and high reliability constraints must be satisfied for the correct functioning of these safety-critical features, which can be achieved by using the AUTOSAR (Automotive Open System Architecture) standard. The AUTOSAR standard was introduced to simplify automotive system design while offering inter-operability, scalability, extensibility, and flexibility. The current version of AUTOSAR does not assist in the replication of tasks for recovering from task failures. Instead, the standard assumes that architecture designers will introduce custom extensions to meet such reliability needs. The introduction of affordable techniques with predictable properties for meeting reliability requirements will prove to be very valuable in future versions of AUTOSAR.In this paper, we propose a new Software-Component (SW-C) allocation algorithm called R-FLOW (Reliable application-FLOW-aware SW-C partitioning algorithm) for fail-stop processors to support fault-tolerance with bounded recovery times, and we integrate the R-FLOW algorithm into AUTOSAR. R-FLOW leverages different types of replication schemes to satisfy reliability and…
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Speech-Controlled Wearable Computers for Automotive Shop Workers

Carnegie Mellon Univ.-Christian Bürgy, James H. Garrett
Robert Bosch Corporation, RTC-Markus Klausner
Published 2001-03-05 by SAE International in United States
Vehicle inspection in repair shops is often still based on paper forms. Information Technology (IT) does not yet support the entire inspection process. In this paper, we introduce a small wearable IT device that is controlled by speech and enables service technicians to wirelessly access relevant data and to perform on-site communication. Users can carry this device in a pocket and use a small headset to enter speech and receive audio feedback. This system provides a completely speech-enabled functionality and thus offers a hands-free operation. After showing the applicability of wearable computers in this environment, we developed a proprietary hardware system consisting of a thin-client connected via a Digital Enhanced Cordless Telecommunications (DECT) link to a standard Personal Computer (PC) that runs a speech engine and hosts a database. Several field tests in garages helped us during the evolution of our prototypes where service technicians critiqued the prototypes.
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Life Cycle Inventories of Conventional and Alternative Automobile Fuel/Propulsion Systems:Summary and Conclusions

Carnegie Mellon Univ.-Lester B. Lave, H. MacLean, R. Lankey, S. Joshi, F. McMichael, A. Horvath, C. Hendrickson
Published 2000-04-26 by SAE International in United States
We compare the life cycle inventories of near–term fuel–propulsion technologies. We analyze fossil fuels (conventional and reformulated gasolines, low sulfur diesel, and compressed natural gas (CNG)), ethanol from biomass, and electricity, together with internal combustion engines (port and direct injection, spark and compression ignited) and electric vehicles (battery–powered, hybrid electric, and fuel cell). The fuel economy and emissions of conventional internal combustion engines powered by gasoline continue to improve. Unless emissions of pollutants and greenhouse gases (GHG) are stringently regulated or gasoline prices more than double, gasoline powered internal combustion engines will continue to dominate the light duty fleet. Two appealing alternative fuels are CNG and biomass ethanol. CNG cars have low emissions, including GHG and the fuel is less expensive than gasoline. Biomass ethanol can be renewable and have no net carbon dioxide (CO2) emissions. The improved fuel economy and lower emissions of hybrid and fuel cell vehicles do not justify their higher costs. We conclude that neither fuel availability nor environmental emissions need prevent personal transportation vehicles from dominating urban transportation over the…
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Alternative Vehicle Power Sources: Towards a Life Cycle Inventory

Carnegie Mellon Univ.-Francis McMichael, Heather MacLean, Lester Lave
U.S. Environmental Protection Agency-Rebecca Lankey
Published 2000-04-26 by SAE International in United States
Three alternatives to internal combustion vehicles currently being researched, developed, and commercialized are electric, hybrid electric, and fuel-cell vehicles. A total life-cycle inventory for an alternative vehicle must include factors such as the impacts of car body materials, tires, and paints. However, these issues are shared with gasoline-powered vehicles; the most significant difference between these vehicles is the power source. This paper focuses on the most distinct and challenging aspect of alternative-fuel vehicles, the power sources. The life-cycle impacts of battery systems for electric and hybrid vehicles are assessed. Less data is publicly available on the fuel cell; however, we offer a preliminary discussion of the environmental issues unique to fuel cells. For each of these alternative vehicles, a primary environmental hurdle is the consumption of materials specific to the power sources.
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A Life Cycle Comparison of Alternative Transportation Fuels

Carnegie Mellon Univ.-Lester Lave, Heather Maclean
Michigan State Univ.-Satish Joshi
Published 2000-04-26 by SAE International in United States
The paper analyzes energy use and emissions per GJ of various fuels delivered to the vehicle fuel tank, covering extraction, fuel production, transportation, storage, and distribution phases of the life cycle of alternative fuels. Drawing on a number of existing studies, the modeling issues and approaches, main results and insights are summarized. The range of estimates in various studies is large; however, common patterns can be observed. The analysis indicates, that conventional gasoline fuel cycle has robust advantages with respect to energy efficiency, conventional pollutant emissions, and most importantly, existing infrastructure compared to alternative fuels. Fossil fuel based alternatives like CNG, NG–Methanol, NG–FTL do not result in significant improvement in fuel cycle environmental performance. Biofuels offer the benefits of lower and even negative GHG emissions, sustainability, and domestic fuel production. The herbaceous and woody biomass–based ethanol options are more attractive than producing ethanol and biodiesel from food products.
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