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Viewing 211 to 240 of 21553
2015-04-14
Journal Article
2015-01-0255
Claudia Meis, Stefan Mueller, Stephan Rohr, Matthias Kerler, Markus Lienkamp
Battery aging in electric and hybrid vehicles is one major issue, which has to be considered during all stages of vehicle lifecycle. It depends on many factors, as the cell chemistry, the cell design and stress factors as current rate, ∆DOD and temperature. Those factors have been identified to be of major importance due to their nonlinear and mutual influence on the battery parameters capacity and inner resistance. Therefore, battery aging models are essential to gain insights about battery aging without the need of extensive measurements. In literature, various battery aging models with widely differing abilities are described. The aim of this paper is to deliver a decision guide for utilizing the most appropriate aging model for the major stages of vehicle lifecycle: vehicle-development, -operation (on- and off-board) and -post-operation. First, this paper summarizes the correlation of many known stress factors on battery parameters considering all factors separately.
2015-04-14
Technical Paper
2015-01-0279
Fumio Narisawa, Masahiro Matsubara, Masataka Nishi, Tomohito Ebina
Electronic control and software systems in automotives are being increasing both in its functions and sizes to achieve better controllability and reduction of fuel consumptions. The higher safety level is also demanded, and introduction of the functional-safety standard is progressing to the in-vehicle system in recent years. In safety critical systems, it is necessary to diagnose failure and to transit a system surely to a safe state, even if failure of hardware occurs. Therefore, verification of the failure diagnosis part of the basic software which takes charge of signal inputs and outputs processing is highly required for high accountability and the explanatory to a third party. In order to diagnose failure, the hardware and software which are originally operating independently need to cooperate in principle. Verification of hardware and software cooperating systems are not straight-forward, because the number of combinations of conditions will be too much for testing.
2015-04-14
Technical Paper
2015-01-0272
Ludovic Pintard, Michel Leeman, Abdelillah Ymlahi-Ouazzani, Jean-Charles Fabre, Karama Kanoun, Matthieu Roy
The complexity and the criticality of automotive electronic embedded systems are steadily increasing today, and that is particularly the case for software development. The new ISO 26262 standard for functional safety is one of the answers to these challenges. The ISO 26262 defines requirements on the development process in order to ensure the safety. Among these requirements, Fault Injection (FI) is introduced as a dedicated technique to assess the effectiveness of the safety mechanisms and demonstrate the correct implementation of the safety requirements. Our work aims at developing an approach that will help integrate FI in the whole development process in a continuous way, from system requirements to the verification and validation phase. This leads us to explore the benefits of safety analyses (FMEA, FTA, CPA or FFI Analysis…) for the definition of the test plan and particularly define efficient FI tests cases.
2015-04-14
Technical Paper
2015-01-0268
Pablo Oliveira Antonino, Mario Trapp, Ashwin Venugopal
Safety requirements are crucial artifacts in the specification of safety-critical systems, since, as recommended by standards such as ISO 26262 and the DO-178C, they must result from a safety analysis of the architecture and must ultimately be addressed by architecture elements. Because of the key role of safety requirements in safety engineering, it is important to assure that they meet certain quality attributes. In particular, the “completeness” and “consistency” of safety requirements have been widely discussed, as industrial evidence has shown that the lack of guidance on how to specify safety requirements that are traceable to the architecture and to failure propagation models is one of the main reasons for their incompleteness and inconsistency, and, consequently, a root cause of safety incidents. For example, industry practitioners have revealed to us that it is common to document traceability ad-hoc, just prior to submitting a product for certification.
2015-04-14
Technical Paper
2015-01-0294
Takamasa Koshizen, MAS Kamal, Hiroyuki Koike
In order to mitigate traffic congestion, in this paper, we propose an effective approach of smoothing traffic flows by introducing smart cars. It is relied on the smartphone-based technology of detecting traffic congestion, initially developed by Honda Motor Co. Ltd throughout 2011-2013. The detection technology is basically aimed to correct erratic driving behaviors such as aggressive acceleration or rapid braking, and is referred as "smooth driving". Generally, it is known that traffic congestion will likely occur when volume of traffic generates demand for a space greater than the available road capacity. Nevertheless, driving patterns relative to reaction time, sensitivity and time headway, can also be crucial for traffic stability and congestion mitigation. So far, our driving strategy combined with the congestion detection has considered achieving the driving smoothness for "single" lane in particular.
2015-04-14
Journal Article
2015-01-0313
Ugo Rosolia, Francesco Braghin, Andrew Alleyne, Edoardo Sabbioni
This paper presents a nonlinear control approach to achieve good performances in vehicle path following and collision avoidance when the vehicle is driving under cruise highway conditions. Nonlinear model predictive control (NLMPC) is adopted to achieve online trajectory control based on a simplified vehicle model. GMRES/Continuation algorithm is used to solve the online optimization problem. Simulation and experimental results show that the proposed controller is capable of tracking the desired path as well as avoiding the obstacles.
2015-04-14
Technical Paper
2015-01-0328
Wilko Jansen, Joe Amodeo, Sam Wakelam, Kamalesh Bhambare
The level of infotainment in today’s vehicles and the customer expectation of the functionality means a significant effort is required on thermal management of the systems. This to guarantee their full operation under all operating conditions. The worse case thermal conditions the system will get exposed to are caused by solar loading on the cabin or heat up as a result of cabin heating. The simulation of the two load cases, summer case – solar load driven and the winter case – cabin heating system driven will be discussed in current paper. The long soak conditions during these tests result in the modelling requirement for long natural convection periods. This is creating a challenge for the conventional CFD simulations in turn around time. New simulation methodology has resulted in significant speed up enabling these fully transient simulation in a reasonable turnaround time to enable programme support.
2015-04-14
Technical Paper
2015-01-0317
Jongsang Seo, Kyongsu Yi
This paper describes a robust model predictive control (MPC) framework of lane change for automated driving vehicles. In order to develop a safe lane change for automated driving, the driving mode and lane change direction are determined with environmental information, sensor uncertainties, and collision risks. The safety margin is calculated using predicted trajectories of surround and subject vehicles. The MPC based combined steering and longitudinal acceleration control law has been designed with extended bicycle model over a finite time horizon. A reachable set of vehicle state is calculated on-line to guarantee that MPC state and input constraints are satisfied in the presence of disturbances and uncertainties. Simulation studies has been conducted and the proposed framework has been successfully implemented on a test vehicle.
2015-04-14
Technical Paper
2015-01-0290
Amin Tahmasbi-Sarvestani, Hadi Kazemi, Yaser P. Fallah, Mohammad Naserian, Allan Lewis
Pedestrians account for a significant ratio of traffic fatalities; as a result, research on methods of reducing vehicle-pedestrian crashes is of importance. In this paper, we describe a system architecture that allows the use of vehicle-to-pedestrian (V2P) communication as a means of generating situational awareness and eventually predicting hazards and warning drivers and pedestrians. In contrast, vehicle-to-vehicle (V2V) and vehicle-to-infrastructure (V2I) communication for safety applications, V2P has not received much attention. One major reason for this lack of attention had been the unavailability of communication mechanisms between pedestrians and vehicles. Recent advances in enabling Wi-Fi and dedicated short range communication (DSRC) based communication using smart-phones is changing this picture. As a result, V2P communication can be considered as a possible solution.
2015-04-14
Journal Article
2015-01-0371
Rupesh Sonu Kakade, Prashant Mer
Human thermal comfort is a principal objective of the climate control systems such as the automotive air conditioning system. Applying the results of research studies on human thermal comfort to the practical problems require quantitative information of the thermal environmental parameters, such as the impinging solar radiation. Photovoltaic-cell based sensor is commonly used in automotive climate control systems for the measurement of impinging solar radiation intensity. The erroneous information from sensor can cause thermal discomfort. Such an erroneous measurement can be due to physical or environmental parameters. Shading of a solar sensor due to opaque body elements of vehicle is one such environmental parameter that is known to give incorrect measurement. Fundamental geometric principles can be used to determine if sensor is shaded, for a given position of the sun with respect to vehicle and for a given geometry of the vehicle passenger compartment.
2015-04-14
Journal Article
2015-01-1379
Hideki Matsumura, Shinichiro Itoh, Kenichi Ando
Recently, lithium ion cells are being used in more and more electric and hybrid motor vehicles. However, accidents due to thermal runaway of the cells have been reported, involving abnormal heat, smoke, and fire. Since each of these vehicles contains many cells, if the thermal runaway of one cell triggers that of another and thus causes thermal runaway propagation, a car fire or other serious accident may occur. This study aims to ensure the safety of motor vehicles with lithium ion cells. To identify such accident risks, we conducted a basic experiment to clarify the phenomenon of thermal runaway propagation following a thermal runaway. In the experiment, seven laminate-type lithium ion cells were tightly stacked one on another, with a thermocouple placed at the center of the surface of each cell. Then, the center of the cell in the middle of the seven stacked cells was overcharged to trigger a thermal runaway.
2015-04-14
Journal Article
2015-01-1386
Devin SJ Caplow-Munro, Helen Loeb, Venk Kandadai, Flaura Winston
Inadequate situation awareness and response are increasingly recognized as prevalent critical errors that lead to young driver crashes. In order to assess a young driver’s key driving performance indicators (including situation awareness), our team at the Children’s Hospital of Philadelphia developed and validated a Simulated Driving Assessment (SDA) in which drivers are safely and reproducibly exposed to the most prevalent potential serious crash scenarios. Many of the standardized safety measures can be calculated in near real-time from simulator variables. Assessment of situation awareness, however, largely relies on time-consuming data reduction and video coding. The objective of this research was to develop a near real-time automated method for analyzing general direction and location of driver’s gaze in order to assess situation awareness.
2015-04-14
Journal Article
2015-01-1389
Yu Zhang, Linda Angell, Silviu Pala, Ifushi Shimonomoto
The need to provide both connectivity and safety to today’s driver presents an enormous challenge to the automotive industry. A holistic solution for this challenge is to minimize driver distraction and enhance driving safety at the design phase. This creates an immediate need for techniques that can objectively evaluate the demand associated with human machine interfaces (HMIs). The study presented here assessed the feasibility of one promising approach for objective evaluation of HMIs, which compares the workload of in-vehicle tasks to the workload associated with “comparison tasks” or “benchmarking tasks.” In this study, participants drove a production vehicle (Ford Explorer 2013) while performing two types of benchmarking tasks as well as radio tasks (which used the vehicle’s embedded system). All the tests were conducted on a 3-mile oval test track. Participants performed all tasks on a straight segment of the track.
2015-04-14
Journal Article
2015-01-1519
Robert Suender, Günther Prokop, Thomas Roscher
Starting from the USA in 2008 and followed by the European Union commencing in 2012, legal requirements concerning “Tire Pressure Monitoring Systems” (TPMS) for passenger cars and light trucks will be introduced in China as well and therefore in the third of the three largest automobile markets worldwide. Changes of pressure dependent physical tire properties such as dynamic roll radius and a certain tire Eigen mode, which are included in the ABS-wheel speed signals, indicates pressure loss in an indirect manner. Systems with corresponding working principles are called “indirect Tire Pressure Monitoring System” (iTPMS). Since the tire is a structural element with varying characteristics according to the design parameters, the roll radius and frequency behavior due to pressure loss is variable as well. As a consequence, tires have to be evaluated regarding there compatibility to iTPMS during the vehicle development process.
2015-04-14
Journal Article
2015-01-0132
Sibi Visht Sankara Narayanan, Diane Peters
Typically, when someone needs to perform occasional towing tasks, such as towing a boat on a trailer, they have two choices. They can either purchase a larger, more powerful vehicle than they require for their regular usage, or they can rent a larger vehicle when they need to tow something. In this project, we propose a third alternative: a trailer with an on-board power supply, which can be towed by a small vehicle. This system requires a means of sensing how much power the trailer’s power supply should provide, and an appropriate control system to provide this power. In this project, we design and model the trailer, a standard small car, and the control system, and evaluate the concept’s feasibility. We have selected a suitable power source for the trailer, a DC motor, coupled directly to the trailer’s single drive wheel, which allows us to dispense with the need for a differential.
2015-04-14
Journal Article
2015-01-0133
Clark Kinnaird
As many automotive functions migrate from purely mechanical to electrically-driven, the use of efficient brushless DC motors is becoming prevalent. This paper discusses the design of a BLDC controller, including the technical tradeoffs, hardware implementation, and testing results. Brushless DC motors are well suited to automotive applications due to their reliability and high efficiency. In applications such as oil pumps, water pumps, and turbo blowers where the motor lifetime and power dissipation are key parameters, these motors solve many design challenges. This design example examines the specific requirements for a compact solution for a water pump, but the design methodology and tradeoffs also apply to other motor control applications where efficient control of motor speed is needed. Like many applications, this design uses sensorless commutation algorithms, reducing cost and size.
2015-04-14
Journal Article
2015-01-0146
Salah Alhasia, Sharif Gindy, Selin Arslan, Badih Jawad, Chris Riedel
As the need for super high speed components (pumps, motors, etc) continue to grow rapidly, so does the need to make measurements at speeds higher than ever before. Bearings are a major component in any rotating system. With continually increasing speeds, bearing failure modes take new unconventional forms that often are not understood. Such measurements are impossible if bearings fail to perform. This paper will address the dynamic modes a bearing passes through and the potential failure modes associated with each. A review of the state of the art of current failure modes will be given, and then a hypothesis on some new failure modes associated with particular speeds will be discussion. The paper will also describe an apparatus that was designed especially to study these phenomena. Range of speed studied is 0- 60,000 rpm. Preliminary measurements indicated that this range breaks into three different zones, each with its own unique possible failure characteristics.
2015-04-14
Journal Article
2015-01-0149
Can Wang, Gangfeng Tan, Xuexun Guo, Zhewen Tian, Zhanwei Tian, Jiafan Li
In summer, when vehicle parks in the direct sunlight, the closed cabin temperature would rises sharply which affects the occupants step-in-car comfort Solar powered vehicle parking ventilation system adopts the solar energy to drive the original ventilator. Thus, the carbin temperature could be dramatically decreased and the riding comfort could be also improved. This research analyzed the modified crew cabin thermal transfer model. Then the performance of the solar powered ventilation system is optimized combined with the power supply characteristics of the photovoltaic element. The storage and reuse of the solar power is achieved on condition that the cabin temperature could be steadily controlled. The research shows that, compared to parameters of environment temperature and the air velocity, the cabin temperature is more effected by the solar radiation intensity.
2015-04-14
Journal Article
2015-01-0152
Rafal Tomasz Dlugosz, Michał Szulc, Marta Kolasa, Pawel Skruch, Krzysztof Kogut, Paweł Markiewicz, Mateusz Orlowski, Maciej Różewicz, Anna Ryszka, Dominik Sasin, Tomasz Talaska
Modern safety algorithms in automotive industry have to be fast enough to assure an appropriate safety level in systems that feature high dynamics. On the other hand, such algorithms more and more frequently must be realizable in hardware with limited computation resources. Usually there is a trade-off between those two aspects and thus both new system level and new hardware level solutions have to be pursued. One of the key blocks in any signal processing paths are filters used, for example, to remove the noise in order to enhance input data in following step processed by the safety algorithms. Looking from this point of view filters facilitate the work of such algorithms that potentially can be simplified in this way. During the design process of any filter, various trade-offs exist between such parameters as group delay that results from the filter length, steepness of the transient band, attenuation in the stopband, etc.
2015-04-14
Journal Article
2015-01-0153
Reinhold Blank
Today, the electrical and electronic system in vehicles is one of the core systems – with big influence on functionality and quality. And it is – besides the engine – the most expensive part of the vehicle. The ongoing pressure on saving cost (and weight) is also a major challenge to the developers of the E/E system. Every cent saved on a car creates substantial savings, since most systems are applied to platforms with several million cars per year. A cost saving target of $20 per car (without negative influence on the functionality and quality) sounds impossible for most insiders. This presentation identifies some areas where the potential for savings is not (fully) exhausted. For each area there are examples out of the global automotive industry where substantial savings with $10 or more have been achieved. Furthermore, the presentation will propose approaches for “Value engineering” and “Redesign2Cost”.
2015-04-14
Journal Article
2015-01-0154
Lei Rao
The ability to provide a tool integrated environment for quick exploration and optimization of system architecture design alternatives is of paramount importance to Automotive industry. It can help to reduce development and production costs as well as production time to the market. Given a large number of design alternatives, engineers cannot evaluate them manually. Hence a flexible and scalable tool that helps engineers to automatically explore the design space and optimally select a design meeting the design objectives and constraints becomes a key to the succeed in this area. This paper discusses lessons learned through hands-on experiences on an existing commercial tool in the market and provides in-depth insights of development process and complexities.
2015-04-14
Journal Article
2015-01-0156
Alexandr Murashkin, Luis Silva Azevedo, Jianmei Guo, Edward Zulkoski, Jia Hui Liang, Krzysztof Czarnecki, David Parker
The number of software-intensive and complex electronic automotive systems is continuously increasing. Many of these systems are safety-critical and pose growing safety-related concerns. ISO 26262 is the automotive functional safety standard developed for the passenger car industry. It provides guidelines to reduce and control the risk associated with safety-critical systems that include electric, electronic, and programmable parts. The standard uses the concept of Automotive Safety Integrity Levels (ASILs) to decompose and allocate safety requirements of different stringencies to the elements of a system architecture in a top-down manner. ASILs are assigned to system-level hazards and then iteratively decomposed and allocated to relevant subsystems and components. ASIL decomposition rules may give rise to multiple alternative allocations, leading to an optimization problem of finding cost-optimal allocations.
2015-04-14
Journal Article
2015-01-0161
Hua Huang, Di Di, Yuqiang Chu, Clemens Guehmann
With the continuous growth in the emission requirements and higher riding comfort demand, the shift quality becomes more and more an important evaluation index of the automated transmission control algorithms. Traditionally, the shift quality is assessed subjectively by the driver's feeling according to the ATZ grade from 1 (very dissatisfied) to 10 (outstandingly satisfied). Then the calibration engineer adjusts the control parameters in the transmission control unit (TCU) till the shift quality meets the requirements. However, the real vehicle calibration has disadvantages, such as low reproducibility of the shifting event and high dependences on the driver's driving habit. In consequence, finding the correlation between the control parameters and the desired shifting quality needs professional knowledge and skills.
2015-04-14
Journal Article
2015-01-0164
Smitha Kizhakkae Palakkal, Priti Ranadive, Naveen Boggarapu, Rakesh Rao, Pallavi Kalyanasundaram
The automotive industry today follows Model Based Development (MBD) for developing modern automotive applications. This method involves creating models for a given system under design and then using tools like Matlab/Simulink to auto-generate code for target platforms. This method is popular since maintenance of MBD based applications is simple and less time consuming as compared to maintaining application code. Thus, MBD facilitates correct designs and easy maintenance of automotive applications. However, there are legacy automotive applications that are not developed using models. It is difficult to accommodate and test any changes in such application codes since it requires extensive testing. Additionally, for application code generated from models, many a times, code is changed during testing and these changes are not reflected in the model. Hence, there is a need to convert legacy automotive application codes to models.
2015-04-14
Journal Article
2015-01-0163
Madhura Medikeri, Thomas Tasky, Johannes Richenhagen
With the increasing popularity of seamless gear changing and smooth driving experience along with need for high fuel efficiency, transmission system development has rapidly increased in complexity, and so has the transmission control software. For this reason, extensive testing and documentation along with quick and efficient development methods are required. FEV responds to these challenges by developing and integrating a transmission software architecture called “PERSIST” with an automated verification and validation process called “Nightly Build”. The “PERSIST” architecture divides the software and reduces complexity while making it more modular. The FEV software development process incorporates AUTOSAR standards and safety standards such as ISO 26262 in a structure that aids in the reusability of functions and components, thereby reducing development and testing time.
2015-04-14
Journal Article
2015-01-0177
Thomas Fuhrman, Shige Wang, Marek Jersak, Kai Richter
Multi-core systems are promising a cost-effective solution for 1) advanced vehicle features requiring dramatically more software and hence an order of magnitude more processing power, 2) redundancy and mixed-IP, mixed-ASIL isolation required for ISO 26262 functional safety, and 3) integration of previously separate ECUs and evolving embedded software business models requiring separation of different software parts. In this context, designing, optimizing and verifying the mapping and scheduling of software functions onto multiple processing cores becomes key.
2015-04-14
Journal Article
2015-01-0168
Steffen Lampke, Simon Schliecker, Dirk Ziegenbein, Arne Hamann
The underlying theories of, both, control engineering and real-time systems engineering, assume idealized system abstractions that mutually neglect central aspects of the other discipline. Control engineering theory, on the one hand, usually assumes jitter free sampling and insignificant (constant) input-output latencies disregarding complex real-world timing effects. Real-time engineering theory, on the other hand, uses abstract performance and resource models that neglect the functional behavior, and derives worst-case situations that have little expressiveness for control functionalities in automotive systems. As a consequence, there is a lot of potential for a systematic co-engineering between both disciplines, increasing design efficiency and confidence. We have taken a standard control-engineering tool (Simulink) and combined it with state-of-the-art real-time system design and analysis tools (SymTA/S and TraceAnalyzer from Symtavision).
2015-04-14
Journal Article
2015-01-0179
Ralph Mader, Armin Graf, Gerd Winkler
The combustion engine will be the dominant drive for motor vehicles despite all the advances in the electrification of the drive train, for many years. The greater are the challenges for the automotive industry, especially in fuel consumption (CO2) and the environmental impacts of other emissions. From the fuel supply to the engine, up to the exhaust after treatment, new or improved functions are needed, which are integrated into increasingly powerful control electronics. This modern electronic engine management and powertrain controller will remain key components in the vehicle. As most of the microcontrollers for future applications will be in a multi-core topology, this article gives an overview about how PowerSAR® supports this architectures. It shows the concepts applied in the basic software as well as for the application software designed for maximum throughput.
2015-04-14
Journal Article
2015-01-0183
Georg Macher, Muesluem Atas, Eric Armengaud, Christian Kreiner
The number of embedded systems in the automotive domain has grown significantly in recent years. This trend is also strongly supported by the ongoing replacement of traditional mechanical systems with modern embedded systems. This enables the deployment of more advanced control strategies, thus providing new benefits for the customer and environment. At the same time, the higher degree of integration, complexity, and the safety-criticality and real-time constraints of these systems raise new challenges. Distributed system development, short time-to-market intervals, and automotive safety standards (such as ISO 26262) require efficient and consistent product development along the entire development lifecycle. Safety standards such as ISO 26262 for road vehicles have been established to provide guidance during the development of safety-critical systems. These standards rely on risk identification and mitigation strategies.
2015-04-14
Journal Article
2015-01-0196
Varun M. Navale, Kyle Williams, Athanassios Lagospiris, Michael Schaffert, Markus-Alexander Schweiker
This paper will present an overview of the evolution & revolution of automotive E/E architectures and how we at Bosch, envision the technology in the future. The paper will discuss bottlenecks for current E/E architectures and drivers for their evolution. Functionalities such as automated driving, connectivity and automotive security have gained increasing importance over the past few years. The importance of these functionalities will continue to grow as these cutting-edge technologies mature and market acceptance increases. Implementation of these functionalities in mainstream vehicles will demand a paradigm shift in E/E architectures with respect to communication networks, power networks, connectivity, safety and security. This paper will expound on these points at a system level.
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