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Technical Paper
2014-04-01
Manuel Lorenz, Dusan Fiala, Markus Spinnler, Thomas Sattelmayer
Abstract Cabin heating and cooling loads of modern vehicles, notably electrically driven, represent a major portion of the overall vehicle energy consumption. Various concepts to reduce these loads have thus been proposed but quantitative experimental analysis or numerical predictions are scarcely available. Conventional 1D or zonal cabin models do not account adequately for strongly inhomogeneous cabin climate conditions. In this paper a new cabin model is presented, which delivers both temporally and spatially resolved data. The model uses a dynamic coupling algorithm including a CFD simulation of the cabin airflow, a model of the cabin structure and the detailed passenger Fiala Physiological Comfort (FPC) model. The coupling not only includes heat transport between the cabin air and the surrounding surfaces, but also considers important interactions with the occupants, including e.g. the release of moisture into the cabin air by respiration and sweating predicted by the Fiala Physiological Comfort model and the heat exchange between occupant body parts and solid surfaces by radiation and conduction.
Technical Paper
2014-04-01
Mitsuru Enomoto, Michiko Kakinuma, Nobuhito Kato, Haruo Ishikawa, Yuichiro Hirose
Abstract Design work for truck suspension systems requires multi-objective optimization using a large number of parameters that cannot be solved in a simple way. This paper proposes a process-based systematization concept for ride comfort design using a set-based design method. A truck was modeled with a minimum of 13 degrees of freedom, and suspension performance under various vehicle speeds, road surface conditions, and load amounts was calculated. The range of design parameters for the suspension, the range of performance requirements, and the optimal values within these ranges were defined based on the knowledge and know-how of experienced design engineers. The final design of the suspension was installed in a prototype truck and evaluated. The performance of the truck satisfied all the objectives and the effectiveness of the set-based design approach was confirmed.
Technical Paper
2014-04-01
Eric Frank, Peter Jacobsen
Abstract As the demand for Sound Quality improvements in vehicles continues to grow, robust analysis methods must be established to clearly represent end-user perception. For vehicle sounds which are tonal by nature, such as transmission or axle whine, the common practice of many vehicle manufacturers and suppliers is to subjectively rate the performance of a given part for acceptance on a scale of one to ten. The polar opposite of this is to measure data and use the peak of the fundamental or harmonic orders as an objective assessment. Both of these quantifications are problematic in that the former is purely subjective and the latter does not account for the presence of masking noise which has a profound impact on a driver's assessment of such noises. This paper presents the methodology and results of a study in which tonal noises in the presence of various level of masking noise were presented to a group of jurors in a controlled environment. Their subjective ratings were collected and correlated to noise and vibration metrics.
Technical Paper
2014-04-01
Bryan Randles, Daniel Voss, Isaac Ikram, Christopher Furbish, Judson Welcher, Thomas Szabo
Determination of vehicle speed at the time of impact is frequently an important factor in accident reconstruction. In many cases some evidence may indicate that the brake pedal of a striking vehicle was disengaged, and the vehicle was permitted to idle forward prior to impacting the target vehicle. This study was undertaken to analyze the kinematic response of various vehicles equipped with automatic transmissions while idling, with the transmissions in drive and the brake pedals disengaged. An array of sedans, SUV's and pickup trucks were tested under 3 roadway conditions (flat, medium slope and high slope). The vehicle responses are reported and mathematical relationships were developed to model the idle velocity profiles for flat and sloped roadway surfaces.
Technical Paper
2014-04-01
Nicholas P. Skinner, John D. Bullough
Abstract Rear automotive lighting systems employing dynamic features such as sweeping or flashing are not commonly used on vehicles in North America, in part because they are not clearly addressed in vehicle lighting regulations. Nor is there abundant evidence suggesting they have a substantial role to play in driver safety. The results of a human factors investigation of the potential impacts of dynamic rear lighting systems on driver responses are summarized and discussed in the context of safety, visual effectiveness and the present regulatory context.
Technical Paper
2014-04-01
William N. Newberry, Stacy Imler, Michael Carhart, Alan Dibb, Karen Balavich, Jeffrey Croteau, Eddie Cooper
Abstract It is well known from field accident studies and crash testing that seatbelts provide considerable benefit to occupants in rollover crashes; however, a small fraction of belted occupants still sustain serious and severe neck injuries. The mechanism of these neck injuries is generated by torso augmentation (diving), where the head becomes constrained while the torso continues to move toward the constrained head causing injurious compressive neck loading. This type of neck loading can occur in belted occupants when the head is in contact with, or in close proximity to, the roof interior when the inverted vehicle impacts the ground. Consequently, understanding the nature and extent of head excursion has long been an objective of researchers studying the behavior of occupants in rollovers. In evaluating rollover occupant protection system performance, various studies have recognized and demonstrated the upward and outward excursion of belted occupants that occurs during the airborne phase of a rollover, as well as excursion from vehicle-to-ground impacts.
Technical Paper
2014-04-01
Renaud Deborne, Skárlet Khouri Silva, Andras Kemeny
Abstract By the action on the steering wheel, the driver has the capability to control the trajectory of its vehicle. Nevertheless, the steering wheel has also the role of information provider to the driver. In particular, the torque level at the steering wheel informs the driver about the interaction between the vehicle and the road. This information flow is natural due to the mechanical chain between the road and the steering wheel. Many studies have shown that steering wheel torque feedback is crucial to ensure the control of the vehicle. In the context of uncoupled steering (steer-by-wire vehicle or driving simulators), the torque rendering on the steering wheel is a major challenge. In addition, of the trajectory control, the quality of this torque is a key for the immersion of drivers in virtual environment such as in driving simulators. The torque-rendering loop is composed of different steps. At first, a vehicle dynamics model computes the torque level at the steering wheel regarding the vehicle state (steering wheel position, vehicle speed, etc.).
Technical Paper
2014-04-01
Alessandro Naddeo, Nicola Cappetti, Orlando Ippolito
Abstract General comfort may be defined as the “level of well-being” perceived by humans in a working environment. The state-of-the-art about evaluation of comfort/discomfort shows the need for an objective method to evaluate the “effect in the internal body” and “perceived effects” in main systems of comfort perception. In the early phases of automotive design, the seating and dashboard command can be virtually prototyped, and, using Digital Human Modeling (DHM) software, several kinds of interactions can me modeled to evaluate the ergonomics and comfort of designed solutions. Several studies demonstrated that DHM approaches are favorable in virtual reachability and usability tests as well as in macro-ergonomics evaluations, but they appear insufficient in terms of evaluating comfort. Comfort level is extremely difficult to detect and measure; in fact, it is affected by individual perceptions and always depends on the biomechanical, physiological, and psychological state of the tester during task execution.
Technical Paper
2014-04-01
Se Jin Park, Seung Nam Min, Murali Subramaniyam, Dong-Hoon Lee, Heeran Lee, Dong Gyun Kim
Abstract Seating comfort is one of the most important indicators of the performance of automotive seats. The objective and subjective evaluation of seating comfort plays an important role in the development of seating systems. Objective methods are primarily based on evaluating the influence of vibrations on the driver's seat and assessing the seat pressure ratio. The primary goal of this study was to evaluate the comfort of two car seats (sedan and compact) by comparing a subjective technique with an objective technique like body pressure ratio for a sample of 12 subjects. The results show that the pressure ratio for IT (ischial tuberosity) and L4/L5 were significantly greater for the seat of a compact car than the seat of a sedan car. The subjective comfort was significantly greater for the seat of the sedan car and females than the seat of the compact car and males, respectively. The combination of valid objective measures with subjective ratings of comfort and discomfort may give information of use to seat designers.
Technical Paper
2014-04-01
Scott Allen Ziolek
Abstract Seat comfort is an important factor in the development of a vehicle; however, comfort can be measured in many ways. Many aspects of the experimental design such as the duration of the drive test, the questions asked, and the make-up of the test subjects are known to influence comfort results. This paper provides the background methodology and results of a Seat comfort study aimed at assessing long-term driving seat comfort.
Technical Paper
2014-04-01
Brian Pinkelman
Abstract Experience tells us that one can develop a technically comfortable seat where the seat fits and supports the occupant. The pressure distribution is optimized and the seat and packaging are such that a good posture is attainable by many. The dynamic characteristics of the seat and the vehicle are technically good. Despite all this the customer is not satisfied. Despite it being a technically comfortable seat, it does meet the customers' expectations and/or priorities and thus the comfort provided is lacking. This paper seeks to explore that gap between the seat and the user by modeling comfort using techniques similar to those found in the social sciences where models often focus on user or individual behavior. The model is built upon but diverges from the Cobb Douglas consumer utility model found in economics. It is presented as theory and presents a very different perspective on comfort. The model should be used not as a replacement but a complement to the more traditional technical models of comfort that model the seat.
Technical Paper
2014-04-01
Prasad Kumbhar, Ning Li, Peijun Xu, James Yang
In vehicle driving environment, the driver is subjected to the vibrations in horizontal, vertical, and fore-aft directions. The human body is very much sensitive to whole body vibration and this vibration transmission to the body depends upon various factors including road irregularities, vehicle suspension, vehicle dynamics, tires, seat design and the human body's properties. The seat design plays a vital role in the vibration isolation as it is directly in contact with human body. Vibration isolation properties of a seat depend upon its dynamic parameters which include spring stiffness and damping of seat suspension and cushion. In this paper, an optimization-based method is used to determine the optimal seat dynamic parameters for seat suspension, and cushion based on minimizing occupant's body fatigue (occupant body absorbed power). A 14-degree of freedom (DOF) multibody biodynamic human model in 2D is selected from literature to assess three types of seat arrangements. The human model has total mass of 71.32 kg with 5 body segments.
Collection
2014-04-01
As information and entertainment to and from the vehicle (Telematics) become more prolific it is critical to increase our understanding of how the driver understands and uses Telematics functions. Equally critical is how those functions impact the driver. The papers in this technical paper collection will address these issues.
Technical Paper
2014-04-01
Lee Carr, Dan Barnes, Jennifer Crimeni
Abstract Prior to the widespread implementation of ABS brake technology in light vehicles, driver training often included instruction to “pump the brakes” to avoid locking the wheels. Many driver education programs now recommend maintaining high brake pedal force and relying on ABS. It is sometimes asserted that drivers desiring to stop a vehicle quickly still “pump the brakes”. Investigators sought to understand whether drivers desiring to decelerate quickly pump the brakes, especially in a way that may deplete the vacuum stored in a vehicle's brake booster if so equipped, or whether they apply the brakes in a manner corresponding to their desired deceleration. The National Highway Traffic Safety Administration (NHTSA) conducted a testing program to examine driver braking behavior in crash avoidance maneuvers. The data for those 245 test runs were reanalyzed, assessing patterns of brake pedal force application to determine whether pedal force variation was sufficient in magnitude and duration to reflect driver intent.
Technical Paper
2014-04-01
Richard Young
A key aim of research into cell phone tasks is to obtain an unbiased estimate of their relative risk (RR) for crashes. This paper re-examines five RR estimates of cell phone conversation in automobiles. The Toronto and Australian studies estimated an RR near 4, but used subjective estimates of driving and crash times. The OnStar, 100-Car, and a recent naturalistic study used objective measures of driving and crash times and estimated an RR near 1, not 4 - a major discrepancy. Analysis of data from GPS trip studies shows that people were in the car only 20% of the time on any given prior day at the same clock time they were in the car on a later day. Hence, the Toronto estimate of driving time during control windows must be reduced from 10 to 2 min. Given a cell phone call rate about 7 times higher when in-car than out-of-car, and correcting for misclassification of some post-crash calls as pre-crash, the final required downward adjustment of the Toronto and Australian RR estimates is about 7 times.
Technical Paper
2014-04-01
Adeel Yusuf, John Avery
Abstract The framework for the connected HMI with respect to the configuration and computation of personalization data is presented. The connectivity medium of the future car would be based on either an embedded internet connection through the mobile data services, Bluetooth based data connection based on the user smartphone, Wi-Fi based connection using a wireless network connection or an optimized hybrid approach based on the availability of the connectivity medium or the preference of the user. It is assumed that the car cannot remain directly-connected at all times and the computational requirements of the advanced personalization application cannot be optimized using the inbuilt HMI hardware in the vehicle alone. Our algorithm is based on the concept of Constant Data Availability (CODA) distributed file system and the Distributed Application Processing framework (DAPF). The CODA distributed network filesystem is used for caching of data to perform disconnected operations during the non-availability of a suitable connectivity medium.
Technical Paper
2014-04-01
Rudolf Mortimer, Errol Hoffmann, Aaron Kiefer
Abstract Relative velocity detection thresholds of drivers are one factor that determines their ability to avoid rear-end crashes. Laboratory, simulator and driving studies show that drivers could scale relative velocity when it exceeded the threshold of about 0.003 rad/sec. Studies using accident reconstruction have suggested that the threshold may be about ten times larger. This paper discusses this divergence and suggests reasons for it and concludes that the lower value should be used as a true measure of the psychological threshold for detection of relative velocity.
Technical Paper
2014-04-01
Chinmoy Pal, Tomosaburo Okabe, Kulothungan Vimalathithan, Muthukumar Muthanandam, Jeyabharath Manoharan, Satheesh Narayanan
Abstract A comprehensive analysis was performed to evaluate the effect of BMI on different body region injuries for side impact. The accident data for this study was taken from the National Automotive Sampling System-Crashworthiness Data System (NASS-CDS). It was found that the mean BMI values for driver and front passengers increases over the years in the US. To study the effect of BMI, the range was divided into three groups: Thin (BMI<21), Normal (BMI 24-27) and Obese (BMI>30). Other important variables considered for this study were model year (MY1995-99 for old vehicles & MY2000-08 for newer vehicles), impact location (side-front F, side-center P & side-distributed Y) and direction of force (8-10 o'clock for nearside & 2-4 o'clock for far-side). Accident cases involving older occupants above 60 years was omitted in order to minimize the bone strength depreciation effect. Results of the present study indicated that the Model Year has influence on lower extremity injuries. Occurrence of pelvis injury was found to be influenced by BMI and was validated with logistic regression analysis.
Technical Paper
2014-04-01
Mark William Arndt
Abstract The current certification requirements under CFR 49, Part 567 state that GVWR of a motor vehicle shall not be less than the sum of the unloaded vehicle weight, rated cargo weight and 150 pounds times the number of designated seating positions. Actual occupant weight distributions versus certified weight per occupant seat causes a potential conflict between a vehicle's in-use weights versus its certified GVWR. Population weight distributions were developed based upon The Center for Disease Control's (CDC) publication of 2007 - 2010 anthropometric reference data and publically available weights of a special population from high school football teams. For five buses from small (18-seat) to large (55-seat), key parameters were measured. The weight distributions and bus parametric data were combined in a probabilistic analysis to explore the probability that passengers and rated cargo would result in weight distributions that exceeded tire load capability, Gross Axle Weight Rating (GAWR), or Gross vehicle Weight Rating (GVWR).
Technical Paper
2014-04-01
Masashi Tsushima, Eiichi Kitahara, Taichi Shiiba, Takumi Motosugi
The adoption of the electronic controlled steering systems with new technologies has been extended in recent years. They have interactions with other complex vehicle subsystems and it is a hard task for the vehicle developer to find the best solution from huge number of the combination of parameter settings with track tests. In order to improve the efficiency of the steering system development, the authors had developed a steering bench test method for steering system using a Hardware-In-the-Loop Simulation (HILS). In the steering HILS system, vehicle dynamics simulation and the tie rod axial force calculation are required at the same time in the real-time simulation environment. The accuracy of the tie rod axial force calculation is one of the key factors to reproduce the vehicle driving condition. But the calculation cannot be realized by a commercial software for the vehicle dynamics simulation. A multibody kinematics model of strut suspension was developed for the tie rod axial force calculation.
Technical Paper
2014-04-01
Mingyu Wang, Edward Wolfe, Debashis Ghosh, Jeffrey Bozeman, Kuo-huey Chen, Taeyoung Han, Hui Zhang, Edward Arens
Traditional vehicle air conditioning systems condition the entire cabin to a comfortable range of temperature and humidity regardless of the number of passengers in the vehicle. The A/C system is designed to have enough capacity to provide comfort for transient periods when cooling down a soaked car. Similarly for heating, the entire cabin is typically warmed up to achieve comfort. Localized heating and cooling, on the other hand, focuses on keeping the passenger comfortable by forming a micro climate around the passenger. This is more energy efficient since the system only needs to cool the person instead of the entire cabin space and cabin thermal mass. It also provides accelerated comfort for the passenger during the cooling down periods of soaked cars. Additionally, the system adapts to the number of passengers in the car, so as to not purposely condition areas that are not occupied. The present paper reports on a fundamental study of localized cooling to achieve comfort in a vehicle environment.
Technical Paper
2014-04-01
Ibrahim A. Badiru
The automotive industry is one of the most competitive enterprises in the world. Customers face an ever-expanding number of entries in each market segment vying for their business. Sales price, brand image, marketing, etc. all play a role in purchase decisions, but the factor distinguishing products that consistently perform in the market place is the ability to satisfy the customer. Steering character plays a critical role in the customer driving experience and can be one of the most heavily debated topics during a new vehicle program. The proliferation of EPS steering systems now allows engineers to calibrate steering feel to almost any desired specification. This raises a key question: What subjective & objective characteristics satisfy customers in a particular market segment? Answering this question requires continued research to develop objective metrics correlated to subjective steering attributes and increased understanding of customer preferences for objective performance parameters.
Technical Paper
2014-04-01
Tawhid Khan, Mark Williams
This paper describes a comparative study aimed at identifying cultural differences in automotive-HMI usability. This was part of a larger research to investigate in depth the problems users experience with vehicle-HMI in emerging-regions and help in the development of HMI design guidelines to include cultural consideration. Culture is recognised as a significant influence on user behaviour, as it correlates with certain preferences and abilities. A system may be fully usable for one group of users and environmental conditions but totally unsuitable for another. Even if a conscientious engineer designs a proper human-machine-interface for use in a given environment, the designer is often unable to foresee effects of a different culture on vehicle's HMI usability. Culture has different patterns of social behaviour and interaction which have led many researchers to develop cultural-models to describe these differences. With these in mind, current focus of this study seeks to address three interrelated questions, 1) Are there elements within automotive-HMI that can be identified as culturally specific?
Technical Paper
2014-04-01
Kasiraja Thangapandian, Kumaran Bharatheedasan, Binoy Melatt Vythakkatt
With ongoing integration of various systems in the Vehicle, the usage of display unit is increasing day-by day. The necessity to access data, stored on a remote system, via a human machine interface (HMI) is growing and also the need for developing a Graphical User Interface (GUI) in an efficient manner. The customer/user request to view or browse the system via display is becoming more complex and it is very annoying for the customer/user to wait for a system reaction on his input to the local system for a longer time. With the above limitations we would need to develop the GUI for quick turnaround with high quality. In this paper we are about to discuss on the Model View Controller (MVC) architecture, platform based approach, modular approach based on Core - Server for GUI development, auto code generation, behavioral model simulation, reusable packages and various tools that are used in development of GUI. The selection process of GUI tools is now turning to be vital during the development phase.
Technical Paper
2014-04-01
Amardeep Sathyanarayana, Seyed Omid Sadjadi, John H. L. Hansen
Towards developing of advanced driver specific active/passive safety systems it is important to be able to continuously evaluate driving performance variations. These variations are best captured when evaluated against similar driving patterns or maneuvers. Hence, accurate maneuver recognition in the preliminary stage is vital for the evaluation of driving performance. Rather than using simulated or fixed test track data, it is important to collect and analyze on-road real-traffic naturalistic driving data to account for all possible driving variations in different maneuvers. Towards this, massive free style naturalistic driving data corpora are being collected. Human transcription of these massive corpora is not only a tedious task, but also subjective and hence prone to errors/inconsistencies which can be due to multiple transcribers as well as lack of enough training/instructions. These human transcription errors can potentially hinder the development of algorithms for advanced safety systems, and lead to performance degradations.
Technical Paper
2014-04-01
Yinghao Huang, Wenduo Wang, Chen Fang, Yi Murphey, Dev S. Kochhar
A transportable instrumentation package to collect driver, vehicle and environmental data is described. This system is an improvement on an earlier system and is called TIP-II [13]. Two new modules were designed and added to the original system: a new and improved physiological signal module (PH-M) replaced the original physiological signals module in TIP, and a new hand pressure on steering wheel module (HP-M) was added. This paper reports on exploratory tests with TIP-II. Driving data were collected from ten driver participants. Correlations between On-Board-Diagnostics (OBD), video data, physiological data and specific driver behavior such as lane departure and car following were investigated. Initial analysis suggested that hand pressure, skin conductance level, and respiration rate were key indicators of lane departure lateral displacement and velocity, immediately preceding lane departure; heart rate and inter-beat interval were affected during lane changes. Correlation analyses of car-following data are ongoing.
Technical Paper
2014-04-01
Michael Flannagan, Mitsuhiro Uchida, John Michael Sullivan, Mary Lynn Buonarosa
This study was designed to investigate how the spectral power distribution (SPD) of LED headlamps (including correlated color temperature, CCT) affects both objective driving performance and subjective responses of drivers. The results of this study are not intended to be the only considerations used in choosing SPD, but rather to be used along with results on how SPD affects other considerations, including visibility and glare. Twenty-five subjects each drove 5 different headlamps on each of 5 experimental vehicles. Subjects included both males and females, in older (64 to 85) and younger (20 to 32) groups. The 5 headlamps included current tungsten-halogen (TH) and high-intensity discharge (HID) lamps, along with three experimental LED lamps, with CCTs of approximately 4500, 5500, and 6500 K. Driving was done at night on public roads, over a 21.5-km route that was selected to include a variety of road types. Vehicle instrumentation was used to derive the measures of objective driving performance.
Technical Paper
2014-04-01
Chuqi Su, Zhengzhong Chu
Driving comfort is one of the most important indexes for automobile comfort. Driving posture comfort is closely related to the drivers' joint angles and joint torques. In present research, a new method is proposed to identify the most comfortable driving posture based on studying the relation between drivers' joint angles and joint torques. In order to truly reflect a driving situation, the accurate human driving model of 50 percent of the size of Chinese male is established according to the human body database of RAMSIS firstly. Biomechanical model based on accurate human driving model is also developed to analyze and obtain dynamic equations of human driving model by employing Kane method. The joint torque-angle curves of drivers' upper and lower limbs during holding wheel or pedal operation can be obtained through dynamic simulation in the MATLAB. Through curve-fitting analysis, the minimum joint torque of a driver' limb and the optimal joint angel can be found. As an important reference, these parameters can be used to optimize driving seat structure and offer an important support for the optimization of cab package.
Technical Paper
2014-04-01
Clive D'Souza
The purpose of this paper is to demonstrate the impact of low- floor bus seating configuration, passenger load factor (PLF) and passenger characteristics on individual boarding and disembarking (B-D) times -a key component of vehicle dwell time and overall transit system performance. A laboratory study was conducted using a static full-scale mock-up of a low-floor bus. Users of wheeled mobility devices (n=48) and walking aids (n=22), and visually impaired (n=17) and able-bodied (n=17) users evaluated three bus layout configurations at two PLF levels yielding information on B-D performance. Statistical regression models of B-D times helped quantify relative contributions of layout, PLF, and user characteristics viz., impairment type, power grip strength, and speed of ambulation or wheelchair propulsion. Wheeled mobility device users, and individuals with lower grip strength and slower speed were impacted greater by vehicle design resulting in increased dwell time. To ensure safe, efficient and equitable access to the diverse spectrum of transit riders, transit system design needs approaches that transcend existing minimum federal accessibility design standards.
Technical Paper
2014-04-01
Vincent Laurent, Christophe Then, Gerhard Silber
Comfort is a main factor in customer's decision when buying a car. The seat plays a very important role, as it is the interface between occupant and vehicle. Pressure distribution is today's most common approach to characterize seat comfort, but it shows limitations. Analysis of human inter-tissue stress tends to be relevant for an objective comfort assessment. This paper presents the construction and validation of a CAE human model, based on Magnetic Resonance Imaging scans and in-vivo tests data. Correlation between objective criteria and subjective evaluation will be investigated, comfort performance of a real seat will be predicted.
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