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Technical Paper

Multifunctional Glasses for Automotive

1996-04-01
91A109
The windows of a vehicle have to satisfy the following driver and passenger needs concerning visibility and climate perception both related to active safety: transparency, reluctance, dazzling, glare and diffused light (scattering). All functions are related to visibility and so to the optics of glazing, solar control, deicing, defogging, demisting. The task of material science is to find the multifunctional glasses solving simultaneously problems of visibility, safety and comfort. Particular kind of glasses, colored, wired, coated, electrochromic, liquid crystal, photochromic can be already considered solutions which can operate passively or actively. The example of passive solar control and active heatable coated glasses is shown as a possible practical multifunctional glass very soon.
Technical Paper

Trends and Forecasts for Turbocharging

1988-03-01
871147
Predictable and unpredictable forces will change the direction of the charge-air systems industry. The driver of diesel engine development will be the stringent emissions regulations of the 1990s. The drivers in the gasoline engine market will be improved fuel economy, performance, durability and emissions. Forces will also influence the charge-air marketplace, including changes in emission standards, national fiscal policies, political issues, fuel prices, alternate fuels and consumer tastes. The world community mandate for engines that are clean, quiet, durable and fuel efficient will be satisfied, increasingly, by first-tier component suppliers developing integrated systems solutions.
Technical Paper

Modeling and Measurement of Occupied Car Seats

1999-05-17
1999-01-1690
An overview of model development for seated occupants is presented. Two approaches have been investigated for modeling the vertical response of a seated dummy: finite element and simplified mass-spring-damper methods. The construction and implementation of these models are described, and the various successes and drawbacks of each modeling approach are discussed. To evaluate the performance of the models, emphasis was also placed on producing accurate, repeatable measurements of the static and dynamic characteristics of a seated dummy.
Technical Paper

A Model-Based Failsafe System for the Continental TEVES Electronic-Stability-Program (ESP)

2000-05-15
2000-01-1635
The Electronic Stability Program (ESP) is a vehicle dynamics control system that supports the driver in critical driving situations. A basic component integrated in the ESP-system is an on-line sensor monitoring system which is mainly used for detecting faults in sensors as early as possible so that an erroneous control or system malfunction can be prevented. Aim of this contribution is to present a model based sensor monitoring system for ESP that was developed, implemented, and is produced in large volumes by Continental Teves.
Technical Paper

Bosch ESP Systems: 5 Years of Experience

2000-05-15
2000-01-1633
Although the total number of car occupants involved in accidents in Germany has not significantly reduced during the past 10 years, the number of fatalities has steadily decreased. Most of the severe accidents result from a loss of control of the car. The problem of the driver losing control of his car will be explained. This problem is then used to formulate the goal for the vehicle dynamics control system ESP (Electronic Stability Program, also known as VDC). The approach chosen to reach this goal will then be shown. It will be shown that the vehicle slip angle is a crucial indicator for the maneuverability of the automobile. Since the complete vehicle state is not readily available, estimation algorithms are used to supply the control algorithms with sufficient information. With the automatic control of the slip angle the required yaw moment can be generated by individual wheel slip control.
Technical Paper

Using μ Feedforward for Vehicle Stability Enhancement

2000-05-01
2000-01-1634
Vehicle stability augmentation has been refined over many years, and currently there are commercial systems that control right/left braking and throttle to create vehicles that remain controlled when road conditions are very poor. These systems typically use yaw rate and lateral acceleration in their control philosophy. The tire/road friction coefficient, μ, has a significant role in vehicle longitudinal and lateral control, and there has been associated efforts to measure or estimate the road surface condition to provide additional information for the stability augmentation system. In this paper, a differential braking control strategy using yaw rate feedback, coupled with μ feedforward is introduced for a vehicle cornering on different μ roads. A nonlinear 4-wheel car model is developed. A desired yaw rate is calculated from the reference model based on the driver steering input.
Technical Paper

Dynamic Analysis of Crew Seats and Cockpit Interiors

2000-05-09
2000-01-1674
Improved safety standards are becoming a focus of the aerospace industry. In particular, standards for occupant protection have been changed to include dynamic seat testing and occupant injury assessment. Methods to model these situations are evolving. A method of modeling an occupant on a crew seat during a sled test is presented. This method combines a rigid body occupant model with a finite element model of the crew seat structure. Validation to sled test results obtained with the model is also presented. Modeling dynamic events with MADYMO software has been proven to be efficient and accurate in many aerospace and automotive applications. Using this tool, a model was developed to investigate how modeling can be used efficiently to provide guidance in crashworthy design. Both finite element methods (FEM) and multibody techniques were used to create a detailed model of a typical aircraft crew seat.
Technical Paper

Design and Test of an Improved Crashworthiness Small Composite Airframe

2000-05-09
2000-01-1673
The goals of this NASA Phase II SBIR program were to develop design methodology to improve occupant survivability in small composite airplanes. Current technology small airplanes absorb crash energy primarily in the cabin structure. The current study tried to increase strength of the occupant compartment and design energy absorbing structure outside the passenger compartment. Dynamics of the crash event were analyzed using a PC version of DYNA3D. Four full scale tests in two crash scenarios were conducted at the NASA Impact Dynamics Test Facility with test parameters set to allow direct comparison with prior NASA/FAA tests. Results indicate that occupant survivability can be improved with moderate weight penalty.
Technical Paper

A Stochastic Approach for Occupant Crash Simulation

2000-04-02
2000-01-1597
Stochastic simulation is used to account for the uncertainties inherent to the system and enables the study of crash phenomenon. For analytical purposes, random variables such as material crash properties, angle of impact, human response and the like can be characterized using statistical models. The methodology outlined in this approach is based on using the information about the probability of random variables along with structural behavior in order to quantify the scatter in the structural response. Thus the analysis gives a more complete picture of the actual simulation. Practical examples for the use of this technique are demonstrated and an overview of this approach is presented.
Technical Paper

Utilizing a Genetic Algorithm to Optimize Vehicle Simulation Trajectories: Determining Initial Velocity of a Vehicle in Yaw

2000-05-01
2000-01-1616
A method was developed for determining the unknown initial velocity of vehicles in yaw based upon evidence of the vehicle’s trajectory. The problem is formulated as an optimization problem by minimizing the error between a simulation trajectory and the known vehicle trajectory as per tire marks. A search simulation is coded in Matlab. An objective function is formulated based upon the error between the search simulation’ trajectories and the trajectory prescribed by the tire mark evidence. Initial conditions and step driver inputs are the design variables. A genetic algorithm routine coded in Matlab, GAOT (Genetic Algorithm Optimization Toolbox), is implemented to determine the solution vector that results in a simulation trajectory that minimizes the objective function. Target simulations are created using EDVSM (Engineering Dynamics Vehicle Simulation Model). The optimization algorithm is implemented and errors in the resultant velocities are reported.
Technical Paper

Emulating the Behavior of Truck Drivers in the Longitudinal Control of Headway

1999-11-15
1999-01-3706
This paper describes control system and psychological concepts enabling the development of a simulation model suitable for use in emulating driver performance in situations involving the longitudinal control of the distance and headway-time to a preceding vehicle. The developed model has mathematical expressions and relationships pertaining to the driver's skill in operating the brake and accelerator (“inverse dynamics”) and the driver's perceptual and decision-making capabilities (“desired dynamics”). Simulation results for driving situations involving braking and accelerating are presented to aid in understanding the research work.
Technical Paper

Steering Performance Evaluation - Heavy-Duty Highway Tractor Wander Test

1999-11-15
1999-01-3764
Heavy-duty highway tractors are the topic of various studies and tests to understand vehicle wander as a contributing factor to driver fatigue. Subtle variations in steering system characteristics can create measurable differences in performance, and operators may have different subjective opinions of the same system. This paper's purpose is to examine wander test setup and data analysis for tests conducted on an International® Model 9200 tractor-trailer at the Navistar Technology and Engineering Center in Fort Wayne, Indiana. Instrumented data and subjective ratings were collected using five power steering gears, evaluated by six drivers, operating over a specific test route.
Technical Paper

How Diagnostics Contribute to Vehicle Productivity and Driver Retention

1999-11-15
1999-01-3751
This paper begins with an outline of the cost structure of operating a commercial vehicle. The focus is on maintenance costs and how diagnostics and prognostics can lower costs. The paper then describes a link between vehicle productivity, driver productivity and driver satisfaction. Examples of onboard and offboard diagnostic systems will be used to illustrate how users create a vehicle that is “the best place to work” for drivers.
Technical Paper

INNOVATIVE ELECTRONICS A Key to Safety, Driver Retention, and Customer Service

1999-11-15
1999-01-3750
The following information is intended to provide a front line perspective of what benefits have been realized in safety, driver acceptance, and customer service, given the level of technology available to the medium and heavy duty truck and bus industry today. It does not specifically address the manner or method of technology utilized for such achievement, moreover it addresses the enhancements that specific components have made possible. Personal experiences are presented to support the benefits and a wish list of the latest technology available concludes this presentation.
Technical Paper

High-Level In-Vehicle Decision Support

1999-11-15
1999-01-3752
This paper documents the current realities of in-vehicle navigation systems in terms of their functionality, scope and responsiveness. It discusses the evolution of these systems with the advent of wireless communications. Addressed are the issues associated with delivery and utilization of real-time traffic, incident, and weather information to and by in-vehicle navigation systems. Also discussed are other High-level in-vehicle decisions that can be supported by the marriage of wireless communications with in-vehicle navigation. Applications considered range from the choosing of alternate waypoints and destinations (where to get gas, where to park), to the host of nRouteCommerce transactions that can be more efficiently achieved with the support of in-vehicle navigation (reserving a parking space, resetting household thermostats as you approach home). Implications on driver workload, in-vehicle processing, wireless bandwidth and Internet traffic are discussed.
Technical Paper

Ergonomic Designs of Mercedes-Benz Trucks at DaimlerChrysler

1999-11-15
1999-01-3736
This paper describes the procedure used to ensure that new trucks of the brand Mercedes-Benz meet the ergonomic requirements of all drivers, using the example of the semitrailer. Mercedes-Benz trucks are sold in different countries. Because of this, varying legal requirements, different sizes of drivers and different lifestyles and habits have to be considered. To solve this problem perfectly, new methods and tools have been acquired, resulting in increasing optimization of the process of truck development.
Technical Paper

Using Modern Technology to Improve Truck Seating

1999-11-15
1999-01-3735
Many advancements have been made through the use of technology that give seat manufacturers the capability to provide greatly improved truck seats. Until recently the design and development of new seating was accomplished primarily through static surveys. Modern technologies available today will reduce cost, development time, and the overall effort associated with utilizing real people to develop a seating project. In many instances when these seats were placed into vehicles with actual truck drivers riding in them for many hours a day, the drivers inputs resulted in multiple revisions to the original seat to satisfy their comfort issues. With modern technologies such as computer generated seat modeling, pressure mapping, and our state of the art test equipment such as a six–axis ride simulator, it has become part of any new seat development program to acquire field ride data in specific trucks and duplicate these inputs in the test laboratory.
Technical Paper

Optimal Suspension Damping for Improved Driver- and Road- Friendliness of Urban Buses

1999-11-15
1999-01-3728
Dynamic interactions of urban buses with urban roads are investigated in view of the vibration environment for the driver and dynamic tire forces transmitted to the roads. The static and dynamic properties of suspension component and tires are characterized in the laboratory over a wide range of operating conditions. The measured data is used to derive nonlinear models of the suspension component, and a tire model as a function of the normal load and inflation pressure. The component models are integrated to study the vertical and roll dynamics of front and rear axles of the conventional and modern low floor designs of urban buses. The resulting nonlinear vehicle models are thoroughly validated using the fieldmeasured data on the ride vibration and tire force response of the buses.
Technical Paper

Investigation of Wheeled Tractors Ride Comfort Using Hydraulic Semi-Active Suspension System

1999-11-15
1999-01-3727
In this paper, an electronically controlled hydraulic semiactive system for the seat suspension of wheeled tractors is theoretically designed to improve the driver ride comfort. Using a three degrees of freedom mathematical model, the damping force controller is designed based on optimal control theory and Nelder / Mead Simplex minimization method to perform a limited state feedback information. The controller considers the damping constraint which adapts the actual damping between the prescribed limits. The model results are generated when excited by a statistically random road profile. The results are presented in time and frequency domains. The driver vertical acceleration for semi-active and conventional passive systems are compared at similar root mean square (r.m.s) value of suspension working space. The semiactive system achieved a significant improvement, 18 percent, over the passive system with no power requirement from the tractor engine.
Technical Paper

Life Cycle Considerations as a Foundation for Improved Cost Assessments

2000-04-26
2000-01-1481
Key drivers in our global economy are mainly cost. The growing importance of environmental themes does not change this view. Today very often economic performance and environmental friendliness are considered to be non-compatible. The reasoning for this is mainly, that environmental protection is seen defensive and end-of-pipe oriented. If an organizations emphasis is only legal compliance, such arguments are especially true. Here filters, sewage plants and waste management are real cost drivers. In order to overcome this non-beneficial situation, new approaches are inevitable. Offensive approaches are required to meet both, economic and environmental targets. LCA has in the past only been used to assess a systems environmental performance. Therefore many data were collected and assessed, but only from an environmental standpoint. However, this time and cost intensive data collection has also significantly contributed to arguments against the use of LCA.
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