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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

Application of the 3-D CAD Manikin RAMSIS to Heavy Duty Truck Design at Freightliner Corporation

2000-06-06
2000-01-2165
This paper describes application examples of RAMSIS, a 3-D CAD human model for ergonomic truck evaluations, to truck design. RAMSIS realistically simulates truck driver postures and locations, an important prerequisite to having confidence in subsequent ergonomic analyses. We show examples of how visibility evaluations compare to traditional SAE methods, arm reach and force evaluation; and an example for entry/exit evaluations.
Technical Paper

Factors Affecting Truck Driver's Perceived Comfort

2001-04-30
2001-01-1571
Truck driver's perception of ride quality/comfort is influenced by many factors relating to the driver, the vehicle and road surface roughness. A subjective rating survey was undertaken to identify the range of roughness wavelengths in the longitudinal road surface profile that affect the perceived ride of heavy articulated vehicles. They were found to range between 4.8 and 19.5 meters. Accordingly, a new roughness index called Profile Index (PI) was established. During the survey, data was collected on factors such as driver's age, years of driving experience, weight, vehicle's age, loading condition, cab location, type of driving axle suspension, weather condition and time of the rating. The effects of these factors were studied at different PI levels to test the viability of the PI as a measure of the perceived heavy vehicle ride and to establish if any of the above factors influenced the drivers' judgments during the survey.
Technical Paper

Heavy Vehicle Ride and Driver Comfort

2001-03-05
2001-01-0386
The ride environment of the heavy vehicle driver is the product of the applied excitation and the response properties of the vehicle. Road surface roughness is considered as a major source of excitation. However, road sections with similar roughness values may have different roughness characteristics and ride qualities. This study showed that the perceived ride quality of truck drivers is influenced by the roughness content in the waveband 4.8-19.5m. Accordingly, a new roughness index was developed that gives good predictions of the perceived truck ride and correlates well with the levels of whole body vibrations transmitted through the driver's seat while traversing the test sections.
Technical Paper

Evaluation of the effect of air bags in multi-year light truck NCAP tests

2001-06-04
2001-06-0095
The New Car Assessment Program (NCAP) has evaluated the crashworthiness of numerous vehicles since 1979. Each year selected models were frontally crashed at 35 mph into a fixed barrier. Due to increased interest by the public in vehicle safety as part of their car-buying decisions, NHTSA has recently undertaken an expanded program of consumer information on vehicle safety issues. As part of this program, an analysis was performed to determine the effectiveness of light-truck driver air bags to reduce the risk of severe injury as measured by the head and chest injury responses of selected NCAP tests. The light trucks tested most frequently were analyzed to obtain reliable estimates of air bag effectiveness. The vehicles were tested with all the restraints available on that model, which in the case of the early years were safety belts, and in the latter years were a combination of safety belts and air bags.
Technical Paper

Heavy Trucks and Fatal Crashes: An Unresolved Dilemma

1981-02-01
810518
Heavy Trucks (HT) are an integral part of the transportation system of the eighties. However, analyses of HT crashes from FARS, BMCS and North Carolina crash files indicate that HT pose great danger for occupants of vehicles with which they collide. Furthermore, during the past few years, fatal crash involvement rates of HT have been dramatically increasing and in 1978, the rate was twice that of passenger cars. To account for the safety hazards associated with HT, three hypotheses have been suggested. Changes in HT design and in qualifying HT drivers are recommended to improve HT safety.
Technical Paper

The M.A.N. Articulated Bus

1981-11-01
811276
Sharp increases in operating costs in recent years have caused transit authorities to look for relief through higher bus driver productivity. Use of high-capacity buses can result in increased driver productivity. An important evaluation of nearly 400 high-capacity articulated buses has been underway in cities across the United States since 1978. Some results of that evaluation are now available, and a significant expansion of the nation’s articulated bus fleet is underway. This paper discusses the history of the articulated bus, the results of the evaluation of M.A.N. articulated buses in the U.S., and the M.A.N. program for expansion of articulated bus service in the U.S.
Technical Paper

The FFG Telebus II — Specially Designed to Give Greater Mobility to the Disabled

1981-11-01
811281
Telebus II is a low floor construction vehicle especially designed for the transport of physically disabled passengers. Its design allows for all kind of problems in connection with wheel chair drivers. The main characteristics being a vehicle body which can be lowered to road level so that disabled passengers can enter the car via a front resp. lateral right hand door without outside help. Special restraint systems for wheel chairs as well as special purpose seats for the disabled are standard equipment. The vehicle has a self-supporting superstructure, independent air suspension and is powered by a transverse rear 65 kW Diesel engine with automatic transmission.
Technical Paper

An Analysis of Commercial Vehicle Speed Control Concepts

1982-02-01
821258
Speed control concepts are devices, designs, or techniques which, when used separately or in combination, reduce a vehicle 's road speed to a more fuel-efficient level. The study encompassed five general categories of speed control: engine speed governors/power train numerical ratios, road speed governors, tachographs/trip recorders, cruise controls, and driver training and motivation programs. Although fleet operating experience has demonstrated that the proper use of speed control can save fuel and have other beneficial side effects, three factors affect the development of speed control programs: driver resistance, management commitment, and operational difficulties. While speed control programs can vary, companies with successful programs thoroughly investigate the market, train and motivate their drivers, and implement the program slowly with careful monitoring and structured tests.
Technical Paper

A Computer-Based Study of the Yaw/Roll Stability of Heavy Trucks Characterized by High Centers of Gravity

1982-02-01
821260
A class of heavy truck vehicles, characterized primarily by high centers of gravity, was studied using analysis and computer simulation to identify and understand the relationship between directional and roll stability of such vehicles during steady turning maneuvers. Findings of the computer-based study suggest: (1) directional instability (yaw divergence) is possible for such vehicles during steady turning while operating at elevated speeds on horizontal road surfaces, (2) yaw divergence will lead to rollover in the absence of corrective steering action and/or reduced speed, and (3) the primary mechanism responsible for precipitating yaw divergent behavior in such vehicles is the nonlinear sensitivity of truck tire cornering stiffness to vertical load acting in combination with typical heavy truck fore/aft roll stiffness distributions. In addition, the influences of roadway superelevation and driver steering control as contributors to vehicle stabilization are examined and discussed.
Technical Paper

Designing the New Mack MH COE to Optimize Driver Environment

1982-02-01
820972
The heavy duty truck industry in recent years has faced an ever greater demand for driver comfort and convenience features. This demand was met in the design of a new cab-over-engine truck cab by providing much more room within existing length and width limitations, greater adjustment to suit more drivers, “places to put things,” optimum control positions, and numerous component design features for more “livability.”
Technical Paper

Truck Cab Environment: The View From The Trucking Managers' Perspective

1981-02-01
810221
Considerable attention is being focused on the short and long term effects of driving on truck drivers. The effects of the cab environment, its temperature control, its size, its integrity, and its ride and handling quality are subjects of interest. The motor carrier industry views these matters differently from other concerned parties. This perspective is explained in general terms in this paper. Gaps in the knowledge concerning drivers are mentioned and a systematic research program is suggested to encompass the total driver/vehicle package.
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