This SAE Information Report presents the background and rationale for SAE J1574-1.The motor vehicle industry is working toward a more complete understanding of the factors affecting the motions of vehicles on the roadway, by using a variety of techniques that predict responses to road and operator inputs. The capability to predict responses is desirable so that vehicles can be designed for optimum safety and utility. In addition to the force and moment properties of the pneumatic tires, a number of vehicle and suspension parameters affect the response of the vehicle; these include weight, center-of-gravity location, moments of inertia, suspension ride and roll rates, suspension kinematic and compliance properties, and shock absorber characteristics. These parameters must be quantified in order to predict vehicle responses.Measurement of most of these parameters will be limited to determining their values in the linear range for use in directional control simulations. The limitation to linear range characteristics primarily reflects current measurement practice, to which SAE J1574-1 is directed. In the case of mass and inertia properties, this limitation clearly does not apply. For those to which it does apply, it is not felt to be a serious limitation since most of the measurement techniques can be extended beyond the linear range through appropriate increases in steering or suspension displacement or loading. Use of the measured parameters in simulations is assumed as the most frequent use. However, this does not seem to limit their use to simulations. Vehicle and suspension characteristics appropriate for simulation can equally well be used for vehicle and suspension characterization and comparison, suspension development and optimization, and processing of road test data.As noted in SAE J1574-1, vehicles addressed will be limited to passenger cars, light trucks, and on-highway recreational and commercial vehicles with two or more axles of approximately the same wheel track. This excludes bicycles, motorcycles, tricycles, and vehicles intended primarily for off-highway use. This limitation is largely a recognition of the types of vehicles historically measured for ride and directional control simulation, since SAE J1574-1 has been written to document the current state-of-the-art rather than to expand it. Additionally, inclusion of these other vehicles might well require measurement of other chassis characteristics to properly simulate their dynamic characteristics. The measurement of these additional characteristics may not be supported by widespread experimental practice. This document was revised to correct typographical errors in Equations 25 and 26.

The parameters measured according to this SAE Recommended Practice will generally be used in simulating directional control performance in the linear range. (The "linear range" is the steady-state lateral acceleration below which steering wheel angle can generally be considered to be linearly related to lateral acceleration.) But they may be used for certain other simulations (such as primary ride motions), vehicle and suspension characterization and comparison, suspension development and optimization, and processing of road test data. This document is intended to apply to passenger cars, light trucks, and on-highway recreational and commercial vehicles, both non-articulated and articulated. Measurement techniques are intended to apply to these vehicles, with alterations primarily in the scale of facilities required. But some differences do exist between passenger cars and trucks, especially heavy trucks, such as differences in body/frame flexibility, suspension stiffness, and suspension friction. These will be addressed in this document or SAE J1574-2, where appropriate.

Embark on a journey through the pulsating heart of global commerce with the Commercial Vehicle Dictionary—a comprehensive guide illuminating the intricate language of transportation. From seasoned professionals to curious enthusiasts, this indispensable resource unveils the dynamic world of commercial vehicles, blending precision, innovation, and sustainability. Navigate with confidence as you explore a meticulously curated lexicon covering vehicle classifications, advanced technologies, safety protocols, regulatory frameworks, and emerging trends. Whether optimizing routes, tending to fields, or fascinated by machinery, this dictionary serves as your beacon through the ever-evolving landscape of commercial vehicles. Empower yourself with knowledge, enhance communication, and deepen your understanding of this multifaceted industry. Whether deciphering engine technologies, mastering logistics management, or staying updated on industry standards, let this dictionary be your compass in the vast realm of commercial vehicles. Dive into the rich tapestry of terms and concepts that shape the language of transportation—your journey begins here. (ISBN: 9781468607888 ISBN:9781468607895 ISBN:9781468607901 DOI:10.4271/9781468607895)

The fourth edition of the Handbook of Human Factors and Ergonomics has been completely revised and updated. This includes all existing third edition chapters plus new chapters written to cover new areas. These include the following subjects: Managing low-back disorder risk in the workplace Online interactivity Neuroergonomics Office ergonomics Social networking HF&E in motor vehicle transportation User requirements Human factors and ergonomics in aviation Human factors in ambient intelligent environments As with the earlier editions, the main purpose of this handbook is to serve the needs of the human factors and ergonomics researchers, practitioners, and graduate students. Each chapter has a strong theory and scientific base, but is heavily focused on real world applications. As such, a significant number of case studies, examples, figures, and tables are included to aid in the understanding and application of the material covered.

Off-road vehicles employed in agriculture, construction, forestry and mining sectors are known to exhibit comprehensive levels of terrain-induced ride vibration and relatively lower directional stability limits, especially for the articulated frame-steered vehicles (AFSV). The transmitted whole-body vibration (WBV) exposure levels to the human operators generally exceed the safety limits defined in ISO-2631-1 and the European Community guidelines. Moreover, the directional stability limits are generally assessed neglecting the contributions due to terrain roughness and kineto-dynamics of the articulated frame steering (AFS) system. Increasing demand for high load capacity and high-speed off-road vehicles raises greater concerns for both the directional stability limits and WBV exposure. The criterion for acceptable handling and stability limits of such vehicles do not yet exist and need to be established. Furthermore, both directional stability performance and ride vibration characteristics are coupled and pose conflicting vehicle suspension design requirements. This dissertation research focuses on enhancement of ride, and roll- and yaw-plane stability performance measures of frame-steered vehicle via analysis of kineto-dynamics of the AFS system and hydro-pneumatic suspensions. A roll stability performance measure is initially proposed for off-road vehicles considering magnitude and spectral contents of the terrain elevations. The roll dynamics of an off-road vehicle operating on random rough terrains were investigated, where the two terrain-track profiles were synthesized considering coherency between them. It is shown that a measure based on steady-turning root-mean-square lateral acceleration corresponding to the sustained period of unity lateral-load-transfer-ratio prior to the absolute-rollover, could serve as a reliable measure of roll stability of vehicles operating on random rough terrains. The simulation results revealed adverse effects of terrain elevation magnitude on the roll stability, while a relatively higher coherency resulted in lower terrain roll-excitation and thereby higher roll stability. The yaw-plane stability limits of an AFSV are investigated in terms of free yaw-oscillations as well as transient steering characteristics through field measurements and simulations of kineto-dynamics of the AFS system. It was shown that employing hydraulic fluid with higher bulk modulus and increasing the steering arm lengths would yield higher yaw stiffness of the AFS system and thereby higher frequency of yaw-oscillations. Greater leakage flows and viscous seal friction within the AFS system struts caused higher yaw damping coefficient but worsened the steering gain and articulation rate. A design guidance of the AFS system is subsequently proposed. The essential objective measures are further identified considering the AFSV's yaw oscillation/stability and steering performances, so as to seek an optimal design of the AFS system. For enhancing the ride performance of AFSV, a simple and low cost design of a hydro-pneumatic suspension (HPS) is proposed. The nonlinear stiffness and damping properties of the HPS strut that permits entrapment of gas into the hydraulic oil were characterized experimentally and analytically. The formation of the gas-oil emulsion was studied in the laboratory, and variations in the bulk modulus and mass density of the emulsion were formulated as a function of the gas volume fraction. The model results obtained under different excitations in the 0.1 to 8 Hz frequency range showed reasonably good agreements with the measured stiffness and damping properties of the HPS strut. The results showed that increasing the fluid compressibility causes increase in effective stiffness but considerable reduction in the damping in a highly nonlinear manner. Increasing the gas volume fraction resulted in substantial hysteresis in the force-deflection and force-velocity characteristics of the strut. A three-dimensional AFSV model is subsequently formulated integrating the hydro-mechanical AFS system and a hydro-pneumatic suspension. The HPS is implemented only at the front axle, which supports the driver cabin in order to preserve the roll stability of the vehicle. The validity of the model is illustrated through field measurements on a prototype vehicle. The suspension parameters are selected through design sensitivity analyses and optimization, considering integrated ride vibration, and roll- and yaw-plane stability performance measures. The results suggested that implementation of HPS to the front unit alone could help preserve the directional stability limits compared to the unsuspended prototype vehicle and reduce the ride vibration exposure by nearly 30%. The results of sensitivity analyses revealed that the directional stability performance limits are only slightly affected by the HPS parameters. Further reduction in the ride vibration exposure was attained with the optimal design, irrespective of the payload variations.

Semi-active Suspension Control provides an overview of vehicle ride control employing smart semi-active damping systems. These systems are able to tune the amount of damping in response to measured vehicle-ride and handling indicators. Two physically different dampers (magnetorheological and controlled-friction) are analysed from the perspectives of mechatronics and control. Ride comfort, road holding, road damage and human-body modelling are studied. Mathematical modelling is balanced by a large and detailed section on experimental implementation, where a variety of automotive applications are described offering a well-rounded view. The implementation of control algorithms with regard to real-life engineering constraints is emphasised. The applications described include semi-active suspensions for a saloon car, seat suspensions for vehicles not equipped with a primary suspension, and control of heavy-vehicle dynamic-tyre loads to reduce road damage and improve handling.

Through appendices and diagrams, Car Suspension and Handling, 4th Edition outlines the purpose and history of vehicle suspension systems, while defining the basic parameters of suspension geometry. In addition, the book delves into human sensitivity to vibration, and offers data on durability, tire background information, steering calculations and suspension calculations.

The main functions of an automotive suspension system are to provide vehicle support, stability and directional control during handling conditions and to provide effective isolation from road disturbance. These different tasks result in conflicting design requirements. Directional control and stability requires a suspension that is neither very stiff nor very soft. Insensitivity to external loads requires a stiff suspension, whereas good ride comfort demands a soft suspension. In a conventional passive suspension system, the designer is faced with the problem of choosing the suspension stiffness and damping parameters, which inevitably involves a difficult compromise in view of the wide range of conditions over which a vehicle operates. Ride and handling performances of a vehicle suspension system often present engineers conflicting design goals. For decades, engineers have studied active control for vehicle suspension systems to resolve this conflict. The intent of the system is to replace the classical passive elements by a controlled system that can supply unlimited force to the system. This type of active suspension system has proven capable of achieving improvement over passive systems* The objective for this work is to study and develop a test facility that can improve the state-of-the-art in indoor vehicle suspension simulation testing on a quarter-car vehicle.In summary, a new quarter-car test rig has been designed and built. In an attempt to provide the concept, a well known control scheme, used for this application & in replicating vehicle response signals, we decided to compile a machine, working at much less input cost.