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This paper will discuss the vehicle top-down design approach that includes the non-linearity and sub-system interactions such as tire and road, (left and right) interaction between two or more parts connected by bushings, springs, bolts, stabilizer-bar, etc… The proposed method would allow for the inclusion of realistic boundary conditions and proper load simulation, and it would provide the ability to visualize and evaluate dynamic structural phenomena and complex component interaction. This approach would also facilitate the evaluation of design changes that may affect load propagation and/or load magnitude. All of the advantages of the sub-system analysis method mentioned above would allow for a greater understanding of the sub-system as a whole and help correctly identify the design requirements needed for the individual components that make up such chassis subsystems.

Durability of automotive structures is a primary engineering consideration that is evaluated during a vehicle's design and development. In addition, it is a basic expectation of consumers, who demand ever-increasing levels of quality and dependability. Automakers have developed corporate requirements for vehicle system durability which must be met before a products is delivered to the customer. To provide early predictions of vehicle durability, prior to the construction and testing of prototypes, it is necessary to predict the forces generated in the vehicle structure due to road inputs. This paper describes an application of the “virtual proving ground” approach for vehicle durability load prediction for a vehicle on proving ground road surfaces. Correlation of the results of such a series of simulations will be described, and the modeling and simulation requirements to provide accurate simulations will be presented.

Kinetic Pty Ltd and Tenneco Automotive have developed a passive suspension system hereafter referred to as a Kinetic2 system. The motivation for the design of the system is discussed, and the function of the system is briefly explained. In a previous paper, the system has been shown to improve the stability and rollover resistance of a small SUV. In this study vehicle response characteristics are found by simulating a typical sinusoidal sweep maneuver. Improved handling is evaluated by simulating NHTSA’s yaw acceleration feedback fishhook test. Lastly ride is studied by simulating the vehicle driving over a characteristic stretch of California Freeway #5. All of the simulations were performed on a small SUV in standard form and equipped with the Kinetic system. Results of the ADAMS simulation are presented, and benefits are discussed.

Gasoline-electric hybrid vehicles are becoming popular due to their high fuel efficiency and lower emission. While this technology has proven effective for passenger cars and light SUVs, it is not as effective for heavier vehicles. Hydraulic hybrid vehicles offer an alternative hybridization technology for heavier vehicles. This alternative technology is especially effective for frequent-stop vehicles including city buses, delivery vehicles, and refuse trucks. This paper, using simulations, investigates the noise and vibration problem of hydraulic hybrid vehicles. The noise and vibration is mainly caused by the moving parts of the pump/motor, which is the main component of hydraulic hybrid systems. The variable speed motion of the pump/motor inner parts takes place under time-varying levels of hydraulic high pressure. The proposed solution consists of magnetorheological (MR) mounts isolating the hybrid system from the vehicle chassis.

Rollover propensity is an important safety issue which should be considered early in the design of a vehicle. Although there is a trend toward higher-tech solutions to mitigate rollover risk, we feel that a vehicle designer should also be fully aware of the impact many of the vehicle's design parameters have on rollover propensity. Such awareness is essential to making appropriate engineering tradeoffs throughout the vehicle development process. In this paper, we present a study performed to gain a better understanding of the factors affecting the roll tendency of a vehicle. The equations of motion for a vehicle ignoring suspension effects and tire deflections are developed to gain an understanding of the physics involved and to preliminarily identify factors using a generic Matlab™ code. Further and more complete analysis was then completed using ADAMS™ Car.

In this research, the handling behavior of an intermediate class passenger car has been optimized by altering its front suspension parameters. For this purpose, a validated virtual model of the car, constructed by Adams/Car software, has been used. The utilized objective function is a combination of eight criteria indicating handling characteristics of the car. To reduce the amount of optimization parameters, a sensitivity analysis has been done by implementing the Design of Experiments method capabilities. Optimization has been done using the Response Surface Method. The obtained optimization results show a considerable improvement in the system response.

In general, the longitudinal position of the center of gravity of a vehicle has a great influence on lateral acceleration in critical cornering. Most rear-wheel-drive vehicles (front engine, rear-wheel drive) have a tendency to be over-steered because the driving power acts on the rear wheels, and so the forward weight distribution is large. As such, the vehicle has an under-steer tendency in this respect and an overall balance is achieved. On the other hand, because formula cars are very light compared to general vehicles, the used area of the vertical wheel load-maximum cornering force characteristic, differs greatly from general vehicles. That is, although general vehicles use a nonlinear area for the vertical wheel load-maximum cornering force characteristic of the tire, a comparatively light formula car uses an almost linear area in the vertical wheel load-maximum cornering force characteristic of the tire.

The paper deals with undertaken theoretical analysis and experiments of adaptation of a control system modeling of Magneto-Rheological Fluid (MRF) dampers (shock absorbers) in vehicle suspension system. Low energy requirements (20 W per damper max) are a characteristic feature of it. To create this suspension system physical and mathematical models of the vehicle were built. Models used were generated by ADAMS/Car and MATLAB® applications. The aim of this project is to create a Fuzzy Logic Controller Optimized by the Genetic Algorithms (FLCOGA). A significant reduction of vertical acceleration and counteraction against moments of forces acting around the longitudinal and transverse axes of the vehicle in varied ride conditions is the objective of control. In continuation of R&D, the elements of genetic optimization are enriched by genetic learning systems.

Global Chassis Control (GCC) from Continental Teves, a logical development of the current Electronic Stability Control (ESC), aims to ensure the best possible levels of active safety, ride quality and driving pleasure under the given driving conditions, using the available configuration of electronically controlled chassis subsystems. The system makes the vehicle easier to control in extreme situations at the same time as maximizing ride comfort and ensuring more responsive handling.

The paper deals with the methodology implemented by Magneti Marelli and Politecnico di Torino Vehicle Dynamics Research group to develop and verify the software of active chassis and powertrain control systems through a Hardware-In-the-Loop automated procedure. It is a general procedure which can be adopted for all the active chassis control systems, not only for their development but also for the verification of their reliability. The steps of the procedure are described in the first part of the paper. The specific application on which this paper is focused concerns robotized gearboxes.

This paper focuses on modeling of torque-biasing devices of a four-wheel-drive system used for improving vehicle stability and handling performance. The proposed driveline system is based on nominal front-wheel-drive operation with on-demand transfer of torque to the rear. The torque biasing components of the system are an electronically controlled center coupler and a rear electronically controlled limited slip differential. Kinematic modeling of the torque biasing devices is introduced including stage transitions during the locking stage and the unlocking/slipping stage. Analytical proofs of how torque biasing could be used to influence vehicle yaw dynamics are also included in the paper. A yaw control methodology utilizing the biasing devices is proposed. Finally, co-simulation results with Matlab®/Simulink® and CarSim® show the effectiveness of the torque biasing system in achieving yaw stability control.

In an effort to understand steering systems performance and properties at the microscopic level, we developed Multibody simulations that include multiple three-dimensional gear surfaces that are in a dynamic state of contact and separation. These validated simulations capture the dynamics of high-speed impact of gears traveling small distances of 50 microns in less than 10 milliseconds. We exploited newly developed analytic, numeric, and computer tools to gain insight into steering gear forces, specifically, the mechanism behind the inception of mechanical knock in steering gear. The results provided a three dimensional geometric view of the sequence of events, in terms of gear surfaces in motion, their sudden contact, and subsequent force generation that lead to steering gear mechanical knock. First we briefly present results that show the sequence of events that lead to knock.

The Nondimensional Tire Model is based on the idea of data compression to load-independent curves. Through the use of appropriate transforms, tire data can be manipulated such that, when plotted in nondimensional coordinates, all data falls on a single curve. This leads to a highly efficient and mathematically consistent tire model. In the past, data for slip angle and slip ratio has been averaged across positive and negative values for use with the transforms. In this paper, techniques to handle tire asymmetries in lateral and longitudinal force are presented. This is an important advance, since in passenger cars driving/braking data is almost always asymmetric and, depending on tire construction, lateral force data may follow likewise. In addition, this paper is the first to explore the inclusion of inflation pressure as an operating variable in the Nondimensional Tire Theory.

This paper investigates the use of GPS to estimate vehicle sideslip and tire information. Both a one antenna GPS antenna/receiver and dual GPS antenna method are studied. Analysis of the accuracy that can be achieved using the two different GPS solutions is provided. The algorithms are then validated on a fully instrumented Infiniti G35 sedan. Experimental data is given showing the performance of the GPS based sideslip estimates compared against a simple bicycle model and a Datron™ velocity sensor.

The paper presents the approach followed by Politecnico di Torino Vehicle Dynamics Research team to design an electro-mechanical Active Roll Control (ARC) system. The first part of the paper describes the targets of the system, which has to improve both comfort and handling. Different solutions for the implementation of the electro-mechanical actuation were evaluated. A prototype of the electro-mechanical Active Roll Control was built and experimentally tested in the Vehicle Dynamics Laboratory of the Department of Mechanics of Politecnico di Torino, by adopting a Hardware-In-the-Loop (HIL) test bench. The experimental results show the benefits of the system, both in a stand alone configuration and integrated with an Electronic Stability Control (ESC) system.

Vehicle roll dynamics is strongly influenced by suspension properties such as roll center height, roll steer and roll camber. In this paper, the effects of suspension properties on vehicle roll response has been investigated using a multi-body vehicle dynamics program. A full vehicle model equipped with front MacPherson and rear multilink suspensions has been used for the study. Roll dynamics of the vehicle were evaluated by performing fixed timing fishhook maneuver in the simulation. Variations of vehicle roll response due to changes in the suspension properties were assessed by quantitatively analyzing the vehicle response through simulation. Critical suspension design parameters for vehicle roll dynamics were identified and adjusted to improve roll stability of the vehicle model with passive suspension. Design of Experiments has been used for identifying critical hardpoints affecting the suspension parameters and optimization techniques were employed for parameter optimization.

Some systems like the ESP already exist to support the driver for the stabilization of the vehicle. But the next generation of active safety system will have to deal with a wider environment of the vehicle, to go closer to the limit of the vehicle dynamic etc. With such a complexity the systems will also have to take into account their own limits and to reduce their actions when they have a low confidence, e.g. when sensors are degraded. This article describes firstly a virtual driver and secondly a decision control that fuses their command depending on their confidences in order to improve the reliability of the command level.

An increasing number of chain systems have used low cost blade tensioners. However, its functional mechanism had not been logically figured out. One reason for this is that a blade tensioner generates large transversal vibration. Consequently, in the case of the longitudinal model, the load prediction accuracy was inadequate. Accordingly, a link-by-link model was created, allowing transversal vibration to be taken into account. As a result, the features of a chain system using a blade tensioner were clarified, thus enabling the chain load and behavior to be predicted with a higher degree of accuracy than before.

An automated machine has been designed with true offset fastening to join shear-tie/frame assemblies to the fuselage of the Boeing 787 Dreamliner. The machine can access fasteners located close to structural components that are very deep. This is accomplished by offsetting the fastening axis from the axis of the head for true offset fastening. The head can be positioned next to the structural component and the offset fastening tooling ‘reaches’ out to the fastener location (Figure 1). By using a true offset, the fastening machine can access fasteners that would be otherwise inaccessible by traditional automated equipment. The machine can also be lighter and more accurate when compared to fastening machines with traditional tooling.

One of the most important aims of the automotive industry is to provide the best possible protection for drivers, passengers and pedestrians. Through their CAPS (Combined Active and Passive Safety) program (see Figure 1), Bosch is developing new functions which help to achieve these goals and contribute to accident mitigation and/or reduction of accident severity. By linking existing active and passive automobile safety systems and extending these by adding systems for monitoring and evaluating the vehicle's environment, the foundation for new safety functions is created. The growing number of airbags in vehicles provides more and better protection against injury for the occupants. In addition, active safety systems such as the ESP® Electronic Stability Program help to prevent an accident occurring in the first place. If these systems are linked together, they can share information and provide even better safety for drivers and passengers through new functions.