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Viewing 1 to 30 of 7569
2015-04-14
Technical Paper
2015-01-1517
David Stalnaker, Ke-Jun Xie, Terence Wei
Tire manufacturers need to perform various types of testing to determine tire performance under representative vehicle load conditions. However, test results are influenced by a number of external variables other than tire construction. Vehicle load distribution and suspension properties are some of those external variables which can have a significant effect on tire wear rate and durability. Therefore, in order to measure tire performance in a controlled and repeatable manner, a representative vehicle and associated tire load conditions are needed. Laboratory or indoor tire testing offers many advantages over vehicle fleet testing. It provides a well-defined test environment and repeatable results without influence from external factors. Indoor testing has been largely developed around the process of simulating tire wear performance on a specific reference vehicle, including its specific weight distribution, suspension characteristics, and alignment.
2015-04-14
Technical Paper
2015-01-1510
Edoardo Sabbioni, Davide Ivone, Francesco braghin, Federico Cheli
Estimation of friction coefficient and sideslip angle represents a key-point for improving control systems for vehicle safety, e.g. ESP (Electronic Stability Control), VDC (Vehicle Dynamics Control), etc. A model-based approach (state observer or Kalman filter) is generally used on purpose. Benefits induced by in-tyre sensors on sideslip angle and friction coefficient estimation are investigated in this paper. Thus tyre cornering force measurements are added to the ones usually present on-board vehicle (steer angle, lateral acceleration and yaw rate) and used to implement an Extended Kalman Filter (EKF) based on a single-track vehicle model. Tyre-road contact forces are assumed to be provided once per wheel turn by a smart tyre constituted of two tri-axial accelerometers glued on the tyre inner liner. Performance of the proposed observer is evaluated on a series of handling maneuvers and its robustness to road bank angle and tyre/vehicle parameters variation is discussed.
2015-04-14
Technical Paper
2015-01-1505
Ibrahim A. Badiru
Vehicle pull is a condition experienced by customers where a constant torque at the steering wheel is required to maintain the vehicle on a straight path. Vehicle lead is a condition where a non-zero steering wheel angle is required to maintain a straight path. There are many potential causes for vehicle pull or lead—road condition, suspension asymmetry, and tire characteristics to name a few. Both vehicle pull and lead can cause customer dissatisfaction with the vehicle as well as drive OEM warranty service costs. Electronic Power Steering (EPS) systems have overtaken Hydraulic Power Steering (HPS) as the predominate steering architecture for new passenger vehicles. One of the key benefits of EPS is the ability to program value added features (VAF) into the EPS controller. These features can significantly enhance the pleasure and safety of the driving experience for the customer. EPS pull compensation is a feature that reduces the driver workload to compensate a vehicle pull.
2015-04-14
Technical Paper
2015-01-1504
Ning Wei Bao
A ball screw regenerative shock absorber was designed for the relief of the vehicle vibration and the energy recovery of the vehicle vibration. The effect of its main parameters on the suspension system was numerically analyzed. According to the principle of the ball screw regenerative suspension system, a mathematical model of the ball screw regenerative shock absorber was established regarding the ball screw rotational inertia, the motor rotational inertia, the screw lead and the radius of the screw nut. A suspension dynamic model based on the ball screw regenerative shock absorber was developed combining the road model and the two-degrees-of-freedom suspension dynamic model.
2015-04-14
Technical Paper
2015-01-1501
Ryusuke Hirao, Kentaro Kasuya
Many electronic control components have been introduced into vehicles with the aims of improving their safety and comfort, and saving energy. Various suspension systems have been developed, to reconcile ride feeling with control stability at a high level. Development efforts have been particularly active in the field of semi-active suspension, prompted by its superior energy-saving and cost performance. Algorithm which is based on skyhook control has been applied mostly to the ride comfort control of semi-active suspension system of vehicle. Also, at the time of steering, control for enhancing damping force are commonly used as handling control to restrain transitional roll angle. Therefore, in this development we developed new ride comfort control and new handling control, and constructed a system which uses only vehicle height sensor as dedicated sensor and uses damping force variable damper of pressure control type.
2015-04-14
Technical Paper
2015-01-1497
Hideaki Shibue, Devesh Srivastava
Torsion beam suspensions are lightweight and low-cost, and they are therefore frequently used for the rear of small front-wheel drive vehicles. The configuration of the suspension is simple and it comparatively consists of fewer components. However, it is difficult to predict their characteristics and satisfy the target of the performance in the early stages of development in particular, because it should realize the various performance elements demanded of a suspension in a single part. A great deal of research has been conducted on the cross-sectional shape of the beam section, but up to the present there has been almost no discussion of the effect of property of the trailing arms on suspension characteristics. This paper discusses tests conducted to study the effect of the rigidity of the trailing arms, and considers the mechanism of that effect.
2015-04-14
Technical Paper
2015-01-1523
Takahiro Uesaka, Tatsuya Suma
Simulating road noise while a vehicle is operating shortens the development period and reduces the number of prototypes, which lowers development costs. Realizing road noise simulation identifies the force transmitted to the suspension through the tires and wheels from vibration between the road surface and the tires. There are significant variations between static state characteristics and vibration characteristics of tires in motion, which are challenging to measure. The effects of reduction of the elastic modulus of the rubber in the tires due to repeated loads accompanying contact with the ground, and of Coriolis and centrifugal forces resulting from the rolling motion are known. Detailed analysis of the eigenvalue fluctuations produced by Coriolis force based on measurements taken using sensors installed inside the tires has recently been reported. Knowledge is still lacking in areas such as the specifics of how the input from the tires changes due to these fluctuations.
2015-04-14
Technical Paper
2015-01-1436
Divyanshu Joshi, Anindya Deb, Manoj Mahala, Clifford Chou
In the past few decades, increasing concern for vehicle occupant safety and comfort has motivated the development of advanced tools for vehicle dynamics analysis. To date, most of the published work on vehicle stability predominantly employs basic handling models such as 2-DOF (degrees of freedom) bicycle model, as well as 3, 4 and 5-DOF models that capture lateral and yaw dynamics alone or coupled with longitudinal, roll and pitch dynamics. 2-DOF quarter car, 4-DOF half car and 7-DOF full car models are found to be the most popular configurations for ride comfort analysis. It is noted that ride comfort and stability have mostly been dealt with independently by researchers, however, a coupling may exist in reality when a vehicle encounters road irregularities, bumps, potholes, etc. while undergoing a maneuver.
2015-04-14
Technical Paper
2015-01-1590
Atsushi Hirano
As one of the larger components of the vehicle, the wheels have great potential for enhancing fuel economy. As such, there is a need to reduce the weight of the wheels. The wheels are subject to a variety of stresses from the road surface while cruising. Therefore, while making them lighter, it is necessary at the same time to ensure the various types of performance required of the wheels. As automakers are particularly concerned with safety, they set very strict performance requirements for the wheels and subject them to appropriate testing and evaluation. Although many aspects of the relationship between the wheels’ various characteristics and their handling stability have not been explained, experiments have shown that wheel stiffness influences vehicle dynamic performance. Nonetheless, it is rare during vehicle development for automakers to study wheel stiffness in terms of its effect on vehicle dynamic performance.
2015-04-14
Technical Paper
2015-01-1584
Daniel E. Williams
The classic two-degree-of-freedom yaw-plane or “bicycle” vehicle model is augmented with two additional states to describe lane-keeping behavior, and further augmented with an additional control input to steer the rear axle. A simple driver model is hypothesized where the driver closes a loop on a projected lateral lane position. The driver can select the preview distance to compensate driver/vehicle dynamics, consistent with the “cross-over” model found in the literature. A rear axle steer control law is found to be a function of front axle steering input and vehicle speed that exhibits stability similar to a positive real system, while at the same time improving the ability of the driver/vehicle system to track a complex curved lane and improving steady-state maneuverability. The theoretically derived control law bears similarity to practical embodiments allowing a deeper understanding of the functional value of steering a rear axle.
2015-04-14
Technical Paper
2015-01-1575
Tomokazu Honda
Automobile manufacturers have recently been carrying out research and practical application of torque vectoring systems that enhance vehicle maneuverability using direct yaw moment control by differential distribution of torque to the right and left wheels. Honda has also put an Active Torque Transfer System (ATTS) in the 1997 model Prelude as a torque vectoring system for FF vehicles. Subsequently, Honda also put the Super Handling All Wheel Drive (SH-AWD) into practical application as a system for AWD vehicles in 2004, installing it in the Legend. The SH-AWD is a four-wheel flexible control system that simultaneously controls torque distribution to front and rear wheels as well as to left and right wheels. Similarly, other manufacturers have also devised, and put into practical application, various types of electronically controlled AWD systems with torque vectoring mechanisms. These are developing into devices for enhancing vehicle maneuverability.
2015-04-14
Technical Paper
2015-01-1572
D. Metz, J. Sneddon
Deteriorated roadway surfaces (potholes) encountered under everyday driving conditions produce external vehicle disturbance inputs that are potentially destabilizing and highly transient. We examine vehicle behavior in response to such inputs through simulation. Idealized pothole geometrical configurations are used to represent common deteriorated roadway surfaces, and as environments in the HVE simulation suite of programs. Differences in vehicle behavior are catalogued and the potential for destabilized vehicle behavior is examined, particularly under conditions in which only one side of the vehicle contacts the pothole. Vehicle types employed in the simulations consist of a sedan, sports car and SUV. Results show that many combinations of speed, vehicle type and pothole configuration have significant destabilizing effects on vehicles.
2015-04-14
Technical Paper
2015-01-1594
Johannes Edelmann, Massimiliano Gobbi, Giampiero Mastinu, Manfred Ploechl, Giorgio Previati
The friction estimation at the tyre-ground contact is crucial for the active safety of vehicles. Friction estimation is a key problem of vehicle dynamics and the ultimate solution is still unknown. However the proposed approach, based on a simple idea and on a simple hardware, provides an actual solution. The idea is to compare the tyre characteristic at a given friction (nominal characteristic) with the actual characteristic that the tyre has while running. The comparison among these two characteristics (the nominal one and the actual one) gives the estimate of the actual friction coefficient. The mentioned comparison is an efficient but complex algorithm based on a mathematical formulation of the tyre characteristic. The estimation method is based on force and torque measurements in real time by a relatively simple smart wheel which is able to detect the three forces and the three moments acting at the hub. Both the theoretical and experimental issues are discussed in the paper.
2015-04-14
Technical Paper
2015-01-1570
Daniel Vilela, Rubens Pinati, Scott Larsen, Erick Rodrigues, Renato Serrati
This study presents the comparison of vehicle level handling performance results obtained using physical test tire data and a tire developed by means of Finite Element Method. Real tires have been measured in laboratory to obtain the tire force and moment curves in terms of lateral force and align torque as function of tire slip angle and vertical force. The same tire construction has been modeled with Finite Element Method and explicit formulation to generate the force and moment response curves. Pacejka Magic Formula tire response models were then created to represent these curves from both physical and virtual tires. In the sequence, these tire response models were integrated into a virtual multibody vehicle model developed to assess handling maneuvers.
2015-04-14
Technical Paper
2015-01-1498
Yuyao jiang, Weiwen Deng, Sumin Zhang, Shanshan Wang, Qingrong Zhao, Bakhtiar Litkouhi
Driver steering torque feedback is one of the critically important factors in the consideration and measurement both on vehicle design and performance, and on model accuracy of vehicle dynamics. On the one hand, driver steering torque feedback is one of the key measures on human-machine interface for drivers’ comfort and intuitive road feel, such as return-to-center capability, on-center feel and ease of steering effort, etc. This mainly involves the design of vehicle dynamics as a whole, but in particular, vehicle steering system. On the other hand, it is also the most determining factor to the quality of drivers’ interaction with or driver-in-loop simulation of vehicle dynamics models, such as driver simulator, etc.
2015-04-14
Technical Paper
2015-01-0667
Kei Ichikawa
The importance of reducing road noise is increasing . Methods that enhance acoustic sensitivity and reduce the force transferred from the suspension to the body are used to reduce road noise. Reduction of body suspension mounting point compliance has been used as a method of reducing acoustic sensitivity. There were cases where this method reduced acoustic sensitivity, the road noise pressure was not reduced; this study focused on the suspension transfer force and analyzed its mechanism of change using the Transfer Function Synthesis Method. The results showed that the balance between the body suspension mounting point, suspension bush and suspension arm tip compliance is an important factor influencing the change in suspension transfer force.
2015-04-14
Technical Paper
2015-01-1506
Bastian Scheurich, Tilo Koch, Michael Frey, Frank Gauterin
Today, body vibration energy of passenger cars gets dissipated by linear working shock absorbers. A new approach substitutes the damper of a passenger car by a cardanic gimbaled flywheel mass. The constructive design leads to a rotary damper in which the vertical movement of the wheel carrier leads to revolution of the rotational axis of the flywheel. In this arrangement, the occurring precession moments are used to control damping moments and to store vibration energy. A gyroscope is set to high speed revolutions by an electric motor and a gimbal is used for bearing. The gimbal consists of an outer ring which is connected to the vertical movement of the wheel carrier. Right-angled to the outer ring, there is an inner ring pivoting the gyroscope right-angled. In order to avoid undesirable body movements, the directional vector of the angular velocity of the gyroscope is parallel to the car’s yaw axis.
2015-04-14
Technical Paper
2015-01-1579
Jun Nakahara, Koji Yamazaki, Yusuke Otaki
There exist some cars which ride performance become less comfortable on smooth road. If vibration transmissibility of suspension system on such a vehicle is evaluated by means of equivalent dynamic stiffness, it is found that the increase of storage stiffness deteriorates the vibration transmissibility of suspension due to the steep rising of hysteresis on wheel-stroke to wheel-load curve when excitation amplitude become small. To improve the ride-comfort performance on smooth road, therefore, the rising shape of wheel stroke curve due to hysteresis components, such as shock-absorber, ball-joints and rubber bushes, should be adjusted to prevent the increase of storage stiffness at small amplitude of suspension stroke. For investigating the hysteresis characteristics of these components, appropriate simulation models, which can reproduce their characteristics accurately, must be installed in the vehicle model and their parameters have to be determined with sufficient accuracy.
2015-04-14
Technical Paper
2015-01-1564
Joshua L. Every, Dennis Guenther, Gary Heydinger
It has been established that when passenger car, and commercial vehicle drivers, apply the brakes, in an emergency situation, multi-stage braking is often observed. The typical view of multi-stage braking is that, drivers initially apply the brakes at a constant lower level of pressure, approximately 30%-50% of system capacity. After a short period of time (generally assumed to be related to drivers perceiving the situation) the driver will then apply the brake system at full capacity. The reality of this behavior is more complex. The reality of multi-stage brake application is that drivers often not only maintain constant brake force but also exhibit a reducing level of brake force. The presence of this behavior indicates that a further understanding of driver braking behavior is necessary if this behavior is desired to be fully understood and modeled. A frequency content based method of evaluating driver braking behavior is presented.
2015-04-14
Technical Paper
2015-01-1315
Antonio Carlos Botosso, Tarcisio Antonio Hess Coelho
This paper presents the results of a study about the influence of the body stiffness on the overall vehicle dynamic behavior. It is intended to show which external factor may cause differences on the vehicle responses due to the body stiffness, based on evaluations with no specific metric. A selection of representative vehicle measurements has been considered for this assessment and each individual external factor (wheel vertical displacements and external accelerations) has been evaluated for a vehicle with two different bodies (rigid and flexible). Thus, it is possible to identify the sensitivity of the dynamic behavior of the vehicle when subjected to external factors and verify in which situation it is more affected by body stiffness that justify its consideration on CAE (Computer Aided Engineering) analyses.
2015-04-14
Technical Paper
2015-01-1499
Tadatsugu Takada, Kazuki Tomioka
Honda developed the right and left independent toe-angle control system (first-generation P-AWS) in the Acura RLX in 2013 and announced it as the first in the world. As indicated in a previous paper, “Independent Left and Right Rear Toe Control System,” with this system Honda has realized an excellent balance between the fun of handling that is at the driver’s will (INOMAMA) and driving performance with a sense of stability. This first-generation P-AWS is designed to be optimal to the vehicle specifications (suspension axial force, steering gear ratio, etc.) of the Acura RLX. Honda is due to widely adapt P-AWS to other models from now on. Following this, we developed the next-generation P-AWS system (second-generation P-AWS) in order to reconcile system performance and low cost wherever possible, in order to be adaptable for all ACURA models.
2015-04-14
Technical Paper
2015-01-1507
Kentaro Komori, Takahito Nagataki
Research on passenger vehicles responds to mechanical loss-reduction demands for improving fuel economy. Handling, steering feel, and ride-comfort can be attributed to the steering and suspension. We researched friction behavior in terms of low- or high- friction coefficients, and in terms of static-kinetic transient motion. We improved the vehicle handling and ride comfort by giving the appropriate friction to the tie-rod end ball joint. Controlling friction behavior, we used diamond-like carbon (DLC) coating submitted to boundary lubrication. Different DLC coatings varied widely in hydrogen content, mechanical properties and micro-surface roughness were applied to the ball joint studs. The larger the micro-surface roughness in asperity of DLC coatings, the higher the kinetic friction torque. The friction behaviors corresponded to the DLC properties.
2015-04-14
Technical Paper
2015-01-1589
Michael W. Neal, Walter Cwycyshyn, Ibrahim Badiru
The goal of this paper is to discuss the critical aspects of damper tuning for production vehicles. These aspects include ride and handling performance attributes, damper basics, conflicts in achieving desirable results, tuning philosophies and the influence of the damper design. The marketplace has become increasingly competitive. Customer preference, cost, mass and regulatory pressures often conflict. Yet each year more vehicles are required to do all these things well. Damper tuning can play a significant role in resolving these conflicts. Although many papers have been written on the theory behind damper design and capabilities, there has been very little written about the techniques of tuning dampers for production vehicles. This paper attempts to discuss the critical aspects of damper tuning for production vehicles in four sections. The first section discusses the performance attributes of ride and handling. The second section provides a basic understanding of dampers.
2015-04-14
Technical Paper
2015-01-1520
Massimiliano Gobbi, Giampiero Mastinu, Federico Ballo, Giorgio Previati
A wheel able to measure the generalized forces at the hub of a race motorcycle has been developed and used. The wheel has a very limited weight (about 2 kg). It is made from magnesium with a special structure to sense the forces and provide the required level of stiffness. The wheel has been tested both indoor for preliminary approval according to internal standards and on the track. The three forces and the three moments at the hub can be measured with a resolution of respectively 1N and 0.3Nm. Twelve strain gauges are positioned at relevant locations to sense the generalized forces. Utilizing an encoder (angle resolution 0.06°), a simultaneous ADC sampling is performed on the six strain gauges bridges outputs while coupling the force/torque output with the absolute wheel angular position. The sincronous sampling allows seamless real-time measurements at vehicle speed up to 400 km/h.
2015-04-14
Technical Paper
2015-01-1565
Qingzhang chen
A regenerative braking system coordinated controller was developed for a front wheel drive BEV that also includes an ultra-capacitor storage system. This controller integrates the dual-motor regenerative braking with the hydraulic braking and stability control systems. The vehicle braking mode and the distribution of braking torque were determined according to the vehicle braking requirements, vehicle status and energy storage system (battery plus ultra-capacitor) state, and the stability control torque was provided according to the real-time vehicle stability condition. Simulation results show that, compared with a motor unilateral independence control strategy, the integrated coordinated controller improves the vehicle’s stability when the vehicle corners while braking.
2015-04-14
Technical Paper
2015-01-0642
Per Hyldahl, Sebastian Andersen, Sebastian Mikkelsen, Ole Balling
The modeling of a vehicle’s suspension system is one of the most crucial tasks when designing and optimizing modern vehicles. One of the preferred tools to assist the designers to perform this task is multibody dynamics. When using multibody dynamics, it is possible to model arbitrary systems with high mechanical complexity, include non-linear characteristics of e.g. springs and dampers, and simulate the systems behavior in the time domain to assess its performance in various scenarios. A non-trivial job when building a vehicle model, is estimating the characteristics of the many suspension components that exhibits non-linear behavior during operation of the vehicle. Examples of such components are rubber bushings and stabilizer bars. Especially the latter can be difficult to characterize using an idealized spring with a non-linear force-deflection curve, since its stiffness depends highly on its geometry and deformation stage.
2015-04-14
Technical Paper
2015-01-0614
Ye Zhao, Liangmo Wang, Xiangli Yang, Liukai Yuan, Zunzhi Zhang
Abstract: In most cases, researches on the ride performance of air suspension system are based on simplified mathematical models which could be too theoretical or not be able to consider the coupling relationship between the various components so that they behave far away from the actual vehicle system. This paper represents the study on the ride performance of an air suspension vehicle based on the complex whole vehicle model which was established though ADAMS and Matlab. The applying of flexible components helped to improve the model accuracy and the tensile and compression tests of the air spring were used to establish the interconnected four-gasbag air suspension system. The vehicle ride performance was studied through the co-simulation between ADAMS and Matlab. The accuracy of the results were verified by the vehicle test results, which demonstrated the reliability of the whole model.
2015-04-14
Technical Paper
2015-01-0665
Yongchang DU, Yujian Wang, Pu Gao, Yingping Lv
Modelling of disc in brake squeal analysis is complicated because of the rotation of disc and the sliding contact between disc and pads. Many analytical or analytical numerical combined modeling methods have been developed considering the disc brake vibration and squeal as a moving load problem. Yet in the most common used complex eigenvalue analysis method, the moving load nature normally has been ignored. In this paper, a new modelling method for rotating disc from the point of view of modal is presented. First finite element model of stationary disc is built and modal parameters are calculated. Then the dynamic response of rotating disc which is excited and observed at spatial fixed positions is studied. The frequency response function is derived through space and time transformation. The equivalent modal parameter is extracted and expressed as the function of rotation speed and original stationary status modal parameters.
2015-04-14
Technical Paper
2015-01-0668
Yongchang DU, Pu Gao, Yujian Wang, Yingping Lv
The study and prevention of unstable vibration is a challenging task for vehicle industry. Improving predicting accuracy of braking squeal modal is of great concern. Closed-loop coupling disc brake model is widely used in complex eigenvalue analysis and further analysis. The coupling stiffness of disc rotor and pads is one of the most important parameters in the model. But in most studies the stiffness is calculated by simple static force-deformation simulation. In this paper, a closed-loop coupling disc brake model is built. Initial values of coupling stiffness are estimated from static calculation. Experiment modal analysis of stationary disc brake system with brake line pressure and brake torques applied is conducted. Then an optimization process is initiated to minimize the differences between modal frequencies predicted by the stationary model and those from test. Thus model parameters more close to reality are found.
2015-04-14
Technical Paper
2015-01-1356
Atishay Jain
Swingarm, originally known as the swing fork or pivoted fork is a dynamic structural part of the rear suspension of most modern motorcycles. It is used to hold the rear axle firmly, while pivoting vertically on the frame, to allow the suspension to absorb bumps in the road. Driving and braking loads are also transmitted through the swing arm, and thus, it plays a major role in vehicle dynamics. Weight minimization is important in a swingarm as it is largely an unsprung mass. The conventional swingarm design includes steel tubing and sheet metal structures. Due to higher forces near the pivot, conventional swingarm are inherently over-designed as they use tubular structures of same cross section through the entire length of the swingarm. An aluminum alloy swingarm design even when subjected to casting manufacturing constraints, has the potential for better material layout and weight minimization.
Viewing 1 to 30 of 7569