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2015-04-14
Technical Paper
2015-01-1516
Mohammed K Billal
The component level wheel crush test will help to predict the wheel crush load under static condition. In passenger car, the frontal wheel has to absorb the energy during the crush and it should not intrude more in to the occupant compartment. Using virtual tools, the wheel crush load can able to predict for the new designs and the new design changes can be made quickly to meet the requirement. During the wheel crush, the crack will initiate and propagate, then the major failure will occur. In virtually, this failure can be achieved using progressive damage and failure material model. This material model is having the capability to predict the damage initiation due to the ductile and shear failure. After damage initiation, the material stiffness is degraded progressively according to the specified damage evolution response. The progressive damage models allow for a smooth degradation of the material stiffness, in both quasi-static and dynamic situations.
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
2015-01-1514
Deepak Tiwari, Japveer Arora
A typical wheel development process involves designing a wheel based on a defined set of criteria and parameters followed by verification on CAE. The virtual testing is followed by bench level and vehicle level testing post which the design is finalized for the wheel. This paper aims to establish the learnings which were accomplished for one such development processes. The entire wheel development process had to be analyzed from scratch to arrive at a countermeasure for the problem. This paper will not only establish the detailed analysis employed to determine the countermeasure but also highlight its significance for the future development proposals. The paper first establishes the failure which is followed by the detailed analysis to determine the type of failure, impact levels and the basic underlying conditions. This leads to a systematic approach of verification which encompasses the manufacturing process as well as the test methodology.
2015-04-14
Technical Paper
2015-01-1512
Sairom Yoo, Md Salah Uddin, Hyeonu Heo, Jaehyung Ju, Doo Man Kim, Seok-Ju Choi
In an effort to develop tires with low rolling resistance, nonpneumatic tires (NPTs) with low viscoelastic energy loss materials are receiving more attention. For better design of NPTs for better fuel efficiency, one may need to analyze rolling energy loss of NPTs at a component level. The objective of this study is to develop a tool to quantify rolling energy loss and thermal dissipation of NPTs at a component level. For varying vehicle loads and rolling speeds, we suggest a thermo-mechanical model of an NPT with hexagonal cellular spokes to investigate temperature distribution of the NPT caused by hysteresis and convection loss into air. Using a hyper-viscoelastic model developed from a uniaxial (tensile and compression) testing and dynamic mechanical analysis (DMA), a thermo-mechanical model is developed by combining longitudinal shear deformation induced hysteresis and cooling to air.
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
2015-01-1518
Emmanuel O. Bolarinwa, Oluremi Olatunbosun
Three-dimensional (3D) Finite element (FE) tyre models have been widely used for tyre design, vehicle design and dynamic investigations. Such tyre models have the inherent advantage of covering a wide range of tyre modelling issues such as the detailed tyre geometry and material composition, in addition to an extensive coverage of tyre operational conditions such as the static preload, inflation pressure and driving speed. Although tyre vibration behaviour, in different frequency ranges are of general interest, both for the vehicle interior and exterior noise, the present study is limited to a frequency of 100 Hz which is prevalent in most road induced NVH ride and handling problems. This study investigates tyre vibration behaviour using a propriety FE code. Such investigation plays an important role in the study of vehicle dynamics.
2015-04-14
Technical Paper
2015-01-0624
Mustafa Arat, Emmanuel O. Bolarinwa
The increasing demand of energy use in transportation systems combined with the limited supply of fossil hydrocarbons to support conventional engines has led to a strong resurgence in interest for electric vehicles (EVs). Although EVs offer the possibility of decoupling the issue of energy source from the primary torque generator in an automobile, the current technology is yet to match the well-developed internal combustion (IC) systems, especially in terms of energy capacity and travel range. In this study, the influence of rolling-resistance on the energy efficiency and road holding of electric vehicles is described. Rolling resistance is taken in the context of energy loss (e.g. the mechanical energy converted into other sources of energy) for a unit distance traveled by the tire.
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
2015-01-1582
Jiawang Yong, Nenggen Ding, Feng Gao, Wei Wang, Xianrong Hu
Comparing with traditional braking systems of automobiles, the brake-by-wire (BBW) system has a higher dynamic response and is more suitable for using in new energy vehicles to facilitate their regenerative braking. As the two main categories of BBW systems, the well-known electro-hydraulic braking system and electro-mechanical braking system are not compact enough and their failsafe function has always been a worrying aspect. A new BBW system called integrated braking system (IBS) is proposed in recent years. The IBS implements power-assisted braking and active braking by means of just an integrated unit. The integrated unit is also used for building up and reducing the brake pressure, to implement the ABS and antislip regulation. In this paper a new structure of IBS is presented, it is mainly composed of motor, ball screw, master cylinder and four 2/2-way valves.
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
2015-01-1591
Zhe Zhang, Yingchao Zhang, Jie Li
Vehicle stability under steady or transient crosswind gusts is an important parameter for vehicle design for stability. Experienced drivers know that the process of the truck overtakes car, the car is likely to be sucked into the truck, which is due to the role of strong crosswind gust generated during overtaking. In the role of the environment of the wind, the trajectory of the vehicles driving on the highway or bridge may be changed which even lead to accidents. Therefore, it is very important to be able to evaluate the handling and stability of vehicles under the condition of direction changes and discontinuous crosswind gusts, which is an important aspect of the active safety level. In order to achieve a quantitative criterion for rating the crosswind sensitivity of vehicles in above-mentioned condition, different kinds of methods are applied.
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
2015-01-1495
Qiushi Wang, Shenjin Zhu, Yuping He
Articulated heavy vehicles (AHVs) exhibit poor directional performance that is attributed to the high accident rate of these vehicles. Many control strategies have been proposed to increase the safety of AHVs. Optimal controllers based on the Linear Quadratic Regulator (LQR) technique have been explored to enhance the lateral stability of AHVs; these controllers are designed under the assumption that the vehicle model parameters and operating conditions are given and they remain as constants. However, in reality, the vehicle system parameters and operating conditions may vary. For example, the payload of trailer may vary within a huge range. To address the vehicle model parametric variation issue, this paper proposes a model reference adaptive controller for active trailer steering of AHVs. The adaptive controller is designed based on a tractor-semitrailer model with three degrees of freedom; to ensure the convergence of the controller, Lyapunov theory is applied.
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
2015-01-1586
Guirong Zhuo, Jin Wang, Fengbo Zhang
The automobile driving system, of which tire is an important part, ensures the drivability handing stability and riding comfort of the vehicle. The magic formula tire model is put forward by H.B.Pacejka, which is a semi-empirical tire model. The magic formula tire model is a steady state tire model that can accurately reflect the tire characteristics. This model may fully express longitudinal force, lateral force, self-aligning torque, turning torque, rolling resistance torque and longitudinal and lateral force for combined slips mode. It has highly commonality and is the most widely used tire model in study of vehicle dynamics nowadays. Also the magic formula tire model has disadvantage. The model contains too much parameters, so that the method of parameter identification of magic formula tire model is too complex, which course an inconvenience in the engineering application.
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
2015-01-0622
H. Metered, A. Elsawaf, T. Vampola, Z. Sika
Proportional integral derivative (PID) control technique is the most common control algorithm applied in various engineering applications. Also, particle swarm optimization (PSO) is extensively applied in various optimization problems. This paper introduces an investigation into the use of a PSO algorithm to tune the PID controller for a semi-active vehicle suspension system incorporating magnetorheological (MR) damper to improve the ride comfort and vehicle stability. The proposed suspension system consists of a system controller that determine the desired damping force using a PID controller tuned using PSO, and a continuous state damper controller that estimate the command voltage that is required to track the desired damping force. The PSO technique is applied to solve the nonlinear optimization problem to find the PID controller gains by identifying the optimal problem solution through cooperation and competition among the individuals of a swarm.
2015-04-14
Technical Paper
2015-01-1502
Liangyao Yu, Wenwei Xuan, Liangxu Ma, Jian Song, Xianmin Zhu, Shuai Cheng
Energy saving is one of the most popular and significant motifs of contemporary and future vehicles. A relatively large amount of concern is concentrated on the power steering system as over 70% of the fuel consumed by conventional HPS system is unnecessary and avoidable, so the application of advance power steering systems like EPS and EHPS can help a lot on saving energy. Although the EHPS system has been widely used among passenger cars, SUV, Pickup trucks and Vans, it is now still infeasible on the conventional heavy duty vehicles because of the contradiction between the limitation of the 24V electric power system and the power demand of the electric motor of the general EHPS system. As a solution for this problem, a new type of EHPS system was investigated, which can decrease the demand of the motor power significantly, so that it can be applied to heavy duty vehicles.
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.
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