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Viewing 241 to 270 of 10325
2015-04-14
Journal Article
2015-01-0623
Jiaquan Chen, Min Qin, Yongfeng Jiang, Lingge Jin, Yin-Ping Chang
Abstract A twist beam rear suspension system is modeled, analyzed and optimized in this paper. An ADAMS model is established based on the REC (Rigid-Elastic Coupling) Theory, which is verified by FEM (Finite Element Method) approach, the effects of the geometric parameters on the twist beam suspension performance are investigated. In order to increase the calculation efficiency and improve the simulation accuracy, a neural network model and NSGA II (Non-dominated Sorting Genetic Algorithm II) are adopted to conduct a multi-objective optimization on a twist beam rear suspension system.
2015-04-14
Journal Article
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
Journal Article
2015-01-1566
Youngil Koh, Kyongsu Yi, Kilsoo Kim
Abstract This paper presents a tire slip-angle based speed control race driver model. In developing a chassis control system for enhancement of high-speed driving performance, analysis of the vehicle-driver interaction at limit handling is one of the main research issues. Thus, a driver model which represents driving characteristics in a racing situation is required to develop a chassis control system. Since a race driver drives a vehicle as fast as possible on a given racing line without losing control, the proposed driver model is developed to ensure a lateral stability. In racing situation, one of the reasons which cause the lateral instabilities is an excessive corner-entry speed. The lateral instability in that moment is hard to handle with only a steering control. To guarantee the lateral stability of the vehicle while maximizing a cornering speed, a desired speed is determined to retain a tire slip-angle that maximizes lateral tire forces without front tire saturation.
2015-04-14
Journal Article
2015-01-1568
Hyundong Heo, Eunhyek Joa, Kyongsu Yi, Kilsoo Kim
Abstract This paper describes an Integrated Chassis Control (ICC) strategy for improving high speed cornering performance by integration of Electronics Stability Control (ESC), Four Wheel Drive (4WD), and Active Roll Control System (ARS). In this study, an analysis of various chassis modules was conducted to prove the control strategies at the limits of handling. The analysis is focused to maximize the longitudinal velocity for minimum lap time and ensure the vehicle lateral stability in cornering. The proposed Integrated Chassis Control algorithm consists of a supervisor, vehicle motion control algorithms, and a coordinator. The supervisor monitors the vehicle status and determines desired vehicle motions such as a desired yaw rate, longitudinal acceleration and desired roll motion. The target longitudinal acceleration is determined based on the driver's intention and vehicle current state to ensure the vehicle lateral stability in high speed maneuvering.
2015-04-14
Journal Article
2015-01-1567
Scott Bradley Zagorski, Tomoya Ushimura, James Post
Abstract In this research, a three degree-of-freedom (DOF) rack-type electric-based power steering (EPS) model is developed. The model is coupled with a three DOF vehicle model and includes EPS maps as well as non-linear attributes such as vibration and friction characteristics of the steering system. The model is simulated using Matlab's Simulink. The vibration levels are quantified using on-vehicle straight-line test data where strain-gauge transducers are placed in the tie-rod ends. Full vehicle kinematic and compliance tests are used to verify the total steering system stiffness levels. Frequency response tests are used to adjust tire cornering stiffness levels as well as the tire dynamic characteristics such that vehicle static gain and yaw natural frequency are achieved. On-center discrete sinusoidal on-vehicle tests are used to further validate the model.
2015-04-14
Journal Article
2015-01-1570
Daniel Vilela, Rubens Pinati, Scott Larsen, Erick Rodrigues, Renato Serrati
Abstract This study presents the comparison of vehicle handling performance results obtained using physical test tire data and a tire model 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
Journal Article
2015-01-1579
Jun Nakahara, Koji Yamazaki, Yusuke Otaki
Abstract In many cars, ride is less comfortable on smooth roads. This is because when the hysteresis in the suspension components rises steeply, the increase of the equivalent spring constant at small amplitude deteriorates the vibration isolation of the suspension. Therefore suspension components should be designed to prevent a steep rises in hysteresis. Investigating the influence of hysteresis, component models, which can reproduce such hysteresis characteristics, should be installed with model parameters in the vehicle model. Using conventional methods, these parameters can be accurately identified if measurement data is provided; however, it is difficult at the earlier phase of vehicle development. Then, if conflicting performances, such as ride and handling, are to be improved, both should be considered concurrently as early in a phase of vehicle development as possible and the design specifications for suspension components should be determined to satisfy both performances.
2015-04-14
Journal Article
2015-01-1580
He Dengbo, Lu Hui, Yu Fan
Abstract The vehicle chassis integrated control system can improve the stability of vehicles under extreme conditions using tire force allocation algorithm, in which, the nonlinearity and uncertainty of tire-road contact condition need to be taken into consideration. Thus, An MPC (Model Predictive Control) controller is designed to obtain the additional steering angle and the additional yaw moment. By using a robust optimal allocation algorithm, the additional yaw moment is allocated to the slip ratios of four wheels. An SMC (Sliding-Mode Control) controller is designed to maintain the desired slip ratio of each wheel. Finally, the control performance is verified in MATLAB-CarSim co-simulation environment with open-loop manoeuvers.
2015-04-14
Journal Article
2015-01-1584
Daniel E. Williams
Abstract 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. A rear axle steer control law is found to be a function of front axle steering input and vehicle speed that exhibits high speed stability and improved low speed 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
Journal Article
2015-01-1589
Michael W. Neal, Walter Cwycyshyn, Ibrahim Badiru
Abstract 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
Journal Article
2015-01-1594
Johannes Edelmann, Massimiliano Gobbi, Giampiero Mastinu, Manfred Ploechl, Giorgio Previati
Abstract The friction estimation at the tire-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 tire characteristic at a given friction (nominal characteristic) with the actual characteristic that the tire has while running. The comparison among these two characteristics (the nominal one and the actual one) gives the desired friction coefficient. The friction coefficient is expressed in vector form and a number of running parameters are identified. The mentioned comparison is an efficient but complex algorithm based on a mathematical formulation of the tire characteristic.
2015-04-14
Journal Article
2015-01-1597
Kazuto Yokoyama, Masahiro Iezawa, Hideyuki Tanaka, Keiichi Enoki
Abstract Mitsubishi Electric has developed a concept car “EMIRAI 2 xEV” that features an electric vehicle (EV) powertrain for safe, comfortable, eco-friendly driving experiences in the future. The vehicle was exhibited during the 2013 Tokyo Motor Show and the 2014 Automotive Engineering Exposition. The xEV is a four-wheel-drive EV with three motors: a water-cooled front motor and two air-cooled rear motors with integrated inverters. The rear wheels can be driven independently. The degrees of freedom of the actuation can realize improved maneuverability and safety. The vehicle is also equipped with an onboard charger with a built-in step down DC/DC converter, an EV control unit, a battery management unit, and electric power steering. All of the instruments are developed by Mitsubishi Electric. Motion control systems for the xEV have been developed based on our proprietary motor control technology.
2015-04-14
Journal Article
2015-01-1755
Atsushi Hirano
Abstract This paper studies various wheel stiffness configurations, with the aim of enhancing driving stability while minimizing the increase in weight associated with an increase in stiffness. Reinforcement was added to the wheel disk and the wheel rim of standard aluminum wheels for passenger vehicles in order to produce four wheels with different stiffness configurations. The effects of disk stiffness and rim stiffness on tire contact patch profiles and driving stability were quantitatively evaluated. From the results of tests with the four wheels, it was observed that disk stiffness and rim stiffness have differing effects on tire contact patch profiles, and on driving stability. Disk stiffness influences especially tire contact patch length, and tire contact patch length influences especially maneuverability in driving stability. Rim stiffness influences especially tire contact patch area, and tire contact patch area influences especially stability in driving stability.
2015-04-13
Article
The basic concept of the tire hasn’t changed since stone rollers used to help build the pyramids--it’s the way we make them and the design that has changed, says Ydo Doornbos of Trelleborg Wheel Systems Americas.
2015-04-10
Standard
J3081_201504
This document is written to address acceleration and deceleration control issues related to Heavy Duty Trucks and Buses greater than 10 000 GVW.
2015-04-08
WIP Standard
ARP1907C
This Aerospace Recommended Practice (ARP) covers the functional, design, construction, and test requirements for Automatic Braking Systems. Installation information and lessons learned are also included.
2015-04-07
Article
The new Spicer AdvanTEK tandem axle concept is optimized for trucks that implement engine “downspeeding,” combining the traction offered by a 6x4 configuration with the reduced drivetrain losses of a 6x2.
2015-03-30
Technical Paper
2015-01-0101
Piyapong Premvaranon, Jenwit Soparat, Apichart Teralapsuwan, Wuttipong Sritham, Chi-na Benyajati, Nathapol Taweewong
Abstract Due to recent oil price crisis and an ever-increasing public awareness on environmental issues, an interest in electric vehicles (EV) has increased tremendously in Thailand and other Asian countries over the last few years. In this study, a prototype of 9-metre battery electric vehicle (BEV) bus was chosen as a vehicle of interest to undergo a series of field test by operating the lead acid battery powered electric bus in order to estimate a power demand of the bus as well as to evaluate a battery performance characteristic Two different types of battery were employed in this study i.e. a flooded-type deep cycle lead acid battery and a valve regulated lead acid (VRLA) battery. The effect of different driving modes available from the drive motor i.e. normal, max power, max range, as well as regenerative braking feature would be investigated while an influence of drivers were also taken into account to ensure the repeatability of the obtained results.
2015-03-30
Technical Paper
2015-01-0081
Hsin Guan, Chunguang Duan, Pingping Lu, Jun Zhan, Yunting He
Abstract With the development of computer and vehicle research to high frequency, the driving simulator plays an important role on vehicle research and pre-development. The driving simulator have already been used for research about human factors, advanced active system (ABS, ESP et al), the vehicle dynamics and intelligent transportation systems (ITS) et al. The crucial requirement for a driving simulator is that it should have realistic behavior. The realistic behavior base on high-fidelity dynamics models especially tire model. “Tire/road” model is of special importance model for its influence on vehicle performances. The forces for accelerating, braking and steering are all came from tire road contact. The simulator simulation faces all possible driving scenes as driving in the real word, like parking on the hill, stop and start again, sharp steering and sharp braking et al.
2015-03-30
Technical Paper
2015-01-0082
Husain Kanchwala, Carlos Bordons
Abstract Electric vehicles (EVs) have been gaining a lot of focus and attention as they run clean and are environment friendly. EVs use in-hub motors, which can be independently controlled, improving this way the maneuverability and allowing augmented control actions. This paper discusses the development of a Model Predictive Controller (MPC) to improve vehicle handling characteristics. Wheel torques are independently controlled using direct yaw moment and side slip control method to pro-actively improve vehicle handling. At high values of side slip the steering is no more capable of generating yaw moment and vehicle becomes laterally unstable. By unequal torque distribution a restoring yaw moment is generated and vehicle stability is ensured. The MPC computes the optimal couple traction/braking torque of the four in-wheel motors, from basic driving slogans, which are, steering angle and desired speed.
2015-03-30
Technical Paper
2015-01-0090
Cherdsak Chuaymung, Chi-na Benyajati, Sutee Olarnrithinun
Abstract A vehicle of interest in this paper was a light agriculture truck. In order to obtain reliable predictions of stress generated in the frame under loads, a combination of experimental tests and computer simulations was arranged. Since the focused deformations were bending and torsion modes, the truck driven up one-wheel ramp and two-wheel ramp was investigated. Strains results obtained from both tests and simulations were compared. The discussions and conclusions were made regarding the accuracy and further improvements of the simulations.
2015-03-25
Magazine
Bringing it all together Ian Adcock catches up with GKN's newly appointed president, Group Technology, Rob Rickell. Graphene Supreme Ian Adcock discovers what role graphene is likely to play in the vehicles of tomorrow. What lies beneath? Automotive Design looks into chassis developments that are designed to ensure local preferences are catered for globally.
2015-03-23
Article
The company has expanded its additive manufacturing material capabilities to support metal 3-D printing of complex high-hardness parts and the ability to customize properties layer-by-layer through “gradient material design.”
2015-03-19
Standard
J2633_201503
This SAE lab test procedure should be used when performing the following specialized weathering tests for wheels; Florida Exposure, QUV, Xenon and Carbon Weatherometer. In addition to these procedures, some additional post-weathering tests may be specified. Please refer to customer specifications for these requirements.
2015-03-19
Standard
J2634_201503
This SAE practice is intended for the sample preparation of test pieces for automotive wheels and wheel trim. The practice provides a consistent scribing method for use on test panels and or component parts with substrate chemical pretreatment and coating systems. Test specimens can then be subjected to various corrosion tests in order to evaluate performance without significant variations of the degree of exposure of the substrate. The scribing is used to create a break in the coating/finishing as can occur in the field through gravel and other damaging conditions. Significant variability is attributed to surface contour, coating hardness/softness, operator reproducibility, and the scribing tool and it's condition.
2015-03-13
Standard
J1965_201503
This SAE Recommended Practice applies to fasteners/fixing nuts as specified in SAE J694 and SAE J1835 used for disc wheels and demountable rim attachment respectively. Only the test methods necessary to assure proper wheel or rim assembly are specified. Fasteners for less common and special applications are not included.
2015-03-11
Article
Novel aluminum-rich steel alloy could find structural use in road vehicles and even aircraft.
2015-03-10
Technical Paper
2015-01-0016
Changxin Wang, Wenku Shi, Zan Li, Fuxiang Guo
Abstract This paper presents the study of chassis tuning of a commercial vehicle, which has a rear suspension with dual stage leaf spring assembly and a front suspension with double wishbone torsion bar. To balance the handling and ride performance of the vehicle, it is necessary to tune the key suspension parameters of the chassis including the dual stage stiffness of the leaf spring, the contact load of the leaf spring, the torsional rigidity of the torsion bar, the force curve of the front and rear dampers etc. The chassis tuning process of a physical commercial vehicle was first put forward. In the proposed flowchart, the kinematics and statics of front & rear suspensions were checked at the beginning of the tuning. Then the tire mechanical characteristics were tested by using a plate-type tire tester and the inertial parameters of the vehicle were indirectly measured. The K&C characteristics of front and rear suspensions were also tested and compared with the benchmark vehicle's.
2015-03-10
Technical Paper
2015-01-0017
Yufeng Wang, Zhizhong Wang, Liangyao Yu, Jian Song
Abstract Many types of brake by wire systems have been developed in past years, such as EMB (Electro-mechanical Brake) [1, 2], DEHB (Distributed Electro-hydraulic Braking System) [3] and EWB (Electric Wedge Brake) [4]. When the vehicle need braking in long period such as waiting for traffic light or downhill braking in those brake systems, the current will sustain very long time with very high level. This current will result in high temperature in motor, and will damage the power supplier. When a new DEHB is developing, a holding function is added in this DEHB. The holding function is self-energized when holding the brake, and automatic released after the brake. Advantageously, after activation of the holding function, the current delivered to the motor for braking is substantially decreased, especially, will be zero when the brake torque is not need to adjust.
2015-03-10
Technical Paper
2015-01-0025
Jaeyong Park, Joonhong Park, JinHee Lee, Yong-Sub Yi, TeaWon Park
Abstract In the view point of driving safety, the crosswind sensitivity of a vehicle becomes more important, as the driving speed in highway gets higher in these days. The sensitivity of a vehicle to crosswind depends on many factors, including the design of the suspension and aerodynamics of the body, etc. However, the knowledge about this phenomenon has still to be improved, in order to develop vehicle with optimum characteristics for crosswind stability. In this research, the physics behind the sensitivity of a vehicle is discussed in detail through various kinds of virtual test using computer aided engineering (CAE) simulation scheme. In the first, a reliable simulation model for vehicle, driver, wind generator and interactions among them is built. This simulation model is verified by comparison with test results of real vehicle. Then, the sensitivity analysis is carried out to find out the most influential design parameters.
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