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Viewing 31 to 60 of 10186
2015-04-14
Journal Article
2015-01-1566
Youngil Koh, Kyongsu Yi, Kilsoo Kim
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
2015-01-1565
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
2015-01-1574
Tao Sun, Yuping He
The phase-plane approach is a powerful tool for analyzing yaw stability of single-unit vehicles. Articulated vehicles, such as car-trailer combinations, consist of multiple vehicle units. Multi-unit vehicles exhibit unique dynamic features compared against single-unit vehicles. For example, a car-trailer may experience one of the three unstable motion modes, i.e., jack-knifing, trailer sway and rollover. Considering the distinguished configurations and dynamic features of articulated vehicles, it is questionable whether the phase-plane approach is applicable to the analysis of the lateral stability of the multi-unit vehicles. In order to address the problem, case studies are conducted to test the effectiveness of the application of the phase-plane to the analysis of the lateral stability of a car-trailer combination with and without an active trailer differential braking (ATDB) system.
2015-04-14
Journal Article
2015-01-1568
Hyundong Heo, Eunhyek Joa, Kyongsu Yi, Kilsoo Kim
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. At first, the maximum velocity is described based on vehicle dynamics and tire characteristics. Next, an analysis of the wheel slip angle is studied to enhance the vehicle lateral stability in high speed. 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.
2015-04-14
Journal Article
2015-01-1585
Zubin Trivedi, Vivek Lakhera
The design of a vehicle must almost always consider the role of its handling in the product identity. In case of passenger vehicles especially, the design priority is how the dynamics behavior shall be perceived by the driver as well as the passengers. One of such many handling parameters is the vehicle roll, i.e. its rotation about the X axis as per VCS, which is usually quantified by the vehicle’s steady state roll gradient. This number gives an indication of the rotation of the vehicle body in response to a lateral force, as in the case while cornering, and is a standard accepted metric for vehicle roll behavior. However it does not necessarily indicate the roll as sensed by a person seated inside it, driver or passenger. It is often observed that a person seated inside a vehicle with a higher roll gradient may in some cases feel significantly lesser roll motion and have a more secure feel, than the same in some other vehicle with a lower roll gradient; and vice versa.
2015-04-14
Journal Article
2015-01-1580
He Dengbo, Lu Hui, Yu Fan
In this paper, a vehicle chassis integrated control system is designed to improve vehicle stability by wheel torque control and steering wheel control, i.e. allocating desired yaw moment and lateral force to slip ratio of four wheels and also applying additional steering angle. In the designed system, a model predictive controller (MPC), a robust optimal allocation algorithm and a sliding-mode controller are respectively designed to overcome the uncertainty and nonlinearity of tire-road contacts. The controller system includes three levels: 1) In high level, by using designed MPC controller in which a linear time-varying model is used as the inner model, the desired yaw rate and lateral force are calculated based on a bicycle model and driver steering input.
2015-04-14
Journal Article
2015-01-1755
Atsushi Hirano
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.
2015-04-14
Technical Paper
2015-01-0689
R. Rajendran, G. Ramanjaneyulu, T R Tamilarasan, Vladimir I. Semenov
Cryogenic treatment has a good potential to significantly increase the service life of automotive components, where friction and wear are the major factors in their operation leading to failure. Cryogenic treatment changes the surface as well as the core properties of the component in comparison with other treatments. It has significant improvement in dimensional stability, wear resistance and toughness. Numerous studies have been conducted on cryogenic treatment of steels and tool steels showing significant improvements in wear resistance, only minimal work has been done in cast irons. In this study the effects of cryogenic treatment on the wear resistance, hardness, tensile strength, toughness and microstructure of spheroidal graphite iron was assessed. The deep cryogenic treatment was carried out at 87 K for 12h and annealed in the chamber itself. The samples were then tempered at 473 k for 1 h.
2015-04-14
Journal Article
2015-01-1564
Joshua L. Every, Dennis A. Guenther, Gary J. Heydinger
Typically, when one thinks of advanced driver assistance systems (ADAS), systems such as Forward Collision Warning (FCW) and Collision Imminent Braking (CIB) come to mind. In these systems driver assistance is provided based on knowledge about the subject vehicle and surrounding objects. A new class of these systems is being implemented. These systems not only use information on the surrounding objects but also use information on the driver's response to an event, to determine if intervention is necessary. As a result of this trend, an advanced level of understanding of driver braking behavior is necessary. This paper presents an alternate method of analyzing driver braking behavior. This method uses a frequency content based approach to study driver braking and allows for the extraction of significantly more data from driver profiles than traditionally would have been done.
2015-04-14
Journal Article
2015-01-1567
Scott Bradley Zagorski, Tomoya Ushimura, James Post
Many vehicle dynamics handling simulations have utilized a constant speed two degree-of-freedom bicycle model. To add greater fidelity, a third (roll) degree-of-freedom has been included. The input to this model is typically road wheel angle. However, in an actual vehicle, the driver’s input is handwheel angle. Usually, to relate the two a simple kinematic relationship, on-center steering ratio, is used; however, the system dynamics of the steering system have considerable influence on overall vehicle response. By considering the chassis and steering system at an early stage of development then the interaction of the two can be characterized. Power steering system models are typically hydraulic-based power steering (HPS); however, contemporary power steering systems are predominantly electric-based (EPS). This research develops an EPS model which includes a three degree-of-freedom (DOF) steering model coupled with a three degree-of-freedom vehicle model and EPS maps.
2015-04-14
Technical Paper
2015-01-1572
L. Daniel 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
Journal Article
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
2015-01-1573
Guirong Zhuo, Hui Shen, Shenchen Wu, Yilin Ren
In order to regulate the hydraulic braking force accurately and independently by controlling high speed on-off valves (HSV), parameterized finite element models of HSV are established based on the measured ABS hydraulic actuator unit (HCU) parameters and its transient electromagnetic characteristics are analyzed by the ANSYS software. During the process, an ABS HCU developed by TRW Inc is dismantled and interrelated parameters are acquired to build an HSV CAD model, which mainly consists of drive circuit, electromagnet and mechanical-hydraulic module. Next, 12V voltage is selected as step loading and the 2D transient electromagnetic fields are analyzed. The inductance L is acquired, together with the ampere turns Ni of the solenoid and the electromagnetic force F of the valve core, which is dealt into F-x-Ni and L-x-Ni 3D data sheets. In the end, an accurate physical model of HSV is accomplished by the AMESim software.
2015-04-14
Journal Article
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
2015-01-1586
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
Journal Article
2015-01-1597
Kazuto Yokoyama, Masahiro Iezawa, Hideyuki Tanaka, Keiichi Enoki
Mitsubishi Electric has developed a concept car “EMIRAI 2 xEV” that features an electric vehicle (EV) powertrain for safe, comfortable, and eco-friendly driving experiences in the future. The body of vehicle was exhibited during Tokyo Motor Show 2013 for the first time. xEV is a four-wheel-drive EV that has three motors: a water-cooled front motor and two air-cooled rear motors with integrated inverters. 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 built-in step down DC/DC converter, an EV control unit, a battery management unit, and an electric power steering. All of the instruments are developed in Mitsubishi Electric Corporation. Motion control systems for xEV have been developed on the basis of our proprietary original motor control technology.
2015-04-14
Journal Article
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
Journal Article
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
2015-01-1578
Kaoru Kusaka, Nobuyuki Nagayama
Tire is one of the most important parts of vehicle chassis which characterizes chassis performance greatly and affects wide range of vehicle performances and qualities such as handling response and directional stability, braking distance, ride comfort, noise and vibration, fuel consumption and so on because all the movement of vehicle is raised by forces and moments from tires. And tire is also one of the largest chassis components which influences overall vehicle layout like wheel base or track width. Therefore the basic specification of the tire should be properly determined so that that size of the tire can satisfy the needs for vehicle performance better with smaller resources. In the field of the vehicle development, computer simulations plays more important role on vehicle performance improvement so that the vehicle design can satisfy the rapidly changing demand of the customers by shorter period of product development.
2015-04-14
Journal Article
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
2015-01-1582
Jiawang Yong, Feng Gao, Nenggen Ding, 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
2015-01-0316
Kazuto Yokoyama, Masahiro Iezawa, Yohei Akashi, Toshihide Satake, Yukiyasu Akemi, Satoru Inoue, Ryotaro Suzuki
Parking assist systems which relieve burden of drivers have been put into practice in the world. Mitsubishi Electric has also been developing several technologies to achieve the system. Peripheral environment around the car in a parking lot is detected with Mitsubishi Electric’s ultrasonic sensors, and an algorithm makes a map of the environment to determine whether or not the car can park at an available space. On the basis of the created map, a smooth and efficient path to drive and park the car is generated with an optimization technique. While the car is moving to the available space, the position and attitude of the vehicle is estimated from wheel speed sensors and yaw rate one. Steering is automatically controlled with a Mitsubishi Electric’s electric power steering system. In particular, this paper focuses on a speed control which can be applied to an automatic driving control including an automatic parking system.
2015-04-14
Technical Paper
2015-01-0634
Adebola Ogunoiki, Oluremi Olatunbosun
This paper presents a statistical characterisation of the effects of variations in vehicle parameters using a quarter vehicle model as a case study. A quarter vehicle model of a commercial sport utility vehicle (SUV) is created in a multi-body dynamics simulation environment to reproduce the real-life behaviour of the SUV. The model is validated by correlating the data collected from both the model and laboratory test rig to the same road input. In order to ensure that only the effects of the variation of the vehicle parameters are captured, a time domain drive signal for a kerb strike on the on the physical vehicle is generated from the proving ground data collected during durability testing of the vehicle.
2015-04-14
Technical Paper
2015-01-0637
Mohammed K Billal, Guilherme Carneiro, Renan Ozelo, Makarand Kulkarni
During the service life, the impacts of vehicle against potholes result in damage for the wheel and suspension components. Knowing the internal forces generated in the suspension components during this event would helpful to design the critical components. Measurement of these loads in physical test is more costly and not feasible for new designs. There are several virtual tools and methods available to predict the loads during this event. Using the ABAQUS FE solver, the non-linear dynamic behavior could be captured accurately during the impact. The tire model plays an important role during this event by absorbing energy during the impact. The CAE tire model is validated with some physical tests results and it is used in the vehicle pothole impact simulation. In vehicle pothole physical test, the force and acceleration measurement are taken and compared with the CAE results. The effect of the tire pressure variations and the vehicle speed at pothole impact is also studied.
2015-04-14
Technical Paper
2015-01-0646
Jian Ou, Qing-lin Zhang, Yong Zhang, E-chuan Yang, Mei-zhi Liu
[Abstract] Vehicle transient response characteristics under steering angle input are very important to vehicle handling stability. It is of important significance to study the vehicle transient response by multi-body dynamics simulation. Be aimed at the delay of transient response under steering angle input, which gets from the tests for a new vehicle development under high speed during conditions, the following research works are carried out in this paper. (1) The lag time of transient response under steering angle input is too long for a new vehicle in its tests. And the subjective reaction of operators shows that the lag time increase obviously under high speed during conditions. Aiming at this problem, the feasibility of simulation and optimization using multi-body dynamics method is studied theoretically in this paper. (2) Based on the theory of multi-body dynamics, combining the finite element methods, a rigid -flexible coupling vehicle model is established in ADAMS/Car.
2015-04-14
Technical Paper
2015-01-0652
Hui Hua, Lifu Wang, Hengmin Qi, Jie Zhang, Nong Zhang
Air spring due to its superior ride comfort performance has been widely used in distance passenger transporting vehicles. Since the requirements for ride comfort and handling performance are contradict to each other, handling performance and even roll stability are sacrificed to some extent to obtain good ride comfort. Due to the complex terrain and limited manufacturing level, in the past several years, bus rollover accidents with serious casualties have been reported frequently and bus safety has attracted more and more attention from bus manufacturers in China. On one hand the bus standards have to be raised, and on the other hand, novel solutions which can effectively improve the roll stability of air spring bus are needed to replace the inadequate of anti-roll bars.
2015-04-14
Technical Paper
2015-01-0657
Binglu Tu, Kai Shen
This innovation is a Developed Anti-Lock Brake System (DABS for short) to automatically and precisely identify, correct and verify the peak-value slip ratio S0'' (i.e. braking force = adhesion force) when ε (namely the utilization ratio of adhesion coefficient, which is defined as the quotient of maximum braking strength divided by adhesion coefficient when ABS works) =1, and control S0'' to output continuously. It is a revision on the theory, method and algorithm of current ABS control that intermittently produces S0''. The objects are to eliminate the hidden unsafety of sideslip or ε<1 due to excessive or insufficient braking force, have more simplified structure and reduced costs than ABS, and improve the eligibility from ε≥0.75 to ε≥0.95.
2015-04-14
Technical Paper
2015-01-0654
Bing Zhu, Jiapeng Gong, Jian Zhao, Jian Wu, Weiwen Deng
The permanent-magnet DC motor, which directly connected to the hydraulic pump, is a significant component of hydraulic control unit (HCU) in an anti-lock braking system (ABS). It drives the pump to dump the brake fluid from the low-pressure accumulator back to master cylinder and make sure the pressure decrease of wheel cylinder in ABS control. Obviously, the motor should run fast enough to provide sufficient power and prevent the low-pressure accumulator from fully charging. However, the pump don’t need always run at full speed for the consideration of energy conservation and noise reduction. Therefore, it is necessary to accurately regulate the speed of the DC motor in order to improve quality of ABS control. In this paper, a DC motor model was established using Matlab/Simulink software at first. Then the ABS hydraulic brake system model was present in AMESim.
2015-04-14
Technical Paper
2015-01-0658
Min Zhou, Lifu Wang, Jie Zhang, Nong Zhang
Hydraulic suspensions with different interconnecting configurations can decouple suspension mode and improve performance of a particular mode. In this paper, two types of interconnected suspensions are compared for off-road vehicle trafficability. Traditionally, anti-roll bar, a mechanically interconnected suspension system, connecting left and right suspension, decouples roll mode from the bounce mode and results in a stiff roll mode and a soft bounce mode, which is desired. However, anti-roll bars fail to connect the front wheel motions with the rear’s, thus the wheels’ motions in the warp mode are affected by anti-roll bars and it results an undesired stiffened warp mode. A stiffened warp mode limits the wheel-ground contact and may cause one wheel lift up especially during off-road drive. In contrast to anti-roll bars, two types of hydraulic suspensions which interconnect four wheels (for two-axis vehicles) can further decouple warp mode from other modes.
2015-04-14
Technical Paper
2015-01-1405
Guanjun Zhang, Feng Yu, Zhigao OuYang, Huiqin Chen, Zhonghao Bai, Libo Cao
Abstract: The combination of passive and active vehicle safety technology can effectively improve vehicle safety. Most of them predict vehicle crashes using radar or video, but it can’t be applied extensively currently due to high cost. Another collision forecasting method is more economic which base on driver behavior and vehicle status, such as acceleration, angular velocity of the brake pedal and so on. But acceleration and angular velocity of the brake pedal will change with drive and vehicle change. In order to study the effect of different drives and vehicle types on braking acceleration and angular velocity of the brake pedal, six volunteers were asked to drive five vehicles for simulating the working conditions of emergency braking, normal braking, inching braking and passing barricades under different velocities. All the tests were conducted on asphalt road, and comprehensive experimental design was used to arrange test content.
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