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Viewing 121 to 150 of 10218
2015-04-14
Journal Article
2015-01-0645
Jian Zhao, Jin Zhang, Bing Zhu
The longitudinal dynamics control is one of the essential tasks of vehicle dynamics control. In present, longitudinal dynamics control usually adjust the slip ratio of driving wheels by means of controlling the engine, transmission or braking pressure to achieve satisfied performances in stability and acceleration. In order to improve performance of longitudinal dynamics control, the coordination of the control of different parts in powertrain have to be considered. In addition, the proposed algorithms usually adopt the logic methods for simple and quick response based on less road condition information, which cannot achieve optimal performance on various road conditions. Focusing on these two issues, an integrated longitudinal vehicle dynamics control algorithm with tire/road friction estimation is proposed.
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
Journal Article
2015-01-0643
Dzmitry Savitski, Kristian Hoepping, Valentin Ivanov, Klaus Augsburg
Anti-lock braking system (ABS) independently from the vehicle type is aimed to realize the maximally possible deceleration level and reduce the stopping distance during the braking maneuver where wheels are tending to lock. However, for better braking performance and system adaptability ABS must consider vehicle specifications and conditions in which this vehicle is going to be used. As it is experimentally approved in the represented research tire pressure variation produces noticeable influence on tire stiffness and peak friction coefficient. As consequence such changes in tire characteristics can cause distortion of the ABS functions and the stopping distance will significantly vary. In proposed research phenomenon of tire pressure variation in relation to the ABS control functions is experimentally investigated. For this purpose developed continuous ABS control algorithm was implemented to the full-electric vehicle with four individual on-board electric motors.
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
Journal Article
2015-01-0649
Liangyao Yu, Shuhao Huo, WenWei Xuan, Lei Zuo
Conventional viscous shock absorbers, in parallel with suspension springs, passively dissipate the excitation energy from road irregularity into heat waste, to reduce the transferred vibration which causes the discomfort of passengers. In order to achieve better ride comfort and maneuverability, active suspensions have been proposed for decades. However, large energy consumption, which significantly increases the fuel consumption for conventional vehicles or battery consumption for electric vehicles, limits its widely utilization despite of better suspension performance. Considering the trade-off between the energy consumption and suspension performance, energy-harvesting shock absorbers, which have the potential of conversion of kinetic energy into electric power, have been proposed as semi-active suspension. Because of the high energy density of the rotary shock absorber, a rotational energy-harvesting shock absorber with mechanical motion rectifier (MMR) is used in this paper.
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
2015-01-0614
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
2015-01-1578
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
Technical Paper
2015-01-0607
Xincheng Liang, Jingshan Zhao
This paper proposes a theoretical model to interpret the heat generation mechanism and thermal failure of shock absorber. For a common structure of double-tube shock absorber, all frictions between two contacting components of shock absorber are calculated particularly. The heat generation mechanism and heat distribution can be explained with the theoretical model. Thermal failure is a recurrent malfunction for traditional shock absorber, which leads to shorten the service lives of vehicle components. Heat generation experiments are accomplished to validate the thermal degeneration of shock absorber. So this study is meaningful to develop a new system of vibration attenuation that is essential to improve the riding comfort and handling stability of vehicles.
2015-04-14
Technical Paper
2015-01-0608
Gang Tang, Hengjia Zhu, Yunqing Zhang, Ying Sun
The vehicle ride comfort behavior is closely associated with the vibration isolation system such as the primary suspension system, the engine mounting system, the cab suspension system and the seat suspension system. Air spring is widely used in the cab suspension system for its low vibration transmissibility, variable spring rate and inexpensive automatic leveling. The mathematical model of the pneumatic system including the air spring, the leveling valve and the pipe is presented. The frequency dependency of the air spring’s stiffness characteristic is highlighted. The air spring dynamic model is validated by comparing the results of the experiments and the simulation. The co-simulation method using ADAMS and AMESim is applied to integrate the pneumatic system into the cab multi-body dynamic model. The simulation and ride comfort test results under random excitation are compared.
2015-04-14
Technical Paper
2015-01-0627
Xiaoguang Yang, Oluremi Olatunbosun, Daniel Garcia-Pozuelo, Emmanuel Bolarinwa
The development of intelligent tyre technology from concept to application covers multi-disciplinary fields. During its development course, computational method has a significant effect on understanding tyre behaviour, assisting design of intelligent tyre prototype system and developing tyre parameters estimation algorithm, etc. In this paper, finite element tyre model was adopted for developing strain-based intelligent tyre system. The finite element tyre model was created considering tyre composite structure and nonlinear material properties, which was also validated by fundamental test. It is used to study tyre strain characteristics by steady state simulation for straight line rolling, traction and braking, and cornering rolling. Tyre loading conditions were estimated by feature extraction and data fitting. This process forms the fundamentals for identifying tyre loadings from strain information on potential sensor locations.
2015-04-14
Technical Paper
2015-01-0626
Adam C. Reid, Moustafa El-Gindy, Fredrik Oijer, David Philipps
The purpose of this research paper is to outline the methodology and procedure used for the development of a wide base rigid ring tire model. A rigid ring model is a mechanical representation of a tire model in which its in-plane and out-of-plane characteristics and behaviour can be captured. The FEA construction of the tire model is first completed to match all known information regarding the physical dimensions and material properties of the tire. For information that is unknown, an optimization-based parameter tuning algorithm is then run in order to solve for said parameters while matching any experimental data that is supplied. A series of virtual experiments are then conducted which replicate laboratory tests as well as some high speed maneuvers in order to isolate for specific tire dynamic parameters.
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
Journal Article
2015-01-0656
Amir Soltani, Francis Assadian
A new control strategy for wheel slip control, considering the complete dynamics of the electro-hydraulic brake (EHB) system, is developed and experimentally validated in Cranfield University’s HiL system. The control system is based on closed loop shaping Youla-parameterisation method. The plant model is linearized about the nominal operating point, a Youla parameter is defined for all stabilizing feedback controller and control performance is achieved by employing closed loop shaping technique. The stability and performance of the controller are investigated in frequency and time domain, and verified by experiments using real EHB smart actuator fitted into the HiL system with driver in the loop.
2015-04-14
Journal Article
2015-01-0655
Francesco Calabrese, Manfred Baecker, Carlos Galbally, Axel Gallrein
Current state-of-the-art tire models may show a certain lack of accuracy in some advanced handling applications. This lack of accuracy is partly due to thermal effects. In reality, the tire rubber temperature can dramatically increase under certain conditions. The tire friction coefficient strongly depends on the temperature level. As a direct consequence of the temperature variations, the tire’s handling performance changes, e.g. when the temperature significantly differs from its optimal value, the tire’s grip level declines. As a result, the vehicle’s longitudinal and lateral behavior is influenced. This paper shows that in order to increase the reliability of the tire models also in the described extreme conditions, it is necessary to couple a thermo-dynamical model with a mechanical one. The thermal model is important to estimate the temperature propagation inside the tire structure and the temperature evolution over time.
2015-04-14
Journal Article
2015-01-0314
Junyung Lee, Beomjun Kim, Jongsang Seo, Kyongsu Yi, Jihyun Yoon, Bongchul Ko
Abstract This paper presents an automated driving control algorithm for the control of an autonomous vehicle. In order to develop a highly automated driving control algorithm, one of the research issues is to determine a safe driving envelope with the consideration of probable risks. While human drivers maneuver the vehicle, they determine appropriate steering angle and acceleration based on the predictable trajectories of the surrounding vehicles. Therefore, not only current states of surrounding vehicles but also predictable behaviors of that should be considered in determining a safe driving envelope. Then, in order to guarantee safety to the possible change of traffic situation surrounding the subject vehicle during a finite time-horizon, the safe driving envelope over a finite prediction horizon is defined in consideration of probabilistic prediction of future positions of surrounding vehicles.
2015-04-14
Journal Article
2015-01-0518
Hirokuni Fuchigami
Abstract In this research, a new wire material made using surface-reforming heat treatment was developed in order to enhance the corrosion fatigue resistance of suspension springs. The aim of surface reforming is to improve hydrogen embrittlement characteristics through grain refinement and to improve crack propagation resistance by partial softening of hardness. The grain refinement method used an α'→γ reversed transformation by rapid short-term heating in repeated induction heating and quenching (R-IHQ) to refine the crystal grain size of SAE 9254 steel spring wire to 4 μm or less. In order to simultaneously improve the fatigue crack propagation characteristics, the possibility of reducing the hardness immediately below the spring surface layer was also examined. By applying contour hardening in the second IHQ cycle, a heat affected zone (HAZ) is obtained immediately below the surface.
2015-04-14
Journal Article
2015-01-0489
Jason Rogers
Abstract A 3D-and-Excel-based predictive tool was developed to determine trunk spring movement for preventing recurrence of a noise problem. While effective, the tool could not completely explain measured results on the completed body unit (CBU). Since design data is used as the input, it was hypothesized that the difference between predicted and actual results was related to tolerance variation on the actual vehicle. Using Siemens® Variation Analysis software, the CBU was built and simulated virtually with tolerances using a Monte Carlo model. The study found that the hypothesis was correct; tolerance variation was fully responsible for the differences. In addition, the study also allowed accurate prediction of failure rates.
2015-04-14
Journal Article
2015-01-0642
Per Hyldahl, Sebastian Andersen, Sebastian Mikkelsen, Ole Balling
Abstract This study concerns the modeling of the stabilizer bar in a car suspension. This is a crucial and difficult task if its non-linear behavior should be captured correctly. In this study, the modeling of a stabilizer bar is done using beam finite elements based on the absolute nodal coordinate formulation (ANCF). An ANCF beam element is reviewed and its implementation in a multibody dynamics framework is explained. The specific element is chosen since it is assumed to be appropriate for modeling stabilizer bars. To test the feasibility of using the chosen ANCF beam element for modeling stabilizer bars, several numerical studies have been performed. These include eigenfrequency and static analyzes where results obtained using ANCF beam elements are compared with results obtained using other methods.
2015-04-14
Journal Article
2015-01-0622
H. Metered, A. Elsawaf, T. Vampola, Z. Sika
Abstract 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
Journal Article
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
Journal Article
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
Journal Article
2015-01-0667
Kei Ichikawa
Abstract Cabin quietness is one of the important factors for product marketability. In particular, the importance of reducing road noise is increasing in recent years. Methods that reduce acoustic sensitivity as well as those that reduce the force transferred from the suspension to the body (the suspension transfer force) are used as means of reducing road noise. Reduction of the compliance of the body suspension mounting points has been widely used as a method of reducing acoustic sensitivity. However, there were cases where even though this method reduced acoustic sensitivity, road noise did not decrease. This mechanism remained unclear. This study focused on the suspension transfer force and analyzed this mechanism of change using the transfer function synthesis method. The results showed that the balance between the body's suspension mounting points, suspension bush, and suspension arm-tip compliance is an important factor influencing the change in suspension transfer force.
2015-04-14
Journal Article
2015-01-1309
Hyunggyung Kim
This paper describes about the development of new concept’s rear wheel guards for the reduction of Road Noise in the passenger vehicle using test. The new wheel guards are proposed by various frequency chamber concept and different textile layers concept. Two wheel guards were verified by small cabin resonance test and vehicle test. Through new developing process without vehicle test, Result of road noise will be expected when new concepts and materials of wheel guard is applied into automotive vehicle. As this concept consider tire radiation noise frequency and multilayers sound control multilayers, 2 concepts reduced road noise from 0.5 to 1.0 dB The suggested Estimation method of part reverberant absorption method is similar to result of vehicle tests by part absorption index. Furthermore, optimization of frequency band to wheel guards will reduce more 0.5 dB noises in vehicle.
2015-04-14
Journal Article
2015-01-1511
Srikanth Sivaramakrishnan, Kanwar Bharat Singh, Peter Lee
Anti-lock Braking System (ABS) is a critical safety component and its performance is crucial for every vehicle manufacturer. The tire plays an important role during an ABS braking maneuver as it is the component that connects the vehicle to the ground and is responsible for generating braking force. The steady-state and transient properties of the tire affect the operation of the vehicle’s ABS system. The main objective of this study is to investigate how tire design changes influence its interaction with the ABS and its eventual effect on stopping distance. This was conducted through an experimental study where tires were built with three levels of variation in carcass stiffness, tread stiffness and tread compound. Following this, ABS braking maneuvers were performed on instrumented vehicles with regular ABS and high-performance ABS using these tires on all four wheels.
2015-04-14
Journal Article
2015-01-1521
Kanwar Bharat Singh, Srikanth Sivaramakrishnan
Tread depth, inflation pressure, tire temperature, and road surface condition are among the most notable factors that have a noticeable effect on the tire force and moment characteristics. They can vary significantly during the operation of a tire and can effectively modify tire (and thus vehicle) performance. This study presents details of an adaptive magic formula (MF) tire model capable of coping with changes to the tire operating condition. More specifically, extensions have been made to the magic formula expressions for tire cornering stiffness and peak grip level, to account for variations in the tire inflation pressure, load, tread-depth and temperature. As a next step, the benefits of using an adaptive tire model for vehicle control system applications is demonstrated through simulation studies for enhanced vehicle control systems using an adaptive tire model in comparison to traditional control systems based on a non-adaptive tire model with fixed model parameters.
2015-04-14
Journal Article
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
Journal Article
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
Journal Article
2015-01-1556
Mark E. Gleason, Bradley Duncan, Joel Walter, Arturo Guzman, Young-Chang Cho
Abstract One of the remaining challenges in the simulation of the aerodynamics of ground vehicles is the modeling of the airflows around the spinning tires and wheels of the vehicle. As in most advances in the development of simulation capabilities, it is the lack of appropriately detailed and accurate experimental data with which to correlate that holds back the advance of the technology. The flow around the wheels and tires and their interfaces with the vehicle body and the ground is a critical area for the development of automobiles and trucks, not just for aerodynamic forces and moments, and their result on fuel economy and vehicle handling and performance, but also for the airflows and pressures that affect brake cooling, engine cooling airflows, water spray management etc.
2015-04-14
Journal Article
2015-01-1554
Bastian Schnepf, Thomas Schütz, Thomas Indinger
Abstract Efforts in aerodynamic optimization of road vehicles have been steadily increasing in recent years, mainly focusing on the reduction of aerodynamic drag. Of a car's total drag, wheels and wheel houses account for approx. 25 percent. Consequently, the flow around automotive wheels has lately been investigated intensively. Previously, the authors studied a treaded, deformable, isolated full-scale tire rotating in contact with the ground in the wind tunnel and using the Lattice-Boltzmann solver Exa PowerFLOW. It was shown that applying a common numerical setup, with velocity boundary condition prescribed on the tread, significant errors were introduced in the simulation. The contact patch separation was exaggerated and the flow field from wind tunnel measurements could not be reproduced. This investigation carries on the work by examining sensitivities and new approaches in the setup.
Viewing 121 to 150 of 10218

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