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Viewing 1 to 30 of 7853
2016-04-15
Journal Article
2015-01-9020
Emre Sert, Pinar Boyraz
Abstract Studies have shown that the number of road accidents caused by rollover both in Europe and in Turkey is increasing [1]. Therefore, rollover related accidents became the new target of the studies in the field of vehicle dynamics research aiming for both active and passive safety systems. This paper presents a method for optimizing the rear suspension geometry using design of experiment and multibody simulation in order to reduce the risk of rollover. One of the major differences of this study from previous work is that it includes statistical Taguchi method in order to increase the safety margin. Other difference of this study from literature is that it includes all design tools such as model validation, optimization and full vehicle handling and ride comfort tests. Rollover angle of the vehicle was selected as the cost function in the optimization algorithm that also contains roll stiffness and height of the roll center.
2016-04-05
Technical Paper
2016-01-0447
Manfred Baecker, Axel Gallrein, Francesco Calabrese, Remco Mansvelders
A sudden pressure loss can lead to an instability of the car. This instability can lead - without aid of systems such as e.g. Electronic Stability Control (ESC) - to an emergency situation, possibly resulting in an accident. But also with an ESC system such a situation is an unusual application case, because the vehicle system (car+tires) properties change very rapidly, resulting in a highly dynamic response of the system and moreover to a fuzzy and unclear description of the vehicle system. From this point of view, a proper validation and verification of an ESC system for such an application seems to have a big safety relevance. The authors have set up a simulation case to simulate a sudden tire inflation pressure loss and its consequences to the car stability. Using this simulation setup enables a CAE engineer to pre-develop ESC systems and/or to validate and test these systems for a realistic and relevant use case.
2016-04-05
Technical Paper
2016-01-1570
Xin Gao
When heavy truck is traveling in high speed or braking urgently, the tire will produce heat due to the friction with ground and absorb heat from high-heat environment to rise the inside pressure, which may run the risk of a flat tire. To make sure the characters of tire, it’s inadequacy to transform tire property as the point of departure. Based on the way of enhanced heat transfer, the tire pressure control system designed by this article is mainly increasing heat loss through convection. Using air flow direction around tire during driving and combining the deflector set on wheel hub retards air flow around tire. So tire temperature is reduced by means of heat exchanged fully.Firstly, theoretical calculation on pressure characteristic inside tire is carried out. Combining upwind flow field by using relevant software, Simulation analysis on tire pressure is done. According to the results of simulation and theoretical calculation, confirmatory experiments are designed.
2016-04-05
Technical Paper
2016-01-0437
Bin Tang
In order to ensure that coach drivers have good manipulation and road feeling at different speeds, variable assist characteristic of electronically controlled hydraulic power steering system (ECHPS) in a coach was designed based on drivers’ preferred steering torque. Two degrees of freedom vehicle model, steering system model and model of steering resistance moment were established for following simulation. The design method of assist characteristic was proposed. Feature points of assist characteristic curves were calculated via coach drivers’ preferred steering torque and steering resistance moment at different speeds by means of simulation. For realization of the variable assist characteristic, the optimization model of rotary valve parameters was put forward, with the minimum of quadratic sum of the difference between assisted oil pressure under characteristic speed and characterized assisted oil pressure defined as objective function.
2016-04-05
Technical Paper
2016-01-0442
Xing Xu, Zou Nannan
Interconnected air suspension system can change vehicle’s operation characteristics by exchanging gas of air springs. In this paper, we analyze the structure and working principle of interconnected air suspension based on thermodynamics and vehicle dynamics. Then air suspension’s mathematical model including interconnected characteristics is established to study gas exchange principle of air suspension system. Interconnected pipeline parameters and excitation phase differences’ influence on characteristics of air suspension system in whole vehicle are calculated and analyzed. Simulation results show that the stiffness of air suspension is reduced when air springs of suspension system interconnected, as well as it decreases gradually with the increase of interconnected pipeline diameter; the stiffness of air springs is minimum if the excitation phase difference of both sides of air springs is 180 degree.
2016-04-05
Technical Paper
2016-01-1566
Liangyao Yu, Xiaoxue Liu, Kefeng Yang, Xiaohui Liu, Shuhao Huo
This paper focuses on reviewing the existing studies of in-tire energy harvesting systems. Energy harvesting systems are widely applied in different areas. But studies in the application of energy harvesters embedded in tires for vehicle control are still rare, most of which focus on solving the problem of power supply of tire pressure sensors. Traditionally the sensors are powered by an embedded battery, which must be changed periodically due to the limited energy storage. Furthermore, the number of in-tire sensors will increase as safety of vehicles has drawn more attention, requiring more in tire electricity supply. So a substitution of the battery, the in-tire energy harvesting system, is worth studying. Currently introduced methods of in-tire energy harvesting principles include piezoelectric, electromagnetic and electrostatic. The source of the energy can be in tire vibration, deformation, rotation and so on.
2016-04-05
Technical Paper
2016-01-0431
Guangqiang Wu, Huwei WU, Xiang Chen
During the process of vehicle creeping, severe vibro-impacts of unloaded or lightly loaded gear pairs in a manual transmission may occur in the powertrain system due to some nonlinear characteristics. Multi-staged stiffness clutch damper, as a main nonlinear component, could have a great influence on powertrain system torsional vibration performance. So a mass-production passenger sedan is taken as the research subject and the nonlinear characteristics impact of multi-staged stiffness clutch damper for vehicle creeping vibration is investigated by using lumped-parameter modeling method. Firstly, a quasi-transient model of an inline four-cylinder and four-stroke engine, based on measured data of cylinder gas pressure versus crankshaft angle, is derived. Effective output torque is achieved and as the input excitation to the driveline. Secondly, a 12 DOFs (Degrees of Freedom) nonlinear and branched torsional vibration model is established.
2016-04-05
Technical Paper
2016-01-1573
Ken Archibald, Kyle Archibald, Donald Neubauer
This paper will document a rationale for wheel straightening based on the rise of declining roads, increased use of lower profile tires, unintended consequences of wheel customization and the reduction in energy consumption. A recommended procedure detailing how A356-T6 wheels can be straightened will be presented. To validate the recommended procedure a sample of wheels was uniformly deformed and straightened and subsequently tested per SAE J328 and SAE J175. Test results are provided that indicate straightened wheels should be fully serviceable in their intended service.
2016-04-05
Technical Paper
2016-01-1063
George Nerubenko
Up to 30% of engine noise is delivered by front end pulley combined with torsional vibration damper, and technically it is the main contributor to recorded engine noise level. So the novel solutions in terms of improving the design and performance of torsional vibration damper would help to reduce radically this component of engine noise. The results of dynamical study of patented torsional vibration damper combined with pulley are presented. Design and structure of torsional vibration damper is based on author’s US Patent 7,438,165 having the self-tuning control system for all frequencies in running engine in all operational regimes. Mathematical model has been used for the analysis of the emitting noise of engine having proposed torsional vibration damper. Attention is paid to mitigation of the sound power levels contributing by engine subsystem “end of crankshaft - torsional vibration damper – pulley”.
2016-04-05
Technical Paper
2016-01-1451
Mingyang Chen, Xichan Zhu, Zhixiong Ma, Lin Li
In china there are many mixed driving roads which cause a lot of safety problems between vehicles and pedalcyclists. Research on driver behavior under risk scenarios with pedalcyclist is relatively few. Driver brake parameters under naturalistic driving are studied in this paper. Brake reaction time and maximum brake jerk are used to evaluate driver brake reaction speed. Average deceleration is used to evaluate the effect of driver brake operation. Maximum deceleration is used to evaluate driver braking ability. Driver behaviors collected in China are classified and risk scenarios with pedalcyclist are obtained. Driver brake parameters are extracted and statistical characteristics of driver brake parameters are obtained. Influence factors are analyzed with univariate ANOVA and regression analysis. The results show that driver brake parameters under risk scenarios with pedalcyclist obey log-normal distribution.
2016-04-05
Technical Paper
2016-01-1602
Suad Jakirlic, Lukas Kutej, Daniel Hanssmann, Branislav Basara, Cameron Tropea
The present work deals with the computational study of aerodynamic behavior of the ‘DrivAer’ car model (Heft et al., 2012, SAE Paper 2012-01-0168), the rear-end shape of which corresponds to a notchback configuration. The ‘DrivAer’ model represents a ‘generic realistic car configuration’ created by ‘merging’ the original geometries of two medium sized cars from the Audi A4 and the BMW 3 series. This 1:2.5 scaled configuration of a corresponding full-scale car was experimentally investigated in the Wind Tunnel A of the Institute of Aerodynamics and Fluid Mechanics at the Technical University in Munich. The car model considered accounts for mirrors, detailed underbody including exhaust system and differential gear and wheels including brake discs and rim details. The computationally considered flow domain, comprising parts of the air duct – nozzle and collector – and the mid part accommodating the car model, was meshed by a grid containing ca. 25 Mio. cells in total.
2016-04-05
Technical Paper
2016-01-0443
Han Zhang, Gang Li, Yu Wang, Yuchuan Gu, Xiang Wang, Xuexun Guo
A vehicular hydraulic electrical energy regenerative semi-active suspension(HEERSS) was presented, and its working principle and performance were analyzed. Firstly, configuration and working principle of the HEERSS were described; Secondly, kinetic equation of HEERSS was deduced, and a skyhook controller was designed for HEERSS. The traditional skyhook control strategy should be changed for the characteristic of HEERSS, because the damping force during extension stroke could be controlled, but not in compression stroke. Thirdly, the performance of HEERSS was compared with passive suspension(PS), traditional semi-active suspension(TSS). The simulation results showed that in the vehicle body resonance frequency and tire resonance frequency, the amplitude of suspension index parameters ranked in a descend order were PS, HEERSS and TSS; but in the transition frequency band, the amplitude of suspension index parameters ranked in a descend order were. TSS, HEERSS and PS.
2016-04-05
Technical Paper
2016-01-1576
Federico Ballo, Gianpiero Mastinu, Massimiliano Gobbi
Mass minimization is a key objective for the design of racing motorcycle wheels. The structural optimization of a front motorcycle wheel is discussed. Topology Optimization approach has been employed for deriving optimized structural layouts. The minimum compliance problem has been solved, symmetry and periodicity constraints have been considered. The wheel has been optimized considering several loading conditions. Actual loads have been measured during track tests. The forces applied by the tire to the rim have been introduced in an original way. Different solutions characterized by different numbers of spokes have been investigated and compared. The actual racing wheel -currently produced- has been further optimized accounting for technological constraints.
2016-04-05
Technical Paper
2016-01-0471
Jian Zhao, Jun Huang, Bing Zhu, Jingwei Shan
As the vehicle chassis is a typical nonlinear system, more and more researches are focused on the nonlinear characteristics of vehicle dynamics to achieve precise vehicle dynamic control. However, the control of nonlinear system is always a hard task to perform. In this paper, a three-degrees-of-freedom (3DOF) planar vehicle model is built firstly, in which the nonlinear terms are considered. Then, the nonlinear model is fuzzified by the T-S fuzzy methodology based on the assumption of sector-bounded nonlinearity. Furthermore, a model-based fuzzy controller of Parallel Distributed Compensation (PDC) is employed, and the controller shares the same fuzzy sets with the T-S fuzzy model. The Linear Matrix Inequality (LMI) technology is utilized to solve the feedback gains for the PDC controller to ensure its performance of the closed-loop control system. Finally, the proposed algorithm is simulated by Matlab/Simulink and CarSim.
2016-04-05
Technical Paper
2016-01-0014
Shun Yang, Weiwen Deng, Haizhen Liu, Rui He, Lei Qian, Wenlong Sun, Ji Gao
Nowadays, the vehicle market puts forward urgent requirement for new kinds of braking booster because the traditional vacuum booster cannot meet the demands of new energy vehicles anymore. However, one problem that all the new plans should face is how to guarantee an ideal pedal feeling. In this paper, a novel mechatronics braking booster is proposed, and servo motor introduced into the booster makes the assist rate can be adjusted under a great degrees of freedom, so the structural parameters and control parameters of the booster should be determined elaborately to get an optimal pedal feeling. The pedal feeling is always represented by the pedal stoke-force curve which is influenced by different parameters.
2016-04-05
Technical Paper
2016-01-0452
Tingyou Ming, Weiwen Deng, Sumin Zhang, Bing Zhu
In this paper, a model predictive control-based trajectory tracking scheme utilizing steering wheel and braking or acceleration pedal was proposed for intelligent vehicle. The control objective is to track a desired trajectory which obtained from the trajectory plan level. The proposed control approach is based on a simplified third-order vehicle model, which consists of a longitudinal vehicle dynamic model and a bicycle model, and a nonlinear model predictive control (NMPC) problem is formulated to best follow a given path by controlling the front steering angle, brake and traction, while fulfilling various physical and design constraints. In order to reduce the computational burden, the NMPC problem is converted to a linear time-varying (LTV) MPC based on successive online linearization of the nonlinear system model. Two different test conditions have been used to verify the effectiveness of the proposed approaches through simulations using Matlab and Carsim.
2016-04-05
Technical Paper
2016-01-0166
Hiroaki Kitano, Hitosugi Kazuo, Hideyuki Tanaka
Accuracy of positioning with GNSS (Global Navigation Satellite System) has been improved in recent years. Especially in Japan, high accuracy GNSS service, QZSS (Quasi Zenith Satellite System), will start in 2018 and the first QZS, “MICHIBIKI” has been already launched. They will broadcast correction data which enhances GNSS performance and realize cm-order positioning. In this paper, we, Mitsubishi Electric develop the estimation algorithm of vehicle position and attitude and also adapt the algorithm to a test vehicle which can trace automatically the calculated path with EPS (Electric Power Steering) and high accuracy GNSS. Although the GNSS receiver calculates the longitude and latitude of the vehicle every second, it’s not enough to control vehicle dynamics smoothly. So we estimate vehicle position and attitude of the vehicle with GNSS and vehicle sensors in high frequency.
2016-04-05
Technical Paper
2016-01-0453
Yingxiao Xu, Xuexun Guo, Gangfeng Tan, Jiawei Li, Yongchi Zhou, Yangjie Ji, LiWen Yu
Eddy current retarder(ECR) shares a large domestic market of auxiliary brakes in China, but shortcomings of the short continuous braking time and the high additional energy consumption are also obvious. The propose of combined braking partakes the braking torque of ECR, while the existing serial-parallel braking strategy can't balance the relationship between the braking stability and the efficiency of energy recovery well. This research puts forward an energy management strategy of combined braking system which aims to maximize energy recovery while ensure the brake stability. The motor speed, braking request and the state of charge(SoC) of storage module are analyzed synthetically to calculate the reasonable braking torque distribution proportion. And the recovered energy is priority for braking unit to reduce the additional energy consumption in this strategy.
2016-04-05
Technical Paper
2016-01-1308
Kristian Lee Lardner, Moustafa El-Gindy, Fredrik Oijer, Inge Johansson, David Philipps
The handling and comfort characteristics of a vehicle are greatly impacted by the tire harmonics and these harmonics are known to be affected by several other external and internal parameters. The first mode of vibration is instigated by the tire moving in the vertical direction. This movement is typical of a tire when it drives over obstacles such as pot holes, or speed bumps over a road profile. More importantly, the force that occurs at the first harmonic is transmitted through the tire spindle to the rim, tire axle, and chassis of the vehicle directly affecting the handling and comfortability of the vehicle which is an important factor for trucks and tractor trailers involving heavy and expensive cargo. The purpose of this study is to determine the effect of tire operating conditions, such as the inflation pressure, speed, and load on the change of frequency of the first mode of vibration.
2016-04-05
Technical Paper
2016-01-0458
Jiawei Li, Gangfeng Tan, Yangjie Ji, Yongchi Zhou, Ziang Liu, Yingxiao Xu
This paper proposed a novel concept of Integrated Energy-recuperation retarder (IEER). Facing the conventional eddy current retarders’ (ECR) braking torque attenuation under high speed domain and the poor braking property of the regenerative brake (RGB) in low speed domain, the IEER is designed to take the advantages of both the ECR and the RGB to overcome their disadvantages. The IEER integrates the rotary eddy current retarder (RECR) and the RGB, both of which share a stator. Slots are grooved on the stator of the IEER, and armature-windings are inserted in slots. Poles are arranged on the rotator. Eddy currents are excited in the stator core, and the current is excited in the armature-windings. Braking torque of the IEER produced by stator core and armature-windings can stack together, and therefore the IEER can provide greater braking torque than the RECR. Besides, the IEER can recover electric energy from armature-windings.
2016-04-05
Technical Paper
2016-01-0439
Tianqi Lv, Peijun Xu, Yunqing Zhang
The powertrain mounting system plays a very important role in controlling the NVH performance of a vehicle. The simulation analysis of powertrain mounting system adopts the linear rotation approximation model based on the premise of powertrain with small rotation angle assumption, but in some extreme loading conditions, powertrain will happen larger angle rotation, so the approximate model calculation results will be inaccurate, the calculation results of inaccurate is likely to cause powertrain interferes with the surrounding parts. This paper build a calculation model of powertrain rigid body dynamics with consideration nonlinear stiffness of the mount, and through the Newton-Raphson's iterative algorithm to solve the displacement and loads of mount system.
2016-04-05
Technical Paper
2016-01-1547
Jun Yin, Xinbo Chen, Lixin Wu, Jianqin Li
Traditional active suspension which is equipped with hydraulic actuator or pneumatic actuator features slow response and high power consumption. However, electromagnetic actuated active suspension benefits quick response and energy harvesting from vibration at the same time. To design a novel active and energy regenerative suspension utilized electromagnetic actuator, this paper analyze the benchmark cars available on the market, and concludes the target cars which are possible to be equipped with electromagnetic actuated active suspension in the future. And the suspension structure of the target cars are analyzed. Compared the linear type and rotary type Permanent Magnet Synchronous Motor (PMSM), the rotary type is selected to construct the actuator of the active suspension. And the traditional mechanisms to transfer the linear motion of the suspension to the rotation motion of the rotary type PMSM are analyzed.
2016-04-05
Technical Paper
2016-01-0428
Ruochen Wang, Renkai Ding, Qing Ye
In order to coordinate the ride comfort and driving safety significantly, “inerter-spring-damper” (ISD) system is proposed in this paper, then “spring-adjustable damper” is adapted to connect with ISD in series, and then, a new type of semi-active suspension system will be established. For the verification of system rationality, ISD semi-active suspension model and the road input and robust controller model are established respectively in the AMESim and MATLAB/Simulink environment based on two degrees of freedom suspension model. Then, ISD robust control semi-active suspension co-simulation is analyzed. Compared with the conventional ISD suspension, the results show that the ISD robust control semi-active suspension can significantly reduce the body vertical vibration, restrain tire resonance and enhance the tire grounding performance, that is, this system can coordinate conflicts between vehicle ride comfort and driving safety.
2016-04-05
Technical Paper
2016-01-1561
Xinxin Shao, Haiping Du, Fazel Naghdy
Significant steering and braking maneuvers in vehicles generally induce significant amount of roll and pitch rotations, which have adverse effect on the directional stability and handling of the vehicle. Furthermore, the excessive pitch motions of the vehicle could adversely affect the driver’s perception of the path and preview ability. Hence, it is crucial to control vehicle attitude (roll and pitch rotations) in response to directional maneuvers and excitations arising from road. Development of a passive anti-pitch anti-roll hydraulically interconnected suspension (AAHIS) with the advantage of improving the directional stability and handling quality of a vehicle is presented. A 7 degrees-of-freedom full car model and a 20 degrees-of-freedom anti-pitch anti-roll hydraulically interconnected suspension model dynamically coupled together through boundary conditions, are developed and used to evaluate vehicle handing dynamic responses under steering/braking maneuvers.
2016-04-05
Technical Paper
2016-01-0093
Haizhen Liu, Rui He, Jian Wu, Wenlong Sun, Bing Zhu
With the development of modern vehicle chassis control systems, such as Anti-skid Brake System (ABS) , Electronic Stability Control (ESC), and regenerative braking system(RBS) for EVs, etc., there comes a new requirement for the vehicle brake system, that is the precise control of the wheel brake pressure. The electro-hydraulic brake system (EHB), which has a ability to adjust four wheels’ brake pressure independently, can be a good match with these systems. However, the tranditional control logic of EHB is based on the PWM (Pulse-Width Modulation), which has a low control accuracy of linear electromagnetic valves. Therefore, this paper will do a research of the linear electro-magnetic valve characteristic analysis, and make a compensation control of linear electro-magnetic valves, at last, achieve the popes of precise pressure control of the EHB system.
2016-04-05
Technical Paper
2016-01-0445
Brian Paul Wiegand
Evaluation of the performance potential of an automotive conceptual design requires some initial quantitative estimate of numerous relevant parameters. Such parameters include the vehicle mass properties, frontal and plan areas, aero drag and lift coefficients, available horsepower and torque, and various tire characteristics such as the rolling resistance... A number of rolling resistance models have been advanced since Robert William Thomson first patented the pneumatic rubber tire in 1845, most of them developed in the twentieth century. Most early models only crudely approximate tire rolling resistance behavior over a limited range of operation, while the latest models overcome those limitations but often at the expense of extreme complexity requiring significant computer resources.
2016-04-05
Technical Paper
2016-01-1309
Yingping Lv, Yongchang Du, Yujian Wang
In this paper, analysis methods for brake squeal including substructure modal composition analysis and substructure modal parameters sensitivity analysis are presented. The methods are based on a new closed-loop coupling disc break model, where the coupled nodal pairs in each coupling interface are connected tightly. This assumption is different from other existing models in literatures, where the interface nodes are coupled through assumed springs. Based on this new model, two analysis methods are derived. Substructure modal composition analysis indicates the contribution of modes of each substructure to the noise mode. Substructure modal parameters sensitivity analysis calculates the sensitivity of each component’s modal frequencies and shape coefficients to the real part of eigenvalues. Finally, the presented analysis methods are applied to analysis a high frequency squeal problem of a squealing disc brake.
2016-04-05
Technical Paper
2016-01-1557
Francesco Castellani, Nicola Bartolini, Lorenzo Scappaticci, Davide Astolfi, Matteo Becchetti
Shock absorber is one of the most relevant sub-systems of the suspension system for a wide range of vehicles. Although a high level of development and tuning has been reached, in order to ensure high safety standards in almost every situation, some dynamic phenomena affecting vehicle handling or NHV can appear. The aim of present work is to improve a mathematical model using experimental data from a prototype of monotube shock absorber developed for research purposes. The model takes into account all the main features affecting the global performance of the device, such as non-linear behaviour and the presence of hysteresis loops. Actually, the most important parameters are analyzed, as flow and orifice coefficients of the valves, coefficients of mechanical compliance of the chambers and oil compressibility, dry and viscous friction coefficients.
2016-04-05
Technical Paper
2016-01-1556
Lalitkumar Maikulal Jugulkar
Semi-active suspension systems have shown a significant improvement over the passive systems. Due to this fact, semi-active dampers have been designed and made commercially available; the control strategies have been adopted and implemented to offer superior ride quality to passenger vehicles. However, the technology is still an emerging one, and elaboration and more research work on different theoretical and practical aspects are required. This work is an attempt to design an understanding of some of those aspects, such as the effect of the semi-active dampers response-time on the performance of the control strategies through analytical and numerical methods. On the other hand, the technology has not yet been adopted for SUV vehicles.
2016-04-05
Technical Paper
2016-01-0463
Juan Sierra, Camilo Cruz, Luis Munoz, Santiago Avila, Elkin Espitia, Jaime Rodriguez
Brake systems are strongly related with safety of vehicles. Therefore a reliable design of the brake system is critical as vehicles operate in a wide range of environmental conditions, fulfilling different security requirements. Particularly, countries with mountainous geography expose vehicles to aggressive variations in altitude and road grade. These variations affect the performance of the brake system. In order to study how these changes affect the brake system, two approaches were considered. The first approach was centered on the development of an analytical model for the longitudinal dynamics of the vehicle during braking maneuvers. This model was developed at system-level, considering the whole vehicle. This allowed the understanding of the relation between the braking force and the altitude and road grade, for different fixed deceleration requirement scenarios. The second approach was focused on the characterization of the vacuum servo operation.
Viewing 1 to 30 of 7853