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Viewing 211 to 240 of 1647
2007-08-05
Technical Paper
2007-01-3643
M. A. A. Emam, S. Shaaban, M. A. El-Nashar, Abdel Aziz M. El-Bassiouni
The main aim of this paper is to optimize pneumatic tyre parameters related that improve tyre flotation and performance on sandy soils. Tyre flotation pressure is the pressure of inflation that makes tyre flotation maximum such that it deforms more than it sinks in the soil. A second aim is to predict the tyre flotation pressure on dry sandy soil by using Artificial Neural Networks (ANNs) Technique. A third aim is to predict a new tyre size that improves flotation on dry sand by using Artificial Neural Networks (ANNs) Technique. Experimental investigation has been carried out on three tubeless tyre of sizes (225/75R15, 235/70R15 and 255/60R15) inflated each with four inflation pressures (50, 100, 150 and 200 kPa) on three dry sand with three densities (Loose, Medium, and High). The investigation aimed at determines the tyre deflection-load, sinkage-load relationships were measured and the tyre flotation pressure.
2007-08-05
Technical Paper
2007-01-3642
Daofei Li, Fan Yu
To optimally allocate control authorities to co-existing active actuators, an integrated chassis controller with main/servo-loop structure is designed to coordinate direct yaw moment control and active steering. Firstly, a sliding mode controller in the main-loop calculates the desired stabilizing forces. Then in the servo-loop, by directly considering limits of road friction and actuators, a quadratic programming based control allocation approach is adopted to reasonably and optimally distribute these deisired forces to tire actuator actions. Co-simulation of Matlab/Simulink and Carsim clarifies that the proposed controller could significantly improve vehicle handling performances.
2007-08-05
Technical Paper
2007-01-3646
Kubilay Yay, I.Murat Ereke
In this paper, first of all, after load distribution of the front and rear axles of domestic midi bus have been measured, force on the parabolic springs of the front axle was calculated. Level of the good, middle and bad roads of Adana city in south of Turkey were determined and strain and displacement data have been recorded from connected strain-gage and LVDT sensors on the front axle parabolic springs of the midi bus. Test mechanism of the front axle suspension system connected chassis like midi bus was assembled in the laboratory. Recorded road roughness displacement, strain, and brake force strain data of the parabolic spring were processed by LMS Tecware, n-code ICE-flow 4.0 and special written computer program for this accelerated life cycle project. In addition to this, rainflow analysis, cumulative damage values, appending brake signals data in these different roads and every road damages have been calculated.
2007-08-05
Technical Paper
2007-01-3645
Kaoru Sawase, Yuichi Ushiroda, Katsumi Inoue
This paper describes the calculative verification of the effect of the right-and-left torque vectoring system in various types of drivetrain, namely, the front wheels only, the rear wheels only, and both front and rear wheels in FWD, RWD, and AWD vehicles. The effect is evaluated by calculating the vehicle dynamics limit; maximum acceleration and cornering ability. The right-and-left vectoring torque, which is needed for expanding the vehicle dynamics limit, is also calculated. And finally, the paper evaluates the suitable wheels for which the system should be applied in each drivetrain. The application to the front wheels is more effective for FWD vehicles. On the other hand, the application to the rear wheels is more effective for RWD and AWD vehicles.
2007-08-05
Technical Paper
2007-01-3638
Mark Shaw
The US requirement for tire pressure monitoring systems (TPMS) will reach the 100% installation rate this year in accordance with the requirements of FMVSS138 promulgated by the NHTSA. The wide variety of semiconductor technologies available now for direct TPMS can solve the requirements for these systems. However, the wide variation in solutions for TPMS can present a number of end customer issues when there are no standard methods or protocols used in their application. This paper will present an advanced TPMS sensor that includes all of the required features for very complex solutions and presents the issues that result from too many variations in the field. Finally a set of suggested protocols are presented that could help reduce the field issues that may be experienced by the end customer.
2007-08-05
Technical Paper
2007-01-3641
D. H Kim, T. O. Tak, M. G. Kuk, J. S. Park, S. E. Shin, S. J. Song, H. H. Chun, C. K. Kim, S. S. Cho, N. Y. Cho
Predicting steering efforts at parking speed condition is critical to achieve ergonomically efficient steering system. The most important factor in calculating steering effort is the static friction torque of tires, which are affected by tire loads, kingpin axis geometry such as camber, caster and kingpin offset. In this research a multi-body approach to calculate steering effort and rack-bar force as a function of tire contact patch friction torque is proposed. For validation, the computed rack-bar force and steering effort are compared to the measured values obtained through actual vehicle test, and they showed good correlation.
2007-08-05
Technical Paper
2007-01-3637
Ren He, Yong-tao Wang, Ying-sheng Zhao
The math model of united brake system is set up on thinking of the influence of the coefficient of the revolving mass changes to linear mass of vehicle, the efficiency of slippage and so on. The simulation model is set up in the Simulink module of Matlab. The result of simulation shows that the braking distance is shortened by the function of united brake system in the emergency brake; the braking ability of the bus is improved. The united brake system can also be used to stop the bus in the nonemergercy brake. The retarder exhausts most of energy of automobile. Thus, the maintenance cost is reduced. The bus can run at steady and economic speed on the hillside path with continuous brake of united brake system.
2007-08-05
Technical Paper
2007-01-3639
Mou Xiangdong
To further improve the travels stabilization and steering characteristics of vehicle, people pay more attention on the steering affect of suspension. Various possess steering function of suspension system on car one after another change into more perfect. The compliance suspension is in among. In this paper it has analysis to steering character of Citroën-ZX series cars compliance suspension. The compliance suspension has been specially research on the affect of probe into roll-steering character to car's handling performance and it has drawn a preliminary conclusion.
2007-08-05
Technical Paper
2007-01-3636
Er. Neeraj Singh Gautam, Prashant Awadhiya
This is a proposed alternative to the Ackermann Steering Mechanism. Synthesis of a six member mechanism taking seven precision points is performed for an automotive steering mechanism. The maximum rotation of inner wheel is taken as 65 degree to attain still less turning radius. The mechanism has been compared with those achieved by Ackerman Steering Mechanism (ASM), Fahey Eight Member Mechanism (FEMM) and Pramanik Six Member Mechanism (PSMM). The suggested mechanism gives fairly the accurate result that falls above the ASM mechanism. The mechanism gives better end response leading to shorter turning radius.
2007-08-05
Technical Paper
2007-01-3674
Tian Chengwei, Zong Changfu, Zheng Hongyu, Zhu Tianjun, Mai Li
Steer-by-wire System is a new conception for steering system, which eliminates those mechanical linkages between hand steering wheel and front wheels, and communicates among the driver and wheels by signals and controllers. All these facilities improve the safety and conformability of the vehicle system and get rid of the mechanical constricts. This paper proposed three vehicle stability control strategies, including front wheel control, yaw rate feedback control and yaw rate& acceleration feedback control. We compared these three control methods by simulation and simulator tests. We also studied the integrated control algorithm of Steer-by-Wire System and 4WS, and compared with 2WS for SBW and the classical 4WS.
2007-08-05
Technical Paper
2007-01-3675
Liu Yahui, Gao Feng, Ji Xuewu
The flow-control type electronically controlled hydraulic power steering system (hereinafter ECHPS) is the simplest form of ECHPS. To get better performance, the power steering gear should be modified. One of the modification methods is cutting short the slot of the valve. One common formula could compute the orifice size of the control valve was given and several valves with different length of slots were analyzed based on the formula. The assistance characteristics of ECHPS with these valves were calculated. At last, two steering gears with different slot length were made for experiment. The results show the assistance characteristics of the short slot valve is better than the long slot one.
2007-08-05
Technical Paper
2007-01-3670
Pyung Hwang, Xuan Wu, Sang-Woon Cho, Young-Bae Jeon
The ventilated disc brake is divided into a disc with several vents, and the pads with the three dimensional geometry. The frictional heat can cause high temperature during the braking process. The thermal distortion of the brake disc can affect the performance of brake system. The object of present work is determination of temperature distribution and thermal distortion in the disc by two dimensional thermal analysis. During brake, heat flux and convective transfer coefficient are considered as a function of time. The brake disc temperature is found to be satisfactory compared with that of the conventional three dimensional analysis. Thermoelastic deformation of the disc is found from the same axisymmetric finite element model with equivalent mechanical properties. The analysis results are also compared to the measured data in the brake disc thermal experiment.
2007-08-05
Technical Paper
2007-01-3666
Lai Fei, Deng ZhaoXiang, Dong Hongliang, Cao Youqiang
Based on the tire and road model of virtual prototype, using the co-simulation of ADAMS&Matlab/Simulink, combining with the optimal control theory, contrastive research is done among the system of passive suspension and front wheel steering the simple combination system of active suspension and four wheel steering and the integrated system of active suspension and four wheel steering. The theory analysis and simulation test indicate the integrated control system can greatly improve handling and riding performance of vehicle.
2007-08-05
Technical Paper
2007-01-3673
Xuanfeng Wang, Yingchun Liang, Chaosheng Huang, Guozeng Ying
The primary objective of this paper is to develop a model that accurately represents the dynamics of drum brake through the components of its configuration. Detailed description will be that dynamic models for brake chamber, brake camshaft and brake shoe are built up respectively with consideration of various resistances from friction, inertia and return spring. These dynamic models are indirectly validated because the calculation values of the models are consistent with the results from the mechanism efficiency experiments of drum brake. According to these dynamic models, two different drum brakes with Involutes and Archimedes cam actuating mechanism have been researched.
2007-08-05
Technical Paper
2007-01-3667
Jia-ling Yao, Jia-qiang Zheng, Wei-yi Cai
In this research, a semi-active suspension system using a quarter car model has been investigated, and a novel model reference sliding mode control scheme in controlling the semi-active suspension system has been proposed. The proposed scheme uses an approximate ideal skyhook system as a reference model. The controller can ensure robustness for a wide range of operating conditions, and is easy to be carried out and eliminates the necessity of a road signal as well as measuring damper force in real-time. The control law is determined so that an asymptotically stable sliding mode will occur in the error dynamics between the plant and the reference model states. A simulation study is performed to prove the effectiveness and robustness of the control approach.
2007-08-05
Technical Paper
2007-01-3663
Myoung-Gu Kim, Chongdu Cho, Chang-Boo Kim
In an automotive disk brake system, when the disk shows TEI at the speed over the critical one, hot spot forms on the disk surface and local contact friction is developed between the disk surface and the pad due to the hot spot. This non-uniform contact friction worsens the local heat concentration on the disk surface and has a direct effect on the disk pad, through which it affects the oil pressure supplier of the disk. The pressure change in the oil pressure supplier then affects the hot spot on the disk surface through the disk pad. This shows that there is a correlation between the vibration caused by the contact friction and the pressure change. The correlation between the pressure change in the disk with hot spot and DTV is analyzed. Since the brake vibration has several periodic elements, the unique characteristics of the brake vibration are analyzed, removing those elements with cepstrum and lifter-spectrum.
2007-08-05
Technical Paper
2007-01-3664
Tobias Niemz, Marcus Reul, Hermann Winner
This paper presents a control algorithm for semi-active suspensions to reduce the braking distance of passenger cars. Active shock absorbers are controlled and used to influence the vertical dynamics during ABS-controlled full braking. The core of the approach presented in this paper is based on a switching control logic which sets the car's body damping to one of the two extrema hard and soft. The control algorithm is implemented in a compact class passenger car. Test drives on a real road, using a braking machine for reproducibility reasons, have been executed. It could be shown that it is possible to reduce the braking distance by affecting on the vertical dynamics of a passenger car in general. This is the first published experimental result of its kind. The amount of reduction depends on the height profile of the testing track.
2007-08-05
Technical Paper
2007-01-3661
Hojoon Cho, Chongdu Cho, Chang-Boo Kim
Major vibration and noise problem relevant to brake disk NVH (Noise, Vibration and Harshness) is judder and squeal. The thermal distortion induced by thermo-elastic instability (TEI) makes hot spots on the surface of brake disk which incur low frequency vibration called judder vibration. In pad-induced squeal noise, out-of-plane mode coupling occur due to variation of friction coefficient between disk and pad induce high frequency noise. Through coupled analysis of these two important phenomena, judder and squeal, an optimum braking system can be designed for higher disk and pad performance. In this study, we conducted numerical and experimental analysis in accordance with variation of disk stiffness in the same friction material (lining) while simultaneously considering hot judder and squeal noise. Results are discussed about their performances in the view of hot judder and squeal problems.
2007-08-05
Technical Paper
2007-01-3659
Taebong Noh, Jaesuk Kim, Jungrak Choi, Hangbyong Cha
Recently steering technology focuses on not only driver's convenience, fuel efficiency, environment friendliness but also improved vehicle stability. Therefore Active Front Steering (AFS) has been widely studied as latest technical trend in steering system. This system can enhance vehicle stability by making additional road wheel angle (called ‘superimposed angle’) based on the vehicle state information such as vehicle speed, steering angle, yaw rate and lateral acceleration. While occurring superimposed steering angle, driver may feel the reaction torque which is caused from abnormal changes of steering effort with AFS mechanism installed. To solve this problem it is required to reduce steering output load in case of superimposed steering by increasing steering assist of rack assist type electric power steering. This paper describes the control method that is compensated reaction torque. And its effect of compensation is validated from test results
2007-08-05
Technical Paper
2007-01-3662
Iljoong Youn, Sanghoon Lee, Nur Uddin, Masayoshi Tomizuka
In this study, preview control algorithms for the active and semi-active suspension systems of a full tracked vehicle are designed based on a 3-D.O.F model and evaluated. The main issue of this study is to make the ride comfort characteristics of a fast moving tracked vehicle better to keep an operator's driving capability. Since road wheels almost trace the profiles of the road surface as long as the track doesn't depart from the ground, the preview information can be obtained by measuring only the absolute position or velocity of the first road wheel. Simulation results show that the performance of the sky-hook suspension system almost follows that of full state feedback suspension system and the on-off semi-active system carries out remarkable performance with the combination of 12 on-off semi-active suspension units.
2007-08-05
Technical Paper
2007-01-3660
Han Byul Chung, Youngsup Son, Paljoo Yoon, Choong Woo Lee, Doo Ho Lee, Young Ok Lee, Chung Choo Chung
A fault detection method with parity equations is proposed in this paper. Due to low cost implementation, the velocity of a motor is not measurable in EPB systems. Therefore, residuals are not reliable with a low resolution encoder to estimate the motor velocity. In this paper, we propose a fault detection method with sensorless estimation using current ripples. The method estimates position and velocity of the motor by detecting periodical oscillations of the armature current caused by rotor slots. This method could estimate position and velocity of the motor with less computational effort than a state observer. Moreover, the method is less sensitive to motor parameters than model-based estimation methods. The effectiveness of this method is validated with experimental data. The simulation results show that various faults have their own residual patterns. Therefore, we could detect the fault by monitoring the residual signals.
2007-08-05
Technical Paper
2007-01-3657
Young Ok Lee, Choong Woo Lee, Han Byul Chung, Chung Choo Chung, Youngsup Son, Paljoo Yoon, Inyong Hwang
This paper presents three types of controllers for Electric Parking Brake (EPB) Systems: bang-bang, linear proportional (P), and nonlinear proportional (P) controller. Mechanical and electrical parts of EPB system are modeled and implemented using Modelica language. There is good agreement between simulation and experimental results. For the stability analysis, the EPB system is modeled as a state-dependent switched system with simplified friction dynamics. From simulation and experimental results, it turns out that the nonlinear P controller provides good uniformity in performance and robustness among them.
2007-08-05
Technical Paper
2007-01-3658
Seongjoo Kim, Jonghyun Pyo
Good road feel means that the driver can interpret road conditions through the steering wheel. This is one of the most important requirements demanded by car makers. However, over-sensitivity in steering transmission could cause inconvenience to the driver especially maneuvering on rough roads and hence must be isolated by the steering system or by other means. To overcome this, firstly we have to distinguish diverse road conditions and apply appropriate control strategy. In this paper we've proposed two control strategies to enhance steering performance on rough roads. The first method analyzes motor position signal of Electric Power Steering (or EPS) where the road roughness is separated from the motor position signal through signal processing. The roughness then is compensated for by using EPS to obtain a better steering feel. The second method utilizes CAN transferred vehicle information from Continuous Damping Control system (or CDC).
2007-08-05
Technical Paper
2007-01-3654
Wang Ruo-Ping
The dynamic characteristics of the hydraulic power steering system(HPSS) are simulated and discussed with SIMULINK software and hydraulic control theory. The characterristic of software SIMULINK is introduced and the dynamical model of valve-controlled hydraulic cylinder is constructed. The dynamic simulation can be made by establishing the dynamic model and the simulation model of HPSS, initializing the parameters of the system, and implementing the dynamic simulation. Lastly, the key factors affecting the dynamic characteristics of HPSS are discussed. The simulation result can provide theoretical basis for designing HPSS and the SIMULINK method is an effective way to simulate the dynamical characteristics of HPSS.
2007-08-05
Technical Paper
2007-01-3656
Seunghoon Woo, Sungmun Park, Youngho Oh
This paper describes a torque steer reduction process for a front-wheel drive car with a high torque engine at the initial stage of vehicle development. Literature reviews for the reduction process and vehicle integration tradeoffs among chassis components, driveline components, and loading condition are included. Drive shaft angle and its stiffness, differential gear stiffness, and power train mount, and vehicle weight distribution are mainly considered. In addition, wheel alignment data such as kingpin offset, kingpin inclination, camber angle, ride height, and dynamic tire radius are also discussed to solve the torque steer problem. This paper introduces an example solution to improve the torque steer during vehicle development stage. In that case, the vehicle parameters should be considered the factors to achieve many requirements. In spite of that restriction of alteration, the result of improvement became better than that of its competitor.
2007-08-05
Technical Paper
2007-01-3725
I. V. Balabin, V. V. Bogdanov
This paper summarizes the result of the bumper's role investigation in the process of reducing the energy-absorbing level during frontal collisions of vehicle. The paper is citing the detailed review and analysis of the stages of bumper's construction evolutions from the point of view of realizing of the passive safety's functions for frontal collision. Also the paper cites the examples of FEM-calculations of the front bumper's panel with the purpose of discovering the fields of strains and deformations. The paper is based on the research performed by the authors for discovering the optimal areas of variation of the bumper's rigidity and mass and, as a result, the construction of impact-safety bumper patented in Russia. The paper contains the recommendations on further bumper's transformations into an impact-safety and trauma-free device for vehicles and pedestrians.
2007-08-05
Technical Paper
2007-01-3745
Jaesoon Park, Taeoh Tak, Mingu Kuk, Daehee Kim, Seungeon Shin
A retractor is the major component of a seatbelt system that restraints passengers by locking the movement of webbing. Recently, in order to increase the effectiveness of seatbelt systems, motorized retractors that remove slack and correct passenger posture just before airbag expansion when collision is predicted are widely used. Key component of motorized retractors is the one-way clutch that engages and disengages the winding action of webbing according to the direction of motor revolution. Analytical investigation of action of the one-way clutch mechanism has been carried out to figure out conditions for one-way locking, and to study the effect of various kinematic and dynamic design variables of one-way clutch. Using combination of ADAMS and LifeMOD softwares, dynamic simulation of operation of motorized retractors including Hybrid-III dummy model has been carried out to evaluate the performance of the motorized retractors in various crash scenarios.
2007-08-05
Technical Paper
2007-01-3558
Lei Li, Changgao Xia, Wei Qin
Taking the five-link suspension of a car as the subject investigated on the basis of ADAMS/Car, this paper builds the parameterized mode of the multi-link suspension. The simulation shows the influence relations among multi-link suspension structure parameter and the wheel location parameter, wheel track, roll center. On the base of this, aim for improving the ride safety and comfort, multi-link suspension optimization model is built and carried out parameter optimization design by using ADAMS/Insight. The result shows that this method is high-performance and can be used in the design of multi-link suspension conveniently.
2007-08-05
Technical Paper
2007-01-3585
Daeyi Jung, Dohyun Jung, Changhyun Jeong, Youseok Kou, Huei Peng
The current test methods are insufficient to evaluate and ensure the safety and reliability of vehicle system for all possible dynamic situations including the worst cases such as rollover, spin-out and so on. Although the known NHTSA J-turn and Fish-hook steering maneuvers are applied for the vehicle performance assessment, they are not enough to predict other possible worst case scenarios. Therefore, it is crucial to search for the various worst cases including the existing severe steering maneuvers. This paper includes the procedure to search for other useful worst case based upon the existing worst case scenarios in terms of rollover and its application in simulation basis. The human steering angle is selected as a design variable and optimized to maximize the index function to be expressed in terms of vehicle roll angle. The obtained scenarios were enough to generate the worse cases than NHTSA ones.
2007-08-05
Technical Paper
2007-01-3586
Jianghui Xin, Shunming Li
With the aim of improving vehicle steering stability through the introduction of active steering control in obstacle avoidance, the author undertook the development of the fuzzy neural networks. By using back propagation neural network as the base, it can use fuzzy theory and neural networks together to form a fuzzy neural networks control system. So it can auto pick-up the fuzzy rule and build the subordinate function. The result of simulation analyses and experiments indicate that the method proposed in the paper can achieve safe and stability in steering control of obstacle avoidance of intelligent mobile vehicle.
Viewing 211 to 240 of 1647