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Viewing 241 to 270 of 1648
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
2007-01-3659
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
2007-01-3661
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
2007-01-3664
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
2007-01-3663
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
2007-01-3667
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
2007-01-3666
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
2007-01-3670
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
2007-01-3675
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
2007-01-3674
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
2007-01-3656
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
2007-01-3641
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
2007-01-3645
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
2007-01-3647
David R. Mikesell, Anmol S. Sidhu, Dennis A. Guenther, Gary J. Heydinger, Ronald A. Bixel
Automating road vehicle control can increase the range and reliability of dynamic testing. Some tests, for instance, specify precise steering inputs which human test drivers are only able to approximate, adding uncertainty to the test results. An automated steering system has been developed which is capable of removing these limitations. This system enables any production car or light truck to follow a user-defined path, using global position feedback, or to perform specific steering sequences with excellent repeatability. The system adapts itself to a given vehicle s handling characteristics, and it can be installed and uninstalled quickly without damage or permanent modification to the vehicle.
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
2007-01-3588
D. V. Abhilash, Manjunatha Gaviappa, Venketesan Sudharshan
. This paper deals with the study of intelligent vehicle safety system. High speeds are achievable with proper design of safe road bearing vehicular components. These speeds are achieved safely, when the physical and mental conditions of the driver are stable. On the event of the driver, not taking the necessary measure to ensure the drivers safety, it is therefore important that the driver is monitored to predict his/her behavior in order to avoid mishaps. This paper explores three ways to ensure the rightness of driver's physical and mental conditions 1) Seat belts to measure the rate of breathing 2) Steering which can measure the heart beat 3) Detection of eye-lid movement
2007-08-05
Technical Paper
2007-01-3592
Nao Saito, Setsuo Arita, Yuji Ichinose, Daisuke Shimma
Our objective in this paper is to show the feasibility of battery-line communication in an automobile in order to lighten the weight of wire harnesses. We experimentally measured the attenuation characteristic of some battery-lines. We showed a throughput of 10.2 Mbps from a cigarette lighter socket to a rear light was obtained via the battery-line by using our prototype modem with an OFDM (Orthogonal Frequency Division Multiplexing) modulation for the battery-line communication. But throughput from the cigarette lighter socket to the battery was 297 kbps because of noises generated from such apparatuses as the engine, air-conditioner and windshield wipers. We expect that it is possible to improve the throughput of battery-line communication by using some error-correcting technique.
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.
2007-08-05
Technical Paper
2007-01-3587
Fen Lin, Youqun Zhao
Two soft-sensing methods which are neural network and Kalman filter for estimating vehicle side slip angle are compared. A radial basis function (RBF) neural network based soft-sensing model is proposed to estimate vehicle side slip angle in driver-vehicle closed-loop system. Vehicle side slip angle is considered as mapping of time series of yaw rate and lateral acceleration which are easily measured, the nonlinear mapping relationship of the three state parameters is established through neural network. In addition the method based on Kalman filter is also given. The results of comparison between estimation and measurement show that the neural network method proposed in this paper has higher accuracy and less computation requirement. It can provide theoretical guidance for design of estimator in vehicle stability control system.
2007-08-05
Technical Paper
2007-01-3582
Tae-Kyung Moon, Seong-Hee Jeong, Jun-Nam Oh
In this paper, we study the trend of research on inter-vehicle communication and implement to a simple control system. This system detects opposite vehicles approaching from invisible areas to the driver, and determine how much risky to the own car. When the risk level is high, it slow downs the vehicle to prevent collision. Finally, we derive key technological issues necessary to develop control system with communication integrated.
2007-08-05
Technical Paper
2007-01-3575
Changfu Zong, Hsiao Hsiang Na, Dan Hu, Deping Wang, Botao Yue
This paper presents a study on steering effort preference of Chinese drivers based on ADSL Driving Simulator. The results of the simulation test demonstrates that Chinese drivers' steering effort preference increases with vehicle speed, which is similar to European and Japanese drivers', but the mean preference effort level itself is lower than that of European and Japanese drivers' and this same steering effort preference increases obviously with lateral acceleration in linear region (lateral acceleration level lower than 0.3g) while not as evidently in nonlinear region (lateral acceleration level higher than 0.3g).
2007-08-05
Technical Paper
2007-01-3591
Satoshi Katahira, Eiji Shibata, Tatsuhiko Monji
SUBARU has developed an advanced stereo camera system as core technology for future intelligent vehicles. The system offers higher performance in the detection of objects on the road including pedestrians as well as better accuracy and environmental resistance, which allow the system to be used in full speed range adaptive cruise control (FSR-ACC) and Pre-crash safety applications. In addition, all the processes for recognition, decision-making and operation have been integrated to improve efficiency and reduce cost.
2007-08-05
Technical Paper
2007-01-3596
WU Li-jun, WANG Jian-qiang, LI Sheng-bo
A HIL simulator for developing vehicle adaptive cruise control systems is presented in this paper. The xPC target is used to establish real-time simulation environment. The simulator is composed of a virtual vehicle model, real components of an ACC system like ECU, electronic throttle and braking modulator, a user interface to facilitate simulation, and brake and accelerator pedals to make interactive driver inputs easier. The vehicle model is validated against data from field test. Tests of an ACC controller in the real-time are conducted on the simulator.
2007-07-23
Technical Paper
2007-01-2066
Hu Li, Gordon E Andrews, Adnan A Khan, Dimitrios Savvidis, Basil Daham, Margaret Bell, James Tate, Karl Ropkins
A FTIR in-vehicle on-road emission measurement system was installed in a EURO 2 emissions compliant SI car to investigate exhaust emissions under different urban traffic conditions. The real time fuel consumption and vehicle traveling speed was measured and logged. The temperatures were measured along the exhaust pipe so as to monitor the thermal characteristics and efficiency of the catalyst. Two real world driving cycles were developed with different traffic conditions. One (WP cycle) was located in a quiet area with few traffic interference and the other one (HPL cycle) was in a busy area with more traffic variations. The test car was pre-warmed before each test to eliminate cold start effect. The driving parameters were analyzed for two real world cycles. The WP cycle had higher acceleration rate, longer acceleration mode and shorter steady speed driving mode and thus harsher than the HPL cycle.
2007-05-15
Technical Paper
2007-01-2255
Paul R. Donavan
Typically, the noise emission from trucks under highway cruise conditions is not reduced as much as it is for light vehicles when quieter pavements are used. Potential reasons for this are that other noise sources beside tire/pavement noise are more significant for trucks than light vehicles and/or the effect of pavement on truck tire noise generation is different than it is for light vehicle. As the cruising passby noise levels of trucks are about 10 dB greater than for light vehicles, this becomes an important issue for highway noise abatement when trucks make up even a relatively small percentage of the traffic flow. To investigate this issue, beam forming and conventional passby testing methods were used to investigate the contribution of both tire/pavement noise and the other noise sources for common types of heavy trucks.
2007-04-16
Technical Paper
2007-01-1106
Vincent Blervaque, Klaus Mezger, Leo Beuk, Jan Loewenau
Digital maps have large potential to enhance or enable Advanced Driver Assistance Systems (ADAS) by extending driver horizon and therefore to contribute to safer, smarter and cleaner road transport. As a predictive sensor called ADAS Horizon, in-vehicle digital maps are an important source of information providing look-ahead capability for ADAS applications and providing further information for on-board sensors to enhance environment perception. This paper reports on results from the European Commission project MAPS&ADAS, part of PReVENT Integrated Project, dedicated to the development, test and validation of a standardized interface (ADAS Interface) between ADAS applications and ADAS map data sources for accessing map data regarding vehicle position.
2007-04-16
Technical Paper
2007-01-1320
Shunji Miyahara
A method, which determines the range and lateral position of a preceding vehicle on the road by a single image, had been proposed. It is based on the Range-Window algorithm (RWA) and Pattern Matching (PM). The RWA estimates the range by using multiple virtual windows of fixed physical size at different distances. The size ratio between the windows and a preceding vehicle determines the best window. The associated range of the window will be the range of the vehicle. The PM complementarily estimates the range by using a template obtained through the RWA. It works especially well when an occlusion occurs due to shadows of road side objects. The range estimation is based on the use of horizontally-modified patterns of the template. Namely this PM can perform the range estimation as well as the object extraction. Here, for the real time operation, the calculation time of this method was evaluated after coding the RWA and PM into C-language (16 bit calculation) from Matlab (64 bit).
2007-04-16
Technical Paper
2007-01-1319
Maxime Flament, Matthias Schulze, Tapani Mäkinen, Joachim Irion
The integrated project PReVENT takes a first comprehensive step towards realising the vision of a safety zone around vehicles by means of complementary safety functions. The foundation for requirements are laid in the analysis of driver behaviour and accidents, followed by a definition of functions needed from a vehicle to prevent the accident from happening or mitigating its consequences. As a result, the most critical accident scenarios are covered by the applications developed. Furthermore, a requirements database is created and requirements are classified into six main categories. A common PReVENT architecture is presented and highlighted by a sub-project focusing on lateral safety applications. Finally, the approach to further integrate individual preventive safety functions on a common platform is outlined.
2007-04-16
Technical Paper
2007-01-1108
Guopei Liu, Denis Gingras
In positioning navigation systems, at any time, any of the sensors can break down or stop sending information, temporarily or permanently. To ensure a practical solution for use in guidance and navigation systems, faulty sensors must be detected and isolated such that their erroneous data will not corrupt the global position estimates. It is well known that Kalman filter is usually being used for data fusion applications. An interesting novel alternative is to use it for fault detection architecture as well. This paper describes the research conducted to evaluate the potential of combining fault detection and data fusion into a single architecture to make a robust positioning navigation system.
Viewing 241 to 270 of 1648