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Viewing 1 to 30 of 7046
2017-09-23
Technical Paper
2017-01-1954
Peng Hang, Xinbo Chen, Fengmei Luo
Path tracking is the rudimentary capability and primary task for autonomous ground vehicles (AGVs). In this paper, a novel four-wheel-independent-steering (4WIS) and four-wheel-independent-drive (4WID) electric vehicle (EV) is proposed which is equipped with steer-by-wire (SBW) system. Compared with conventional front-wheel-steering (FWS) vehicles, 4WIS and 4WID EV has superior maneuverability, handing stability and path-tracking capability thanks to more actuators. Therefore, it is more suitable for a desired AGV. For path-tracking controller design, the nonlinear vehicle model with 2 degrees of freedom (DoF) is built utilizing the nonlinear Dugoff tire model. The nonlinear dynamic model of SBW system is conducted as well considering the external disturbances.
2017-09-23
Technical Paper
2017-01-1962
Hongluo Li, Yutao Luo
With the rapid development of science and technology, intelligent electric vehicle (IEV) has gradually become the research focus to the scholars. The planning of the trajectory and the accurate path tracking ability are the two key technologies to realize the intelligent driving objective. This paper is conducted in this field that related research about intelligent drive to study the optimal steering wheel angle input.This paper proposes a method that dynamically plans the trajectory, not only to achieve quick reaction to the changing driving environment, but also to optimize the balance between vehicle performance and driving efficiency. First of all, the lane changing trajectory was planned based on the positive and negative trapezoidal lateral acceleration method, synchronously, the multi-objective optimization function was built which comprehensive such indexes: lateral acceleration/ lateral acceleration rate/ yaw rate/lane changing time and lane changing distance.
2017-09-23
Technical Paper
2017-01-1964
Xiangkun He, Xuewu Ji, Kaiming Yang, Yulong Liu, Jian WU, Yahui Liu
Highway traffic safety has been the most serious problem in current society, statistics show that 70% to 90% of accidents are caused by driver operational errors. The autonomous emergency braking (AEB) is one of important vehicle intelligent safety technology to avoid or mitigate collision. The AEB system applies the vehicle brakes when a collision is eminent in spite of any reaction by the driver. In some technologies, the system forewarns the driver with an acoustic signal when a collision is still avoidable, but subsequently applies the brakes automatically if the driver fails to respond. This paper presents the development and implementation of a rear-end collision avoidance system based on hierarchical control framework which consists of threat assessment layer, wheel slip ratio control layer and integrated-electro-hydraulic brake (IEHB) actuator control layer.
2017-09-23
Technical Paper
2017-01-2010
Junfeng Yang, Michael Ward, Jahangir Akhtar‎
The INSIGHT project aims to develop driverless shuttles with advanced sensors and control systems for testing pedestrian areas with a focus on improving urban accessibility for disabled and visually-impaired people. The project activities require a safety case to provide guidance to identify and classify hazardous events, and avoid these risks by providing appropriate requirements and processes. The safety approach complying with requirements in ISO 26262 has been employed to generate series of hazardous events, safety goals and functional safety requirements in the vehicle level throughout the entire development lifecycle process. The technical focus of this study is on navigation system, human-machine interaction system and vehicle motion control system, e.g. steering, propulsion, suspension and brake. The malfunctioning behaviour of these system has been assessed, and their safety with layers of protection are produced based on the present method.
2017-09-23
Technical Paper
2017-01-1952
ChengJun Ma, Fang Li, Chenglin Liao, Lifang Wang
With the increasing number of vehicles, the load of urban traffic system becomes more serious, and the Automatic Parking System (APS) plays an important role in alleviating the burden of drivers and improving vehicle safety. Therefore, it is essential to study high performance automatic Parking technology. The APS is consisted of environmental perception, path planning and path following.The path following controls the lateral movement of vehicle during the parking process, and requires the trajectory tracking error to be as small as possible. At present, some control algorithms are used including PID control, pure pursuit control, etc. However, these algorithms relying heavily on parameters and environment, have some problems under large curvature conditions, such as slow response and low precision. To solve this problem, a path following control method based on Model Predictive Control (MPC) algorithm is proposed in this paper.
2017-09-23
Technical Paper
2017-01-1983
Bing Zhu, Shude Yan, Jian Zhao, Weiwen Deng, Ning Bian
Electric power steering system (EPS) is a kind of dynamic control system for vehicle steering, which can amplify the driver steering torque inputs to the vehicle to improve steering comfort and performance, but the present EPS can’t cater to the driving habits of different people. In this paper, a personalized EPS controller is designed based on the driver behavior, which combines real-time driver behavior identification strategy with personalized assistance characteristic curve. Firstly, the driver behavior data acquisition system is designed and established, based on which, the input data of different kinds of drivers along with vehicle signals are collected under typical working conditions, then the identification of driver usage modes on line is realized using the BP neural network.
2017-09-17
Technical Paper
2017-01-2501
ByeongUk Jeong, HYOUNG TAE Ryu, Kwang Ki Jung, Chang Jin Kim
Owing to the enhanced performance of engines these days, more heat should be dissipated in the braking system. Sucess of doing this properly causes more heat to the disc in the brake system which results in the deformation or scratches on the surface of it and a reduction in the appearance of the product. A study for detailed factors to aggravate this was done as a solution to prevent these form happening. In this paper, we present our work based on experiments to study MPU(Metal Pick Up) of the pad and the scoring(scratching)of the disc. MPU of which the main component is "Fe", is formed through the process of fusing the separated materials from the disc by friction wiht the pad, and by local heat generation to the pad. The occurrence of MPU and the possibility of the disc scoring resulting from this were studied by noting "Fe" which was transferred to the surface of the pad to different extent and degree of segregation according to the roughness of disc.
2017-09-17
Technical Paper
2017-01-2496
Enrico Galvagno, Antonio Tota, Alessandro Vigliani, Mauro Velardocchia
Brake systems represent important components for passenger cars since they are strictly related to vehicle safety: Anti-lock Braking Systems (ABS) and Electronic Stability Control (ESC) are the most well-known examples. The paper is focused on the characterization of the braking hydraulic plant and on the design of a pressure following control strategy. This strategy is aimed at pursuing performances and/or comfort objectives beyond the typical safety task. Caliper pressure dynamics is evaluated through a lumped parameter model which is used to design the controller. The low-level logic (focus of the paper) consists of a Feedforward and Proportional Integral controller. A Hardware In the Loop (HIL) braking test bench is adopted for pressure controller validation by providing some realistic reference pressure histories evaluated by a high-level controller.
2017-09-17
Technical Paper
2017-01-2498
David B. Antanaitis, E Lloyd
This paper describes the development work that went into the creation of the J3052 “Brake Hydraulic Component Flow Rate Measurement at High Delta Pressure”, and also shows some example applications of it. The J3052 recommended practice is intended to measure flow characteristics through brake hydraulic components and subsystems driven by pressure differentials above 1 bar, and was anticipated by the task force to be invoked for components and subsystems for which pressure response characteristics are critical for the operation of the system (such as service brake pressure response and stopping distance, or pressure rise rate of a single hydraulic circuit in response to an Electronic Stability Control command).
2017-09-17
Technical Paper
2017-01-2499
Xianyao Ping, Yuxin Pang, YU TANG
The engine brake is widely used as auxiliary brake device for its continuous brake torque. The engine brake performance is usually determined in the laboratory or proving ground according to relevant standards. The main purpose of this paper is to introduce an on-vehicle measurement system to measure the engine brake performance in the driving process. The on-vehicle measurement system makes use of the vehicle driving information to deduce the engine brake performance during transportation, which can reduce the test times in the laboratory or proving ground and the sensor cost. The measurement system based on the vehicle longitudinal dynamics can adapt to various vehicle automatically without measuring the vehicle or engine parameters before installation. And the measurement system can also estimate gross vehicle mass approximately.
2017-09-17
Technical Paper
2017-01-2484
Yoshiyuki Yamaguchi, Tsuyoshi Kondo
We considered the relation between disc brake’s in-plane mode noise and exciting energy which flows into pad surface for improving brake noise performance. The exciting energy is calculated by the pad’s displacement of disc rotating direction and pad thickness direction which is acquired by 3D scanning laser Doppler measurement system.
2017-09-17
Technical Paper
2017-01-2482
Meechai Sriwiboon, Nipon Tiempan, Kritsana kaewlob, Seong K Rhee, Donald Yuhas
Disc pad physical properties are believed to be important in controlling brake friction, wear and squeal. Thus these properties are carefully measured during and after manufacturing for quality assurance. For a given formulation, disc pad porosity is reported to affect friction, wear and squeal. This investigation was undertaken to find out how porosity changes affect pad natural frequency, dynamic modulus, hardness and compressibility for a low-copper formulation and a copper-free formulation, both without underlayer. Pad natural frequency, modulus and hardness all decrease with increasing porosity. When pad compressibility is measured by compressing several times as recommended and practiced, the pad surface hardness is found to increase while pad natural frequency and modulus remain essentially unchanged. However, there is no consistent pattern in compressibility change with increasing porosity, and thus a question arises on the validity of compressibility measurement.
2017-09-17
Technical Paper
2017-01-2488
Manuel Pürscher, Peter Fischer
Vehicle road tests are meaningful for investigations of creep groan noise. However, problems in reproducing experiments and partly subjective evaluations may lead to imprecise conclusions. This work proposes an experimental test and evaluation procedure which provides a precise and objective assessment of creep groan. It is based on systematic corner test rig experiments and an innovative characterization method. The exemplary setup under investigation consisted of a complete front wheel suspension and brake system including all relevant components. The wheel has been driven by the test rig’s drum against a brake torque. The main parameters within a test matrix were brake pressure and drum velocity. Both have been varied stepwise to scan the relevant operating range of the automobile corner system for potential creep groan noise. Additionally, the experiments were extended to high brake pressures, where creep groan cannot be observed under road test conditions.
2017-09-17
Technical Paper
2017-01-2486
Kyung Jae Lee
Brake grinding noise is caused by the friction of the disc and pads. The friction generates vibration and it transmits to the body via the chassis system. We calle it structure-borne noise. To improve the noise in the vehicle development, the aspects of chassis or body's countermeasure occurs many problems, cost and time. In this reason many brake company try to make solution with brake system, like brake friction materials or disc surface. However the countermeasure of excitation system also have a lot of risk. It could occur side-effects of braking performance, and need to reverify brake noise like Creep-groan, Groan, Squeal, Judder and so on. In conclusion, It is very important making robust chassis system in initial vehicle development stage. This paper is about rear brake grind noise path analysis and countermeasure of chassis system. There are two steps to analysis. First step is impact hammer test like FRF, MODAL test.
2017-09-17
Technical Paper
2017-01-2531
Georg Peter Ostermeyer, Bastian Recke
In recent years, characteristic structures in the boundary layer of high-load contacts such as brakes have been reported, which have an important impact on the dynamics of the tribological contact. Usually, local assumptions concerning the friction of these patches are used to reach global conclusions about the brake system. Several numerical methods (e.g. Cellular Automata) have been developed which make use of such assumptions. The validation of these methods through measured data tends to be laborious and costly. Sprag-Slip elements are friction elements which are typically considered to exclusively undergo static friction. Such elements have been sporadically utilized towards describing friction in brake applications. In this paper, many locally distributed Sprag-Slip elements are used to model the global dynamics of braking friction. The results show good agreement with the measured characteristics of brakes.
2017-09-17
Technical Paper
2017-01-2528
Seongjoo Lee, JeSung Jeon, JooSeong Jeong, Byeongkyu Park, ShinWook Kim, ShinWan Kim, Seong Kwan Rhee, Wan Gyu Lee, Young sun Cho
It is widely believed or speculated that higher pad compressibility leads to reduced brake squeal and that caliper design can affect brake squeal. After encountering anecdotalcontradictory cases, this investigation was undertaken to systematically generate basic data and clarify the beliefs or speculations. In order to adjust pad compressibility, it is common to modify molding temperatures, pressures and times, which in addition to changing the compressibility, changes the coefficient of friction at the same time. In order to separate these two effects, NAO disc pads were prepared under the same molding conditions while using different thicknesses for the underlayer to achieve different compressibilities, thus changing compressibility without changing thecoefficient of friction. Test results show brake squeal increasing with increasing compressibility, contrary to the common belief.
2017-09-17
Technical Paper
2017-01-2500
Bo Huang, Longjie Xiao
Head-up Display (HUD) system can avoid divers’ distraction on dashboard and effectively reduce collisions caused by emergency events, which is gradually being realized by researchers around the world. However, the current HUD only displays information like speed, fuel consumption, other information like acceleration and braking can’t be displayed yet. This research will uses the color and position change of the indicator symbol to remind drivers of braking information like braking time, braking severity, which can alert drivers to make braking operations timely and accurately. The system has the advantages of safe, intuition and real-time. The vehicle safety speed is calculated according to the road parameters like adhesion coefficient, slope and curvature as well as vehicle parameters like vehicle mass and centroid. And then the appropriate braking operations like braking time are obtained by combining the vehicle status like speed and steering.
2017-09-17
Technical Paper
2017-01-2487
Yasuyuki kanehira, Yusuke Aoki, Yukio Nishizawa
Brake squeal is uncomfortable noise that occurs while braking. It is an important issue for automobile quality to prevent brake products from squealing. Brake shims are widely used to reduce squeal occurrence rate. In particular, laminated shims can effectively suppress squeal via the viscoelastic damping of an adhesive layer. However, there are cases where the damping performance at low temperature and the durability performance at high temperature deteriorate. In that regard, we thought of applying frictional damping to shims instead of relying on a temperature-sensitive adhesive layer. To study the application of frictional damping as a new damping mechanism for shims, it is necessary to clarify the characteristics thereof. In order to quantify the damping performance of shims, loss factor has been generally measured with a bending mode tester. However, the influence of friction cannot be evaluated because it is measured under pressure-free condition.
2017-09-17
Technical Paper
2017-01-2485
Tarun Teja Mallareddy, Peter Blaschke, Sarah Schneider, Daniel J. Alarcón
Brake squeal is an NVH issue experienced by brake systems and vehicle manufacturers for decades. This leads to customer dissatisfaction and the questioning of quality of the brake system. Advanced testing tools, design modification, dynamometer testing, vehicle validation etc., are performed to study, analyze and eliminate this problem. But, still it continues to exist. One of the most important reasons is the complexity of the brake pad which leads to its non-linear properties. Therefore, it is imperative to understand the behavior of the brake pad, in terms of its dynamic properties (eigenfrequencies, damping and mode shapes), under varying boundary conditions. Experimental Modal Analysis (EMA) is used to study the dynamic properties of any structure and is generally performed under free-free boundary conditions. An approach to study brake pads under pressure condition is a step towards reality, as brake pads squeal only during braking events.
2017-09-17
Technical Paper
2017-01-2492
Dejian Meng, Ziyi Wang, Lijun Zhang, Zhuoping Yu
Supposed disc surfaces have initial disc thickness variation (DTV) with 2 order sine function characteristics, a FE model of ventilated disc brake for transient thermomechanical coupling simulation was established. With the distribution of the temperature, the normal stress and the elastic deformation on disc surfaces for the evaluation, the influences of the initial DTV and its direction and maximum on thermomechanical coupling characteristics were analyzed. The simulation results show that the temperature, the normal stress and the thickness variation have a 2 order sine function characteristic in circumferential direction, which is the most important difference between the thermomechanical coupling characteristics with and without the initial DTV. The 2 order sine function distribution in circumferential direction is related with the initial DTV direction and tendency.
2017-09-17
Technical Paper
2017-01-2490
Qianjin Yang, Baozhi Zhang, Kangrong Ding, Liqiang Song
A brake disc is one of the most critical components in modern vehicle’s brake systems, and is always among the top customer concerns of safety and conformability. To meet the challenges in its applications, strict validation of the brake disc performances in the development process is necessary. These performances include its ability to sustain its designed functions under extreme loading conditions; the high-cycle and low-cycle durability under repeated thermal and/or mechanical loading; and fine NVH performances and environment friendly. Finite element analysis, one of the most popular CAE tools, has become a great validation tool in the brake disc development process. In this paper, a disc brake system under a constant braking torque is analyzed using finite element method, in which the stress and strain in the ventilated brake disc employed are the major concern.
2017-09-17
Technical Paper
2017-01-2491
Baskar Anthonysamy, Arun kumar Prasad, Babasaheb Shinde
Fierce competition in India’s automotive industry has led to constant production innovation among manufacturers. This has resulted in the reduction of the life cycle of the design philosophies and design tools. One of the performance factors that have continues to challenge automotive designer is to design and fine tune the braking performance with low cost and short life cycle. Improvement in braking performance and vehicle stability can be achieved through the use of braking systems whose brake force distribution is variable. Braking force distribution has an important and serious role in the vehicle stopping distance and stability. In this paper a new approach will be presented to achieve the braking force distribution strategy for articulated vehicles. For this purpose, the virtual optimization process has been implemented. This strategy, defined as an innovative braking force distribution strategy, is based on the wheel slips.
2017-09-17
Technical Paper
2017-01-2481
Vishal Mahale, Jayashree Bijwe, Sujeet Sinha
Potassium titanate (KT) fibers/whiskers are used as a functional filler for partial replacement of asbestos in NAO friction materials (FMs). Based on little information reported in open literature; its exact role is not well defined since some papers claim it as the booster for resistance to fade (FR), or wear (WR) and sometimes as damper for friction fluctuations. Interestingly, KT fibers and whiskers (but not powder) are proved as carcinogens by the International Agency for Research on Cancer (IARC). However, hardly any efforts are reported on exploration of influence of KT powder and its optimum amount in NAO FMs (realistic composites) in the literature. Hence a series of five realistic multi-ingredient compositions in the form of brake-pads with similar parent composition but varying in the content of KT powder from 0 to 15 wt% (in the steps of 3) were developed. These composites were characterized for physical, mechanical, chemical and tribological performance.
2017-07-10
Technical Paper
2017-28-1926
Jos Frank, Sohin Doshi, Manchi Rao, Prasath Raghavendran
Abstract In today’s automotive scenario, noise vibration and harshness (NVH) has become a synonym for quality perception. This paper evaluates the problem of vibration and noise experienced in M2 category 40 seat bus and suggests the counter measures. Severe vibration is experienced on the bus floor, predominantly towards rear part of the bus. Vibration along with acoustic boom occurs prominently in 4th gear wide open throttle operating condition between 1300-1600 rpm of the engine. This paper focuses on reducing NVH levels by working on the transfer path with little modifications on power-train. Preliminary torsional measurements conducted on powertrain indicated high torsional excitation in the driveline during the problematic rpm zone. Further, Operational Deflection Shape (ODS) analysis revealed that the transfer path to the cabin is rear differential unit and suspension links. The dominant frequencies were identified along the transfer path and suitable modifications were done.
2017-07-10
Technical Paper
2017-28-1941
Anil Kumar Jaswal, Rajasekhar Madhurakavi, Pradeep Chandrasekaran
Abstract This paper details the methodology used to show the importance of Low rolling resistance tires in Electric Vehicles. Fuel efficiency and range is paramount with most of the electric vehicle buyers. Although many people are now becoming aware of low rolling resistance tires but its development started way back in 1990’s. It is always challenging to achieve low rolling resistance in smaller tires of size 12 inch or 13 inch along meeting the other critical vehicle parameters such as ride and handling, NVH, durability and many more. The reduction in rolling resistance can also affect the traction properties of tires. In case of very low rolling resistance tires the traction will be very less but it can badly affect the other vehicle parameters. Selection of tires further depend upon the RWUP (Real World Usage Profile). It means the vehicle is targeted for which region and what is the condition of roads there.
2017-07-10
Technical Paper
2017-28-1952
Utkarsh Sharma, Simson T. Wilson, Santosh Lalasure, K. Rajakumar
Abstract Today’s automotive industry in the process of better fuel efficiency and aiming less carbon foot print is trying to incorporate energy saving and hybrid technologies in their products. One of the trends which has been followed by Original Equipment Manufacturers (OEMs) is the usage of Electric Power Steering (EPS) system. This has been an effective option to target fuel saving as compared to hydraulically assisted power steering system. EPS has been already tested successfully, not only on system level but also on vehicle level for endurance and performance by OEMs as per their norms and standards. Over the decade, NVH (noise, vibration & harshness) have become one of the touch points for customer perception about vehicle quality. This leads us to a commonly perceived problem in EPS or manual type steering system i.e. rattle noise.
2017-07-10
Technical Paper
2017-28-1985
Hemasunder Banka, Radhika Muluka, Vikram Reddy
Abstract Conventional materials like steel, brass, aluminum etc will fail without any indication, cracks initiation, propagation, will takes place with a short span. Now-a-days to overcome these problem, conventional materials are replaced by hybrid composite material. Not only have this conventional material failed to meet the requirement of high technology applications, like space applications and marine applications and structural applications in order to meet the above requirements new materials are being searched. Hybrid composites materials found to the best alternative with its unique capacity of designing the materials to give required properties and light weight. This paper aims to preparing hybrid composite using artificial fibers. Epoxy as resin and glass fiber as fiber for artificial hybrid composite to make a laminate for preparing leaf spring.
2017-06-05
Technical Paper
2017-01-1804
Chulwoo Jung, Hyeon Seok Kim, Hyuckjin Oh, Kwang Hyeon Hwang, Hun Park
Abstract An efficient method to determine optimal bushing stiffness for improving noise and vibration of passenger cars is developed. In general, a passenger vehicle includes various bushings to connect body and chassis systems. These bushings control forces transferred between the systems. Noise and vibration of a vehicle are mainly caused by the forces from powertrain (engine and transmission) and road excitation. If bushings transfer less force to the body, levels of noise and vibration will be decreased. In order to manage the forces, bushing stiffness plays an important role. Therefore, it is required to properly design bushing stiffness when developing passenger vehicles. In the development process of a vehicle, bushing stiffness is decided in the early stage (before the test of an actual vehicle) and it is not validated until the test is performed.
2017-06-05
Technical Paper
2017-01-1805
Krzysztof Prażnowski, Jaroslaw Mamala
Abstract The vibrations of the sprung mass of a passenger car, traveling along a road surface, are random. They also form its main source but there are besides other factors to consider. The resulting force ratio is overlapped by other phenomena occurring at the interface of the pneumatic tire with the road surface, such as non-uniformity of tires, shape deformations and imbalances. The resulting additional inertia force acts on the kinematic force that was previously induced on the car body. The vibrations of the sprung mass of the car body at the time can be considered as a potential source of diagnostic information, but getting insight their direct identification is difficult. Moreover, the basic identification is complicated because of the forces induced due to the random interference from road roughness. In such a case, the ratio defined as SNR assumes negative values.
2017-06-05
Technical Paper
2017-01-1778
Enrico Galvagno, Antonio Tota, Mauro Velardocchia, Alessandro Vigliani
Abstract This paper explores the potentiality of reducing noise and vibration of a vehicle transmission thanks to powertrain control integration with active braking. Due to external disturbances, coming from the driver, e.g. during tip-in / tip-out maneuvers, or from the road, e.g. crossing a speed bump or driving on a rough road, the torsional backlashes between transmission rotating components (gears, synchronizers, splines, CV joints), may lead to NVH issues known as clonk. This study initially focuses on the positive effect on transmission NVH performance of a concurrent application of a braking torque at the driving wheels and of an engine torque increase during these maneuvers; then a powertrain/brake integrated control strategy is proposed. The braking system is activated in advance with respect to the perturbation and it is deactivated immediately after to minimize losses.
Viewing 1 to 30 of 7046

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