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Viewing 61 to 90 of 10119
2015-04-14
Technical Paper
2015-01-0625
Manfred Baecker, Axel Gallrein, Michael Roller
The tire plays a fundamental role in the generation of acoustically perceptible driving noise and also in the generation of vibrations inside the vehicle. Drivers and passengers will perceive vibrations inside the vehicle as interference of their physical comfort. An essential part of these vibrations will be induced by the road excitation and be transferred via the tire into the vehicle. There are 2 basic ways to study the NVH behavior of a tire or a full vehicle including a tire: • Transient simulation scenario • Frequency based or modal simulation scenario In the first case the tire or full vehicle will be simulated using a transient dynamic simulation method. The vehicle or tire is driving over an arbitrary digitized road profile. There is no need for a stationary driving state or for the necessity of a constant driving velocity.
2015-04-14
Technical Paper
2015-01-1580
He Dengbo, Lu Hui, Yu Fan
In this paper, a vehicle chassis integrated control system is designed to improve vehicle stability by wheel torque control and steering wheel control, i.e. allocating desired yaw moment and lateral force to slip ratio of four wheels and also applying additional steering angle. In the designed system, a model predictive controller (MPC), a robust optimal allocation algorithm and a sliding-mode controller are respectively designed to overcome the uncertainty and nonlinearity of tire-road contacts. The controller system includes three levels: 1) In high level, by using designed MPC controller in which a linear time-varying model is used as the inner model, the desired yaw rate and lateral force are calculated based on a bicycle model and driver steering input.
2015-04-14
Technical Paper
2015-01-0665
Yongchang DU, Yujian Wang, Pu Gao, Yingping Lv
Modelling of disc in brake squeal analysis is complicated because of the rotation of disc and the sliding contact between disc and pads. Many analytical or analytical numerical combined modeling methods have been developed considering the disc brake vibration and squeal as a moving load problem. Yet in the most common used complex eigenvalue analysis method, the moving load nature normally has been ignored. In this paper, a new modelling method for rotating disc from the point of view of modal is presented. First finite element model of stationary disc is built and modal parameters are calculated. Then the dynamic response of rotating disc which is excited and observed at spatial fixed positions is studied. The frequency response function is derived through space and time transformation. The equivalent modal parameter is extracted and expressed as the function of rotation speed and original stationary status modal parameters.
2015-04-14
Technical Paper
2015-01-0668
Yongchang DU, Pu Gao, Yujian Wang, Yingping Lv
The study and prevention of unstable vibration is a challenging task for vehicle industry. Improving predicting accuracy of braking squeal modal is of great concern. Closed-loop coupling disc brake model is widely used in complex eigenvalue analysis and further analysis. The coupling stiffness of disc rotor and pads is one of the most important parameters in the model. But in most studies the stiffness is calculated by simple static force-deformation simulation. In this paper, a closed-loop coupling disc brake model is built. Initial values of coupling stiffness are estimated from static calculation. Experiment modal analysis of stationary disc brake system with brake line pressure and brake torques applied is conducted. Then an optimization process is initiated to minimize the differences between modal frequencies predicted by the stationary model and those from test. Thus model parameters more close to reality are found.
2015-04-14
Technical Paper
2015-01-1345
Srinivas Kurna, Arpit Mathur, Sandeep sharma
In commercial vehicle, Leaf Spring design is an important milestone during product design and development. Leaf springs are the most popular designs having multiple leaves in contact with each other and show hysteresis behavior when loaded and unloaded. Commonly used methods for evaluation of leaf spring strength like endurance trials on field and Rig testing are time consuming and costly. On the other hand, virtual testing methods for strength and stiffness evaluation give useful information early in the design cycle and save considerable time and cost. They give flexibility to evaluate multiple design options and accommodate any design change early in development cycle. A study has been done in VECV to correlate rig result with FEA simulation result of Multi-stage Suspension Leaf Spring, entirely through Finite Element Analysis route. Virtual leaf spring with U-Clamps and Suspension brackets with revolute joints are modeled in FEA which is similar to rig test bed setup.
2015-04-14
Technical Paper
2015-01-1356
Atishay Jain
Swingarm, originally known as the swing fork or pivoted fork is a dynamic structural part of the rear suspension of most modern motorcycles. It is used to hold the rear axle firmly, while pivoting vertically on the frame, to allow the suspension to absorb bumps in the road. Driving and braking loads are also transmitted through the swing arm, and thus, it plays a major role in vehicle dynamics. Weight minimization is important in a swingarm as it is largely an unsprung mass. The conventional swingarm design includes steel tubing and sheet metal structures. Due to higher forces near the pivot, conventional swingarm are inherently over-designed as they use tubular structures of same cross section through the entire length of the swingarm. An aluminum alloy swingarm design even when subjected to casting manufacturing constraints, has the potential for better material layout and weight minimization.
2015-04-14
Technical Paper
2015-01-1371
Samuel T. Bartlett
With the many model variations produced on the same production line because of increasing power train options, fuel efficiency targets, performance and customer demands we saw limitations with our existing suspension mount equipment. Layout options were limited due to guided shifts and transfers. Large supporting frame work took up valuable floor space. Model wheelbase sizes and suspension pallets were limited to the model requirements of the original equipment. We needed an adaptable system to install the engine/front suspension assemblies and the rear suspension assemblies. We found a solution by utilizing the capabilities of 6-axis industrial robots to make the core components of the equipment simpler; many of the functions of a traditional machine can now be accomplished by the robot. We were able to vary install position to optimize handling characteristics and accommodate the model-to-model varieties on the same production line.
2015-04-14
Technical Paper
2015-01-1088
Tomohiko Usui, Tomoya Okaji, Tatsuya Muramatsu, Yoshiyuki Yamashita
A low-cost lock-up damper displaying a high level of damping performance has been developed for use in torque converters in automatic transmissions. The new damper was actualized by sharing parts (the turbine and damper components) and optimizing parameters for damping characteristics. The new torque converter displays equivalent conversion performance to a conventional model while reducing the width of the torus by approximately 30%. The combination of the lock-up damper and the small torus has made it possible to reduce torque fluctuation transmitted to the transmission to less than 50% with no increase in the overall width of the torque converter against a conventional model. This has reduced engine speed when the vehicle is cruising by 400rpm, resulting in an increase in fuel efficiency of approximately 2%.
2015-04-14
Technical Paper
2015-01-1323
DaWei Gao, Cui Ling, Qin Xiao
The geometrical relationship between the shear center of twist beam rear axle and instantaneous roll center of the suspension can be established by using graphical method. The formula of the relationship between roll center of the suspension and shear center of twist beam rear axle, positions of hard points can be derived. Simulation verification was taken by using CAE software and experimental verification was taken by choosing two cars with two different twist beam rear suspension. Veracity of the formula was verified. The basis was provided for development in the early age and subsequent design.
2015-04-14
Technical Paper
2015-01-1328
DaWei Gao, XU Jun, Zheng lin
Taking a domestic brand car as example, this paper is about how to find out a three-point nonlinear stiffness characteristic curve which can meet the requirements of variable stiffness and three-load condition. The new coil spring gives the passive suspension a lot of improvement in riding and safety, changing the nonlinear stiffness characteristic performance from weak to strong. This paper summarizes the optimization design method for the rear suspension coil spring, including the fitting of ideal stiffness characteristic curve,quantitative method for figuring out how the change of vehicle load influences the load on rear suspension axle,the design method of variable stiffness coil spring which corresponds to the change of vehicle load. A new kind of modified ideal point solution for building the objective function was also put forward.
2015-04-14
Technical Paper
2015-01-0216
Ping-Min Hsu, Ming Hung Li, Kuo-Ching Chang
This paper studies noise filtering in an autonomous emergency braking (AEB) system with a sensor fusion between a millimeter wave (MMW) radar and a camera. The AEB system may automatically brake cars by mistake due to the sudden appearance of noise signal if it does not involve any noise filtering mechanism for the object sensor. This may cause some accidents. To avoid such accidents, we propose the filters for three kinds of noise—named as twice harmonic noise, ground noise, and specular refection noise—which are commonly suffered while applying MMW radars. The former is caused by the reflection of a radar wave between a target object and the MMW radar. Based on the concern that the MMW radar evaluates the sensing distance based on the time interval between the transmitting and receiving of the radar wave, one of the sensing distances would be twice as longer as one of others due to the wave reflection. The object featuring this characteristic is further filtered.
2015-04-14
Technical Paper
2015-01-0316
Kazuto Yokoyama, Masahiro Iezawa, Yohei Akashi, Toshihide Satake, Yukiyasu Akemi, Satoru Inoue, Ryotaro Suzuki
Parking assist systems which relieve burden of drivers have been put into practice in the world. Mitsubishi Electric has also been developing several technologies to achieve the system. Peripheral environment around the car in a parking lot is detected with Mitsubishi Electric’s ultrasonic sensors, and an algorithm makes a map of the environment to determine whether or not the car can park at an available space. On the basis of the created map, a smooth and efficient path to drive and park the car is generated with an optimization technique. While the car is moving to the available space, the position and attitude of the vehicle is estimated from wheel speed sensors and yaw rate one. Steering is automatically controlled with a Mitsubishi Electric’s electric power steering system. In particular, this paper focuses on a speed control which can be applied to an automatic driving control including an automatic parking system.
2015-04-14
Technical Paper
2015-01-0159
Zhihui Tan, Zhenfu Chen, Xiaofei Pei, Jie Zhang, Xuexun Guo
Analogous to a vacuum boosted system, Electro-Hydraulic Braking System (EHB) supplies a braking force proportional to driver input, and is especially fit for electric vehicles (EV) and hybrid electric vehicles (HEV). As a key component of EHB, this paper introduces a new integrated master cylinder which is developed from the traditional one. However, the master cylinder is driven by the pump rather than the vacuum booster. Even if the pump fails, the cylinder can also build proper pressure. Meanwhile, in the EHB system, the connection between master cylinder and pedal is structurally decoupled. So the cylinder and pedal can be independently designed and controlled. Furthermore, the pressure surge in the master cylinder will not affect pedal feeling. In this paper, the EHB system is designed including two parts: master cylinder and pedal stroke simulator.
2015-04-14
Technical Paper
2015-01-1500
Marcus Ljungberg, Mikael Nybacka, Gaspar Gil Gómez, Diomidis Katzourakis
This paper present and discusses the process to parameterize an electric power assist steering (EPAS) system, employing solely computer-aided engineering (CAE). It addresses the model and the simulation environment setup as-well-as methods for setting the optimal metric targets, based on correlation studies from expert test drivers. The rationale for the study derives from today’s vehicle manufacturer’s needs, to develop high quality cars in a short period of time that satisfy the consumer needs and to stand out in the competition. Further exploitation of the potentials of simulation and CAE tools is needed to enable quick evaluation of different vehicle concepts and setups without the need of building physical prototypes. The main goal of the current study is to facilitate the aforementioned need by developing and evaluating an optimisation process for the control parameters of an EPAS system by solely using CAE tools.
2015-04-14
Technical Paper
2015-01-1521
Kanwar Bharat Singh, Srikanth Sivaramakrishnan
Tread depth, inflation pressure, tire temperature, and road surface condition are among the most notable factors that have a noticeable effect on the tire force and moment characteristics. They can vary significantly during the operation of a tire and can effectively modify tire (and thus vehicle) performance. This study presents details of an adaptive magic formula (MF) tire model capable of coping with changes to the tire operating condition. More specifically, extensions have been made to the magic formula expressions for tire cornering stiffness and peak grip level, to account for variations in the tire inflation pressure, load, tread-depth and temperature. As a next step, the benefits of using an adaptive tire model for vehicle control system applications is demonstrated through simulation studies for enhanced vehicle control systems using an adaptive tire model in comparison to traditional control systems based on a non-adaptive tire model with fixed model parameters.
2015-04-14
Technical Paper
2015-01-1567
Scott Bradley Zagorski, Tomoya Ushimura, James Post
Many vehicle dynamics handling simulations have utilized a constant speed two degree-of-freedom bicycle model. To add greater fidelity, a third (roll) degree-of-freedom has been included. The input to this model is typically road wheel angle. However, in an actual vehicle, the driver’s input is handwheel angle. Usually, to relate the two a simple kinematic relationship, on-center steering ratio, is used; however, the system dynamics of the steering system have considerable influence on overall vehicle response. By considering the chassis and steering system at an early stage of development then the interaction of the two can be characterized. Power steering system models are typically hydraulic-based power steering (HPS); however, contemporary power steering systems are predominantly electric-based (EPS). This research develops an EPS model which includes a three degree-of-freedom (DOF) steering model coupled with a three degree-of-freedom vehicle model and EPS maps.
2015-04-14
Technical Paper
2015-01-0627
Xiaoguang Yang, Oluremi Olatunbosun, Daniel Garcia-Pozuelo, Emmanuel Bolarinwa
The development of intelligent tyre technology from concept to application covers multi-disciplinary fields. During its development course, computational method has a significant effect on understanding tyre behaviour, assisting design of intelligent tyre prototype system and developing tyre parameters estimation algorithm, etc. In this paper, finite element tyre model was adopted for developing strain-based intelligent tyre system. The finite element tyre model was created considering tyre composite structure and nonlinear material properties, which was also validated by fundamental test. It is used to study tyre strain characteristics by steady state simulation for straight line rolling, traction and braking, and cornering rolling. Tyre loading conditions were estimated by feature extraction and data fitting. This process forms the fundamentals for identifying tyre loadings from strain information on potential sensor locations.
2015-04-14
Technical Paper
2015-01-0628
Bin Li, Xiaobo Yang, Yunqing Zhang, James Yang
As one of the most important components of a vehicle, a tire is essential for vehicle handling, ride comfort as well as durability. Although several decade efforts have been dedicated to tire modeling, there is still room to improve its performance. Currently tire models cannot accurately predict the longitudinal spindle force under severe road conditions. In order to improve the prediction results, a detailed in-plane flexible ring tire model is proposed based on multi body dynamic (MBD) approach in this paper. In this model, we discretize the belt into different belt segments, and each belt segment is considered as a rigid body and attached to a number of parallel tread blocks. This model is able to describe the tire behavior for the transformation among static condition, quasi-static rolling, as well as dynamic rolling conditions.
2015-04-14
Technical Paper
2015-01-1096
Robert Lloyd
Abstract The frequent occurrence of stops and starts on the typical postal delivery route makes it an attractive application for regenerative braking. The transmission described in SAE paper 2014-01-1717 contains all the functions necessary to implement hydraulic regenerative braking including the accumulator and reservoir. This paper describes the substitution of the hydro-mechanical transmission for the present transmission and estimates the performance benefits. The result in a low impact path for the US Postal Service to conform to the congressional mandate to improve the mpg of the vehicles and extend their useful life.
2015-04-14
Technical Paper
2015-01-0314
Junyung Lee, Beomjun Kim, Jongsang Seo, Kyongsu Yi, Jihyun Yoon, Bongchul Ko
This paper presents an automated driving control algorithm for the control of vehicle steering and acceleration of an autonomous vehicle. In order to develop a highly automated driving control algorithm, one of the research issues is to determine a safe driving envelope with the consideration of sensor uncertainties and probable risks. While human drivers maneuver the vehicle, they determine appropriate steering angle and acceleration based on the predictable trajectories of the surrounding vehicles. Therefore, not only current states of surrounding vehicles but also predictable behaviors of that should be considered in designing an automated driving control algorithm. The sensor uncertainties and probabilistic behavior characteristics are analyzed based on driving data collected on a real road.
2015-04-14
Technical Paper
2015-01-1568
Hyundong Heo, Eunhyek Joa, Kyongsu Yi, Kilsoo Kim
This paper describes an Integrated Chassis Control (ICC) strategy for improving high speed cornering performance by integration of Electronics Stability Control (ESC), Four Wheel Drive (4WD), and Active Roll Control System (ARS). In this study, an analysis of various chassis modules was conducted to prove the control strategies at the limits of handling. The analysis is focused to maximize the longitudinal velocity for minimum lap time and ensure the vehicle lateral stability in cornering. At first, the maximum velocity is described based on vehicle dynamics and tire characteristics. Next, an analysis of the wheel slip angle is studied to enhance the vehicle lateral stability in high speed. The proposed Integrated Chassis Control algorithm consists of a supervisor, vehicle motion control algorithms, and a coordinator. The supervisor monitors the vehicle status and determines desired vehicle motions such as a desired yaw rate, longitudinal acceleration and desired roll motion.
2015-04-14
Technical Paper
2015-01-1373
Yulong Lei, Hui Tang, Xingjun Hu, Adm Bin Song
With the continuous improvement of the road condition, commercial vehicles get to be faster and more overloaded than before, which puts higher pressure on the vehicle braking system. Conventional friction braking has been difficult to meet the needs of high-power commercial vehicle. The auxiliary brake equipment will become the future trend for commercial vehicle. Hydraulic retarder is superior secondary braking equipment. Previously hydraulic retarder research mainly focus on flow field analysis, the braking torque calculation, cascade system optimization and control methods for hydraulic retarder. The gas-liquid two-phase flow in working chamber is less researched. Based on this, this article discusses on the hydraulic retarder from two aspects, including CFD numerical modeling method, transient characteristics of oil-filling , which provides support for hydraulic retarder design and matching in the vehicle. The main contents and conclusions are as follows: 1.
2015-04-14
Technical Paper
2015-01-1585
Zubin Trivedi, Vivek Lakhera
The design of a vehicle must almost always consider the role of its handling in the product identity. In case of passenger vehicles especially, the design priority is how the dynamics behavior shall be perceived by the driver as well as the passengers. One of such many handling parameters is the vehicle roll, i.e. its rotation about the X axis as per VCS, which is usually quantified by the vehicle’s steady state roll gradient. This number gives an indication of the rotation of the vehicle body in response to a lateral force, as in the case while cornering, and is a standard accepted metric for vehicle roll behavior. However it does not necessarily indicate the roll as sensed by a person seated inside it, driver or passenger. It is often observed that a person seated inside a vehicle with a higher roll gradient may in some cases feel significantly lesser roll motion and have a more secure feel, than the same in some other vehicle with a lower roll gradient; and vice versa.
2015-03-30
Technical Paper
2015-01-0081
Chunguang Duan, Hsin Guan, Pingping Lu
With the development of computer and vehicle research to high frequency, the driving simulator plays an important role on vehicle research and pre-development. The driving simulator have already used for research about human factor, advanced active system (ABS, ESP et al), the vehicle engineering, intelligent transportation system (ITS) et al. The requirements for a driving simulator are that it should have realistic behavior. One aspect of the realistic behavior is that the driving simulator needs to be able to stop and to start again. The realistic behavior base on high-fidelity dynamic models especially tire model. “Tire/road” model is of special importance model for its influence on vehicle simulation results. The forces for accelerating, braking and steering are all come from tire road contact. The simulator simulation faces all possible driving situations as driving the real vehicle, like parking on the hill, stop and start again, sharp steering, sharp braking et al.
2015-03-10
Technical Paper
2015-01-0053
Rakesh Khanger, Amritashu Bardhan
Abstract Vehicles in India will soon come with star ratings, signifying how environment-friendly they are. The OEM's have braced to improve fuel economy of their existing & upcoming models. Tire rolling resistance is one of the significant factors for vehicle fuel consumption. Improvement in Fuel consumption is always a prime focus area & to improve it all majors are considered. In newly launched models, the low rolling resistance tire development was initiated. The project is challenging as it requires not only achieving low rolling resistance but also other critical vehicle performance parameters like ride, handling, NVH & durability. Effects of Tire construction, rubber compound were analyzed to achieve lower rolling resistance and better durability of tire. In addition, the factors affecting the rolling resistance of tire like inflation pressure, load, and speed are discussed in this paper.
2015-01-23
WIP Standard
ARP4834B
This SAE Aerospace Recommended Practice (ARP) sets forth criteria for the selection, inspection, retread and repair of worn civil aircraft tires, and the means to verify that the retreaded tire is suitable for continued service. This document is applicable to both bias ply and radial aircraft tires qualified subsequent to the adoption of this document.
2015-01-22
WIP Standard
J2975
This procedure describes a method for generating, preparing and analyzing samples of new and unused brake friction materials for their chemical constituents.
2015-01-15
WIP Standard
J1095
This SAE Recommended Practice provides uniform laboratory procedures for fatigue testing of spoke wheels and hubs intended for normal highway use on trucks, buses, truck trailers, and multipurpose passenger vehicles. The hubs included have bolt circle diameters from 165.1 to 335.0 mm (6.50 to 13.19 in). It is up to each hub and/or spoke wheel developer to determine what test method, accelerated load factor and cycle life requirements are applicable to obtain satisfactory service life in a given application. When deviations from the procedures recommended herein are made, it is the responsibility of the hub and/or spoke wheel developer to modify other parameters to obtain satisfactory service life.
2015-01-14
Article
Car put on display is based on electrical and mechanical components from a Renault electric vehicle "city car" simply as a proof of process. Much testing and refinement remain. Help is being provided by Oak Ridge National Laboratory and SABIC.
2015-01-14
Technical Paper
2015-26-0134
Jayant Sinha, Ajit Kharade, Shrihari Matsagar
Abstract An interior sound quality is one of the major performance attribute, as consumer envisage this as class and luxury of the vehicle. With increasing demand of quietness inside the cabin, car manufactures started focusing on noise refinement and source separation. This demand enforces hydraulic power steering pump to reduce noise like Moan and Whine, especially in silent gasoline engine. To meet these requirements, extensive testing and in-depth analysis of noise data is performed. Structured process is established to isolate noises and feasible solutions are provided considering following analysis. a) Overall airborne noise measurement at driver ear level (DEL) inside the cabin using vehicle interior microphone.b) Airborne and Pressure pulsation test by sweeping pump speed and pressure at test bench.c) Waterfall analysis of pump at hemi anechoic chamber for order tracking and noise determination.
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