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2015-04-14
Technical Paper
2015-01-1499
Tadatsugu Takada, Kazuki Tomioka
Honda developed the right and left independent toe-angle control system (first-generation P-AWS) in the Acura RLX in 2013 and announced it as the first in the world. As indicated in a previous paper, “Independent Left and Right Rear Toe Control System,” with this system Honda has realized an excellent balance between the fun of handling that is at the driver’s will (INOMAMA) and driving performance with a sense of stability. This first-generation P-AWS is designed to be optimal to the vehicle specifications (suspension axial force, steering gear ratio, etc.) of the Acura RLX. Honda is due to widely adapt P-AWS to other models from now on. Following this, we developed the next-generation P-AWS system (second-generation P-AWS) in order to reconcile system performance and low cost wherever possible, in order to be adaptable for all ACURA models.
2015-04-14
Technical Paper
2015-01-1524
Ping Chen, Nan Xu, Konghui Guo, Rongsheng Liu
Tire lateral force is essential to vehicle handling and stability under cornering. However, it is difficult for engineers to get tire lateral force under high loading condition due to the loading ability limitation of most tire test machine in the world. Widely used semi-empirical tire lateral force models are obtained by curve-fitting experiments data and don’t possess load prediction ability. The objective of this paper is to predict the tire lateral force model under high-load condition based on low-load tire data. The nonlinear characteristic of tire cornering stiffness vary with load is greatly affected by tire carcass compliance. In this paper, a theoretical tire lateral model was built by considering carcass complex deformation. Combined with the relationship between half-length of tire contact patch and load, the non-linear characteristic of tire cornering stiffness vary with load was obtained.
2015-04-14
Technical Paper
2015-01-1507
Kentaro Komori, Takahito Nagataki
Research on passenger vehicles responds to mechanical loss-reduction demands for improving fuel economy. Handling, steering feel, and ride-comfort can be attributed to the steering and suspension. We researched friction behavior in terms of low- or high- friction coefficients, and in terms of static-kinetic transient motion. We improved the vehicle handling and ride comfort by giving the appropriate friction to the tie-rod end ball joint. Controlling friction behavior, we used diamond-like carbon (DLC) coating submitted to boundary lubrication. Different DLC coatings varied widely in hydrogen content, mechanical properties and micro-surface roughness were applied to the ball joint studs. The larger the micro-surface roughness in asperity of DLC coatings, the higher the kinetic friction torque. The friction behaviors corresponded to the DLC properties.
2015-04-14
Technical Paper
2015-01-1589
Michael W. Neal, Walter Cwycyshyn, Ibrahim Badiru
The goal of this paper is to discuss the critical aspects of damper tuning for production vehicles. These aspects include ride and handling performance attributes, damper basics, conflicts in achieving desirable results, tuning philosophies and the influence of the damper design. The marketplace has become increasingly competitive. Customer preference, cost, mass and regulatory pressures often conflict. Yet each year more vehicles are required to do all these things well. Damper tuning can play a significant role in resolving these conflicts. Although many papers have been written on the theory behind damper design and capabilities, there has been very little written about the techniques of tuning dampers for production vehicles. This paper attempts to discuss the critical aspects of damper tuning for production vehicles in four sections. The first section discusses the performance attributes of ride and handling. The second section provides a basic understanding of dampers.
2015-04-14
Technical Paper
2015-01-1513
Anudeep K. Bhoopalam, Kevin Kefauver
Indoor laboratory tire testing on flat belt machines and tire testing on the actual road yield different results. Testing on the machine offers the advantage of repeatability of test conditions, control of the environmental condition, and performance evaluation at extreme conditions. However, certain aspects of the road cannot be reproduced in the laboratory. It is thus essential to understand the connection between the machine and the road, as tires spend all their life on the road. This research, investigates the reasons for differences in tire performance on the test machine and the road. The first part of the paper presents a review on the differences between tire testing in the lab and on the road, and existing methods to account for differences in test surfaces.
2015-04-14
Technical Paper
2015-01-1520
Massimiliano Gobbi, Giampiero Mastinu, Federico Ballo, Giorgio Previati
A wheel able to measure the generalized forces at the hub of a race motorcycle has been developed and used. The wheel has a very limited weight (about 2 kg). It is made from magnesium with a special structure to sense the forces and provide the required level of stiffness. The wheel has been tested both indoor for preliminary approval according to internal standards and on the track. The three forces and the three moments at the hub can be measured with a resolution of respectively 1N and 0.3Nm. Twelve strain gauges are positioned at relevant locations to sense the generalized forces. Utilizing an encoder (angle resolution 0.06°), a simultaneous ADC sampling is performed on the six strain gauges bridges outputs while coupling the force/torque output with the absolute wheel angular position. The sincronous sampling allows seamless real-time measurements at vehicle speed up to 400 km/h.
2015-04-14
Technical Paper
2015-01-1565
Qingzhang chen
A regenerative braking system coordinated controller was developed for a front wheel drive BEV that also includes an ultra-capacitor storage system. This controller integrates the dual-motor regenerative braking with the hydraulic braking and stability control systems. The vehicle braking mode and the distribution of braking torque were determined according to the vehicle braking requirements, vehicle status and energy storage system (battery plus ultra-capacitor) state, and the stability control torque was provided according to the real-time vehicle stability condition. Simulation results show that, compared with a motor unilateral independence control strategy, the integrated coordinated controller improves the vehicle’s stability when the vehicle corners while braking.
2015-04-14
Technical Paper
2015-01-0642
Per Hyldahl, Sebastian Andersen, Sebastian Mikkelsen, Ole Balling
The modeling of a vehicle’s suspension system is one of the most crucial tasks when designing and optimizing modern vehicles. One of the preferred tools to assist the designers to perform this task is multibody dynamics. When using multibody dynamics, it is possible to model arbitrary systems with high mechanical complexity, include non-linear characteristics of e.g. springs and dampers, and simulate the systems behavior in the time domain to assess its performance in various scenarios. A non-trivial job when building a vehicle model, is estimating the characteristics of the many suspension components that exhibits non-linear behavior during operation of the vehicle. Examples of such components are rubber bushings and stabilizer bars. Especially the latter can be difficult to characterize using an idealized spring with a non-linear force-deflection curve, since its stiffness depends highly on its geometry and deformation stage.
2015-04-14
Technical Paper
2015-01-1508
Lijiao Yu, Hongyu Zheng
As the electric technique develops fast, steering systems change from conventional mechanic steering systems to electrically controlled steering (ECS) systems, including electric power (EPS) system, active front steering (AFS) system and steer-by-wire (SBW) system. ECS could improve vehicles’ steering portability at a low speed and handing stability at a high speed. The study of ECS involves mechanic design, detection of electric components, software design and so on, which need a lot of trials and errors. By now, the development of ECS mostly depends on experiments on hard-ware-in-the-loop (HIL) and real vehicles. Because tests on real vehicles have many short cuts, such as a higher cost, a longer period, etc. HIL is gradually taking the place of real vehicles to carry out kinds of experiments in order to reduce test times, cycles and cost, which has been a main means to research and develop ECS.
2015-04-14
Technical Paper
2015-01-1566
Youngil Koh, Kyongsu Yi, kilsoo kim PhD
This paper presents a tire slip-angle based speed control race driver model. In developing a chassis control system for enhancement of high-speed driving performance, analysis of the vehicle-driver interaction at limit handling is one of the main research issues. Thus, a driver model which represents driving characteristics in a racing situation is required to develop a chassis control system. Since a race driver drives a vehicle as fast as possible on a given racing line without losing control, the proposed driver model is developed to ensure a lateral stability. In racing situation, one of the reasons which cause the lateral instabilities is an excessive corner-entry speed. The lateral instability in that moment is hard to handle with only a steering control. To guarantee the lateral stability of the vehicle while maximizing a cornering speed, a desired speed is determined to retain a tire slip-angle that maximizes lateral tire forces without front tire saturation.
2015-04-14
Technical Paper
2015-01-0614
Ye Zhao, Liangmo Wang, Xiangli Yang, Liukai Yuan, Zunzhi Zhang
Abstract: In most cases, researches on the ride performance of air suspension system are based on simplified mathematical models which could be too theoretical or not be able to consider the coupling relationship between the various components so that they behave far away from the actual vehicle system. This paper represents the study on the ride performance of an air suspension vehicle based on the complex whole vehicle model which was established though ADAMS and Matlab. The applying of flexible components helped to improve the model accuracy and the tensile and compression tests of the air spring were used to establish the interconnected four-gasbag air suspension system. The vehicle ride performance was studied through the co-simulation between ADAMS and Matlab. The accuracy of the results were verified by the vehicle test results, which demonstrated the reliability of the whole model.
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
2015-01-0665
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
2015-01-0159
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
2015-01-1096
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
2015-01-1580
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
2015-01-1585
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.
Viewing 31 to 60 of 10124

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