Display:

Results

Viewing 91 to 120 of 10234
2015-04-14
Technical Paper
2015-01-0492
Gaurav Paliwal, Naveen Sukumar, Umashanker Gupta, Ashutosh Dubey, Nitin Chopra
Abstract The need to develop products faster and to have designs which are first time right have put enormous pressure on the product development timelines, thus making computer aided optimization one of the most important tool in achieving these targets. In this paper, a design of experiments (DOE) study is used, to gain an insight as to, how changes to different parameters of front suspension and steering of a passenger bus affect its kinematic properties and thus to obtain an optimized design in terms of handling parameters such as bump steer, percent ackermann error and lock to lock rotation angle of steering wheel. The conventional hit and trial method is time consuming and monotonous and still is an approximate method, whereas in design of experiments (DOE), a model is repeatedly run through simulations in a single setup, for various combinations of parameter settings.
2015-04-14
Technical Paper
2015-01-1127
Wenbin Liu, Gangfeng Tan, Xiaoqing Tian, Zhiqiang Hu, Yuanqi Gao, Zhi Li, Junyi Yuan, Wei Liu
Abstract The hydraulic retarder is an important auxiliary braking device for the heavy vehicle, which has some characteristics, such as the big brake torque and long duration braking, when the vehicle is traveling in braking state. However, the transmission power loss will be produced when the vehicle is traveling in non-braking state. This transmission power loss is called Air-friction. Firstly, the air flow distribution characteristics of retarder cavity are studied by computational fluid mechanics, and the Air-friction characteristic in different conditions is analyzed. Then, according to the Air-friction characteristics for the condition of different filling density, a set of vacuum air loss reduction system is designed. Meanwhile, the test bench for retarder Air-friction is set up, the test data of the revolution speed, pressure in cavity and air loss resistance is obtained according to the test bench for hydraulic retarder.
2015-04-14
Technical Paper
2015-01-1328
Da-Wei Gao, Xing-Xing Huang, Jun Xu, Song-Lin Zheng
Abstract 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 improvements in riding and safety, changing the nonlinear stiffness characteristic from weak to strong. This paper summarizes the optimization design method for the rear suspension coil spring, which includes 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
2015-01-1501
Ryusuke Hirao, Kentaro Kasuya, Nobuyuki Ichimaru
Abstract New ride control and handling control are developed, and installed in a system using only vehicle height sensor as dedicated sensors and pressure control type semi-active damper. Bi-linear optimal control is applied for controlling ride comfort control constructed observer which is inputted vehicle height sensor for calculating state quantity then used output of the observer. Behavior of vehicle was investigated by vehicle experiment and formalized to further improve the feeling of roll generated by handling control and devised and applied semi-active suspension control method which transiently realize the behavior. Proposed semi-active suspension system not only achieves damping performance as well as skyhook control, but also improves smooth ride comfort and handling performance including roll feeling. In this report, we describe aim, feature and effect of this system.
2015-04-14
Technical Paper
2015-01-1464
Qiang Chen, Miao Lin, Bing Dai, Jiguang Chen
Abstract In China, nearly 25% of traffic fatalities are pedestrians. To avoid those fatalities in the future, rapid development of countermeasures within both passive and active safety is under way, one of which is autonomous braking to avoid pedestrian crashes. The objective of this work was to describe typical accident scenarios for pedestrian accidents in China. In-depth accident analysis was conducted to support development of test procedures for assessing Autonomous Emergency Braking (AEB) systems. Beyond that, this study also aims for estimating the mitigation of potential crash severity by AEB systems. The China In-depth Accident Study (CIDAS) database was searched from 2011 to 2014 for pedestrian accidents. A total of 358 pedestrian accidents were collected from the on-site in-depth investigation in the first phase of CIDAS project (2011-2014).
2015-04-14
Technical Paper
2015-01-1347
Fiona Ruel, Pierre-Olivier Santacreu, Saghi Saedlou, Guillaume Badinier, Jean Herbelin
Abstract In order to meet new environmental regulations (i.e. mass of CO2 rejected in the atmosphere per km), car manufacturers are looking for new solutions to lighten chassis and structural parts in cars. High strength steels formed by hot stamping have proved to be good candidates for achieving better in-use performances together with a lighter structure. In particular, the martensitic stainless steel MaX fulfils the industrial targets for chassis parts in terms of mechanical and fatigue properties. For instance, from a cold formed baseline made of 600 MPa carbon steel, a 50 % mass reduction can be expected with a hot stamped suspension arm made of MaX and included a new clamshell design. However, those parts are often made of a complex assembly of different materials (high strength steels, aluminium and cast iron among others) which are subjected to aggressive environments in service. Therefore galvanic corrosion of those complex assemblies has to be evaluated.
2015-04-14
Technical Paper
2015-01-0527
Pierre-Olivier Santacreu, Guillaume Badinier, Jean-Benoit Moreau, Jean-Marc Herbelin
Abstract A new Ni-free martensitic stainless steel (MSS) was developed for hot stamped automotive parts, especially in order to design lightweight chassis part. After hot stamping simulation, the material exhibited a 1.2 GPa ultimate tensile strength with a minimum of 10% total elongation, in the as-quenched condition (Q) without any tempering treatment (Q+T). Moreover the material's chemical composition was optimized to improve the ductility at low temperature and during high strain rate mechanical testing. As a result, no brittle fracture in impact testing at −40°C was observed, and a good behavior in crash was recorded. To further assess the material's performances, high cycle fatigue properties of the grade have been characterized including the effects of machining and surface treatments. Results show that the fatigue limits at 2 million cycles for a stress ratio of −1, for both bare and shot peened surface are quite high and in the range of 580 MPa to 640 MPa.
2015-04-14
Technical Paper
2015-01-0652
Hui Hua, Lifu Wang, Hengmin Qi, Jie Zhang, Nong Zhang
Abstract Air spring due to its superior ride comfort performance has been widely used in distance passenger transporting vehicles. Since the requirements for ride comfort and handling performance are contradict to each other, handling performance and even roll stability are sacrificed to some extent to obtain good ride comfort. Due to the complex terrain and limited manufacturing level, in the past several years, bus rollover accidents with serious casualties have been reported frequently and bus safety has attracted more and more attention from bus manufacturers in China. On one hand the bus standards have to be raised, and on the other hand, novel solutions which can effectively improve the roll stability of air spring bus are needed to replace the inadequacy of anti-roll bars.
2015-04-14
Technical Paper
2015-01-1497
Hideaki Shibue, Devesh Srivastava
Abstract Torsion beam suspensions are lightweight and low in cost, and they are therefore frequently used as the rear suspensions of small front-wheel drive vehicles. However, it is difficult to predict their characteristics and to satisfy performance targets in the early stages of development in particular, because the various aspects of performance required of a suspension must be achieved by a single structure. A great deal of research has been conducted into the cross-sectional shape of the beam section; however, this paper focuses on the effect of the properties of the trailing arms on suspension characteristics. Two similar test torsion beam suspensions differing only in the rigidity of the trailing arms were fabricated, and kinematics and compliance (K&C) tests were conducted using a 3D measurement system. The lateral compliance test showed the anticipated result that change in toe and camber is greater in the suspension with lower rigidity trailing arms.
2015-04-14
Technical Paper
2015-01-1096
Robert Lloyd
Abstract The frequent stops of the typical postal delivery vehicle make it an attractive application for regenerative braking. The hydro-mechanical automatic 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 of the postal LLV vehicles and estimates the performance benefits. The result represents a low impact path for the US Postal Service to extend the useful life of the LLV vehicles and increase the mpg by approx. 100%. A cost comparison between a convention ICE mid-sized passenger sedan and a similar size gas/hydraulic hybrid vehicle illustrates the cost advantage of the hydraulic approach using the new transmission design. Besides lower cost, the vehicle will have greater initial acceleration and 25%+ better mpg.
2015-04-14
Technical Paper
2015-01-1499
Tadatsugu Takada, Kazuki Tomioka
Abstract Honda announced an independent right and left rear toe control system (first generation) in 2013 and presented it as the world's first. As stated in a previous paper, “Independent Left and Right Rear Toe Control System,” with this system Honda has achieved a balance between an enjoyable driving experience in which handling is performed at the driver's will (“INOMAMA” handling) and stable driving performance.(1) This first generation is optimally designed to the vehicle specifications such as suspension axial force and steering gear ratio of the vehicle to which the system is applied. For more widespread application of independent rear toe control technology, a next generation system (second generation) has been developed, which achieves both cost reduction and flexible system performance which can be adapted to a variety of vehicles. The system development began by setting the required target performance with consideration for adaptation to various car models.
2015-04-14
Technical Paper
2015-01-1601
Long Chen, Mingyuan Bian, Yugong Luo, Keqiang Li
Abstract This paper proposes an estimation method of road-tire friction coefficient for the 4WID EV(4-wheel-independent-drive electric vehicle) in the pure longitudinal wheel slip, lateral sideslip and combined slip situations, which fuses both estimated longitudinal and lateral friction coefficients together, compared with existing methods based on a tire model in one single direction. Unscented Kalman filter (UKF) is introduced to estimate one-directional friction coefficient based on a modified Dugoff tire model. Considering the output results for each direction as a signal for the same target with different noise, MSE-weighted fusion method is proposed to fuse these two results together in order to reach a higher accuracy. The tire forces are estimated with the benefits of the 4WID EV that the driving torque and rolling speed of each wheel can be accurately known. The sideslip angles and slip ratios of each tire are calculated with a vehicle kinematic model.
2015-04-14
Journal Article
2015-01-0691
Salah H. R. Ali, Sarwat Z. A. Zahwi, Hassan H. Dadoura
Abstract The main aim of this work is to develop an identification method to demonstrate the crucial surfaces of automotive braking system. Two brand new brake discs manufactured by two different manufacturers are tested. A typical disc to the one of them was put under working condition in actual braking system. Dimensional and geometrical deviations are investigated using advanced engineering metrological technique. Mechanical properties, tribological characteristics and chemical analyses are investigated. A coordinate measuring machine, universal hardness tester, mass comparator and XRF spectrometer are used in these diagnoses. Measurements of dimensional and geometrical deviations such as disc thickness variations, thickness deviations, straightness, parallelism, runout of disc surfaces are conducted. A comparison between form deviations in disc surfaces have been carried out and analyzed.
2015-04-14
Journal Article
2015-01-1225
Chen Lv, Junzhi Zhang, Yutong Li, Ye Yuan
Abstract Regenerative braking provided by an electric powertrain is far different from conventional friction braking with respect to the system dynamics. During regenerative decelerations, the nonlinear powertrain backlash would excite driveline oscillations, deteriorating vehicle drivability and blended brake performance. Therefore, backlash compensation is worthwhile researching for an advanced powertrain control of electrified vehicles during regenerative deceleration. In this study, a nonlinear powertrain of an electric passenger car equipped with a central motor is modeled using hybrid system approach. The effect of powertrain backlash gap on vehicle drivability during regenerative deceleration is analyzed. To further improve an electric vehicle's drivability and blended braking performance, an active control algorithm with a hierarchical architecture is studied for powertrain backlash compensation.
2015-04-14
Journal Article
2015-01-1680
David H. Myszka, Andrew Murray, Kevin Giaier, Vijay Krishna Jayaprakash, Christoph Gillum
Regenerative brake and launch assist (RBLA) systems are used to capture kinetic energy while a vehicle decelerates and subsequently use that stored energy to assist propulsion. Commercially available hybrid vehicles use generators, batteries and motors to electrically implement RBLA systems. Substantial increases in vehicle efficiency have been widely cited. This paper presents the development of a mechanical RBLA that stores energy in an elastic medium. An open differential is coupled with a variable transmission to store and release energy to an axle that principally rotates in a single direction. The concept applies regenerative braking technology to conventional automobiles equipped with only an internal combustion engine where the electrical systems of hybrid vehicles are not available. Governing performance equations are formulated and design parameters are selected based on an optimization of the vehicle operation over a simulated urban driving cycle.
2015-04-14
Technical Paper
2015-01-0591
Karan R. Khanse, Eric Pierce, Michael Ng, Saied Taheri
Abstract Outdoor objective evaluations form an important part of both tire and vehicle design process since they validate the design parameters through actual tests and can provide insight into the functional performances associated with the vehicle. Even with the industry focused towards developing simulation models, their need cannot be completely eliminated as they form the basis for approving the performance predictions of any newly developed model. An objective test was conducted to measure the ABS performance as part of validation of a tire simulation design tool. A sample vehicle and a set of tires were used to perform the tests- on a road with known profile. These specific vehicle and tire sets were selected due to the availability of the vehicle parameters, tire parameters and the ABS control logic. A test matrix was generated based on the validation requirements.
2015-04-14
Technical Paper
2015-01-0627
Xiaoguang Yang, Oluremi Olatunbosun, Daniel Garcia-Pozuelo, Emmanuel Bolarinwa
Abstract The development of intelligent tire technology from concept to application covers multi-disciplinary fields. During the course of development, the computational method can play a significant role in understanding tire behavior, assisting in the design of the intelligent tire prototype system and in developing tire parameters estimation algorithm, etc. In this paper, a finite element tire model was adopted for developing a strain-based intelligent tire system. The finite element tire model was created considering the tire's composite structure and nonlinear properties of its constituent materials, and the FE model was also validated by physical tests. The FE model is used to study tire strain characteristics by steady state simulation for straight line rolling, traction and braking, as well as cornering. Tire loading conditions were estimated by feature extraction and data fitting.
2015-04-14
Collection
This technical paper collection is focused on vehicle dynamics and controls using modeling and simulation, and experimental analysis of passenger cars, heavy trucks, and wheeled military vehicles. The papers address active and passive safety systems to mitigate rollover, yaw instability and braking issues; driving simulators and hardware-in-the-loop systems; suspension kinematics and compliance, steering dynamics, advanced active suspension technologies; and tire force and moment mechanics.
2015-04-14
Collection
This technical paper collection provides information on steering and suspension related topics as it applies to ground vehicles. Papers address new approaches as well as advances in application of steering, suspension related technologies.
2015-04-14
Journal Article
2015-01-0619
Chih Feng Lee, Dzmitry Savitski, Chris Manzie, Valentin Ivanov
Abstract Geometric imperfections on brake rotor surface are well-known for causing periodic variations in brake torque during braking. This leads to brake judder, where vibrations are felt in the brake pedal, vehicle floor and/or steering wheel. Existing solutions to address judder often involve multiple phases of component design, extensive testing and improvement of manufacturing procedures, leading to the increase in development cost. To address this issue, active brake torque variation (BTV) compensation has been proposed for an electromechanical brake (EMB). The proposed compensator takes advantage of the EMB's powerful actuator, reasonably rigid transmission unit and high bandwidth tracking performance in achieving judder reduction.
2015-04-14
Journal Article
2015-01-0621
Mina M.S. Kaldas, Kemal Çalışkan, Roman Henze, Ferit Küçükay
Abstract There is an increasing customer demand for adjustable chassis control features which enable adaption of the vehicle comfort and driving characteristics to the customer requirements. One of the most promising vehicle control systems which can be used to change the vehicle characteristics during the drive is the semi-active suspension system. This paper presents a Rule-Optimized Fuzzy Logic controller for semi-active suspension systems which can continuously adjust itself not only according to the road conditions but also to the driver requirements. The proposed controller offers three different control modes (Comfort, Normal and Sport) which can be switched by the driver during driving. The Comfort Mode minimizes the accelerations imposed on the driver and passengers by using a softer damping. On the other hand, the increased damping in Sport Mode provides better road holding capability, which is critical for sporty handling.
2015-04-14
Journal Article
2015-01-0623
Jiaquan Chen, Min Qin, Yongfeng Jiang, Lingge Jin, Yin-Ping Chang
Abstract A twist beam rear suspension system is modeled, analyzed and optimized in this paper. An ADAMS model is established based on the REC (Rigid-Elastic Coupling) Theory, which is verified by FEM (Finite Element Method) approach, the effects of the geometric parameters on the twist beam suspension performance are investigated. In order to increase the calculation efficiency and improve the simulation accuracy, a neural network model and NSGA II (Non-dominated Sorting Genetic Algorithm II) are adopted to conduct a multi-objective optimization on a twist beam rear suspension system.
2015-04-14
Journal Article
2015-01-1566
Youngil Koh, Kyongsu Yi, Kilsoo Kim
Abstract 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
Journal Article
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
Journal Article
2015-01-1567
Scott Bradley Zagorski, Tomoya Ushimura, James Post
Abstract In this research, a three degree-of-freedom (DOF) rack-type electric-based power steering (EPS) model is developed. The model is coupled with a three DOF vehicle model and includes EPS maps as well as non-linear attributes such as vibration and friction characteristics of the steering system. The model is simulated using Matlab's Simulink. The vibration levels are quantified using on-vehicle straight-line test data where strain-gauge transducers are placed in the tie-rod ends. Full vehicle kinematic and compliance tests are used to verify the total steering system stiffness levels. Frequency response tests are used to adjust tire cornering stiffness levels as well as the tire dynamic characteristics such that vehicle static gain and yaw natural frequency are achieved. On-center discrete sinusoidal on-vehicle tests are used to further validate the model.
2015-04-14
Journal Article
2015-01-1568
Hyundong Heo, Eunhyek Joa, Kyongsu Yi, Kilsoo Kim
Abstract 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. 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. The target longitudinal acceleration is determined based on the driver's intention and vehicle current state to ensure the vehicle lateral stability in high speed maneuvering.
2015-04-14
Journal Article
2015-01-1570
Daniel Vilela, Rubens Pinati, Scott Larsen, Erick Rodrigues, Renato Serrati
Abstract This study presents the comparison of vehicle handling performance results obtained using physical test tire data and a tire model developed by means of Finite Element Method. Real tires have been measured in laboratory to obtain the tire force and moment curves in terms of lateral force and align torque as function of tire slip angle and vertical force. The same tire construction has been modeled with Finite Element Method and explicit formulation to generate the force and moment response curves. Pacejka Magic Formula tire response models were then created to represent these curves from both physical and virtual tires. In the sequence, these tire response models were integrated into a virtual multibody vehicle model developed to assess handling maneuvers.
2015-04-14
Journal Article
2015-01-1579
Jun Nakahara, Koji Yamazaki, Yusuke Otaki
Abstract In many cars, ride is less comfortable on smooth roads. This is because when the hysteresis in the suspension components rises steeply, the increase of the equivalent spring constant at small amplitude deteriorates the vibration isolation of the suspension. Therefore suspension components should be designed to prevent a steep rises in hysteresis. Investigating the influence of hysteresis, component models, which can reproduce such hysteresis characteristics, should be installed with model parameters in the vehicle model. Using conventional methods, these parameters can be accurately identified if measurement data is provided; however, it is difficult at the earlier phase of vehicle development. Then, if conflicting performances, such as ride and handling, are to be improved, both should be considered concurrently as early in a phase of vehicle development as possible and the design specifications for suspension components should be determined to satisfy both performances.
2015-04-14
Journal Article
2015-01-1584
Daniel E. Williams
Abstract The classic two-degree-of-freedom yaw-plane or “bicycle” vehicle model is augmented with two additional states to describe lane-keeping behavior, and further augmented with an additional control input to steer the rear axle. A simple driver model is hypothesized where the driver closes a loop on a projected lateral lane position. A rear axle steer control law is found to be a function of front axle steering input and vehicle speed that exhibits high speed stability and improved low speed maneuverability. The theoretically derived control law bears similarity to practical embodiments allowing a deeper understanding of the functional value of steering a rear axle.
2015-04-14
Journal Article
2015-01-1580
He Dengbo, Lu Hui, Yu Fan
Abstract The vehicle chassis integrated control system can improve the stability of vehicles under extreme conditions using tire force allocation algorithm, in which, the nonlinearity and uncertainty of tire-road contact condition need to be taken into consideration. Thus, An MPC (Model Predictive Control) controller is designed to obtain the additional steering angle and the additional yaw moment. By using a robust optimal allocation algorithm, the additional yaw moment is allocated to the slip ratios of four wheels. An SMC (Sliding-Mode Control) controller is designed to maintain the desired slip ratio of each wheel. Finally, the control performance is verified in MATLAB-CarSim co-simulation environment with open-loop manoeuvers.
Viewing 91 to 120 of 10234

Filter