Display:

Results

Viewing 151 to 180 of 10698
2016-04-05
Technical Paper
2016-01-1658
Jie Huang, Lu Xiong, Songyun Xu, Zhuoping Yu
Abstract With the development of vehicle electrification, electronic hydraulic brake system is gradually applied. Many companies have introduced products related to integrated electronic hydraulic brake system (I-EHB). In this paper, an I-EHB system is introduced, which uses the motor to drive the reduction mechanism as a power source for braking. The reduction mechanism is composed of a turbine, a worm, a gear and a rack. A control method based on command feed-forward is proposed to improve the hydraulic pressure control of I-EHB. Based on previous research, we simplify the system to first order system, and the theoretical design of the command feed-forward compensator is carried out. The feed-forward controller is applied, including the velocity feed-forward and the acceleration feed-forward, to improve the response speed and tracking effect of the system.
2016-04-05
Technical Paper
2016-01-1552
Renato Galluzzi, Andrea Tonoli, Nicola Amati, Gabriele Curcuruto, Piero Conti, Giordano Greco, Andrea Nepote
Abstract The development of suspension systems has seen substantial improvements in the last years due to the use of variable dampers. Furthermore, the efficiency increase in the subsystems within the automotive chassis has led to the use of regenerative solutions, in which electric machines can be employed as generators to recover part of the energy otherwise dissipated. However, the harvesting capability of regenerative suspensions is often limited by friction and inertial phenomena. The former ones waste mechanical energy into heat, while the latter ones hamper the shock absorption by locking the suspension when subject to dynamic excitation. Besides a suitable design and sizing of components, recent research works highlight the use of the so-called motion rectifier to improve energy recovery by constraining the motion of the electric motor to a single sense of rotation.
2016-04-05
Technical Paper
2016-01-1549
Nicola Bartolini, Lorenzo Scappaticci, Francesco Castellani, Alberto Garinei
Knocking noise is a transient structural noise triggered by piston rod vibrations in the shock absorber that excite the vibration of chassis components. Piston rod vibrations can be caused by valve motion (opening and closing) and dry friction during stroke inversions. This study investigates shock absorber knocking noise in twin tube gas-filled automotive shock absorbers and its aim is to define an acceptance criterion for a sample check of the component. If, in fact, the damper comes from a large mass production, it may happen that small mounting differences lead to different behaviors that result in higher or lower levels of knocking noise. To achieve this goal, experimental tests were carried out using a hydraulic test bench; accelerometers were placed in proximity to the rebound valve and on the piston rod. The vibration phenomenon was then isolated through a post-processing analysis and a damped and unforced lumped mass model was used to characterize the vibration.
2016-04-05
Technical Paper
2016-01-1550
Ming Peng, Xuexun Guo, Junyi Zou, Chengcai Zhang
Abstract This paper presents a novel application of hydraulic electromagnetic energy-regenerative shock absorber (HESA) into commercial vehicle suspension system and vehicle road performance are simulated by the evaluating indexes (e.g. root-mean-square values of vertical acceleration of sprung mass, dynamic tire-ground contact force, suspension deflection and harvested power; maximum values of pitch angle and roll angle). Firstly, the configuration and working principle of HESA are introduced. Then, the damping characteristics of HESA and the seven-degrees-of-freedom vehicle dynamics were modeled respectively before deriving the dynamic characteristics of a vehicle equipped with HESA. The control current is fixed at 7A to match the similar damping effect of traditional damper on the basis of energy conversion method of nonlinear shock absorber.
2016-04-05
Technical Paper
2016-01-1557
Francesco Castellani, Nicola Bartolini, Lorenzo Scappaticci, Davide Astolfi, Matteo Becchetti
Abstract Shock absorber is one of the most relevant sub-systems of the suspension system for a wide range of vehicles. Although a high level of development and tuning has been reached, in order to ensure high safety standards in almost every situation, some dynamic phenomena affecting vehicle handling or NHV (Noise Vibration Harshness) can appear. The aim of present work is to improve a mathematical model using experimental data from a prototype of monotube shock absorber developed for research purposes. The model takes into account all the main features affecting the global performance of the device, such as non-linear behaviour and the presence of hysteresis loops. Actually, the most important parameters are analyzed, such as flow and orifice coefficients of the valves, coefficients of mechanical compliance of the chambers and oil compressibility, dry and viscous friction coefficients.
2016-04-05
Technical Paper
2016-01-1559
Francesco Vinattieri, Tim Wright, Renzo Capitani, Claudio Annicchiarico, Giacomo Danisi
Abstract The adoption of Electrical Power Steering (EPS) systems has greatly opened up the possibilities to control the steering wheel torque, which is a critical parameter in the subjective and objective evaluation of a new vehicle. Therefore, the tuning of the EPS controller is not only becoming increasing complicated, containing dozens of parameters and maps, but it is crucial in defining the basic DNA of the steering feeling characteristics. The largely subjective nature of the steering feeling assessment means that EPS tuning consists primarily of subjective tests on running prototypes. On account of that, this paper presents an alternative test bench for steering feeling simulation and evaluation. It combines a static driving simulator with a physical EPS assisted steering rack. The end goal is to more accurately reproduce the tactile feedback to the driver by including a physical hardware in lieu of complicated and difficult to obtain software models.
2016-04-05
Technical Paper
2016-01-1554
Cheng Gu, Xinbo Chen, Jun Yin
Abstract A novel geared electromagnetic active suspension is proposed in this paper. A pushing rod and a rocker are introduced to transfer the suspension vertical motion to the rotational motion of the motor. Comparing with the common ball-screw active suspension, it presents advantages of simple structure, easy manufacturing and module design. As the state variables of the suspension system cannot be all obtained for the sake of cost, taking the suspension deflection as the measurement, an output feedback LQR optimal controller is adopted, and it is concluded that the system can be stable with damping. Considering the nonlinearity of equivalent stiffness and unsprung mass caused by the system structure, parameter perturbation ranges are concluded through dynamic analysis, and robust H∞ control algorithm is proposed to realize the multi-objective optimization.
2016-04-05
Technical Paper
2016-01-1565
Joydeep Banerjee, John McPhee
Abstract Dynamic modelling of the contact between the tires of automobiles and the road surface is crucial for accurate and effective vehicle dynamic simulation and the development of various driving controllers. Furthermore, an accurate prediction of the rolling resistance is needed for powertrain controllers and controllers designed to reduce fuel consumption and engine emissions. Existing models of tires include physics-based analytical models, finite element based models, black box models, and data driven empirical models. The main issue with these approaches is that none of these models offer the balance between accuracy of simulation and computational cost that is required for the model-based development cycle. To address this issue, we present a volumetric approach to model the forces/moments between the tire and the road for vehicle dynamic simulations.
2016-04-05
Technical Paper
2016-01-1561
Xinxin Shao, Haiping Du, Fazel Naghdy
Abstract Development of a passive anti-pitch anti-roll hydraulically interconnected suspension (AAHIS) with the advantage of improving vehicle directional stability and handling quality is presented. A 7 degrees-of-freedom full car model and a 20 degrees-of-freedom anti-pitch anti-roll hydraulically interconnected suspension model dynamically coupled together through boundary conditions are developed and used to evaluate vehicle handing dynamic responses under steering/braking maneuvers. The modeling of mechanical subsystem is established based on the Newton’s second law and the fluid subsystem is modelled using a nonlinear finite-element approach. A motion-mode energy method (MEM) based on the calculation of the motion-mode energy is employed to investigate the effects of an anti-pitch anti-roll hydraulically interconnected suspension (AAHIS) system on vehicle body-wheel motion-mode energy distribution.
2016-04-05
Technical Paper
2016-01-1542
Shaosong Li, Jiafei Niu, Ren Sheng, Zhixin Yu, Shunhang Zheng, Yongfa Tu
Abstract With motor and reduction mechanism applied to Electric Power Steering (short for EPS) system of automobile, the frictional loss torque of steering system is increased. The common friction compensation control through the sign function of angular velocity or the saturation function of angular velocity is conducted to reduce the frictional loss torque of steering system. However, when the motor used in steering system generates assist torque based on the common friction compensation control, the longitudinal intercepts of steering torque change obviously at different steering wheel angles. The driver will get different frictional loss torque of steering system at different steering wheel angle. The information of steering torque contains the change of steering reaction torque and the frictional loss torque of steering system, so the change of frictional loss torque can cause the fuzzy of road feeling.
2016-04-05
Technical Paper
2016-01-1547
Jun Yin, Xinbo Chen, Lixin Wu, Jianqin Li
Abstract Traditional active suspension which is equipped with hydraulic actuator or pneumatic actuator features slow response and high power consumption. However, electromagnetic actuated active suspension benefits quick response and energy harvesting from vibration at the same time. To design a novel active and energy regenerative suspension (AERS) utilizing electromagnetic actuator, this paper investigates the benchmark cars available on the market and summaries the suspension features. Basing on the investigation, a design reference for AERS design is proposed. To determine the parameters of the actuator, a principle is proposed and the parameters of the actuator are designed accordingly. Compared the linear type and rotary type Permanent Magnet Synchronous Motor (PMSM), the rotary type is selected to construct the actuator of the AERS. Basing on the suspension structure of the design reference model and utilizing rotary type PMSM, a novel AERS structure is proposed.
2016-04-05
Technical Paper
2016-01-1546
Dongpil Lee, Bongchoon Jang, Kyongsu Yi, Sehyun Chang, Byungrim Lee
Abstract This paper describes a reference steering feel tracking algorithm for Electric-Power-Steering (EPS) system. Development of the EPS system with intended steering feel has been time-consuming procedure, because the feedforward map-based method has been applied to the conventional EPS system. However, in this study, a three-dimensional reference steering feel surface, which is determined from current vehicle states, is proposed. In order to track the proposed reference steering feel surface, sliding mode approach is applied to second-order steering dynamics model considering a coulomb friction model. An adaptive technique is utilized for robustness against uncertainties. In order to validate the proposed EPS control algorithm, hardware-in-the-loop simulation (HILS) has been conducted with respect to a typical steering test. It is shown that the reference steering feel is realized well by the proposed EPS control algorithm.
2016-04-05
Technical Paper
2016-01-1545
Huan Liu, Guoying Chen, Changfu Zong
Abstract A new electric power steering system (EPS) dynamic friction model based on normalized Bouc-Wen model is given, as well as its structure form and model features. In addition, experimental method is used to identify corresponding parameters. In order to improve road feel feedback, this paper analyzes the shortcoming of traditional constant friction compensation control method and proposes a variable friction compensation control method which the friction compensation current changes according to the assist characteristic gain. Through simulation and real vehicle test verification, variable friction compensation control method eliminates the effect of basic assist characteristic, and improves the driver’s road feel under high speed.
2016-04-05
Technical Paper
2016-01-1544
Dexin Wang, Frank Esser
Abstract Evaluation of electric steering (EPAS) system performance using vehicle specific load conditions is important for steering system design validation and vehicle steering performance tuning. Using real-time vehicle dynamics mathematical models is one approach for generating steering loads in steering hardware-in-the-loop (HIL) testing. However achieving a good correlation of simplified mathematical models with real vehicle dynamics is a challenge. Using rack force models from measured steering tie rod forces or from simulations using a high-fidelity vehicle dynamics model is an effective data-driven modelling method for testing EPAS systems under vehicle specific load conditions. Rack force models are identified from physical measurements or validated vehicle simulations of selected steering test maneuvers. The rack force models have been applied in steering system performance evaluation, benchmarking, and steering model validation.
2016-04-05
Technical Paper
2016-01-1602
Suad Jakirlic, Lukas Kutej, Daniel Hanssmann, Branislav Basara, Cameron Tropea
The present work deals with a computational study of a ‘DrivAer’ car model, the rear-end shape of which corresponds to the Notchback configuration (Heft et al. [1] and Heft [2]). The study investigates the effects of the underbody geometry and wheel rotation on the aerodynamic performance. The configurations with detailed and smooth underbody as well as with stationary and rotating wheels are considered. The computational model applied relies on a VLES (Very Large Eddy Simulation) formulation, Chang et al. [3]. The residual turbulence related to the VLES framework is presently modelled by a RANS-based (Reynolds-Averaged Navier-Stokes), four-equation (D(k,ɛ,ζ, f)/Dt) near-wall eddy-viscosity model, Hanjalic et al. [4].
2016-04-05
Technical Paper
2016-01-1573
Ken Archibald, Kyle Archibald, Donald Neubauer
Abstract This paper will document a rationale for wheel straightening based on the rise of declining roads, increased consumer preference for lower profile tires, unintended consequences of wheel customization and the reduction in energy consumption. A recommended patented procedure detailing how A356-T6 wheels can be straightened will be presented. To validate the recommended procedure a sample of wheels was uniformly deformed and straightened and subsequently tested per SAE J328 and SAE J175. Test results are provided that indicate straightened wheels should be fully serviceable in their intended service. A laboratory protocol to replicate the wheel flange cracks is described. The protocol is used to demonstrate that wheels without deformations do not result in flange cracks. Conversely wheels with deformations in excess of 1.5mm do result in cracks at less than 750,000 cycles.
2016-04-05
Technical Paper
2016-01-1576
Federico Ballo, Gianpiero Mastinu, Massimiliano Gobbi
Abstract Mass minimization is a key objective for the design of racing motorcycle wheels. The structural optimization of a front motorcycle wheel is presented in the paper. Topology Optimization has been employed for deriving optimized structural layouts. The minimum compliance problem has been solved, symmetry and periodicity constraints have been introduced. The wheel has been optimized by considering several loading conditions. Actual loads have been measured during track tests by means of a special measuring wheel. The forces applied by the tire to the rim have been introduced in an original way. Different solutions characterized by different numbers of spokes have been analyzed and compared. The actual racing wheel has been further optimized accounting for technological constraints and the mass has been reduced down to 2.9 kilograms.
2016-04-05
Technical Paper
2016-01-1575
Federico Ballo, Roberto Frizzi, Gianpiero Mastinu, Donato Mastroberti, Giorgio Previati, Claudio Sorlini
Abstract In this paper the lightweight design and construction of road vehicle aluminum wheels is dealt with, referring particularly to safety. Dedicated experimental tests aimed at assessing the fatigue life behavior of aluminum alloy A356 - T6 have been performed. Cylindrical specimens have been extracted from three different locations in the wheel. Fully reversed strain-controlled and load-controlled fatigue tests have been performed and the stress/strain-life curves on the three areas of the wheel have been computed and compared. The constant amplitude rotary bending fatigue test of the wheel has been simulated by means of Finite Element method. The FE model has been validated by measuring the strain at several points of the wheel during the actual test. From the FE model, the stress tensor time history on the whole wheel over a loading cycle has been extracted.
2016-04-05
Technical Paper
2016-01-1480
Jakub Zebala, Wojciech Wach, Piotr Ciępka, Robert Janczur
Abstract This article presents the results of an analysis of the yaw marks left by a car with normal pressure in all tires and then normal pressure in three tires and zero in one rear tire. The analysis is a continuation of research on influence of reduced tire pressure on car lateral dynamics in a passing maneuver, discussed in the SAE paper No. 2014-01-0466. Preliminary analysis of yaw marks has shown, that a wheel with zero pressure deposits a yaw mark whose geometry differs from the yaw mark made by a wheel with normal pressure based on which we could calculate: critical speed, slip angle and longitudinal wheel slip. The aim of the presented research was to analyze the yaw marks left by car with zero pressure in one rear wheel in order to check the possibility of determining the vehicle critical speed, slip angle and longitudinal wheel slip. It was reached by performing bench and road tests during which the vehicle motion parameters were recorded using GPS Data Logging System.
2016-04-05
Technical Paper
2016-01-1391
Subash Sudalaimuthu, Mohamed Sithik, Roberto Pesce Jr, Chandra Mouli Sankaran
Abstract Based on current trends, there is a huge demand for lightweight components, which improves fuel efficiency and reduces cost of the vehicle. Stiffness based optimization process is simple and straightforward while durability (Misuse load case) based optimizations are relatively complex due to its highly nonlinear behavior. However, durability performances are critical in a front cradle design. So a process needs to be identified for creating a new light weight front cradle design. This study talks about the process of identifying new cast aluminium cradles achieving NVH and durability performance. Load path study using topology optimization is done based on compliance method for the durability load case. A concept model is generated from the topology results. This concept model is further optimized for thickness of ribs and walls by the application of various shape variables. All the critical non linear durability load cases are linked for the shape optimization study.
2016-04-05
Technical Paper
2016-01-1451
Mingyang Chen, Xichan Zhu, Zhixiong Ma, Lin Li
Abstract In China there are many mixed driving roads which cause a lot of safety problems between vehicles and pedalcyclists. Research on driver behavior under risk scenarios with pedalcyclist is relatively few. In this paper driver brake parameters under naturalistic driving are studied and pedalcyclists include bicyclist, tricyclist, electric bicyclist and motorcyclist. Brake reaction time and maximum brake jerk are used to evaluate driver brake reaction speed. Average deceleration is used to evaluate the effect of driver brake operation. Maximum deceleration is used to evaluate driver braking ability. Driver behaviors collected in China are classified and risk scenarios with pedalcyclist are obtained. Driver brake parameters are extracted and statistical characteristics of driver brake parameters are obtained. Influence factors are analyzed with univariate ANOVA and regression analysis.
2016-04-05
Technical Paper
2016-01-1453
I-Hsuan Lee, Bi-Cheng Luan
Abstract Autonomous emergency braking (AEB) systems is one of the functions of the Advanced Driver Assists System to avoid or mitigate vehicle frontal collisions. Most of the previous studies focus on two-car scenario where the host vehicle monitors the distances to the vehicles in front, and automatically applies emergency brake when a collision is imminent. The purpose of this paper is to develop an Advanced-AEB control system that mitigates collisions in a multi-car scenario by measuring the distances to the vehicles in front as well as those to the vehicles behind using the concept of impedance control. A simple gain-scheduling PI controller was designed for the host vehicle to track the reference inputs generated by the impedance control. The preliminary simulation results demonstrate that the proposed AEB is effective in mitigating the collisions in a 3-car following scenario.
2016-04-05
Technical Paper
2016-01-1327
Zhenfeng Wang, Mingming Dong, Junfeng Xiang, Pu Gao, Liang Gu, Yushuai Wang
Abstract The study of mechanical properties special in the characteristics of elastic element is a challenging task for vehicle industry. Since torsion bar spring acts as an important part of elastic element, and improves performance of torsion bar spring is of great concern. The effects of the torsion bar spring pre-setting precision on the presetting performance are presented. Based on elastic-plastic theories, the algebraic model of torsion bar spring is established to analyze the stress, torque and residual stress under the yield and plastic conditions in pre-setting process. Then, the stress and strain states of various torsion bar springs in different conditions are simulated using the validated finite element model in ABAQUS software. The simulation results show the effects of torsion error on the pre-setting performance are less than 5% in the pre-setting process.
2016-04-05
Technical Paper
2016-01-1555
Jack Ekchian, William Graves, Zackary Anderson, Marco Giovanardi, Olivia Godwin, Janna Kaplan, Joel Ventura, James R. Lackner, Paul DiZio
Abstract It is widely anticipated that autonomous vehicles will offer increased productivity and convenience by freeing occupants from the responsibility of driving. However, studies indicate that the occurrence of motion sickness in autonomous vehicles will be substantially higher than in conventionally driven vehicles. Occupants of autonomous vehicles are more likely to be involved in performing tasks and activities, such as reading, writing and using a computer or tablet, that typically increase the occurrence of motion sickness. The authors present a novel high bandwidth active suspension system, GenShock®, and tailored control algorithms targeted toward mitigating motion sickness in autonomous vehicles. GenShock actuators can actively push and pull the wheels of a vehicle in order to keep the chassis level and reduce heave, pitch, and roll motion.
2016-04-05
Standard
J230_201604
This SAE Recommended Practice covers a high-strength corrosion-resisting steel wire, uniform in mechanical properties, intended for the manufacture of springs and wire forms. It covers processing requirements of springs and forms fabricated from this wire.
2016-04-05
Standard
J217_201604
This SAE Recommended Practice covers a high-quality corrosion resisting steel wire, cold drawn, formed, and heat treated to produce uniform mechanical properties. It is magnetic in all conditions. It is intended for the manufacture of springs and wire forms that are to be heat treated after forming to enhance the spring properties. This document also covers processing requirements of the springs and forms fabricated from this wire.
2016-04-05
Standard
J510_201604
This SAE Standard is limited to concise specifications promoting an adequate understanding between spring maker and spring user on all practical requirements in the finished spring. The basic concepts for the spring design and for many of the details have been fully addressed in HS-J788, SAE Information Report, Manual on Design and Application of Leaf Springs, which is available from SAE Headquarters. NOTE: For leaf springs made to metric units, see SAE J1123.
2016-04-05
Technical Paper
2016-01-1308
Kristian Lee Lardner, Moustafa El-Gindy, Fredrik Oijer, Inge Johansson, David Philipps
Abstract The purpose of this study is to determine the effect of tire operating conditions, such as the tire inflation pressure, speed, and load on the change of the first mode of vibration. A wide base FEA tire (445/50R22.5) is virtually tested on a 2.5m diameter circular drum with a 10mm cleat using PAM-Crash code. The varying parameters are altered separately and are as follows: inflation pressure, varying from 50 psi to 165 psi, rotational speed, changing from 20 km/h to 100 km/h, and the applied load will fluctuate from 1,500 lbs. to 9000 lbs. Through a comparison of previous literature, the PAM-Crash FFT algorithmic results have been validated.
2016-04-05
Technical Paper
2016-01-1063
George Nerubenko
Abstract Up to 30% of engine noise is delivered by front end pulley combined with torsional vibration damper, and technically it is the main contributor to recorded engine noise level. So the novel solutions in terms of improving the design and performance of torsional vibration damper would help to reduce radically this component of engine noise. The results of dynamical study of patented torsional vibration damper combined with pulley are presented. Design and structure of torsional vibration damper is based on author’s US Patent 7,438,165 having the self-tuning control system for all frequencies in running engine in all operational regimes. Mathematical model has been used for the analysis of the emitting noise of engine having proposed torsional vibration damper. Attention is paid to mitigation of the sound power levels contributing by engine subsystem “end of crankshaft - torsional vibration damper - pulley”.
2016-04-05
Technical Paper
2016-01-1652
Jungmin Na, Gibin Gil
Abstract This paper presents a new method to find the tire cornering characteristics that satisfy the required handling performance of a vehicle in the early tire development process. The tire cornering characteristics should be considered in the sense of not only absolute levels but also balance between front and rear tires in order to satisfy handling performance of a vehicle. As a result, it is difficult to find the appropriate tire characteristics when trial-and-error approach is used. In this study, the virtual optimization technique is applied to find the required tire cornering characteristics in more efficient way. The optimization framework consists of a vehicle dynamic simulation tool to predict the handling performance of a vehicle and an optimization tool to find the optimal solution. The objective function and the constraints are defined in terms of vehicle handling objective parameters associated with the subjective assessment.
Viewing 151 to 180 of 10698

Filter