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Viewing 1 to 30 of 7913
2016-06-15
Technical Paper
2016-01-1832
Ramakrishna Kamath
Intermediate shaft assembly is used to connect steering gear to the steering wheel. The primary function of the intermediate shaft is to transfer torsional loads. There is a high probability of noise propagating through the Intermediate shaft to the driver. The current standard for measuring the noise is by performing vehicle level subjective evaluations. If improperly clamped at either of the yokes, a sudden change in the direction of the torsional load on the Intermediate shaft can generate a displeasing noise. Noise can also be generated from the constant velocity joint. Intermediate shaft noise can be measured using a microphone or can be correlated to acceleration values. The benefit of measuring the acceleration over sound pressure level is the reduction of complexity of the test environment and test set up. The nature of the noise in question requires the filtering of low frequency data. This paper presents a new test procedure that has been developed by General Motors.
2016-06-15
Technical Paper
2016-01-1834
Florian Fink, Gregor Koners
Abstract This paper describes the prediction process of wheel forces and moments via indirect transfer path analysis, followed by an analysis of the influence of wheel variants and suspension modifications. It proposes a method to calculate transmission of noise to the vehicle interior where wheel forces and especially moments were taken into account. The calculation is based on an indirect transfer path analysis with geometrical modifications of the frequency response functions. To generate high quality broadband results, this paper also points out some of the main clearance cutting criteria. The method has been successfully implemented to show the influence of wheel tire combinations as well as the influence of suspension modifications. Case studies have been performed and will be presented in this paper. Operational noise and vibration measurements have been carried out on Daimler NVH test tracks. The frequency response functions were estimated in an acoustic laboratory.
2016-06-15
Journal Article
2016-01-1827
Giorgio Bartolozzi, Marco Danti, Andrea Camia, Davide Vige
Abstract The time to market in the automotive industry is constantly decreasing pushing the carmaker companies to increase the efforts in numerical simulations and to decrease the number of prototypes. In the NVH field, this time constraint reflects in moving the well-established finite element simulations towards the so called “full-vehicle simulations”. Specifically, the CAE techniques should be able to predict the complete behavior of the vehicles in mission conditions, so to reproduce some usual tests, such as the “coast down” test on different roads. The aim of this paper is to present a methodology to improve rolling noise simulations exploiting an integrated full-vehicle approach. An accurate modeling of all the subsystems is needed, with particular attention to the wheels and the suspension systems. Therefore, the paper firstly covers the modeling approach used to obtain the FE models of tires and suspension system.
2016-06-15
Technical Paper
2016-01-1765
Kelly Savva, Ahmed Haris, Eliot Motato, Mahdi Mohammadpour, Stephanos Theodossiades, Homer Rahnejat, Patrick Kelly, Alexander Vakakis, Lawrence Bergman, Donald McFarland
Abstract Legislation on vehicle emissions and the requirements for fuel efficiency are currently the key development driving factors in the automotive industry. Research activities to comply with these targets point to engine downsizing and new boosting technologies, which have adverse effects on the NVH performance, durability and component life. As a consequence of engine downsizing, substantial torsional oscillations are generated due to high combustion pressures. Meanwhile, to attenuate torsional vibrations, the manufacturers have implemented absorbers that are tuned to certain frequency ranges, including clutch dampers, Dual Mass Flywheel (DMF) and centrifugal pendulum dampers. These devices add mass/inertia to the system, potentially introducing negative effects on other vehicle attributes, such as weight, driving performance and gear shiftability.
2016-06-15
Journal Article
2016-01-1777
Sebastian Oberst, Zhi Zhang, Joseph CS Lai
Abstract Despite significant progress made in the past 20 years in discovering some of the mechanisms of brake squeal, it remains difficult to predict the underlying friction-induced instabilities reliably. Most numerical analyses are based on linear deterministic analyses of structural vibrations such as the complex eigenvalue analysis (CEA). However, nonlinear multi-scale processes govern friction contact with high sensitivities to operating and/or environmental conditions. In addition, uncertainties in the material properties and boundary conditions such as contact and friction laws are rarely considered. Hence, it is quite common to underpredict or overpredict the number of instabilities and extensive brake noise dynamometer tests are still required in industry to ensure acceptable brake noise performance. In this paper, simplified finite element brake models are used to illustrate the role of nonlinearity in brake squeal.
2016-06-15
Technical Paper
2016-01-1779
Sergio Carvajal, Daniel Wallner, Reinhard Helfrich, Michael Klein
Abstract Numerical methods for brake squeal analysis are widely accepted in industry. The use of complex eigenvalue analysis is a successful approach to predict the appearance of squeal noise. Using simulation in an early design stage reduces time to market, saves costs, and improves the physical behavior and robustness of the brake system. State of the art of brake simulation comprises sampling for many parameter sets in a wide range of interesting values. Based on high performance, stability maps can be created in short time containing many results, which gives a deep insight into the brake behavior under varying parameters. An additional benefit of sampling is the possibility to detect parts with high potential for improving the NHV comfort. In the sequel, mathematical optimization methods like topology optimization or shape optimization are used for systematic improvements.
2016-04-15
Journal Article
2015-01-9020
Emre Sert, Pinar Boyraz
Abstract Studies have shown that the number of road accidents caused by rollover both in Europe and in Turkey is increasing [1]. Therefore, rollover related accidents became the new target of the studies in the field of vehicle dynamics research aiming for both active and passive safety systems. This paper presents a method for optimizing the rear suspension geometry using design of experiment and multibody simulation in order to reduce the risk of rollover. One of the major differences of this study from previous work is that it includes statistical Taguchi method in order to increase the safety margin. Other difference of this study from literature is that it includes all design tools such as model validation, optimization and full vehicle handling and ride comfort tests. Rollover angle of the vehicle was selected as the cost function in the optimization algorithm that also contains roll stiffness and height of the roll center.
2016-04-05
Technical Paper
2016-01-1566
Liangyao Yu, Xiaoxue Liu, Kefeng Yang, Xiaohui Liu, Shuhao Huo
This paper focuses on reviewing the existing studies of in-tire energy harvesting systems. Energy harvesting systems are widely applied in different areas. But studies in the application of energy harvesters embedded in tires for vehicle control are still rare, most of which focus on solving the problem of power supply of tire pressure sensors. Traditionally the sensors are powered by an embedded battery, which must be changed periodically due to the limited energy storage. Furthermore, the number of in-tire sensors will increase as safety of vehicles has drawn more attention, requiring more in tire electricity supply. So a substitution of the battery, the in-tire energy harvesting system, is worth studying. Currently introduced methods of in-tire energy harvesting principles include piezoelectric, electromagnetic and electrostatic. The source of the energy can be in tire vibration, deformation, rotation and so on.
2016-04-05
Technical Paper
2016-01-1562
Hongyu Zheng, Jinghuan Hu, Jidong Lv
There is no mechanical connection between steering wheel and front wheel in vehicle Steer by Wire. The advantages of steer by wire system such as its modular structure and variable steering ratio provide wide development prospect for vehicle performance. Accurate, stable coupling between modules is the basis of its normal operation, the property of variable steering ratio influences vehicle handling stability directly, they are all the core component of Steer-by-Wire system control method. In steering angle ratio and road feeling control algorithm of steer by wire system, the parameters of steering system and electrical machine have important influence on control algorithm. Therefore, establishing steer by wire vehicle simulation platform and steer by wire experimental verification platform should be arranged at first.
2016-04-05
Technical Paper
2016-01-1564
Shyama Ashok kumar S
Abstract Field Oriented Control (FOC) has been widely used for controlling Brushless DC motors (BLDC) used in Electric Power Assisted Steering (EPAS) systems. This is majorly because FOC provides better performance at lower speed, compared to other algorithms available in market. But the design complexities and cost of EPAS ECUs are much higher due to transformations and the rotor position sensor involved. This paper suggests the use of Direct Torque Control (DTC) over FOC, due to its quicker dynamic response, lower complexity and better response at higher speed. A simple Ripple Reduction Strategy (RRS) with data smoothening and filtering is introduced to improve the performance at lower speed. The DTC with RRS is modeled in MATLAB /Simulink. The Simulation results are compared with that of FOC, to prove the effectiveness of DTC.
2016-04-05
Journal Article
2016-01-1175
Ran Bao, Richard Stobart
Abstract A control strategy has been designed for a city bus equipped with a pneumatic hybrid propulsion system. The control system design is based on the precise management of energy flows during both energy storage and regeneration. Energy recovered from the braking process is stored in the form of compressed air that is redeployed for engine start and to supplement the engine air supply during vehicle acceleration. Operation modes are changed dynamically and the energy distribution is controlled to realize three principal functions: Stop-Start, Boost and Regenerative Braking. A forward facing simulation model facilitates an analysis of the vehicle dynamic performance, engine transient response, fuel economy and energy usage.
2016-04-05
Technical Paper
2016-01-1075
Jonathan Plail, Petr Grinac, Helen Ballard
Abstract In this paper, a mathematical model for simulating the 3D dynamic response of a valve spring is described. The 3D model employs a ‘geometrically exact’ 3D beam connected between each mass of the discretised mass-elastic system. Shear deformations within the beam are also considered, which makes it a Timoshenko type finite element. Results from the 3D model are compared with results from a more conventional 1D model. To validate the results further, some results are compared with real test data that was gathered during a technical consulting project. In this project, a prototype valvetrain that was originally giving acceptable durability began to wear the spring seats when a new batch of springs were procured and tested. 1D and 3D simulation results were used to help understand the cause of the failure and to make recommendations to resolve the issue. Results showed that the 3D model was able to predict the spring seat loads with greater precision than the 1D spring could.
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
2016-01-1059
Huyao Wu, Fei Huo
Abstract The parameter vibration is a hot topic for nonlinear vibration. Some results of its study have been used in aerospace, machining technology, motor vibration and many other fields, and the sport that people play on the swing is a classic one. In this paper, by creating the model of standard human body and swing, a biomechanical compound pendulum consisting of nine bodies and relevant force elements consisting of springs and dampers are regarded, then the movement is simulated in ADAMS. The time history of the swinging angle of the system is measured and the trace of the mass center is also displayed. Furthermore, in order to examine the stability of the system, the phase portraits are provided, and the stable diagram is obtained under different values of relevant parameters.
2016-04-05
Technical Paper
2016-01-1640
Zhuoping Yu, Songyun Xu, Lu Xiong, Wei Han
Abstract An integrated-electro-hydraulic brake system (I-EHB) is presented to fulfill the requirements of active safety. Because I-EHB can control the brake pressure accurately and fast. Furthermore I-EHB is a decoupled system, so it could make the maximum regenerative braking while offers the same brake pedal feeling and also good for ADAS and unmanned driving application. Based on the analysis of current electrohydraulic brake systems, regulation requirements and the requirements for brake system, the operating mode requirements of I-EHB are formed. Furthermore, system topological structure and a conceptual design are proposed. After the selection of key components, the parameter design is accomplished by modeling the system. According to the above-mentioned design method, an I-EHB prototype and test rig is made. Through the test rig, characteristics of the system are tested. Results show that this I-EHB system responded rapidly.
2016-04-05
Journal Article
2016-01-1639
Jonathan Loyola, Francis Assadian
Abstract An investigation into two new control strategies for the vehicle Anti-lock Braking System (ABS) are made for a possible replacement of current non-optimal slip control methods. This paper applies two techniques in order to maximize the braking force without any wheel locking. The first considers the power dissipated by the brake actuator. This power method does not use slip to construct its reference signal for control. A heuristic approach is taken with this algorithm where one searches for the maximum power dissipated. This can open up easier implementation of regenerative braking concurrently with ABS on an electro-hydraulic braking system. Parameter scheduling is explored in this algorithm. The second algorithm employs the use of perturbation based Extremum Seeking Control (ESC) to provide a reference slip and a Youla controller in a negative feedback loop.
2016-04-05
Journal Article
2016-01-1644
Haizhen Liu, Weiwen Deng, Rui He, Lei Qian, Shun Yang, Jian Wu
Abstract This paper presents a power assisted braking control based on a novel mechatronic booster system. A brake pedal feel control unit is first discussed which includes a pedal emulator with an angular sensor to detect driver’s pedal travel, a signal processing module with a Kalman filter for sensor signal conditioning, and a driver braking intention detection and behavior recognition module based on the displacement and velocity of the pedal travel. A power assisted braking control is then presented as the core of the system which consists of controls on basic power assist, velocity compensation and friction compensation. The friction is estimated based on a generic algorithm offline. A motor controller is designed to provide the desired torque for the power assist. Finally, a novel mechatronic booster system is designed and built with an experimental platform set up with a widely adopted rapid prototype system using dSPACE products, such as MicroAutoBox, RapidPro, etc.
2016-04-05
Journal Article
2016-01-1635
Donald F. Tandy, Jung Bae, Jason Colborn, Clay Coleman
Abstract Recreational Off Road Vehicles (ROVs) which are sometimes referred to as side-by-sides, have increased in popularity over the last decade. These vehicles are available in many different sizes and performance characteristics from a host of different manufacturers and also have a variety of different missions, just as there are many types of off road terrain. The United States Federal Government, through the Consumer Product Safety Commission (CPSC), has advocated and proposed vehicle handling and rollover resistance standards for the side-by-sides which have a top speed above 25 miles per hour (these are not defined as “low speed vehicles”). For the sake of repeatability, the proposed maneuvers are to be performed on a high friction hard surface (like asphalt) as opposed to the off road surfaces (i.e. grass, sand, dirt, mud. rocks, etc.) that these vehicles are designed to be operated on.
2016-04-05
Journal Article
2016-01-1637
Hongyuan Zang, Zhuoping Yu, Lu Xiong
Abstract To analyze the K&C (kinematics and compliance), handling and stability performance of the vehicle chassis, some simulations are usually performed using a multi-body dynamics software named ADAMS. This software introduces assumptions that simplify the components of the suspension as rigid bodies. However, these assumptions weaken the accuracy of the simulation of ADAMS. Therefore the use of flexible bodies in K&C and handling and stability simulation in ADAMS is needed to conduct more precise suspension system designs. This paper mainly analyses the influences of the subframe flexibility on handling and stability simulation in ADAMS/Car. Two complete vehicle models are built using ADAMS/Car and Hypermesh. The only difference between the two models is the subframe of the front McPherson suspension. One of the subframes is simplified as a rigid body. The other one is a flexible body built using the MNF file from Hypermesh.
2016-04-05
Technical Paper
2016-01-1638
Eunhyek Joa, Kyongsu Yi, Kilsoo Kim
Abstract This paper presents the integrated chassis control(ICC) of four-wheel drive(4WD), electronic stability control(ESC), electronic control suspension(ECS), and active roll stabilizer(ARS) for limit handling. The ICC consists of three layers: 1) a supervisor determines target vehicle states; 2) upper level controller calculates generalized forces; 3) lower level controller, which is contributed in this paper, optimally allocates the generalized force to chassis modules. The lower level controller consists of two integrated parts, 1) longitudinal force control part (4WD/ESC) and 2) vertical force control part (ECS/ARS). The principal concept of both algorithms is optimally utilizing the capability of the each tire by monitoring tire saturation, with tire combined slip. By monitoring tire saturation, 4WD/ESC integrated system minimizes the sum of the tire saturation, and ECS/ARS integrated system minimizes the variance of the tire saturation.
2016-04-05
Journal Article
2016-01-1649
Jose Velazquez Alcantar, Farhad Assadian
Abstract Optimizing/maximizing regen braking in a hybrid electric vehicle (HEV) is one of the key features for increasing fuel economy. However, it is known [1] that maximizing regen braking by braking the rear axle on a low friction surface results in compromising vehicle stability even in a vehicle which is equipped with an ESP (Enhanced Stability Program). In this paper, we develop a strategy to maximize regen braking without compromising vehicle stability. A yaw rate stability control system is designed for a hybrid electric vehicle with electric rear axle drive (ERAD) and a “hang on” center coupling device which can couple the front and rear axles for AWD capabilities. Nonlinear models of the ERAD drivetrain and vehicle are presented using bond graphs while a high fidelity model of the center coupling device is used for simulation.
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.
2016-04-05
Technical Paper
2016-01-1647
Jing Li, Xiong Yang, Hui Miao, Zheng Tang Shi
Abstract A program of integrated electro-hydraulic braking system is proposed, and its structural composition and working principle are analyzed. According to the structural and mechanical characteristics of all key components, through some reasonable assumptions and simplifications, a motor, a brake master cylinder, four brake wheel cylinders, solenoid valves and an ESP (Electronic Stability Program) algorithm model is set up and simulations of typical braking conditions are carried out based on the Matlab/Simulink. Finally, after the assembly of each sub-model is complete and combining a vehicle which is set up in CarSim software environment, simulation tests and comprehensive performance analysis of the active safety stability control for a vehicle in double lane change and single lane change situations are carried out respectively.
2016-04-05
Journal Article
2016-01-1646
Tao Xu, Yanhua Shen, Wenming Zhang
Abstract The traditional hydraulic steering mode in articulated motor-driven vehicle makes the vehicle structure complex. Further more, the forces between the front and rear part of the articulated vehicle could damage the articulated joint body in the process of vehicle steering. However, skid steering mode could make the vehicle steer with the different speed of each wheel, which is flexible without hydraulic steering system. The purpose of this paper is to introduce the principle of skid steering mode in articulated motor-driven vehicle. In this paper, the theory of traditional wheeled vehicle’s skid-steering mode and hydraulic steering mode of articulated vehicle are used to establish the in-situ skid-steering kinematic and dynamic model. Based on the model, the vehicle trajectory and the dynamic relationships among the body structure of the vehicle, longitudinal forces, lateral forces of each wheel are described.
2016-04-05
Journal Article
2016-01-1648
M. Kamel Salaani, Sughosh Rao, Joshua L. Every, David R. Mikesell, Frank Barickman, Devin Elsasser, John Martin
Abstract The rapid innovation underway with vehicle brake safety systems leads to extensive evaluation and testing by system developers and regulatory agencies. The ability to evaluate complex heavy truck braking systems is potentially more rapid and economical through hardware-in-the-loop (HiL) simulation which employs the actual electronics and vehicle hardware. Though the initial HiL system development is time consuming and expensive, tests conducted on the completed system do not require track time, fuel, vehicle maintenance, or technician labor for driving or truck configuration changes. Truck and trailer configuration and loading as well as test scenarios can be rapidly adjusted within the vehicle dynamics simulation software to evaluate the performance of automated safety interventions (such as ESC) over a wide range of conditions.
2016-04-05
Journal Article
2016-01-1619
Lara Schembri Puglisevich, Adrian Gaylard, Matthew Osborne, Jonathan Jilesen, Adriano Gagliardi
Abstract Brake disc materials are being utilised that have low noise/dust properties, but are sensitive to contamination by surface water. This drives large dust shields, making brake cooling increasingly difficult. However, brake cooling must be delivered without compromising aerodynamic drag and hence CO2 emissions targets. Given that front brake discs sit in a region of geometric, packaging and flow complexity optimization of their performance requires the analysis of thermal, aerodynamic and multi-phase flows. Some of the difficulties inherent in this task would be alleviated if the complete analysis could be performed in the same CAE environment: utilizing common models and the same solver technology. Hence the project described in this paper has sought to develop a CFD method that predicts the amount of contamination (water) that reaches the front brake discs, using a standard commercial code already exploited for both brake disc thermal and aerodynamics analysis.
2016-04-05
Technical Paper
2016-01-1628
Gurdeep Singh Pahwa, Baskar Anthonysamy, Karan Shah
Abstract Lateral Stability is an important attribute which must be accounted for in the pick-up truck segment vehicles. If designed in an improper way, undesirable effects such as oversteer or tail sway may occur. Excessive yaw rate magnitudes, or tail sway, can reduce the confidence of the driver during severe lane change events. The concept architecture of the vehicle plays an important role in how stable the vehicle will be. High yaw rate or tail sway during limit cornering was reported during prototype vehicle evaluations. The tested vehicle configuration incorporated a double wish bone front suspension with an antiroll bar and a rear solid axle suspension with leaf springs and an antiroll bar. The feedback was critically analysed using computer simulations of the condition found in on track testing. Since the vehicle was still with the validation team, quick solution was necessary. This paper discusses the process which resulted in improved vehicle performance.
2016-04-05
Technical Paper
2016-01-1627
Liangxiu Zhang, Guangqiang Wu
Abstract In order to improve the robustness and stability of autonomous vehicle at high speed, a path tracking approach which combines front steering and differential braking is investigated in this paper. A bicycle model with 3-DOFs is established and a linear time-varying predictive model using front steering as its control input can be derived. Based on model predictive theory, the path tracking issue using linear time-varying model predictive control can be transformed into an online quadratic programming problem with constraints. The expected front steering angle can be obtained from online moving optimization. Then the direct yawing control is adopted to treat two types of differential braking control. The first one investigates steady-state gain of yaw rate in linear 2-DOFs vehicle model, and designs a stable differential braking controller which is based on reference yaw rate.
2016-04-05
Journal Article
2016-01-1630
Benjamin Hirche, Beshah Ayalew
In this paper, a soft computing approach to a model-free vehicle stability control (VSC) algorithm is presented. The objective is to create a fuzzy inference system (FIS) that is robust enough to operate in a multitude of vehicle conditions (load, tire wear, alignment), and road conditions while at the same time providing optimal vehicle stability by detecting and minimizing loss of traction. In this approach, an adaptive neuro-fuzzy inference system (ANFIS) is generated using previously collected data to train and optimize the performance of the fuzzy logic VSC algorithm. This paper outlines the FIS detection algorithm and its benefits over a model-based approach. The performance of the FIS-based VSC is evaluated via a co-simulation of MATLAB/Simulink and CarSim model of the vehicle under various road and load conditions. The results showed that the proposed algorithm is capable of accurately indicating unstable vehicle behavior for two different types of vehicles (SUV and Sedan).
2016-04-05
Journal Article
2016-01-1526
Daniel V. McGehee, Cheryl A. Roe, Linda Ng Boyle, Yuqing Wu, Kazutoshi Ebe, James Foley, Linda Angell
Abstract Pedal misapplications may be rare, but the outcomes can be tragic. A naturalistic driving study with 30 drivers was conducted to gain a better understanding of foot pedal behaviors. Foot movements were observed from the moment subjects entered and positioned themselves in their vehicle, and continued through starting the ignition, shifting into gear, accelerating to driving speed, and finally, resting their foot after parking the vehicle. A coding methodology was developed to categorize the various foot movements and behaviors. Over 3,300 startup and parking sequences were coded. This paper describes the unique challenges involved in classifying foot movements and behaviors when drivers’ intentions are not known. For example, hesitant or interrupted foot movements often occurred when a driver was transitioning from a gas pedal press to a brake pedal press.
Viewing 1 to 30 of 7913