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Viewing 211 to 240 of 19895
2017-03-28
Technical Paper
2017-01-0428
Tianqi Lv, Yan Wang, Xingxing Feng, Yunqing Zhang
Abstract Steering returnability is an important index for evaluating vehicle handling performance. A systematic method is presented in this paper to reduce the high yaw rate residue and the steering response time for a light duty truck in the steering return test. The vehicle multibody model is established in ADAMS, which takes into consideration of the frictional loss torque and hydraulically assisted steering property in the steering mechanism, since the friction, which exists in steering column, spherical joint, steering universal joint, and steering gear, plays an important role in vehicle returnability performance. The accuracy of the vehicle model is validated by road test and the key parameters are determined by executing the sensitivity analysis, which shows the effect of each design parameter upon returnability performance.
2017-03-28
Technical Paper
2017-01-0429
Michael Holland, Jonathan Gibb, Kacper Bierzanowski, Stuart Rowell, Bo Gao, Chen Lv, Dongpu Cao
Abstract This paper outlines the procedure used to assess the performance of a Lane Keeping Assistance System (LKAS) in a virtual test environment using the newly developed Euro NCAP Lane Support Systems (LSS) Test Protocol, version 1.0, November 2015 [1]. A tool has also been developed to automate the testing and analysis of this test. The Euro NCAP LSS Test defines ten test paths for left lane departures and ten for right lane departures that must be followed by the vehicle before the LKAS activates. Each path must be followed to within a specific tolerance. The vehicle control inputs required to follow the test path are calculated. These tests are then run concurrently in the virtual environment by combining two different software packages. Important vehicle variables are recorded and processed, and a pass/fail status is assigned to each test based on these values automatically.
2017-03-28
Technical Paper
2017-01-0430
Bangji Zhang, Kaidong Tian, Wen Hu, Jie Zhang, Nong Zhang
Abstract This paper introduces a vehicle model in CarSim, and replaces a portion of its standard suspension system with an HIS model built in an external software to implement co-simulations. The maneuver we employ to characterize the HIS vehicle is a constant radius method, i.e. observing the vehicle’s steering wheel angle by fixing its cornering radius and gradually increasing its longitudinal speed. The principles of the influence of HIS systems on cornering mainly focus on two factors: lateral load transfer and roll steer effect. The concept of the front lateral load transfer occupancy ratio (FLTOR) is proposed to evaluate the proportions of lateral load transfer at front and rear axles. The relationship between toe and suspension compression is dismissed firstly to demonstrate the effects of lateral load transfer and then introduced to illustrate the effects of roll motion on cornering.
2017-03-28
Technical Paper
2017-01-0415
Xingxing Feng, Peijun Xu, Penglei Fu, Yunqing Zhang
Abstract This work is motivated by the fact that the surface of a terrain may vary with local pavement properties and number of passes of the vehicle, which means the roughness coefficient and waviness of the terrain may vary in specific intervals. However, in traditional random terrain models, the roughness coefficient and waviness of the terrain are assumed as constants. Therefore, this assumption may be not very reasonable. A novel random terrain model is presented where the roughness coefficient and waviness of the terrain are expressed by interval numbers instead of constants. A 5-degree-of-freedom ride dynamic model of the vehicle with uncertain parameters is derived. The power spectral density (PSD) and root mean square value (RMS) of the vehicle ride responses are shown and analyzed. Analysis results indicate that the vehicle responses vary in specific intervals under the random terrain excitation with interval parameters.
2017-03-28
Journal Article
2017-01-0418
Gregory McCann, Prashant Khapane
Abstract An increase in data measurement and recording within vehicles has allowed Anti-lock Braking Systems (ABS) to monitor a vehicle’s dynamic behavior in far more detail. This increased monitoring helps to improve vehicle response in scenarios such as braking whilst cornering and braking on uneven surfaces. The Durability and Robustness (D&R) CAE department within Jaguar Land Rover discovered that the lack of a complex ABS system in virtual vehicle models was contributing to poor lateral and longitudinal loads correlation throughout the suspension and mounting systems. D&R CAE started a project to incorporate Continental’s ABS system, provided by ‘©Continental AG’ for physical JLR vehicles, into SIMPACK virtual vehicles by means of a co-simulation (2017 n.d.). The work involved collaboration between 3 departments in Jaguar Land Rover and ultimately led to implementation of the ABS into the JLR standard automotive virtual database.
2017-03-28
Journal Article
2017-01-0419
Yuliang Yang, Yu Yang, Ying Sun, Jian Zeng, Yunquan Zhang
Abstract In addition to ride comfort, handling stability and other conventional vehicle performances, we should also focus on other aspects of performance to a center axle trailer combination, such as the maximum stable side-inclination, the anti-rolling stability, the lateral stability and so on. Based on the finite element method, a rigid-flexible coupling model for the truck combination was built and analyzed in the multi-body environment (ADAMS), in which the key components of the chassis and cab suspension were treated as flexible bodies. A series of simulations were carried out to evaluate the lateral stability of the center axle trailer in accordance with the relevant regulations of the vehicle. The influence of design variables on the lateral stability was studied by an experiment. Furthermore, in order to improve the lateral stability of the trailer combination, the optimal design was obtained by the co-simulation of the ADAMS/Car, iSIGHT and Matlab.
2017-03-28
Technical Paper
2017-01-0396
Guobiao Yang, Changqing Du, Dajun Zhou, Hao Wang, Elizabeth Lekarczyk, Lianxiang Yang
Abstract Vehicle weight reduction is a significant challenge for the modern automotive industry. In recent years, the amount of vehicular components constructed from aluminum alloy has increased due to its light weighting capabilities. Automotive manufacturing processes, predominantly those utilizing various stamping applications, require a thorough understanding of aluminum fracture predictions methods, in order to accurately simulate the process using Finite Element Method (FEM) software or use it in automotive engineering manufacture. This paper presents the strain distribution of A5182 aluminum samples after punch impact under various conditions by Digital Image Correlation (DIC) system, its software also measured the complete strain history, in addition to sample curvature after it was impacted; therefore obtaining the data required to determine the amount of side-wall-curl (Aluminum sheet springback) present after formation.
2017-03-28
Journal Article
2017-01-1669
Keiichiro Numakura, Kenta Emori, Akinori Okubo, Taku Shimomura, Tetsuya Hayashi
Abstract This paper presents the technologies incorporated in an electric vehicle (EV)/hybrid electric vehicle (HEV) inverter built with power semiconductors of silicon carbide (SiC) metal-oxide-semiconductor field-effect transistors (MOSFETs) instead of conventional silicon (Si) insulated gate bipolar transistors (IGBTs). A SiC inverter prototype of 2.9 L in size for driving an 80-kW motor was fabricated and evaluated on a motor test bench. The SiC inverter prototype attained average efficiency of 98.5% in the Worldwide harmonized Light-duty Test Cycle (WLTC) driving mode. The two main technologies achieved with this SiC inverter prototype are described. The first one is a new direct-cooled power module with a thick copper (Cu) heat spreader located under the semiconductors that improves thermal resistance by 34% compared with a conventional direct-cooled power module.
2017-03-28
Technical Paper
2017-01-1672
Siddartha Khastgir, Gunwant Dhadyalla, Stewart Birrell, Sean Redmond, Ross Addinall, Paul Jennings
Abstract The advent of Advanced Driver Assistance Systems (ADAS) and automated driving has offered a new challenge for functional verification and validation. The explosion of the test sample space for possible combinations of inputs needs to be handled in an intelligent manner to meet cost and time targets for the development of such systems. This paper addresses this research gap by using constrained randomization techniques for the creation of the required test scenarios and test cases. Furthermore, this paper proposes an automated constrained randomized test scenario generation framework for testing of ADAS and automated systems in a driving simulator setup. The constrained randomization approach is deployed at two levels: 1) test scenario randomization 2) test case randomization.
2017-03-28
Technical Paper
2017-01-1682
Matthew von der Lippe, Mark Waterbury, Walter J. Ortmann, Bernard Nefcy, Scott Thompson
Abstract The FMEA and DV&PV process of developing automotive products requires identifying and repeatedly testing critical vehicle attributes and their response to noise factors that may impair vehicle function. Ford has developed a new automated scripting tool to streamline in-vehicle robustness testing and produce more accurate and repeatable results. Similar noise factors identified during the FMEA process are grouped together, condensed, and scripts are developed to simulate these noise factors using calibration parameters and vehicle controls. The automated testing tool uses the API of a calibration software tool and a graphical scripting interface to consistently simulate driver inputs with greater precision than a human calibrator and enable more sophisticated controls, which would have previously required experimental software builds.
2017-03-28
Technical Paper
2017-01-1683
Adit Joshi
Software for autonomous vehicles is highly complex and requires vast amount of vehicle testing to achieve a certain level of confidence in safety, quality and reliability. According to the RAND Corporation, a 100 vehicle fleet running 24 hours a day 365 days a year at a speed of 40 km/hr, would require 17 billion driven kilometers of testing and take 518 years to fully validate the software with 95% confidence such that its failure rate would be 20% better than the current human driver fatality rate [1]. In order to reduce cost and time to accelerate autonomous software development, Hardware-in-the-Loop (HIL) simulation is used to supplement vehicle testing. For autonomous vehicles, path following controls are an integral part for achieving lateral control. Combining the aforementioned concepts, this paper focuses on a real-time implementation of a path-following lateral controller, developed by Freund and Mayr [2].
2017-03-28
Technical Paper
2017-01-1575
Andrei Keller, Sergei Aliukov, Vladislav Anchukov
Abstract Trucks are one of the most common modes of transport and they are operated in various road conditions. As a rule, all-wheel drive trucks are equipped with special systems and mechanisms to improve their off-road capability and overall efficiency. The usage of blocked mechanisms for power distribution is one of the most popular and effective ways to improve the off-road vehicle performance. However, the lock of differential may adversely affect the stability and control of vehicle because of the unobvious redistribution of reactions acting on wheels, which consequently leads to poor performance and safety properties. Problems of rational distribution of power in transmissions of all-wheel drive vehicles, as well as research in the field of improving directional stability and active safety systems are among the priorities in modern automotive industry.
2017-03-28
Journal Article
2017-01-1574
Sindhura Buggaveeti, Mohit Batra, John McPhee, Nasser Azad
Abstract System identification is an important aspect in model-based control design which is proven to be a cost-effective and time saving approach to improve the performance of hybrid electric vehicles (HEVs). This study focuses on modeling and parameter estimation of the longitudinal vehicle dynamics for Toyota Prius Plug-in Hybrid (PHEV) with power-split architecture. This model is needed to develop and evaluate various controllers, such as energy management system, adaptive cruise control, traction and driveline oscillation control. Particular emphasis is given to the driveline oscillations caused due to low damping present in PHEVs by incorporating flexibility in the half shaft and time lag in the tire model.
2017-03-28
Technical Paper
2017-01-1579
Liang-kuang Chen, Chien-An Chen
Abstract The development of an integrated controller for a 4WS/4WD electric bus is investigated. The front wheel steering angle is assumed to be controlled by the human driver. The vehicle is controlled by the rear wheel steering and the yaw moment that can be generated by the differential torque/brake control on each wheel. The high speed cornering is used as the testing scenario to validate the designed controller. Due to the highly nonlinear and the multiple-input and multiple-output nature, the control design is separated into different stages using the hierarchical layer control concept. The longitudinal speed is controlled using a PI controller together with a rule-based speed modification. The other two control inputs, namely the rear wheel steering and the DYC moment, are then designed using the state-dependent Riccati equation method. The designed controllers are evaluated using computer simulations first, and the simulations showed promising results.
2017-03-28
Technical Paper
2017-01-1580
Smitha Vempaty, Yuping He
Abstract Ensuring the lateral stability and handling of a car-and-trailer combination remains one of the challenges in safety system design and development for articulated vehicles. This paper reviews the state-of-the-art approaches for car-trailer lateral stability control. A literature review covering the effects of external factors, such as aerodynamic forces, tire forces, and road & climatic conditions, is presented. To address the effects of these factors, researchers have previously investigated numerous passive and active safety control techniques. This paper intends to identify the inadequacies of the passive safety approaches and analyzes promising active-control schemes, such as active trailer steering control (ATSC), active trailer braking (ATB) and model reference adaptive controller (MRAC). A comparative study of these control strategies in terms of applicability and cost effectiveness is performed.
2017-03-28
Technical Paper
2017-01-1606
Sergey P. Gladyshev, Pavel Gladyshev, Irina Okrainskaya
Abstract In this paper, we consider a new design of synchronous motor with salient poles rotor and all coils placed on the stator. This design, uses a laminated silicon steel rotor, which is not so expensive as a rotor with super strong permanent magnets. This design of machine eliminates copper rings on the rotor and brushes which is used in regular synchronous motors, and eliminates disadvantages involved with these arrangements. In an earlier publication, authors considered the opportunity realization of synchronous mode operation in the machine with salient pole rotor and DC stator excitation. Now, we consider the new synchronous mode operation with individual DC excitation of each the alternative current (AC) windings for realization the first, second and third phase synchronous machines. In theoretical basics of analyses and design of synchronous motors we pay more attention to the single-phase motor because it is the basis for design polyphase synchronous machines.
2017-03-28
Technical Paper
2017-01-1591
Haotian Cao, Xiaolin Song, Zhi Huang
Abstract Generally speaking, lateral steering control method which ensures a good performance in tracking quality and handle quality simultaneously for autonomous vehicle is a changeling task. In order to keep the vehicle to stay safe when facing with severe situations such as an emergency lane change, a switched MPC lateral steering controller, which is on the basis of the stability feature of the vehicle, is presented in this paper. First, a MPC steering controller based on the 3DOF nonlinear vehicle model is derived, a comparative study of different vehicle models for MPC prediction are made. It proves that the presented MPC controller based on 3DOF nonlinear vehicle model possesses an advantage of balancing the conflicts between the tracking quality and handling quality of the vehicle.
2017-03-28
Technical Paper
2017-01-1592
Jingdong Cai, Saurabh Kapoor, Tushita Sikder, Yuping He
Abstract In this research, active aerodynamic wings are investigated using numerical simulation in order to improve vehicle handling performance under emergency scenarios, such as tight cornering maneuvers at high speeds. Air foils are selected and analyzed to determine the basic geometric features of aerodynamic wings. Built upon the airfoil analysis, the 3-D aerodynamic wing model is developed. Then, the virtual aerodynamic wings are assembled with the 3-D vehicle model. The resulting 3-D geometry model is used for aerodynamic analysis based on numerical simulation using a computational fluid dynamics (CFD) software package. The CFD-based simulation data and the vehicle dynamic model generated are combined to study the effects of active aerodynamic wings on handling performance of high-speed vehicles. The systematic numerical simulation method and achieved results may provide design guidance for the development of active aerodynamic wings for high-speed road vehicles.
2017-03-28
Journal Article
2017-01-1589
Giampiero Mastinu, Fabio Della Rossa, Massimiliano Gobbi, Giorgio Previati
Abstract The paper deals with the bifurcation analysis of a simple mathematical model describing an automobile running on an even surface. Bifurcation analysis is adopted as the proper procedure for an in-depth understanding of the stability of steady-state motion of cars (either cornering or running straight ahead). The aim of the paper is providing the fundamental information for inspiring further studies on vehicle dynamics with or without a human driver. The considered mechanical model of the car has two degrees of freedom, nonlinear tire characteristics are included. A simple driver model is introduced. Experimental validations of the model are produced. As a first step, bifurcation analysis is performed without driver (fixed control). Ten different combinations of front and rear tire characteristics (featuring understeer or oversteer automobiles) are considered. Steering angle and speed are varied. Many different dynamical behaviors of the model are found.
2017-03-28
Journal Article
2017-01-1586
Narayanan Kidambi, Gregory M. Pietron, Mathew Boesch, Yuji Fujii, Kon-Well Wang
Abstract A variety of vehicle controls, from active safety systems to power management algorithms, can greatly benefit from accurate, reliable, and robust real-time estimates of vehicle mass and road grade. This paper develops a parallel mass and grade (PMG) estimation scheme and presents the results of a study investigating its accuracy and robustness in the presence of various noise factors. An estimate of road grade is calculated by comparing the acceleration as measured by an on-board longitudinal accelerometer with that obtained by differentiation of the undriven wheel speeds. Mass is independently estimated by means of a longitudinal dynamics model and a recursive least squares (RLS) algorithm using the longitudinal accelerometer to isolate grade effects. To account for the influences of acceleration-induced vehicle pitching on PMG estimation accuracy, a correction factor is developed from controlled tests under a wide range of throttle levels.
2017-03-28
Technical Paper
2017-01-1588
Yucheng Liu, Collin Davenport, James Gafford, Michael Mazzola, John Ball, Sherif Abdelwahed, Matthew Doude, Reuben Burch
Abstract A dynamic modeling framework was established to predict status (position, displacement, velocity, acceleration, and shape) of a towed vehicle system with different driver inputs. This framework consists of three components: (1) a state space model to decide position and velocity for the vehicle system based on Newton’s second law; (2) an angular acceleration transferring model, which leads to a hypothesis that the each towed unit follows the same path as the towing vehicle; and (3) a polygon model to draw instantaneous polygons to envelop the entire system at any time point. Input parameters of this model include initial conditions of the system, real-time locations of a reference point (e.g. front center of the towing vehicle) that can be determined from a beacon and radar system, and instantaneous accelerations of this system, which come from driver maneuvers (accelerating, braking, steering, etc.) can be read from a data acquisition system installed on the towing vehicle.
2017-03-28
Journal Article
2017-01-1584
Peng Hang, Xinbo Chen, Fengmei Luo, Shude Fang
Abstract Compared with the traditional front-wheel- steering (FWS) vehicles, four-wheel-independent-steering (4WIS) vehicles have better handing stability and path-tracking performance. In view of this, a novel 4WIS electric vehicle (EV) with steer-by-wire (SBW) system is proposed in this paper. As to the 4WIS EV, a linear quadratic regulator (LQR) optimal controller is designed to make the vehicle track the target path based on the linear dynamic model. Taking the effect of uncertainties in vehicle parameters into consideration, a robust controller utilizing μ synthesis approach is designed and the controller order reduction is implemented based on Hankel-Norm approximation. In order to evaluate the performance of the designed controllers, numerical simulations of two maneuvers are carried out using the nonlinear vehicle model with 9 degrees of freedom (DOF) in MATLAB/Simulink.
2017-03-28
Technical Paper
2017-01-1585
Renxie Zhang, Lu Xiong, Zhuoping Yu, Wei Liu
Abstract A dynamic controller is designed for unmanned skid-steering vehicle. The vehicle speed is controlled through driving torque of engine to achieve the desired vehicle speed and the steering is controlled through hydraulic braking on each side of the vehicle to achieve the desired yaw rate. Contrary to the common approaches by considering non-holonomic constraints, tire slip and saturation of actuators torque influencing the driving and braking are considered, based on the analysis of vehicle dynamic model and nonlinear tire model. Hence, with conditional integrators, the dynamic controller overcoming integral saturation is designed to ensure the accurate tracking for desired signals under influence of tire forces and constraint of actuators. In addition, the exponential kind filter is utilized to enhance the ability of smoothing noise of wheel speed. To perform small radius cornering maneuvers, a dynamic control strategy for steering when vehicle speed is zero is also designed.
2017-03-28
Journal Article
2017-01-1597
Christoforos Chatzikomis, Aldo Sorniotti, Patrick Gruber, Matthew Bastin, Raja Mazuir Shah, Yuri Orlov
Abstract Electric vehicles with multiple motors permit continuous direct yaw moment control, also called torque-vectoring. This allows to significantly enhance the cornering response, e.g., by extending the linear region of the vehicle understeer characteristic, and by increasing the maximum achievable lateral acceleration. These benefits are well documented for human-driven cars, yet limited information is available for autonomous/driverless vehicles. In particular, over the last few years, steering controllers for automated driving at the cornering limit have considerably advanced, but it is unclear how these controllers should be integrated alongside a torque-vectoring system. This contribution discusses the integration of torque-vectoring control and automated driving, including the design and implementation of the torque-vectoring controller of an autonomous electric vehicle for a novel racing competition.
2017-03-28
Journal Article
2017-01-1595
Mustafa Ali Arat, Hans-Martin Duringhof, Johan Hagnander, Eduardo L. Simoes
Abstract This paper presents a brake control strategy with a novel approach to the allocation of actuator effort in an electric vehicle. The proposed strategy relies on a combination of the conventional hydraulic braking system and the electric machine in order to improve braking performance. The higher response frequency of the electric machine is paired with the additional braking torque employed by the hydraulic brakes using an integrated control allocation strategy, which allows for a constant availability of a faster and more accurate modulation of both wheel torque and wheel speed. Therefore, the availability of an electric machine as a fast longitudinal actuator yields to an improved tracking of the desired wheel slip, especially when compared to the hydraulic actuators used in traditional braking applications.
2017-03-28
Technical Paper
2017-01-1596
Amar Penta, Rohit Gaidhani, Sampath Kumar Sathiaseelan, Prasad Warule
Abstract Electrical and Series Hybrid Vehicles are generally provided with single speed reduction gearbox. To improve performance and drive range, a two-speed gearbox with coordinated control of traction motor and gearshift actuator is proposed. For a two-speed gearbox, gearshift without clutch would increase the shifting effort. Active Synchronization is introduced for a smoother gearshift even without clutch. The quality of gearshift is considered as a function of applied shift force and time taken. To enhance the quality of the gearshift further, the location of the synchronizer in the transmission system is optimized. To validate the improvement in the quality of the gearshift, a mathematical model of the two-speed gearbox incorporating proposed location of synchronizer assembly along with active synchronization is developed. The qualitative and quantitative analysis of the results achieved is presented.
2017-03-28
Technical Paper
2017-01-1593
Sunil kumar Pathak, Yograj Singh, Vineet Sood, Salim Abbasbhai Channiwala
Abstract A drive cycle is a time series of vehicle speed pattern developed to simulate real world driving conditions. These driving cycles are used for estimating vehicle on-road energy consumption, vehicle emissions, and traffic impact. Vehicle operating on fossil fuels are a significant source of air pollution, and these are being replaced by a small electrical vehicle in congested road traffic conditions, such as densely populated residential areas, near hospitals and market places, etc. The electrical vehicle run quieter and does not produce emissions like combustion engines. So far, there is no existing drive cycle officially developed for electric three wheelers which can represent real world driving pattern in India. In this study, 15 electrical auto rickshaws were driven by different drivers in various routes of a Tier II city of India and vehicle speed and time pattern were recorded using onboard Global Positioning System (GPS).
2017-03-28
Technical Paper
2017-01-1594
Guirong Zhuo, Kun Xiong, Subin Zhang
Abstract Micro electric vehicle has gained increasingly popularity among the public due to its compact size and reasonable price in China in recent years. Since design factors that influence the power of electric vehicle drive-motor like maximum speed, acceleration time and so on are not fixed but varies in certain scopes. Therefore, to optimize the process of matching drive-motor’s power, qualitatively and quantitatively studies should be done to determine the optimal parameter combination and improve the design efficiency. In this paper, three basic operating conditions including driving at top speed, ascending and acceleration are considered in the matching process. And the Sobol’ method of global sensitivity analysis (GSA) is applied to evaluate the importance of design factors to the drive-motor’s power in each working mode.
2017-03-28
Technical Paper
2017-01-1353
Michael G. Leffert
Abstract This paper compares the material consumption and fire patterns which developed on four nearly identical compact sedans when each was burned for exactly the same amount of time, but with different wind speed and direction during the burns. This paper will also compare the effects of environmental exposure to the fire patterns on the vehicles. The burn demonstrations were completed at an outdoor facility in southeast Michigan on four late model compact sedans. The wind direction was controlled by placing the subject vehicle with either the front facing into the wind, or rear facing into the wind. Two of the burns were conducted when the average observed wind speed was 5-6kph and two of the burns were conducted at an average observed wind speed of 19kph.
2017-03-28
Journal Article
2017-01-1352
David Gardiner
Abstract This paper presents an experimental study of the vapour space flammability of Fuel Ethanol (a high-ethanol fuel for Flexible Fuel Vehicles, commonly known as “E85”) and gasoline containing up to 10% ethanol (commonly known as “E10”). The seasonal minimum vapour pressure limits in specifications for automotive spark ignition fuels are intended, in part, to minimize the formation of flammable mixtures in the headspace of vehicle fuel tanks. This is particularly important at subzero temperatures, where the headspace mixture may not be rich enough to prevent combustion in the presence of an ignition source such as a faulty electrical fuel pump. In the current study, the upper temperature limits of flammability were measured for field samples of “E85” and “E10”, and a series of laboratory-prepared blends of denatured ethanol, Before Oxygenate Blending (BOB) gasoline, and n-butane.
Viewing 211 to 240 of 19895