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Viewing 1 to 30 of 139
2017-06-05
Technical Paper
2017-01-1901
Christian Glandier, Stefanie Grollius
Abstract This paper presents the application to full vehicle finite element simulation of a steady state rolling tire/wheel/cavity finite element model developed in previous work and validated at the subsystem level. Its originality consists in presenting validation results not only for a wheel on a test bench, but for a full vehicle on the road. The excitation is based on measured road data. Two methods are considered: enforced displacement on the patch centerline and enforced displacement on a 2D patch mesh. Finally the importance of taking the rotation of the tire into account is highlighted. Numerical results and test track measurements are compared in the 20-300 Hz frequency range showing good agreement for wheel hub vibration as well as for acoustic pressure at the occupant’s ears.
2017-06-05
Technical Paper
2017-01-1863
Bhaskar Avutapalli, Mayuresh Pathak, Shalini Solipuram, Ken Buczek, Aaron Lock
Abstract Road noise and speech intelligibility are becoming ever more important, irrespective of the vehicle size, due to vehicle refinement as well as connectivity with mobile communication equipment. With better aerodynamic designs, development of refined powertrains, and a tectonic shift from I.C. engine to electric motors, road noise and wind noise will become more apparent to the customer and hence will become a priority for automakers to refine their vehicles. This paper describes the efforts undertaken to identify the road noise paths and develop countermeasures for a compact SUV vehicle. A hybrid test/CAE approach was followed to improve road noise performance of this vehicle. This effort involved developing tire CAE models from physical hardware and creating synthesized road-load input from data taken on roads.
2017-03-28
Technical Paper
2017-01-0091
Songyao Zhou, Gangfeng Tan, Kangping Ji, Renjie Zhou, Hao Liu
Abstract The mountainous roads are rugged and complex, so that the driver can not make accurate judgments on dangerous road conditions. In addition, most heavy vehicles have characteristics of large weight and high center of gravity. The two factors above have caused most of the car accidents in mountain areas. A research shows that 90% of car accidents can be avoided if drivers can respond within 2-3 seconds before the accidents happen. This paper proposes a speed warning scheme for heavy-duty vehicle over the horizon in mountainous area, which can give the drivers enough time to respond to the danger. In the early warning aspect, this system combines the front road information, the vehicle characteristics and real-time information obtained from the vehicle, calculates and forecasts the danger that may happen over the horizon ahead of time, and prompts the driver to control the vehicle speed.
2017-03-28
Technical Paper
2017-01-0080
Qilu Wang, Bo Yang, Gangfeng Tan, Shengguang Xiong, XiaoXiao Zhou
Abstract Mountain road winding and bumpy, traffic accidents caused by speeding frequently happened, mainly concentrated on curves. The present curve warning system research are based on Charge-coupled Device, but the existing obstacles, weather , driving at night and road conditions directly affect the accuracy and applicability. The research is of predictability to identify the curves based on the geographic information and can told the driver road information and safety speed ahead of the road according to the commercial vehicle characteristic of load, and the characteristics of the mass center to reduce the incidence of accidents. In this paper, the main research contents include: to estimate forward bend curvature through the node classification method based on the digital map.
2017-03-28
Technical Paper
2017-01-0079
Hao Liu, Gangfeng Tan, Mengying Yang, Xiaoxiao Zhou, Yu Tang
Abstract Road traffic congestion sometimes happens at tunnel exit even without high traffic flow. One reason is that the deceleration process is imperceptible when the vehicle is driving to the tunnel exit with gradual upgrade slopes. Nowadays regulations are more concentrated in transport sectors, and control measures are applied to vehicles through the tunnel. This process is careless of vehicles’ specific characteristics and easily distract the driver attention. In this paper, a tunnel climbing acceleration reminder system is introduced. When the speed drop is detected and the analysis show this is due to the driver's unconscious behavior, the system will remind the driver to speed up. Based on the dynamic model and the tunnel properties, the relationship between the throttle opening degrees and the duration with the speed change is studied. Then, the engine braking is considered for the variation of speeds and slopes.
2017-03-28
Technical Paper
2017-01-0410
Aref M. A. Soliman
Abstract Although active suspension improved vehicle ride comfort, their two main drawbacks are the required high component costs and energy input levels for active suspension. The semi-active and twin accumulator suspensions are proposed which addresses these two drawbacks. Ride performances for passive, twin accumulator and semi-active are examined theoretically using half vehicle model. The power consumed in rolling resistance and power dissipation in suspension for passive, twin accumulator and semi-active suspension systems are evaluated. The effect of road disturbance on the vehicle ride performance for twin accumulator and semi-active suspension systems is studied. The rolling resistance power losses are also investigated. The results showed that the optimum twin accumulator suspension system over all road roughness/speed conditions would have adaptable spring stiffness and damping coefficients which could be changed depending on the road conditions.
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
Technical Paper
2017-01-1504
Peter Tkacik, Zachary Carpenter, Aaron Gholston, Benjamin James Cobb, Sam Kennedy, Ethan Blankenship, Mesbah Uddin, Surya Phani Krishna Nukala
Abstract Wind tunnel aerodynamic testing involving rolling road tire conditions can be expensive and complex to set up. Low cost rolling road testing can be implemented in a 0.3m2 Eiffel wind tunnel by modifying a horizontal belt sander to function as a moving road. This sander is equipped with steel supports to hold a steel plate against the bottom of the wind tunnel to stabilize the entire test section. These supports are bolted directly into the sander frame to ensure minimal vibrational losses or errors during testing. The wind tunnel design at the beginning of the project was encased in a wooden box which was removed to allow easier access to the test section for installation of the rolling road assembly. The tunnel was also modified to allow observers to view the testing process from various angles.
2017-03-28
Technical Paper
2017-01-1137
Xiaofeng Yin, Han Lu, Xiaohua Wu, Yongtong Zhang, Wei Luo
Abstract For the vehicle equipped with stepped automatic transmission (SAT) that has a fixed number of gears, gearshift schedule is crucial to improve the comprehensive performance that takes into account power performance, fuel economy, and driver’s performance expectation together. To optimize and individualize the gearshift schedule, an optimization method and an improved performance evaluation approach for multi-performance gearshift schedule were proposed, which are effective in terms of reflecting the driver's expectation on different performance. However, the proposed optimization method does not consider the influence of the road slope on the comprehensive performance. As the road slope changes the load of vehicle that is different from the load when a vehicle runs on a level road, the optimized gearshift schedule without considering road slope is obviously not the optimal solution for a vehicle equipped with SAT when it runs on ramp.
2017-03-28
Technical Paper
2017-01-0085
Wanyang Xia, Yahui Wu, Gangfeng Tan, Xianyao Ping, Benlong Liu
Abstract Typical vehicle speed deceleration occurs at the freeway exit due to the driving direction change. Well conducting the driver to control the velocity could enhance the vehicle maneuverability and give drivers more response time when running into potential dangerous conditions. The freeway exit speed limit sign (ESLS) is an effect way to remind the driver to slow down the vehicle. The ESLS visibility is significant to guarantee the driving safety. This research focuses on the color variable ESLS system, which is placed at the same location with the traditional speed limit sign. With this system, the driver could receive the updated speed limit recommendation in advance and without distraction produced by eyes contract change over the dashboard and the front sight. First, the mathematical model of the drivetrain and the engine brake is built for typical motor vehicles. The vehicle braking characteristics with various initial speeds in the deceleration area are studied.
2017-03-28
Technical Paper
2017-01-1730
Gridsada Phanomchoeng, Sunhapos Chantranuwathana
Abstract Nowadays, the tendency of people using bicycles as the way of transportation has increased as well as the tendency of the bicycle accidents. According to the research of National Highway Traffic Safety Administration (NHTSA), National Survey on Bicyclist and Pedestrian Attitude and Behavior, the major root causes of bicycle accidents are from the road surface condition. Thus, this work has developed the system to detect the road surface condition. The system utilizes the laser and camera to measure the height of road. Then, with the information of the road height and bicycle speed, the road surface condition can be classified into 3 categories due to severe condition of the road. For the secure road, cyclists could safely ride on it. For the warning road, cyclists need to slow down the speed. Lastly, for the dangerous road, cyclists have to stop their bicycles.
2017-03-28
Technical Paper
2017-01-0103
Thomas Beyerl, Bernard Ibru, Charvi Popat, Deborah Ojo, Alexander Bakus, Jessica Elder, Valentin Soloiu
Abstract Autonomous vehicles must possess the capability to navigate complex intersections, which do not conform to typical models. Such intersections may have multiple roadways of different classes, highly acute angles, or unique multi-modal combinations. These may include railway grade crossings, bicycle lanes, or unique signal arrangements. Conventional navigation systems, which gather data from the surrounding area then plan a path through the collected data require faultless and complex analysis of extremely unstructured environments. The vehicle must then avoid obstacles as well as successfully navigate the intersection with extremely low tolerance for error. Computer decision making challenges can arise from this method of navigation, especially when interacting with non-autonomous vehicles.
2017-03-28
Technical Paper
2017-01-1487
Russ Norton, Ben Bulat, Ahmed Mohamed
Abstract A semi-active suspension system is designed to improve secondary ride by lowering damping levels while maintaining or enhancing primary ride control and vehicle handling. In order to provide optimized ride comfort, base damping levels are reduced. Reduced damping levels increase damaging loads through pothole events. The Road Load Mitigation (RLM) algorithm seeks to resolve the tradeoff of high damping levels required to control the vertical and horizontal spindle loads and the need for lower damping forces to improve secondary ride. As the base active damping forces are increased to control these loads, ride benefits or vehicle ride comfort is diminished. RLM looks at suspension velocity at all four corners independently to determine if a pothole signature is detected and requires compensation. Compensation is delivered quickly to reduce wheel drop into the pothole thereby reducing damaging loads.
2017-03-28
Technical Paper
2017-01-1433
Enrique Bonugli, Joseph Cormier, Matthew Reilly, Lars Reinhart
The purpose of this study was to determine the frictional properties between the exterior surface of a motorcycle helmet and ‘typical’ roadway surfaces. Motorcycle helmet impacts into asphalt and concrete surfaces were compared to abrasive papers currently recommended by government helmet safety standards and widely used by researchers in the field of oblique motorcycle helmet impact testing. A guided freefall test fixture was utilized to obtain nominal impact velocities of 5, 7 and 9 m/s. The impacting surfaces were mounted to an angled anvil to simulate an off-centered oblique collision. Helmeted Hybrid III ATD head accelerations and impact forces were measured for each test. The study was limited to a single helmet model and impact angle (30 degrees). Analysis of the normal and tangential forces imparted to the contact surface indicated that the frictional properties of abrasive papers differ from asphalt and concrete in magnitude, duration and onset.
2017-03-28
Journal Article
2017-01-1552
Mehriar Dianat, Maciej Skarysz, Graham Hodgson, Andrew Garmory, Martin Passmore
Abstract The motivation for this paper is to predict the flow of water over exterior surfaces of road vehicles. We present simulations of liquid flows on solid surfaces under the influence of gravity with and without the addition of aerodynamic forces on the liquid. This is done using an implementation of a Coupled Level Set Volume of Fluid method (CLSVOF) multiphase approach implemented in the open source OpenFOAM CFD code. This is a high fidelity interface-resolving method that solves for the velocity field in both phases without restrictions on the flow regime. In the current paper the suitability of the approach to Exterior Water Management (EWM) is demonstrated using the representative test cases of a continuous liquid rivulet flowing along an inclined surface with a channel located downstream perpendicular to the oncoming flow.
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
Journal Article
2017-01-1328
Yoshiteru Tanaka, Jun Yamamura, Atsushi Murakawa, Hiroshi Tanaka, Tsuyoshi Yasuki
Abstract When vehicles run on the flooded road, water enters to the engine compartment and sometimes reaches the position of the air intake duct and electrical parts and causes the reliability problems. Numerical simulation is an effective tool for this phenomenon because it can not only evaluate the water level before experiment but also identify the intrusion route. Recently, the gap around the engine cooling modules tends to become smaller and the undercover tends to become bigger than before in order to enhance the vehicle performance (e.g., aerodynamics, exterior noise). Leakage tightness around the engine compartment becomes higher and causes an increase of the buoyancy force from the water. Therefore the vehicle attitude change is causing a greater impact on the water level. This paper describes the development of a water level prediction method in engine compartment while running on the flooded road by using the coupled multibody and fluid dynamics.
2017-01-10
Technical Paper
2017-26-0309
Sathish Kumar Prasad, J Prakaash, P Dayalan
Abstract Automotive vehicles are subjected to a variety of loads caused by road undulations. The load history data measured from the roads are one of the vital input parameters for physical test as well as virtual durability simulation of vehicles. In general, the automotive vehicles are instrumented and subjected to a variety of driving conditions in diverse roads to obtain representative road load time histories. Acquired road load time history signals from various roads are exhaustive and repetitive in terms of both time length and data size. This results in more computation and virtual simulation processing. Hence it is imperative to reduce the input time signals without compromising on the representation of the actual operating conditions. Signal reduction of measured road load histories for virtual simulation assumes greater significance for durability prediction.
2017-01-10
Journal Article
2017-26-0275
Prashant Pawar, Omkar Joshi, Mangesh Saraf
Abstract Design of vehicle for targeted customer usage is one of the key steps during vehicle development process. Due to globalization, most of vehicles, aggregates, components are being designed for global market considering worldwide load spectrum. Generally for doing this the vehicle response is being measured for different markets but this process is very time consuming. Also for getting these vehicle dependent parameters, exercises need to be repeated on each type/class of vehicle. So there is a need to have a robust procedure, tools which will helps OEM’s to predict the loads, vehicle response for different market segments at an early stage of vehicle development program using the inputs which are vehicle independent. The solution for this could be to use vehicle independent input such as digitized road profiles (2D or 3D) of target customer markets in combination with proper MBD simulation tools.
2016-11-08
Journal Article
2016-32-0051
Keisuke Terada, Takayuki Sano, Kenichi Watanabe, Takashi Kaieda, Kazuhisa Takano
Abstract In recent years three-wheel camber vehicles, with two wheels in the front and a single rear wheel, have been growing in popularity. We call this kind of vehicle A “Leaning Multi Wheel category Vehicle” (hereinafter referred to as a “LMWV”). A LMWV has various characteristics, but one of them stands out in particular. When a LMWV is cornering, if one of the front wheels passes over a section of road surface with a low friction coefficient, there is very little disturbance to the vehicle’s behavior and can continue to be driven as normal. However, there has been no investigation into why these vehicles have this particular characteristic. Consequently, in this paper an investigation was carried out in order to determine the behavior of a LMWV in this situation. First, measurements were taken using an actual vehicle to confirm the situation described above.
2016-10-25
Technical Paper
2016-36-0226
Javier Gutierrez, Guido Tosolin, Alexandre Catala
Abstract The integration of IDIADA Spain virtual Proving Ground (ISVPG) within ADAMS/Car offers a new virtual scenario to carry out detailed analysis of durability as well as Comfort & Ride. Moreover, these high resolution roads (modeled as OpenCRG road format) support model development activities through better correlation with experimental tests. This approach helps to reduce the number of real tests and to shorten development process times. At the same time, this data would be prepared for performance testing to support driving simulator and active system development. The objective of this paper is to demonstrate the benefits to use FTire model for Ride and Comfort applications and the use of flexible bodies for better predictions. The availability of this information will depend on the status of the project and the level of maturity of the simulation input data. As a result, different levels of accuracy will be reached according to the existing input data.
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.
2016-04-05
Technical Paper
2016-01-1680
Suresh Abasaheb Patil, Indrajit Dinkar More
Abstract This paper incorporates the on-road real time ride comfort testing and simulation analysis of the typical passenger cars. The main objective is to analyze the vibrations to the passenger’s seat through the irregularities on road surface. This analysis is carried out with the help state-of-the-art of FFT analyzer for different classes of passenger car for variety of road conditions which have been validated by simulation analysis in the 20-Sim simulation software.
2016-04-05
Technical Paper
2016-01-0479
Kuniaki Goto, Takashi Kondo, Masakiyo Takahira, Eiji Umemura, Masashi Komada, Yasuhiko Nishimura
Abstract Generally, pass-by noise levels measured outdoors vary according to the influence of weather conditions, background noise and the driver’s skill. Manufactures, therefore, are trying to reproduce proving ground driving conditions on a chassis dynamometer. The tire noise that occurs on actual road surfaces, however, is difficult to reproduce in indoor tests. In 2016, new pass-by noise regulations (UN R51-03) will take effect in Europe, Japan and other countries. Furthermore, stricter regulations (2dB) will take effect in 2020. In addition to the acceleration runs required under current regulations, UN R51-03 will require constant speed runs. Therefore, an efficient measurement methods are necessary for vehicle development. To solve the above mentioned issues, an indoor evaluation system capable of reproducing the tire noise that occurs on road surfaces has been developed.
2016-04-05
Technical Paper
2016-01-0120
Libo Huang, Huanlei Chen, Zhuoping Yu, Jie Bai
Abstract Automotive radar is the most important component in the autonomous driving system, which detects the obstacles, vehicles and pedestrians around with acceptable cost. The target tracking is one of the key functions in the automotive radar which estimates the position and speed of the targets having regarding to the measurement inaccuracy and interferences. Modern automotive radar requires a multi-target tracking algorithm, as in the radar field of view hundreds of targets can present. In practice, the automotive radar faces very complicated and fast-changing road conditions, for example tunnels and curved roads. The targets’ unpredictable movements and the reflections of the electromagnetic wave from the tunnel walls and the roads will make the multi-target tracking a difficult task. Such situation may last several seconds so that the continuous tracks of the targets cannot be maintained and the tracks are dropped mistakenly.
2016-04-05
Journal Article
2016-01-0461
Wenfei Li, Haiping Du, Weihua Li
Abstract This paper proposes a new braking torque distribution strategy for electric vehicles equipped with a hybrid hydraulic braking and regenerative braking system. The braking torque distribution strategy is proposed based on the required braking torque and the regenerative braking system’s status. To get the required braking torque, a new strategy is designed based on the road conditions and driver's braking intentions. Through the estimated road surface, a robust wheel slip controller is designed to calculate the overall maximum braking torque required for the anti-lock braking system (ABS) under this road condition. Driver's braking intentions are classified as the emergency braking and the normal braking. In the case of emergency braking, the required braking torque is to be equal to the overall maximum braking torque. In the case of normal braking, the command braking torque is proportional to the pedal stroke.
2014-10-01
Journal Article
2014-01-9030
Sermet Yucel, Melinda Moran Lucking, Jon Magnuson, Germana Paterlini, Benjamin Worel
Fuel economy and performance vary significantly with the vehicle design and configuration, road profile, and payload. The variation is more pronounced for heavy-duty trucks and understanding its origin is critical to maximizing fleet profitability. In this paper we demonstrate a method to continuously estimate fuel consumption breakdown over resistive forces while the vehicle is driven on a public highway. The method is fast, cost-effective, and capable of analyzing trip segments as short as one second. The method utilizes a non-linear Kalman filter and a vehicle dynamical model that has a coupled longitudinal and vertical motion. The paper presents the breakdown of fuel consumption and an estimate of road grade profile obtained by driving a heavy-duty vehicle at the MnROAD research facility in Albertville MN.
2014-04-01
Technical Paper
2014-01-0438
Mitsuhiro Uchida, Yasushi Kita, Takako Minoda(Kimura), Ryuji Ueki, Shoko Kawanobe
Abstract LEDs offer great advantages such as low power consumption and compact size. In addition to the physical benefits, however, they also boast 1.2times the feeling of brightness compared with halogen bulbs, as shown in previous research, and the colors of LED sources have been shown to stand out better than other sources (halogen and HID) used for traffic signs, offering superior perceived Clarity and sharpness. As well as traffic signs, it is essential to be able to see pavement markings clearly when driving an automobile. In this study, tests were carried out on public roadways using automobiles installed with halogen, HID and LED-based headlamps. It was found that the LED sources were found to provide the clearest illumination of the white lines. White lines on an actual road surface were also illuminated with halogen, HID and LED lamps in order to compare the effects of these sources on the visibility of the white lines by static evaluation.
2014-04-01
Technical Paper
2014-01-0867
Diana Hernandez-Alcantara, Luis Amezquita-Brooks, Ruben Morales-Menendez
Abstract Semi-active suspension systems aim to improve the vehicle safety and comfort. For these systems control laws are required to achieve the desired performance improvements. On the other hand, the instrumentation of the vehicle suspension typically consists only in accelerometers, which are used to measure the vertical accelerations. However, velocities and/or displacements are required to implement the most common control algorithms for semi-active suspension systems. For instance, Skyhook and Groundhook controllers require the knowledge of the suspension vertical velocities. In this article several vertical velocities estimation approaches are studied and compared. In practical applications, it is common to use simple integrators to estimate these variables; nonetheless, it is well known that integrator-based estimations present errors due to drift.
2014-04-01
Technical Paper
2014-01-0885
Mustafa Ali Arat, Saied Taheri
Abstract A vehicle's response is predominately defined by the tire characteristics as they constitute the only contact between the vehicle and the road; and the surface friction condition is the primary attribute that determines these characteristics. The friction coefficient is not directly measurable through any sensor attachments in production-line vehicles. Therefore, current chassis control systems make use of various estimation methods to approximate a value. However a significant challenge is that these schemes require a certain level of perturbation (i.e. excitation by means of braking or traction) from the initial conditions to converge to the expected values; which might not be the case all the time during a regular drive.
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