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SAE International Journal of Passenger Cars Electronic and Electrical Systems
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Influencing Factors Research on Vehicle Path Planning Based on Elastic Bands for Collision Avoidance

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Hunan University-Xiaolin Song, Haotian Cao, Jiang Huang
  • Journal Article
  • 2012-01-2015
Published 2012-09-24 by SAE International in United States
This paper presents the different influence factors to vehicle's path planning, including the guide-potential shape and its parameters, the guild-potential influence scale factor, the stiffness of the elastic bands and the speed of the host vehicle. The assessment of emergency path is based on the dynamic performance of the host vehicle, the lateral acceleration and yaw rate, and its mean-square values accesses the stability of the host vehicle when following the path. In order to take evasion maneuvers more steadily, a guide-potential affecting the moving vehicles behind the obstacle is built, which encourages the host vehicle to change lane appropriately. Three different shape guide-potential models, namely half-circle-like, half-ellipse-like and parabola-like, are proposed and compared in this paper. Meanwhile, hazard map of the road environment which includes the lanes, borders and obstacles is generated. Trajectory of low hazard level is generated based on virtual elastic bands which are composed with a number of nodes. Thus, the forces acting on the corresponding nodes of an elastic band are calculated by the directional derivate of those potentials. The…
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Fault-Tolerant Control of EMB Systems

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Kookmin Univ.-Young-Hun Ki, Hyun-Sik Ahn
MOBIS-Jae Seung Cheon
  • Journal Article
  • 2012-01-1795
Published 2012-09-17 by SAE International in United States
In this paper, for the fault-tolerant control of electro-mechanical brakes (EMBs), we continuously estimate several system variables and utilize these estimates to detect faulty sensor outputs. The clamping force is estimated by using the motor position and hysteresis phenomenon during clamping and releasing. Current sensor faults can be easily derived from the characteristics of a three-phase balanced circuit, and the motor position is estimated by applying different methods in low-speed and high-speed regions where a model-based approach is adopted. Using the proposed fault-tolerant logic, we can detect which sensor has a fault during driving or braking. Then, we use a bumpless transfer technique so that the control performance does not deteriorate when the estimated values are substituted for the measured values. The validity and the effectiveness of the proposed fault-tolerant control for an EMB are shown by using EMB hardware-in-the-loop simulations (HILS), so that fault tolerance is guaranteed for a scenario of sensor failures. The HILS consists of an EMB set, a TriCore-based actuator Electronic Control Unit (ECU), a host PC, and a CAN monitoring…
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High-Bandwidth Clamp Force Control for an Electromechanical Brake

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

The University of Melbourne-Chih Feng Lee, Chris Manzie
  • Journal Article
  • 2012-01-1799
Published 2012-09-17 by SAE International in United States
A controller that fully utilizes the available motor capacity of an electromechanical brake to achieve high closed-loop bandwidth is proposed. The controller is developed based on the time-optimal switching curve derived from Pontryagin's Maximum Principle. The control input is scheduled using a switching surface based on the current motor velocity and position offset. Robustness to modeling errors is achieved by introducing a boundary layer in vicinity of the switching curve, reminiscent of a high gain controller. A flexible tuning procedure is also developed to aid in practical implementation, allowing a balanced choice between tracking speed and energy usage. The controller is implemented on a production-ready prototype EMB, and tested over different braking scenarios to assess the performance and robustness relative to the benchmark controllers. It is demonstrated that significant improvements in step response and dynamic tracking are obtained using the proposed approach.
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Adaptive Brake Torque Variation Compensation for an Electromechanical Brake

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

The University of Melbourne-Chih Feng Lee, Chris Manzie
  • Journal Article
  • 2012-01-1840
Published 2012-09-17 by SAE International in United States
A novel method for attenuation of brake judder directly at the source is proposed, utilizing an electromechanical brake to actively compensate for the variation in brake torque that causes judder. Taking advantage of the high-bandwidth closed-loop clamp force tracking performance offered by an electromechanical brake, an adaptive compensator is designed to estimate the brake torque variation (BTV), and to produce a compensating clamp force command to cancel it. The compensator is tested over fixed and varying BTV frequencies by employing a production-ready prototype EMB. It is demonstrated that significant BTV attenuation is obtained using the proposed approach.
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Psychoacoustic Requirements for Warning Sounds of Quiet Cars

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

BMW Group-Alfred Zeitler
  • Journal Article
  • 2012-01-1522
Published 2012-06-13 by SAE International in United States
According to upcoming legislative regulations in certain countries, electric and hybrid-electric vehicles (EVs and HEVs) will have to be equipped with devices to compensate for the lack of engine noise needed to warn pedestrians against the vehicles. This leads to the question of appropriate sound design which has to meet specific psychoacoustic requirements. The present paper focuses on auditory features of warning sounds to enhance pedestrians' safety with a major focus on the detectability of the exterior noise of the vehicle in an ambient noise. For the evaluation of detectability, the psychoacoustic model developed by Kerber and Fastl will be introduced allowing for the prediction of masked thresholds of the approaching vehicle. The instrumental assessment yields estimates of the distance of an approaching vehicle at the point it becomes audible to the pedestrians. This way the risk of collision can be assessed assuming that only auditory cues are used by pedestrians to identify vehicles before crossing a street. The corresponding algorithm was applied in a field study to assess the detectability of selected EVs and…
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Verification of ASSTREET Driver-Agent Model by Collaborating with the Driving Simulator

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Advanced Solutions Technology Japan, Ltd-Jun Tajima, Norihiko Sakamoto
Toyota Central R&D Labs., Inc.-Hiroshi Yasuda
  • Journal Article
  • 2012-01-1161
Published 2012-04-16 by SAE International in United States
This paper proposes a novel method of verifying comprehensive driver model used for the evaluation of driving safety systems, which is achieved by coupling the traffic simulation and the driving simulator (DS). The method consists of three-step procedure. In the first step, an actual driver operates a DS vehicle in the traffic flow controlled by the traffic simulation. Then in the next step, the actual driver is replaced by a driver model and the surrounding vehicle maneuvers are replayed using the recorded data from the first step. Then, the maneuver by the driver model is compared directly with the actual driver's maneuver along the simulation time steps. For example, while turning right (in front of the oncoming traffic), the proposed verification method was applied to our driver-agent model of traffic simulation system ASSTREET (The Advanced Safety System & Traffic REaltime Evaluation Tool) to demonstrate that the proposed method provides a straightforward way of verifying the driver-agent model capability to reproduce the driving behavior including the subtle driving behaviors, such as safety confirmation, that can have…
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Design of an Electric Variable CAM Phaser Controller

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Delphi Automotive-Gordon Cheever Jr, Charles Sullivan, Karl Schten, Ash Punater, Clinton Erickson
  • Journal Article
  • 2012-01-0433
Published 2012-04-16 by SAE International in United States
As the emissions and fuel economy standards for internal combustion engines become ever more stringent, a variety of valvetrain control methods have been developed to improve engine performance. One of these is camshaft (CAM) phasing, which controls the angular position of the CAM relative to the crankshaft allowing changes to the timing of valve lift events. This method has demonstrated advantages including broadening the engine torque curve, increasing peak power at higher RPM, reducing hydrocarbon and NOx emissions, and improving fuel economy. In addition, external EGR systems can be eliminated because internal cylinder dilution control can be achieved by varying CAM timing.Current implementations of CAM phasing use oil-pressure-based electro-mechanical systems. While these systems are relatively low cost and have proven to be robust, they have disadvantages at low oil temperatures and pressures (such as during cranking events). To overcome performance issues of oil based systems, Delphi has created a CAM phasing system using a brushless DC (BLDC) motor to drive the phasing mechanism. This approach provides full control independent of oil conditions and demonstrates increased…
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Characterizations of Deployment Rates in Automotive Technology

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

MIT-Stephen Zoepf, John B. Heywood
  • Journal Article
  • 2012-01-1057
Published 2012-04-16 by SAE International in United States
Passenger cars in the United States continue to incorporate increasing levels of technology and features. However, deployment of technology requires substantial development and time in the automotive sector.Prior analyses indicate that deployment of technology in the automotive sector can be described by a logistic function. These analyses refer to maximum annual growth rates as high as 17% and with developmental times of 10-15 years. However, these technologies vary widely in complexity and function, and span decades in their implementation.This work applies regression with a logistic form to a wide variety of automotive features and technologies and, using secondary regression, identifies broader trends across categories and over time. Developmental time, measured as the time to reach maximum growth, has declined exponentially and now stands at approximately ten years, although individual manufacturers have demonstrated the ability to implement technology more quickly than industry averages. While required safety features and emissions control technologies achieve faster deployment rates than optional features, there is not a clear casual relationship between an early requirement and rapid growth rate.The ability to develop…
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Development of Electronic Control System for a Single Cylinder Motorcycle Engine

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Huazhong Univ. of Science and Technology-Liping Wan Wan, Yankun Jiang, Xin Liu, Jianping Zhang
University of Technology-Sydney-Guang Hong
  • Journal Article
  • 2012-01-0508
Published 2012-04-16 by SAE International in United States
In this paper, an Electronic Control System (ECS) is designed to manage a 125 cc single-cylinder air-cooled motorcycle engine. The aim of this study was to accomplish low cost, high reliability and mainly meet the motorcycle engine emission standard of China Stage III.The intake port fuel injection mode was chosen with a redesigned part of intake pipe. Gathering information of speed, throttle position (TP), inlet temperature and pressure, cylinder temperature, switch-type exhaust gas oxygen sensor and the battery voltage, an Engine Control Unit (ECU) was devised to calculate fuel injecting pulse width, advance ignition angle and control the working conditions of the fuel pump and the exhaust gas oxygen sensor. Additionally, a three-way catalytic converter (TWC) was used to reduce exhaust gas emissions.The basic fuel injection table and ignition advance angles table according to the speed-TP were calibrated accurately through bench test with consideration to engine performance, emission and AFR. Taking account of the cylinder temperature correction term, air pressure correction term, the inlet air temperature and pressure correction terms and the battery voltage term,…
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Impact of Secondary Tasks on Individual Drivers: Not All Drivers Are Created Equally

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

University of Texas at Dallas-Amardeep Sathyanarayana, John Hansen
  • Journal Article
  • 2012-01-0486
Published 2012-04-16 by SAE International in United States
There has been rapid growth in the mobile-phone industry in terms of technology and growing number of users with migration into the car environment. There is also a significant demand for smart phones capable of accessing email, listening to music, organizing daily activities, linking to social networking sites, while the user is on the move. The automotive industry has been significantly impacted by such mobile-phone usage. Driving a car is a complicated and skillful task requiring attention and focus. However many people perceive driving to be easy - second-to-habit or an extension of their natural skills. This complacency encourages drivers to multitask while driving. While many drivers manage this multitasking comfortably, it becomes a distraction and contributes to increased risk while driving for some. Since the effect of multitasking is variable on different drivers, it is important to understand its impact on individual drivers. This study focuses on assessing the impact of several secondary tasks such as speaking over a hand-held mobile phone, tuning the radio, selecting songs from an MP3/CD playlist, speaking to a…
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