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SAE International Journal of Passenger Cars Electronic and Electrical Systems
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Scene Structure Classification as Preprocessing for Feature-Based Visual Odometry

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

German Jordanian University-Nathir A. Rawashdeh
University of Michigan - Dearborn-Mohamed Aladem, Stan Baek, Samir A. Rawashdeh
  • Journal Article
  • 2018-01-0610
Published 2018-04-03 by SAE International in United States
Cameras and image processing hardware are rapidly evolving technologies, which enable real-time applications for passenger cars, ground robots, and aerial vehicles. Visual odometry (VO) algorithms estimate vehicle position and orientation changes from the moving camera images. For ground vehicles, such as cars, indoor robots, and planetary rovers, VO can augment movement estimation from rotary wheel encoders. Feature-based VO relies on detecting feature points, such as corners or edges, in image frames as the vehicle moves. These points are tracked over frames and, as a group, estimate motion. Not all detected points are tracked since not all are found in the next frame. Even tracked features may not be correct since a feature point may map to an incorrect nearby feature point. This can depend on the driving scenario, which can include driving at high speed or in the rain or snow. This article investigates the effect of image structural content on the performance of feature tracking and motion estimation from known VO algorithms. As a preprocessing step, the image frame is divided into regions of…
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Simulation of Arc Quenching in Hermetically Sealed Electric Vehicle Relays

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Esgee Technologies-Anand Karpatne, Douglas Breden
University of Texas at Austin-Laxminarayan Raja
  • Journal Article
  • 2018-01-0765
Published 2018-04-03 by SAE International in United States
The goal of this work is to investigate arc quenching in electric vehicle relays using high-fidelity computational modeling. Rapid arc quenching is an essential quality of state-of-the-art high-voltage mechanical relays in electric vehicles. As a relay begins to break electrical contact, strong arcing can occur. This delays the process of sending a signal to the primary circuit breaker to isolate the load from a sudden current surge. The strength and duration of the arc have a significant impact on the safety of electric vehicles as well as on relay contactor erosion/lifetime. A thermal plasma modeling tool is used to estimate switch-off time in an arc relay using hydrogen and air as working gases. The response of arc dynamics and switch-off time to the gas composition, external magnetic field strength, and chamber pressure is studied. It was observed that a hermetically sealed chamber filled with hydrogen is significantly more efficient than air at quenching the arc. A stronger magnetic field was seen to enhance arc stretch to the wall which rapidly quenches the arc. Further, decreasing…
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Application of Transient Magnetic Fields to a Magnetosensitive Device

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

General Motors LLC-Michael Mandziuk, Laura Ball, Scott Piper
  • Journal Article
  • 2018-01-1349
Published 2018-04-03 by SAE International in United States
EMC Component Validation Responsibilities encompass many realms. One of these realms is the effect of magnetic fields on silicon-based devices. This article describes a method for exposing these devices to magnetic fields with waveforms other than the traditional sinusoidal excitation.The method commonly used to explore the sensitivity of active silicon devices is exposure of the device to a representative sinusoidal field and observation of its reaction or lack thereof. The challenge is to characterize the representative field and be able to verify its effectiveness. Recent vehicle level testing of new designs has brought our attention to time-varying or transient magnetic field shapes that create deviations not previously detected with Military Standard 461 (MIL-STD-461) type sinusoidal magnetic field exposure. A facsimile of a number of existing and well-known vehicle transients are excited through a physical and simulated system to prepare representative and repeatable transient inputs for use with existing lab equipment.
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Pre-Shaping Bursty Transmissions under IEEE802.1Q as a Simple and Efficient QoS Mechanism

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Groupe Renault-Josetxo Villanueva
Onera-Marc Boyer
  • Journal Article
  • 2018-01-0756
Published 2018-04-03 by SAE International in United States
The automotive industry is swiftly moving toward Ethernet as the high-speed communication network for in-vehicle communication. There is nonetheless a need for protocols that go beyond what standard Ethernet has to offer in order to provide additional quality of service (QoS) to demanding applications such as advanced driver-assistance systems (ADAS) or audio/video streaming. The main protocols currently considered for that purpose are IEEE802.1Q, audio video bridging (AVB) with the credit-based shaper (CBS) mechanism (IEEE802.1Qav), and time-sensitive networking (TSN) with its time-aware shaper (TAS) (IEEE802.1Qbv). AVB/CBS and TSN/TAS both provide efficient QoS mechanisms, and they can be used in a combined manner, which offers many possibilities to the designer. Their use however requires dedicated hardware and software components and clock synchronization in the case of TAS. Previous studies have also shown that the efficiency of these protocols depends much on the application at hand and the value of the configuration parameters. In this work, we explore the use of “pre-shaping” strategies under IEEE802.1Q for bursty traffic such as audio/video streams as a simple and efficient alternative…
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Energy Harvesting in Tire: State-of-the-Art and Challenges

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Tsinghua University-Xiaoxue Liu, Liangyao Yu, Sheng Zheng, Jinghu Chang
  • Journal Article
  • 2018-01-1119
Published 2018-04-03 by SAE International in United States
Although energy harvesting systems are extensively used in different fields, studies on the application of energy harvesters embedded in tires for vehicle control are rare and mostly focus on solving power supply problems of tire pressure sensors. Sensors are traditionally powered by an embedded battery, which must be replaced periodically because of its limited energy storage. Heightened interest in vehicle safety is expected to drive increased design and manufacture of in-tire sensors, which in turn, translates to rising demand for power generation in tires. These challenges emphasize the need to investigate the substitution of batteries and in-tire energy harvesting systems. Current in-tire energy harvesting methods involve piezoelectric, electromagnetic, and electrostatic power generation, whose energy sources include tire vibrations, deformations, and rotations. Piezoelectric harvesters are generally compact but operate for short durations. Electromagnetic generators exhibit higher power density but are less efficient than generators made from piezoelectric materials. The challenge presented by electrostatic generators is their requirement for certain launch conditions. The performance of different mechanisms depends on design, which is the key issue examined in…
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A Lane-Changing Decision-Making Method for Intelligent Vehicle Based on Acceleration Field

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Jilin University-Bing Zhu, Shuai Liu, Jian Zhao
  • Journal Article
  • 2018-01-0599
Published 2018-04-03 by SAE International in United States
Taking full advantage of available traffic environment information, making control decisions, and then planning trajectory systematically under structured roads conditions is a critical part of intelligent vehicle. In this article, a lane-changing decision-making method for intelligent vehicle is proposed based on acceleration field. Firstly, an acceleration field related to relative velocity and relative distance was built based on the analysis of braking process, and acceleration was taken as an indicator of safety evaluation. Then, a lane-changing decision method was set up with acceleration field while considering driver’s habits, traffic efficiency and safety. Furthermore, velocity regulation was also introduced in the lane-changing decision method to make it more flexible. Afterwards, the polynomial trajectory planning method was matched up with this lane-changing decision-making method and simulations based on Matlab/Simulink were finally conducted to verify the method presented in this article. As the simulation results showed, adopting the lane-changing decision-making method based on acceleration field, the lane-changing measurements such as starting position, span and driving speed can be optimized with driver’s habits involved. At the same time, the…
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Design and Power-Assisted Braking Control of a Novel Electromechanical Brake Booster

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Jilin University-Pengcheng Chen, Jian Wu, Jian Zhao, Rui He, Haizhen Liu, Changhai Yang
  • Journal Article
  • 2018-01-0762
Published 2018-04-03 by SAE International in United States
As a novel assist actuator of brake system, the electromechanical brake (EMB) booster has played a significant role in the battery electric vehicles and automatic driving vehicles. It has advantages of independent to vacuum source, active braking, and tuning pedal feeling compared with conventional vacuum brake booster. In this article, a novel EMB booster system is proposed, which is consisted of a permanent magnet synchronous motor (PMSM), a two-stage reduction by gears and ball screw, a servo body, and a reaction disk. Together with the hydraulic control unit, it has two working modes: active braking for automatic drive and passive braking for driver intervention. The structure and work principle of the electric brake booster system is first introduced. The precise control from pedal force to hydraulic pressure is the key for such a power-assisted brake actuator. We translate the control problem of force feedback control to position tracking control. Then, a nonlinear control method for power-assisted braking is presented, which could be divided into three parts: (i) signal processing and driver’s braking behavior recognition, (ii)…
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Design of Anti-lock Braking System Based on Regenerative Braking for Distributed Drive Electric Vehicle

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Beihang University-Weiwen Deng
FAW-Volkswagen-Xi Chen
  • Journal Article
  • 2018-01-0816
Published 2018-04-03 by SAE International in United States
In this article, the regenerative braking system is designed, which can realize the torque allocation between electric braking and hydraulic braking, where the cost function designed in this article considers factors of braking torque following effect, energy regenerative power, and hydraulic braking consumed power. In addition, a complete anti-lock braking system (ABS) is designed, which is based on regenerative braking. With the optimal slip ratio as control target, target wheel speed, control wheel speed, braking torque control strategy, and enable/disenable control logic of ABS are determined. By MATLAB/Simulink-DYNA4 co-simulation and real vehicle test, the feasibility and applicability of ABS based on regenerative braking are verified, under the condition of small severity of braking. According to experiment result, the following conclusions can be obtained: ABS based on regenerative braking can meet the braking requirements of small severity of braking; in co-simulation and real vehicle test, the efficiencies of braking energy recovery are more than 60% and 40% under the conditions of ABS triggered, respectively.
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