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Braking Requirements for Optimizing Autonomous Emergency Braking Performance

Applus IDIADA-Álvaro Esquer Molina, Jordi Bargallo
  • Technical Paper
  • 2019-01-2127
To be published on 2019-09-15 by SAE International in United States
Vehicle technology new developments have contributed to improve vehicle structural performance and therefore passive protection, but also the inclusion of electronic control units has provided new opportunities to expand active safety systems. This is the case for systems like anti-lock braking systems (ABS), electronic stability control (ESC) and brake assist (BA) among others. A more advanced generation of active systems includes sensorial units that monitor vehicle’s surrounding and detect potential hazards, such as an imminent collision, and performs an automatically and commanded emergency braking to lessen or mitigate the consequences of the impending accident. For this latest system, the so-called autonomous emergency braking (AEB), various consumer testing protocols, such as Euro NCAP protocols [1], propose and periodically update test catalogues in order to evaluate the performance of such systems and later to inform potential consumers.The aim of this study is to investigate the means of improving AEB performance in terms of efficiency and driver acceptance. For this, performance of current AEB system will be studied and compared with the limits of vehicle’s braking capabilities.
 

Comparative Analysis between American and European Requirements for Electronic Stability Control (ESC) Focusing on Commercial Vehicles

Ford Motor Company-Silvia Faria Iombriller, Wesley Bolognesi Prado, Marco Andre Silva
  • Technical Paper
  • 2019-01-2141
To be published on 2019-09-15 by SAE International in United States
Analysis of road accident has showed that an important portion of fatal crashes involving commercial vehicles is caused by rollovers. ESC systems in commercial vehicles can reduce rollovers, severe understeer or oversteer conditions and minimize occurences of jackknifing conditions. Several studies have estimated that this positive effect of ESC on road safety is substantial. In Europe, Electronic Stability Control (ESC) is expected to prevent by far the most fatalities and injuries: about 3,000 fatalities (-14%), and about 50,000 injuries (-6%) per year. In Europe, Electronic Stability Control Systems is mandatory for all vehicles (since Nov 1st, 2011 for new types of vehicle and Nov 1st 2014 for all new vehicles), including commercial vehicles, trucks and trailers. On 2015, NHTSA published Federal Motor Vehicle Safety Standard (FMVSS) No. 136, Electronic stability control systems for heavy vehicles, requiring electronic stability control (ESC) systems on truck tractors and buses with a gross vehicle weight rating greater than 11,793 kilograms (26,000 pounds) that were implemented until 2017. In South America, CONTRAN Resolution 641/2016 establishes mandatory installation of Electronic Stability…
 

Estimation of Side Slip Angle Interacting Multiple Bicycle Models Approach for Vehicle Stability Control

Andong National University-Bongchoon Jang
Chassis R&D-Youngjin Hyun
Published 2019-04-02 by SAE International in United States
This paper presents an Interacting Multiple Model (IMM) based side slip angle estimation method to estimate side slip angle under various road conditions for vehicle stability control. Knowledge of the side slip angle is essential enhancing vehicle handling and stability. For the estimation of the side slip angles in previous researches, prior knowledge of tire parameters and road conditions have been employed, and sometimes additional sensors have been needed. These prior knowledge and additional sensors, however, necessitates many efforts and make an application of the estimation algorithm difficult. In this paper, side slip angle has been estimated using on-board vehicle sensors such as yaw rate and lateral acceleration sensors. The proposed estimation algorithm integrates the estimates from multiple Kalman filters based on the multiple models with different parameter set. The IMM approach enables a side slip angle estimation from originally equipped vehicle sensors without prior knowledge of tire and road. The proposed estimation algorithm is evaluated via vehicle tests in electronic control unit level. The results have shown that the proposed estimator can successfully estimate…
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Has Electronic Stability Control Reduced Rollover Crashes?

Toyota Motor Corp.-Rini Sherony
Virginia Tech-Luke Riexinger, Hampton Gabler
Published 2019-04-02 by SAE International in United States
Vehicle rollovers are one of the more severe crash modes in the US - accounting for 32% of all passenger vehicle occupant fatalities annually. One design enhancement to help prevent rollovers is Electronic Stability Control (ESC) which can reduce loss of control and thus has great promise to enhance vehicle safety. The objectives of this research were (1) to estimate the effectiveness of ESC in reducing the number of rollover crashes and (2) to identify cases in which ESC did not prevent the rollover to potentially advance additional ESC development.All passenger vehicles and light trucks and vans that experienced a rollover from 2006 to 2015 in the National Automotive Sampling System Crashworthiness Database System (NASS/CDS) were analyzed. Each rollover was assigned a crash scenario based on the crash type, pre-crash maneuver, and pre-crash events. The Insurance Institute for Highway Safety ESC availability database was matched to each NASS/CDS case vehicle by the vehicle make, model, and model year. ESC effectiveness was computed using the quasi-induced exposure method.From 2006-2015, control loss was a factor in 29.7%…
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FMVSS 126 Sine with Dwell ESC Regulation Test for Autonomous Vehicles

Ohio State University-Evan Lowe, Sheng Zhu, Bilin Aksun Guvenc, Levent Guvenc
Published 2019-04-02 by SAE International in United States
Electronic stability control (ESC) has been an essential part of road vehicle safety for almost three decades. In April of 2007, the United States federal government issued a regulation to test the validity of ESC in development vehicles, and the regulation is called Federal Motor Vehicle Safety Standards (FMVSS) 126 in North America (NA), and an equivalent test in other countries outside of NA called ECE13-H (Economic Commission for Europe). While these standards have been used to certify ESC in development passenger cars for over a decade, this has not yet been scrutinized for the application of autonomous vehicles. Autonomous cars have sensors and control systems which can be used to improve ESC, where commercial standard vehicles do not. In this manuscript, we explored how an autonomous vehicle could complete the FMVSS 126 regulation, on its own, without a human driver, and discussed whether the FMVSS 126 (also called Sine with Dwell) test remains a useful regulation for autonomous cars. Additionally, we described a potential general obstacle avoidance capability assessment (GOACA) which could be a…
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A Development of the Model Based Torque Feedback Control with Disturbance Observer for Electric Power Steering System

Hyundai Motor Company-Deukpyo Lee, Yun Gab Lo, Minwoo Han, Kyuwon Kim, Chulhee Kim
Published 2019-04-02 by SAE International in United States
Electric Power Steering (EPS) needs to meet both functional and stability requirements, it plays significant role in controlling vehicle motion. In the meantime, customers emphasizes natural steering feel which can reflect vehicle motion and road surface information while isolate unwanted external disturbances. In general, conventional EPS control algorithms exert assist torque according to driver torque measured from torque sensor, while maintaining stability using stabilizing compensator. However, there exist significant trade-off between steering feel and stability, because the performances of assist torque control and stabilizing compensator are strongly coupled. In this paper a torque feedback control algorithm for EPS system is proposed in order to overcome the trade-off, and to achieve more natural, robust steering feel. The torque feedback algorithm consists of two main components; target torque generator, target torque following controller which can decouple steering feel and stability control performances. Target torque generator defines desired driver torque based on estimated road reaction torque; the road reaction torque estimation is carried out using EPS system dynamics model. Target torque following controller based on lead-lag compensator controls…
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Research on the Driving Stability Control System of the Dual-Motor Drive Electric Vehicle

Chang'an University-Shu Wang, Qiang Yu, Peilong Shi, Man Yu, Shuo Zhang
University of Michigan-Xuan Zhao
Published 2019-04-02 by SAE International in United States
In order to improve the steering stability of the dual-motor drive electric vehicle, Taking the yaw rate and the sideslip angle as the control variables, Using the improved two degree of freedom linear dynamic model and seven degree of freedom nonlinear vehicle dynamics model, The hierarchical structure is used to establish the dual-motor drive electric vehicle steering stability control strategy which consist of the upper direct yaw moment decision-making layer based on the sliding mode controller and the lower additional yaw moment distribution layer based on the optimization theory. The Matlab/Simulink-Carsim joint simulation platform was built. The control strategy proposed in this paper was simulated and verified under the snake test condition and double-line shift test condition. The results show that the proposed control strategy can ensure the vehicle yaw stability, and avoid the safety problem caused by the longitudinal speed reduction when the braking force is used as the yaw moment.
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Active Steering and Anti-Roll Shared Control for Enhancing Roll Stability in Path Following of Autonomous Heavy Vehicle

Tsinghua University-Yulong Liu, Kaiming Yang, Xiangkun He, Xuewu Ji
Published 2019-04-02 by SAE International in United States
Rollover accident of heavy vehicle during cornering is a serious road safety problem worldwide. In the past decade, based on the active intervention into the heavy vehicle roll dynamics method, researches have proposed effective anti-roll control schemes to guarantee roll stability during cornering. Among those studies, however, roll stability control strategies are generally derived independent of front steering control inputs, the interactive control characteristic between steering and anti-roll system have not been thoroughly investigated. In this paper, a novel roll stability control structure that considers the interaction between steering and anti-roll system, is presented and discussed. The proposed control framework is implemented based on dynamic game theory in which heavy vehicle roll stability can be represented as a dynamic difference game so that its two players, namely the active steering (AS) and active anti-roll bar (AARB) system, can work together to provide more roll stability to the heavy vehicle system during cornering. The interactive control strategy between AS and AARB system is obtained by non-cooperative closed-loop feedback Nash game equilibrium theory to ensure optimal roll…
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Porsche's 911: Not slippery when wet

Automotive Engineering: April 2019

Stuart Birch
  • Magazine Article
  • 19AUTP04_14
Published 2019-04-01 by SAE International in United States

Porsche has provided detail on its new Wet Mode technology for its latest, eighth-generation (aka 992-series) 911 coupe. The assistance system, which “listens” for potential wet road danger indicators, has been developed to detect significant wet conditions and deliver a solution for increased driving stability. Described as a “world first” it is a contribution to safety, and something that drivers of early air-cooled 911s (which could present very rapid oversteer situations) would have welcomed with relief.

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Road Tested

Autonomous Vehicle Engineering: March 2019

Lindsay Brooke
  • Magazine Article
  • 19AVEP03_11
Published 2019-03-01 by SAE International in United States

Transportation-infrastructure expert Kirk Steudle reflects on the rapid progress toward the connected-AV future and the challenges ahead.

In the auto industry, mechanical and electrical engineers work from the tire up. Civil engineers work from the tire down,” quips Kirk Steudle. “And although it's taken a while for both to understand each other's jargon, the connected-and-autonomous vehicle is forcing them all together-to solve problems for society's mobility.”

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