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Research on Trajectory Planning for Four-wheel Steering Autonomous Vehicle with V2V Communication

Jilin University-Fangwu Ma, Yucheng Shen, Jiahong Nie, Xiyu Li, Yu Yang, Jiawei Wang, Guanpu Wu
  • Technical Paper
  • 2020-01-0114
To be published on 2020-04-14 by SAE International in United States
Lane-changing is a typical traffic scene effecting on road traffic with high request for reliability, robustness and driving comfort to improve the road safety and transportation efficiency. The development and application of connected autonomous vehicles with V2V communication provides more advanced control strategies to research of lane-changing. Meanwhile, Four-wheel steering is an effective way to improve flexibility of vehicle. The front and rear wheels rotate in opposite direction to reduce the turning radius to improve the servo agility operation at the low speed while those rotate in same direction to reduce the probability of the slip accident to improve the stability at the high speed. Hence, this paper established Ackerman front-wheel steering with proportional rear-wheel steering vehicle dynamic model and quasi real lane-changing scenes to analyze the motion constraints of the vehicles. Then, the polynomial function and Sin function were used for the lane-changing trajectory planning and the extended rectangular vehicle model was established to get vehicle collision avoidance condition. Vehicle comfort requirements and lane-changing efficiency were used as the optimization variables of optimization function.…
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Development and Application of a Collision Avoidance Capability Metric

AAA Northern California Nevada & Utah-Paul Wells, Atul Acharya
Dynamic Research Inc.-Jordan Silberling, Joseph Kelly, John Lenkeit
  • Technical Paper
  • 2020-01-1207
To be published on 2020-04-14 by SAE International in United States
This paper describes the development and application of a newly developed metric for evaluating and quantifying the capability of a vehicle/controller (e.g., Automated Vehicle or human driver) to avoid collisions in nearly any potential scenario, including those involving multiple potential collision partners and roadside objects. At its core, this Collision Avoidance Capability (CAC) metric assesses the vehicle’s ability to avoid potential collisions at any point in time. It can also be evaluated at discrete points, or over time intervals. In addition, the CAC methodology potentially provides a real-time indication of courses of action that could be taken to avoid collisions. The CAC calculation evaluates all possible courses of action within a vehicle’s performance limitations, including combinations of braking, accelerating and steering. Graphically, it uses the concept of a “friction ellipse”, which is commonly used in tire modeling and vehicle dynamics as a way of considering the interaction of braking and turning forces generated at the tire contact patches. When this concept is applied to the whole vehicle, and the actual or estimated maximum lateral and…
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Heavy Vehicles Kinematics of Automatic Emergency Braking Test Track Scenarios

NHTSA-Devin Elsasser
Transportation Research Center Inc.-M. Kamel Salaani, Christopher Boday
  • Technical Paper
  • 2020-01-0995
To be published on 2020-04-14 by SAE International in United States
This paper presents the test track scenario design and analysis used to estimate the performances of heavy vehicles equipped with forward collision warning and automatic emergency braking systems in rear-end crash scenarios. The first part of this design and analysis study was to develop parameters for brake inputs in test track scenarios simulating a driver that has insufficiently applied the brakes to avoid a rear-end collision. In the second part of this study, the deceleration limits imposed by heavy vehicles mechanics and brake systems are used to estimate automatic emergency braking performance benefits with respect to minimum stopping distance requirements set by Federal Motor Vehicle Safety Standards. The results of this study were used to complete the test track procedures and show that all heavy vehicles meeting regulatory stopping distance requirements have the braking capacity to demonstrate rear-end crash avoidance improvements in the developed tests.
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NHTSA's 2018 Heavy Vehicle Automatic Emergency Braking Test Track Research Results

NHTSA-Devin Elsasser
Transportation Research Center Inc.-M. Kamel Salaani, Christopher Boday
  • Technical Paper
  • 2020-01-1001
To be published on 2020-04-14 by SAE International in United States
This paper presents National Highway Traffic Safety Administration’s 2017 and 2018 test track research results with heavy vehicles equipped with forward collision warning and automatic emergency braking systems. Newly developed objective test procedures were used to perform and collect performance data with three single-unit trucks equipped with the crash avoidance systems. The results of this research show that the test procedures are applicable to many heavy vehicles and indicate that performance improvements in heavy vehicles equipped with these safety systems can be objectively measured.
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Self-exploration of Non-holonomic Automated System Under Dynamic Environment

Isuzu Technical Center of America Inc.-Weiyang Zhang, Yong Sun, Haokun He, Wenbo Yu, Pengcheng Cai
  • Technical Paper
  • 2020-01-0126
To be published on 2020-04-14 by SAE International in United States
Exploring an unknown place autonomously is a challenge for robots, especially when the environment is changing. Moreover, in real world application, efficient path planning is crucial for the autonomous vehicles to have timely response to execute a collision-free motion. In this paper we focus on environment exploration which enables an automated system to establish a map of an unknown environment with dynamic objects moving within it. We introduce an exploration package that enables robot’s self-exploration with an online collision avoidance planner. The package consists of exploration module, global planner module and local planner module. We modularize the package so that developers can easily make modifications or even substitutions to some modules for their specific application. In order to validate the algorithm, we designed and built a robot car as a low cost validation platform to test the autonomous vehicle algorithms in the real world. The car has a 22.36 x 11.65 x 7.6 inches, 4X4 brushless short course truck chassis, which has a dynamic model similar to a passenger car, but in a scaled pattern.…
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Driver Perception of Lateral Collision Threats

30 Forensic Engineering-Fabian Erazo, Adam Campbell
  • Technical Paper
  • 2020-01-1198
To be published on 2020-04-14 by SAE International in United States
Drivers presented with a collision threat must assess the likelihood of confrontation and determine if the threat warrants evasive action. The nature of the threat’s movement is critical in assessing a collision threat; however, the influence this visual information on driver behaviour is not well understood. A study was conducted to examine driver hazard perception of laterally-intruding vehicles. Seventeen subjects viewed first-person perspective recordings of a simulated vehicle travelling down a two-lane roadway consisting of several intersections with stop-controlled minor roads. Stopped vehicles were located at approximately half of the minor road intersections. Throughout the study, some of the stopped vehicles accelerated into the subject’s lane of travel at 1 of 6 pre-determined acceleration rates. Subjects were instructed to ‘brake’ their vehicle by pressing the space bar on a keyboard as soon as they perceived that a collision was imminent. Subject responses were measured as the elapsed time between the intruder’s first motion and the initiation of ‘braking’. Subject reaction time (determined using a simple reaction test) was deducted from their overall response to establish…
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Improved Potential Field-based Collision Avoidance Control for Autonomous Vehicles

PATAC-Shiliang Shang, Mengge Guo
Shanghai Jiao Tong University-Weishun Deng, Kaijiong Zhang, Xi Zhang, Fan Yu
  • Technical Paper
  • 2020-01-0123
To be published on 2020-04-14 by SAE International in United States
Limiting factors for autonomous vehicle (AV) to be widely used are not only technical, but also psychological. Considering the psychological feelings of drivers during switching manned to unmanned driving status, this paper proposes an algorithm for avoiding collisions combining driver psychological feelings for AVs. The confidence-limit-distance of the driver is experimentally obtained by many real track tests which require the test driver to approach the obstacle as close as possible. The confidence-limit-distance from driver is defined as the distance between the obstacle and the last steering point allowed for the psychological limit of the driver to avoid collisions. Based on Artificial Potential Field (APF), a road potential field is accordingly established to characterize the characteristics and boundary constraints of the real road. To express the different influences of relative speed and direction on the driver's psychological feeling, the confidence potential field is established based on a two-dimensional normal distribution combining von Mises distribution. A second-order Taylor expansion of road potential field and confidence potential field are firstly introduced into the cost functions for model predictive…
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A collision avoidance strategy of autonomous emergency braking based on the characteristics of driver-vehicle-road

Jiangsu University-Ren He, Dong Zhang
  • Technical Paper
  • 2020-01-1213
To be published on 2020-04-14 by SAE International in United States
With the rise of intelligent transportation systems around the world, research on automobile active safety technology has gained widespread attention. Autonomous Emergency Braking(AEB) which can avoid or mitigate collision by active braking has become a hot research topic in the field of automobile. However, there are some limitations in the present Autonomous Emergency Braking(AEB) collision avoidance strategy, including lack of effective identification of road adhesion conditions, mismatch of active braking system parameters and imperfection of target vehicle motion information, which leads to poor collision avoidance performance on low adhesion coefficient road surface and intervention with the normal driving operation of the driver. A new collision avoidance strategy for AEB is proposed in this paper. Firstly, a new safe distance collision avoidance model is established based on the tire-road maximum friction coefficient in real time, the performance parameters of the active braking system and the motion information of the target vehicle. Secondly, under the premise of not interfering with the driver's normal collision avoidance operation, an AEB collision avoidance strategy that can balance vehicle safety and…
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A Novel Kalman Filter Based Road Grade Estimation Method

FCA US LLC-Cevat Gokcek
  • Technical Paper
  • 2020-01-0563
To be published on 2020-04-14 by SAE International in United States
Accurate, robust and real-time estimation of road grade is extremely important in vehicle control (battery management, transmission shift scheduling, distance-to-empty prediction, anti-lock braking system, collision avoidance, stability control, etc.) to improve safety, stability, efficiency and performance. This paper presents a novel Kalman filter based road grade estimation method using measurements from an accelerometer, gyroscope and tachometer. The accelerometer measures the components of the vehicle acceleration (including the components of the acceleration due to gravity), and the measurements provided by the accelerometer are almost drift free but heavily corrupted by measurement noises. The gyroscope measures the components of the angular velocity of the vehicle, and the measurements provided by the gyroscope are quite clean but disturbed by gyroscope biases. The tachometer measures the longitudinal vehicle velocity, and the measurement provided by the tachometer is also corrupted by measurement noise. The Kalman filter uses the model of the sensors and their outputs, and fuses the sensor measurements to optimally estimate the road grade.
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Development of a MiL/HiL/AViL Approach to Pre-Deployment Testing of Low Speed Urban Road Autonomous Driving in the Context of the Smart Columbus Autonomous Shuttle Deployment Sites

Ohio State University-Xinchen Li, Aravind Chandradoss Arul Doss, Bilin Aksun Guvenc, Levent Guvenc
  • Technical Paper
  • 2020-01-0706
To be published on 2020-04-14 by SAE International in United States
Low speed autonomous shuttles emulating SAE Level L4 automated driving using human driver assisted autonomy have been operating in geo-fenced areas in several cities in the US and the rest of the world. These autonomous vehicles (AV) are operated by small to mid-sized technology companies that do not have the resources of automotive OEMs for carrying out exhaustive, comprehensive testing of their AV technology solutions before public road deployment. Yet, we have a large number of public road deployments of these AV shuttles including two deployment sites in Columbus through the Department of Transportation funded Smart City Challenge project named Smart Columbus. Due to the low speed of operation and hence not operating on roads containing highways, the base vehicles of these AV shuttles are not required to go through rigorous certification tests. The way these vehicles driver assisted AV technology is tested and allowed for public road deployment is continuously evolving but is not standardized and shows differences between different states where these vehicles operate. Safety of operation is achieved by first limiting the…