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Cooperative Mandatory Lane Change for Connected Vehicles on Signalized Intersection Roads

Clemson University-Zhiyuan Du, Bin Xu, Pierluigi Pisu
  • Technical Paper
  • 2020-01-0889
To be published on 2020-04-14 by SAE International in United States
This paper presents a hierarchical control architecture to coordinate a group of connected vehicles on signalized intersection roads, where the vehicles are allowed change lane to follow a prescribed path. The hierarchical control strategy consists of two levels of controllers. The higher level controller acts as a centralized controller, while the lower level controller implemented in each individual car is designed as decentralized controller. In the hierarchical control architecture, the centralized intersection controller estimates the target velocity for each approaching connected vehicle to avoid red light stop based on the signal phase and timing (SPAT) information. Each connected vehicle as a decentralized controller utilizes Model Predictive Control (MPC) to track the target velocity in a fuel efficient manner. The main objective is this paper is to consider mandatory lane changing. As in the realistic scenarios, vehicles are not necessary required to drive in single lane. More specifically, they more likely change their lanes prior to signals. Hence, the vehicle decentralized controllers are prepared to cooperate with the vehicle which has mandatory lane change request (host…
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Automated highway driving motion decision based on optimal control theory

Chongqing University-Wei Yang, Zheng Ling, Yinong Li
  • Technical Paper
  • 2020-01-0130
To be published on 2020-04-14 by SAE International in United States
According to driving scenarios, intelligent vehicle is mainly applied on urban driving, highway driving and close zone driving, etc. As one of the most valuable developments, automated highway driving has great progress. This paper focuses on automated highway driving decision, and considering decision efficiency and feasibility, a hierarchical motion planning algorithm based on dynamic programming was proposed, and simultaneously, road coordinate transformation methods were developed to deal with complex road conditions. At first, all transportation user states are transformed into straight road coordinate to simplify modeling and planning, then a set of candidate paths with Bezier form was developed and with the help of obstacles motion prediction, the feasible target paths with collision-free were remains, and via comparing vehicle performance for feasible path, the optimal driving trajectory was generated. At last, the optimal control model was applied to obtain the motion parameters, which were regarded as the control target for lower level controller. A three-lane highway simulations was designed, and the results demonstrated that the proposed algorithm was valid to avoid obstacles with given speed,…
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Kalman Filter Slope Measurement Method Based on Improved Genetic Algorithm- Back Propagation

Wuhan University of Technology-Haoyu Wang, Donghua Guo, Gangfeng Tan, Zhenyu Wang, Ming Li, Yifeng Jiang, Meng Ye, Kailang Chen
  • Technical Paper
  • 2020-01-0897
To be published on 2020-04-14 by SAE International in United States
How to improve the measurement accuracy of road grade is the key content of the research on the speed warning of commercial vehicles in mountainous roads. If there is a large measurement error, the obtained speed threshold will be biased, posing a safety hazard. Conventional measuring instruments such as accelerometers and gyroscopes generally have noise fluctuation interference or time accumulation error, resulting in large measurement errors. In response to this situation, the Kalman filter method is often used for filtering to reduce the interference of unwanted signals, thereby improving the accuracy of the slope measurement. However, the Kalman filtering method is limited by the estimation error of various parameters, and the filtering effect is difficult to meet the project research requirements. In this paper, the acceleration of vehicle gravity, running speed and acceleration of parallel slope are used as auxiliary measurement parameters to improve the measurement method of mountain road slope. Based on the Kalman model, genetic algorithm (GA) and BP neural network are used to carry out the innovation , covariance matrix and the…
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Customer Perception of Road Induced Structural Feel

General Motors LLC-Mark Stebbins, John Cafeo, Mark Beltramo
  • Technical Paper
  • 2020-01-1080
To be published on 2020-04-14 by SAE International in United States
A vehicle program’s timing and viability can be affected by subjective assessments made by engineering teams predicting customer perceptions of many different attributes. In this paper we explore the relationship of those assessments to match customer perceptions for the attribute of structural feel. The eventual goal of work like this is to develop an objective metric that could be used by the product development organization. The first step in developing a metric is to assess whether road induced structural feel can be sensed by the customer. An internal drive clinic was an effective approach for obtaining customer perception of structural feel. Vehicles which spanned excellent structural feel to poor structural feel were chosen as part of the experimental design. The participants, which comprised three groups (panelists, experts, and executives) were able to rank order the vehicles’ structural feel performance essentially the same and in the order determined a priori. This clinic study indicates that structural feel is strongly related to vehicle ride. Experts are good predictors of both panelists and executive responses. Results from objective…
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Investigation of Transient Aerodynamic Effects on Public Highways in Comparison to Individual Driving Situations on a Test Site

FKFS-Felix Wittmeier, Andreas Wagner, Jochen Wiedemann
German Aerospace Center (DLR)-Henning Wilhelmi, Andreas Dillmann
  • Technical Paper
  • 2020-01-0670
To be published on 2020-04-14 by SAE International in United States
Natural wind, roadside obstacles, terrain roughness, and traffic can influence the incident flow of a vehicle driven on public roads. These on-road conditions differ from the idealized statistical steady-state flow environment utilized in CFD simulations and wind tunnel experiments. To understand these transient on-road conditions better, measurements were taken on a test site and on German Autobahn, resulting in the characterization of the transient aerodynamic effects around a vehicle. A compact car was equipped with a measurement system that is capable of determining the transient airflow around the vehicle and the vehicle’s actual driving state. This vehicle was driven several times on a fixed route to investigate different traffic densities on public highways in southern Germany. The tests were conducted under consistent weather conditions and average wind velocities of 2-5 m/s. During the tests the transient incident flow and pressure distribution on the vehicle surface were measured. With the same vehicle, individual driving situations were recreated on a test site. This paper presents a comparison of the aerodynamic characteristics measured by the vehicle during a…
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Vibration and Dynamic Analysis of Right-angle Geared Drives Considering the Influence of Gear-Shaft-Bearing Assembly Design

Marshall University-Xia Hua
  • Technical Paper
  • 2020-01-0415
To be published on 2020-04-14 by SAE International in United States
Dynamics of hypoid or spiral bevel gears like most high-speed precision gears employed in the powertrains of automobiles, commercial trucks, and off highway vehicles are significantly influenced by the design of the shafts and bearings. The finite element modeling approach is one of the useful methodologies applied to perform gear dynamic analysis. One of the major advantages of the finite element modeling approach is that it is able to account for the gear-shaft-bearing assembly design more accurately than other modeling approaches, for example, the lumped parameter modeling approach. In this paper, the finite element formulation, which can generally represent more complete characteristics of the gear-shaft-bearing assembly design, is employed to investigate how the key design changes of gear-shaft-bearing assembly influence the dynamics of spiral bevel gears. Accordingly, the underlying physics controlling these effects is also uncovered.
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Influence of Background Spectral Distribution on Perceptions of Discomfort Glare

Rensselaer Polytechnic Institute-Rohan M. Nagare, John D. Bullough
  • Technical Paper
  • 2020-01-0637
To be published on 2020-04-14 by SAE International in United States
The advent of light-emitting diode (LED) technology for automotive lighting allows flexibility of the spectral distribution of forward headlighting systems, while meeting current requirements for "white" illumination. As vehicle headlights have become whiter (with more short-wavelength light output) over the past several decades, their potential impacts on visual discomfort for oncoming and preceding drivers have been hotly debated. It is known that a greater proportion of short-wavelength energy increases discomfort glare, and that increasing the background light level (e.g., through roadway lighting) will decrease perceptions of discomfort. More recently it has been demonstrated that the visual system exhibits enhanced short-wavelength sensitivity for perceptions of scene brightness. As a result, roads illuminated by light sources with higher correlated color temperatures (CCTs) will be judged as appearing to be brighter than those illuminated to the same light level by sources with lower CCTs. The present laboratory study was conducted to identify whether the increased scene brightness of a road illuminated with greater short-wavelength light helps to mitigate discomfort glare more than the same scene illuminated to the…
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Toward High Automatic Driving by a Dynamic Optimal Trajectory Planning Method Based on High-order Polynomials

Hunan University-Haotian Cao, Xiaolin Song, Mingjun Li
Waterloo University-Song Zhao
  • Technical Paper
  • 2020-01-0106
To be published on 2020-04-14 by SAE International in United States
Automatic driving has received great attention from a broad of domains such as academia, industry, and government nowadays, while the subsystem of the path-planning for obstacle avoidance is crucial for the high-level automatic driving vehicle. This paper intends to present a novel optimal path planning method for obstacle avoidance on highways. At first, a mapping from the road Cartesian coordinate system to the road Frenet-based coordinate system is built, and the path lateral offset in the road Frenet-based coordinate system is represented by a function of quintic polynomial respecting to the traveled distance along the road centerline. With different terminal conditions regarding its position, heading and curvature of the endpoint, and together with initial conditions of the starting point, the path planner generates a bunch of candidate paths via solving nonlinear equation sets numerically. Then a path selecting mechanism is built which considers a normalized weighted sum of the path length, curvature, heading error to the road centerline, the consistency with the previous path, as well as the road hazard risk. The road hazard is…
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Research on the Best Driving Speed of the Deceleration Bump

Suizhou-WUT Industry Research Institute-Gangfeng Tan
Wuhan University of Technology-Ming Li, Haoyu Wang, Yifeng Jiang, Zhenyu Wang, Kailang Chen, Hanyu Zhang
  • Technical Paper
  • 2020-01-1088
To be published on 2020-04-14 by SAE International in United States
The ride performance and stability of the vehicle will decrease while the vehicle passing a deceleration bump with a relatively high speed. If the speed is too low, the road efficiency and ride comfort will be affected. It is essential to identify a proper speed taking all the factors into consideration. In this paper, the dynamic model of the vehicle passing through the deceleration bump is established. Two kinds of indicators,vibration weighted acceleration RMS and wheel load impact coefficient, are used to comprehensively evaluate the ride comfort and stability. The highway model, vehicle model and two common trapezoidal and circular cross-sections bump models are set up in Carsim. Parameters such as vertical acceleration and tire force at different vehicle speed are obtained. Then use the nonlinear least square method to fit the data, and comprehensively consider the two indicators to get the best speed. Finally, different deceleration bumps are selected for real vehicle test, and the calculation results are optimized. The results show that for the common B-class and C-class vehicles, it is more suitable…
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Empirical Study of the Braking Performance of Pedestrian Autonomous Emergency Braking (P-AEB)

Momentum Engineering Corp.-Omair Siddiqui, Nicholas Famiglietti, Benjamin Nguyen, Ryan Hoang, Jon Landerville
  • Technical Paper
  • 2020-01-0878
To be published on 2020-04-14 by SAE International in United States
Vehicle manufacturers are beginning to improve existing autonomous emergency braking (AEB) algorithms by pedestrian identification and avoidance capability. The Insurance Institute for Highway Safety (IIHS) has performed tests on eleven such vehicles; data is publicly available and was analyzed for this study. The IIHS tests were divided into three scenarios- 1) An adult pedestrian crossing a street on a path perpendicular to the travel line of vehicle, with a vehicle approach speed of 20 or 40 km/h, 2) a child pedestrian crossing a street from behind an obstruction on a path perpendicular to the travel line of a vehicle (approach speeds 20, 40 km/h), and 3) an adult pedestrian near the edge of a road in a path parallel to the travel path of a vehicle (approach speeds 40, 60 kph). An analysis was performed to compare Forward Collision Warning (FCW) engagement time, brake application time, and probability of impact across different manufacturers. It was observed that FCW on time for the 2019 Volvo XC40 lasted from 0.95 sec. - 2.36 sec., whereas for the…