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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 vehicles are allowed to change lane to follow a prescribed path. The proposed hierarchical control strategy consists of two control levels: a high level controller at the intersection and a decentralized low level controller in each car. 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 in this paper is to consider mandatory lane changes. As in the realistic scenarios, vehicles are not required to drive in single lane. More specifically, they more likely change their lanes prior to signals. Hence, the vehicle decentralized controllers must prepare to cooperate with the vehicle that has a mandatory lane change request (host vehicle). The cooperative mandatory lane change is accomplished…
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Research on Factors to Influence Coasting Resistance for Electric Vehicles

Changan Mazda Auto Company-Yong Ren
Chongqing Changan New Energy Auto Co., Ltd.-Guan Gong, Chen Zhao, Xiaohang Zhou, Chenghao Deng, Cheng Yu, Fuyong Yu, Anjian Zhou
  • Technical Paper
  • 2020-01-1068
To be published on 2020-04-14 by SAE International in United States
The research on coasting resistance is vital to electric vehicles, since the smaller the coasting resistance, the longer the coast-down distance. Vehicle coast resistance consists of rolling resistance, vehicle inner resistance and the aerodynamic drag. The vehicle inner resistance is mainly caused by driveline’s friction loss and oil splash loss. The rolling resistance is decided by tire resistance coefficient, which is influenced by tires and road conditions. And the aerodynamic drag is affected by vehicle’s shape and air. In this paper, four factors including tire pressure, road surface condition, atmosphere temperature, and recirculation on or off are examined. Experimental tests have been conducted on three different vehicles: one subcompact sedan, one compact sedan and one subcompact SUV. Then experimental results have been imported to simulation model to investigate the corresponding influence on NEDC range. The outcome shows that, when the tire pressure is 20% less, the average coasting resistance is increased by 1% to 3% depending on vehicle types, which indicates a decrease in NEDC range by around 2%. And with atmosphere temperature in 6…
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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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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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Iterative Dynamic Programming Based Model Predictive Control of Energy Efficient Cruising for Electric Vehicle with Terrain Preview

Nanjing University of Science and Technology-Fei Ju, Liangmo Wang, Qun Wang
Southeast University-Weichao Zhuang
  • Technical Paper
  • 2020-01-0132
To be published on 2020-04-14 by SAE International in United States
As a global optimization method, dynamic programming (DP) can be employed to seek the optimal velocity with minimum energy consumption for EV on given driving cycles. Due to its terrible computational burden, conventional DP is not suitable for real-time implementation especially with higher dimensions. In this paper, we propose an iterative dynamic programming (IDP) approach to reduce computing time firstly. The IDP can obtain the optimal control laws alike the conventional DP by converging the optimal control strategy iteratively and save considerable computing time. Second, the developed IDP and model predictive control (MPC) are combined to establish a real-time cruising controller called IDP-MPC for an EV with terrain preview. In the predictive controller, we use the IDP to solve a constrained finite horizon nonlinear optimization problem. Finally, to assess the performance of the proposed cruising controller, simulation on a realistic urban expressway road terrain is implemented. Energy-saving potential of the IDP-MPC controller is explored by comparing to DP and constant speed (CS) cruising controllers. The comparative study indicates that the IDP-MPC controller can obtain near-optimal…
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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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Experimental Ride Comfort Analysis of an Electric Light Vehicle in Urban Scenario

Politecnico di Torino-Angelo Domenico Vella, Alessandro Vigliani, Antonio Tota, Domenico Lisitano
  • Technical Paper
  • 2020-01-1086
To be published on 2020-04-14 by SAE International in United States
Urban mobility represents one of the most critical global challenges nowadays. Several options regarding design and power sources technologies were recently proposed; among which electric and hybrid vehicles are quite successful to meet the increasingly restrictive environmental targets. This significant goal may affect the perceived vehicle comfort and drivability, especially in everyday urban scenarios. The purpose of this paper is to carry out a comparison in terms of comfort between vehicles belonging to different categories, but all designed for urban mobility: an electric 2-passenger quadricycle used during the demonstration phase of the European project STEVE, an internal combustion engine 2-passenger car (Smart Fortwo), an electric 4-passenger car (Bolloré Bluecar) and an internal combustion engine 4-passenger car (Fiat 500). Leading European car-sharing services use the last three car models. Onboard accelerations at the seat, the feet and the steering wheel are recorded, as suggested by ISO 2631 and ISO 5349 standards. The tests are performed driving on a straight path on two different road surfaces at eight constant vehicle speeds. An optical sensor clamped outside of…
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A Comprehensive Study on the Challenges of Dual Mass Flywheel in Real-World Operating Conditions of the Indian Market

Mahindra & Mahindra Ltd-Vikraman Vellandi, Suresh Kumar Somarajan, Mohan Selvakumar Ganesh
  • Technical Paper
  • 2020-01-1014
To be published on 2020-04-14 by SAE International in United States
The present work is focussed on the real-world challenges of a dual mass flywheel (DMF) equipped vehicle in the Indian market. DMFs are widely used to isolate the drivetrain from the high torsional vibrations induced by the engine. While DMFs can significantly improve noise, vibration and harshness (NVH) characteristics of a vehicle, there are multiple challenges experienced in real-world operating conditions when compared with the single mass flywheel (SMF). The present work explains the challenges of using a DMF in a high power-density diesel powertrain for a multi-purpose vehicle (MPV) application in the Indian market. Measurements on the flat-road operating conditions revealed that the DMF vehicle is very sensitive for launch behaviour and requires a higher clutch modulation. Vibration measurements at the driver’s seat confirm that the SMF vehicle could be launched more comfortably at the engine idle speed of 850 RPM. However, the DMF vehicle needs a "launch assist" of an additional 100 RPM to meet the acceptable vibration levels in line with that of the SMF. Further, the gradient launch performance of the…