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Integrated Regenerative Braking System and Anti-lock Braking System for Hybrid Electric Vehicles & Battery Electric Vehicles

Ford Motor Company-Yixin Yao, Yanan Zhao, Mark Yamazaki
  • Technical Paper
  • 2020-01-0846
To be published on 2020-04-14 by SAE International in United States
Regenerative braking in hybrid electric vehicles is a critical feature to achieve the maximum fuel economy benefit of hybridization. In order to maximize energy recuperation, it is desired to enable regenerative braking during an Anti-lock Braking System (ABS) event. For certain driveline configurations with a single electric motor connected to the axle shaft through an open differential, it has been observed that the regenerative braking torque can increase the wheel slip during the ABS operation, and significantly impact vehicle dynamics. This negative effect introduced by regen braking during ABS control may also lead to hardware failures, such as breaking a drive shaft. This paper describes development of an integrated regenerative braking and ABS control for hybrid and electric drive vehicles, referred to as RBS-ABS Event Control. This control is intended for drivelines containing a single electric motor connected to the axle shaft through an open differential. The design objectives are to recuperate the maximum amount of kinetic energy during an ABS event, and to provide no degraded anti-lock control behavior as seen in vehicles with…
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Energy Efficient Maneuvering of Connected and Automated Vehicles

Southwest Research Institute-Sankar Rengarajan, Scott Hotz, Jayant Sarlashkar, Stanislav Gankov, Piyush Bhagdikar, Michael C. Gross, Charles Hirsch
  • Technical Paper
  • 2020-01-0583
To be published on 2020-04-14 by SAE International in United States
Onboard sensing and external connectivity using Vehicle-to-Vehicle (V2V), Vehicle-to-Infrastructure (V2I) and Vehicle-to-Everything (V2X) technologies will allow a vehicle to "know" its future operating conditions with some degree of certainty, greatly narrowing prior information gaps. The increased development of such Connected and Automated Vehicle (CAV) systems, currently used mostly for safety and driver convenience, presents new opportunities to improve the energy efficiency of individual vehicles. The NEXTCAR program is one such initiative by the Advanced Research Projects Agency – Energy (ARPA-E) to developed advanced vehicle dynamics and powertrain control technologies that leverage such connected information streams. Southwest Research Institute (SwRI) in collaboration with Toyota and University of Michigan is currently working on improving energy consumption of a Toyota Prius Prime 2017 by 20%. This paper provides an overview of the various algorithms that have been developed to achieve the energy consumption target. A breakdown of how individual algorithms contribute to the overall target is presented. The team built a specialized test-bed called CAV dynamometer that integrates a traffic simulator and a hub dynamometer for testing the…
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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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A dynamic trajectory planning for automatic vehicles based on improved discrete optimization method

Chongqing University-Pengyun Zeng, Zheng Ling
  • Technical Paper
  • 2020-01-0120
To be published on 2020-04-14 by SAE International in United States
The dynamic trajectory planning problem for automatic vehicles in complex traffic scenarios is investigated in this paper. A hierarchical motion planning framework is developed to complete the complex planning task. An improved dangerous potential field in the curvilinear coordinate system is constructed to describe the collision risk of automatic vehicles accurately instead of the discrete Gaussian convolution algorithm. At the same time, the driving comfort is also considered in order to generate an optimal, smooth, collision-free and feasible path in dynamics. The optimal path can be mapped into the Cartesian coordinate system simply and conveniently. Furthermore, a velocity profile considering practical vehicle dynamics is also presented to improve the safety and the comfort in driving. The effectiveness of the proposed dynamic trajectory planning is verified by numerical simulation for several typical traffic scenarios.
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Leveraging real-world driving data sets for design and impact evaluation of energy efficient control strategies.

General Motors LLC-Bharatkumar Hegde, Steven E. Muldoon
National Renewable Energy Laboratory-Michael O'Keefe, Jeffrey Gonder
  • Technical Paper
  • 2020-01-0585
To be published on 2020-04-14 by SAE International in United States
Modeling and simulation are crucial in the development of advanced energy efficient control strategies. Utilizing real-world driving data as the underlying basis for control design and simulation lends veracity to projected real-world energy savings. Standardized drive cycles are limited in their utility for evaluating advanced driving strategies that utilize connectivity and on-vehicle sensing, primarily because they are non-causal and are typically intended for evaluating emission and fuel economy under controlled conditions. Real-world driving data, because of its scale, is a useful representation of various road types, driving styles, and driving environments. The scale of real-world data also presents challenges in effectively using it in simulations. A fast and efficient simulation methodology is necessary to handle the large number of simulations performed for design analysis and impact evaluation of control strategies. In this study, we present two methods of leveraging real-world data in both design optimization of energy efficient control strategies and in evaluating the real-world impact of those control strategies upon large-scale deployment. Through these methodologies, strategies with highest impact on energy savings were selected…
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A Smart Measuring System for Vehicle Dynamics Testing

Politecnico di Torino-Enrico Galvagno, Stefano Mauro, Stefano Pastorelli, Antonio Tota
  • Technical Paper
  • 2020-01-1066
To be published on 2020-04-14 by SAE International in United States
A fast measurement of the car handling performance is highly desirable to easily compare and assess different car setup, e.g. tires size and supplier, suspension settings, etc. Instead of the expensive professional equipment normally used by car manufacturers for vehicle testing, the authors propose a low cost solution that is nevertheless accurate enough for comparative evaluations. The paper presents a novel measuring system for vehicle dynamics analysis, which is based uniquely on the sensors embedded in a smartphone and completely independent on the signals available through vehicle CAN bus. Data from tri-axial accelerometer, gyroscope, GPS and camera are jointly used to compute the typical quantities analyzed in vehicle dynamics applications. In addition to signals like yaw rate, lateral and longitudinal acceleration, vehicle speed and trajectory, normally available when working with Inertial Measurement Units (IMU) equipped with GPS, in the present application also the steering wheel angle is measured by artificial vision algorithms that use the phone camera.. The latter signal, besides being important for identifying the maneuver imposed by the driver, it enables the usage…
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An investigation into the Traction and Anti-Lock Braking System Control Design

Ford Motor Company-Ming Kuang, Rajit Johri, Jose Velazquez Alcantar
University of California Davis-Louis Filipozzi, Francis Assadian
  • Technical Paper
  • 2020-01-0997
To be published on 2020-04-14 by SAE International in United States
Wheel slip control is crucial to active safety control systems such as Traction Control System (TCS) and Anti-lock Braking System (ABS) that ensure the vehicle safety by maintaining the wheel slip in a stable region. For this reason, a wide variety of control methods has been implemented by both researchers and in the industry. Moreover, the use of new electro-hydraulic, electro-mechanical brakes and in-wheel electric motors allow for a finer control of the slip, which should further improve the vehicle dynamics and safety. In this paper, we compare two methods for wheel slip control: a loop-shaping Youla parametrization method, and a sliding mode control method. Each controller is designed based on a simple single wheel system. The benefits and drawbacks of both methods are adressed. Finally, the controller performance and stability robustness are then compared based on several metrics in a simulation using a high-fidelity vehicle model with several driving scenarios.
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A Stability-Guaranteed Time-Delay Range for Feedback Control of Autonomous Vehicles

Yildiz Technical University-Ahmet Kirli, Mehmet Selçuk Arslan
  • Technical Paper
  • 2020-01-0090
To be published on 2020-04-14 by SAE International in United States
The vehicles with level-5 autonomy (L5AVs) have no human driver in the loop are also known as self-driving cars. L5AVs are assumed the next generation of ground transportation, which have growing attention from both industry and academia in most recent years. Most of the work related to feedback strategies of L5AVs are on developing mapping systems through a variety of sensors. These systems can be considered as an analogue to the perception and central nervous system of human drivers. For instance, innovative visualization systems are more powerful when compared to the visual perception system of a person, yet, mapping demands high computation loads. This burden causes delay in the feedback loop and thus, it might have an unfavorable influence on proper and safe control action. This study investigates the effect of time delay occurring in mapping systems on the stability of the controlled vehicle. An algorithm entitled as “Cluster Treatment of Characteristic Roots - CTCR” is used to calculate a safe delay range as a remedy for the time delay caused by mapping systems. The…
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Scalable Simulation Environment for Adaptive Cruise Controller Development

The University Of Alabama-David Barnes, Jared Folden, Hwan-Sik Yoon, Paulius Puzinauskas
  • Technical Paper
  • 2020-01-1359
To be published on 2020-04-14 by SAE International in United States
In the development of an Adaptive Cruise Control (ACC) system, a model-based design process uses a simulation environment with models for sensor data, sensor fusion, ACC, and vehicle dynamics. Previous work has sought to control the dynamics between two vehicles both in simulation and in empirical testing environments. This paper outlines a new modular simulation framework for full model-based design integration, to iteratively design ACC systems. The simulation framework uses physics-based vehicle models to test ACC systems in three ways. The first two are Model-in-the-Loop (MIL) testing, using scripted scenarios or Driver-in-the-Loop (DIL) control of a target vehicle. The third testing method uses collected test data replayed as inputs to the simulation to additionally test sensor fusion algorithms. The simulation framework uses 3D visualization of the vehicles and implements mathematical driver comfortability models to better understand the perspectives of the driver or passenger. The addition of a high-fidelity vehicle plant model provides energy consumption and emissions predictions for autonomous, conventional vehicles or hybrid electric vehicles (HEV) in realistic driving scenarios. Finally, the simulations are run…
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A Connected Controls and Optimization System for Vehicle Dynamics and Powertrain Operation on a Light-Duty Plug-in Multi-Mode Hybrid Electric Vehicle

Michigan Technological University-Joseph Oncken, Joshua Orlando, Pradeep K. Bhat, Brandon Narodzonek, Christopher Morgan, Darrell Robinette, Bo Chen, Jeffrey Naber
  • Technical Paper
  • 2020-01-0591
To be published on 2020-04-14 by SAE International in United States
This paper presents an overview of the connected controls and optimization system for vehicle dynamics and powertrain operation on a light-duty plug-in multi-mode hybrid electric vehicle developed as part of the DOE ARPA-E NEXTCAR program by Michigan Technological University in partnership with General Motors Co. The objective is to enable a 20% reduction in overall energy consumption and a 6% increase in electric vehicle range of a plug-in hybrid electric vehicle through the utilization of connected and automated vehicle technologies. Technologies developed to achieve this goal were developed in two categories, the vehicle control level and the powertrain control level. Tools at the vehicle control level include Eco Routing, Coordinated Adaptive Cruise Control (CACC), Eco Approach and Departure (EcoAND) and in-situ vehicle parameter characterization. Tools at the powertrain level include PHEV mode blending, predictive drive-unit state control, and non-linear model predictive control powertrain torque split management. These tools were developed with the capability of being implemented in a real-time vehicle control system. As a result, many of the developed technologies have been demonstrated in real-time…