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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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An Efficient Path Planning Methodology Based on the Starting Region Selection

Hunan University-Xin Chen, Zhaobo Qin, Liang Chen
North China University of Technology-Jingjing Fan
  • Technical Paper
  • 2020-01-0118
To be published on 2020-04-14 by SAE International in United States
Automated parking is an efficient way to solve parking difficulties and path planning is of great concern for parking maneuvers [1]. Meanwhile, the starting region of path planning greatly affects the parking process and efficiency. The present research of the starting region are mostly determined based on a single algorithm, which limits the flexibility and efficiency of planning feasible paths. This paper, taking parallel parking and vertical parking for example, proposes a method to calculate the starting region and select the most suitable path planning algorithm for parking, which can improve the parking efficiency and reduce the complexity. The collision situations of each path planning algorithm are analyzed under collision-free conditions based on parallel and vertical parking. The starting region for each algorithm can then be calculated under collision-free conditions. After that, applicable starting regions for parking can be obtained, and each of those regions corresponds to a parking path planning algorithm. However, there always exists overlapped starting regions, which can be applied to multiple parking path planning algorithms. In order to select the most…
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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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Experimental Investigation of Multiple Injection Strategies on Combustion Stability, Performance and Emissions in a Methanol-Diesel Dual Fuel Non-Road Engine

Indian Institute of Technology-Kasinath Panda, A. Ramesh
  • Technical Paper
  • 2020-01-0308
To be published on 2020-04-14 by SAE International in United States
In this work methanol was port injected while diesel was injected using a common rail system in a single cylinder non-road CI engine. Experiments were conducted with single (SPI) and double (DPI - pilot and main) injection of the directly injected diesel at 75% load and at a constant speed of 1500 rpm. The effects of methanol to diesel energy share (MDES) and injection scheduling on combustion stability, efficiency and emissions were evaluated. Initially, in the SPI mode, the methanol to diesel Energy Share (MDES) was varied, while the injection timing of diesel was always fixed for best brake thermal efficiency (BTE). Increase in the MDES resulted in a reduction in NOx and smoke emissions because of the high latent heat of vaporization of methanol and the oxygen available. Enhanced premixed combustion led to a raise in brake thermal efficiency (BTE). Coefficient of variation of IMEP, peak pressure and BTE were deteriorated which limited the usable MDES to 43%. DPI of diesel i.e. early pilot for enhancing the reactivity of the charge along with main…
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Optimal Cooperative Path Planning Considering Driving Intention for Shared Control

Hunan University-Mingjun Li, Xiao-lin Song, Haotian Cao
University of Waterloo-Dongpu Cao
  • Technical Paper
  • 2020-01-0111
To be published on 2020-04-14 by SAE International in United States
This paper presents an optimal cooperative path planning method considering driver’s driving intention for shared control to address target path conflicts during the driver-automation interaction by using the convex optimization technique based on the natural cubic spline. The optimal path criteria (e.g. the optimal curvature, the optimal heading angle) are formulated as quadratic forms using the natural cubic spline, and the initial cooperative path profiles of the cooperative path in the Frenet-based coordinate system are induced by considering the driver’s lane-changing intention recognized by the Support Vector Machine (SVM) method. Then, the optimal cooperative path could be obtained by the convex optimization techniques. The noncooperative game theory is adopted to model the driver-automation interaction in this shared control framework, where the Nash equilibrium solution is derived by the model predictive control (MPC) approach. Finally, the proposed framework is tested with different driver’s driving intentions to avoid obstacles on a straight road and a curvy road. As a result, the planned path could continuously adapt to the driving intention and various road shapes, and the path…
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Urban Pilot Motion Planning and Control Deployment Via Real-Time Multi-Core Multi-Thread Prototyping

AVL North America Inc.-Yue Sun, Ankit Goila
AVL Research and Engineering Turkey-Damla Demir, Tugba Tapli
  • Technical Paper
  • 2020-01-0125
To be published on 2020-04-14 by SAE International in United States
In this work, the functional development of motion planning and control for SAE level-4 autonomous urban pilot is presented, including its architecture design, algorithm development, software implementation and hardware prototype. First, a completely AVL in-house designed, modular and generic Advanced Driver Assist System (ADAS) and Automated Driving (AD) application architecture is deployed, such that the motion planning and control modules can communicate with decision making, environment modeling and localization modules. Second, A road-navigation-oriented, sampling-and-searching-based iterative spatial-temporal motion planning algorithm is developed and integrated with classical motion control algorithms, via a ©MATLAB/Simulink implementation platform. Finally, the integrated motion planning and control subsystem is prototyped in ©Speedgoat hardware, via a real-time multi-core multi-thread deployment methodology. The proposed motion planning and control deployment has been validated through model in the loop (MIL) and processor in the loop (PIL) simulation environment, which provided the ground work for application integration to conduct road tests on a level-4 AVL demo vehicle.
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A Simulation-Based Approach to Incorporate Uncertainty in Reliability Growth Planning (RGP)

FCA US LLC-Mohammadsadegh Mobin, Mohammad Hijawi
  • Technical Paper
  • 2020-01-0742
To be published on 2020-04-14 by SAE International in United States
Reliability Growth Planning (RGP) is one of the essential parts of reliability improvement process during developing a new complex engineering system. It should receive more attention, especially in the current situation of industry, when a short delay in launching a new product causes the loss of market share. Current models in the reliability growth planning are more deterministic in nature, meaning that they use exact values for the parameters of the model. However, there is always uncertainty in the RG model parameters. This paper proposes a new approach, based on the historical data and enhanced by the simulation approach, which incorporates uncertainty in the reliability growth planning process. Results of the new model are more realistic and accurate, since they are based on the historical data.
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Automotive Engineering: April 2020

  • Magazine Issue
  • 20AUTP04
Published 2020-03-26 by SAE International in United States
The man from ARPA-E Advanced R&D programs directed by Dr. Chris Atkinson are building the energy-efficient mobility future.Executive Insights: BorgWarner VP and CTO Hakan Yilmaz With Delphi Technologies expected to join its portfolio, BorgWarner is focusing on differentiating its product line for emerging propulsion architectures.Sweating the details of C8 development How GM's Corvette engineers tackled challenges in the move to a mid-engine architecture.Mid-engine history of the future Highlighting the many benefits of a century-old vehicle layout whose golden era is with today's performance cars.Editorial EVs and the retail-price resetSAE Standards News Growing the ecosystem for advanced mobility standardsSupplier Eye When a pandemic strikesWhat We're DrivingNew Ultium battery system underpins GM's EV futureLevel 2 driver-assistance systems may be working as intendedLightyear One: 20 miles of solar driving range2020 Corvette Stingray: beautiful - and beautifully imperfectAll-wheel-drive returns to Chrysler Pacifica for 2021Mazda3 compact car spawns 2020 CX-30 CUVQ&A Toyota Motor North America: Group VP of Advanced Mobility R&D Jeff Makarewicz talks about technical, business and product strategy/planning
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A Study on the Development of Aerostructures Design for Assembly Guidelines and Their Effective Use to Proactively Identify Opportunities for Improvement in Mitigating Common Defects of the Aerostructures Assembly

GITAM School of Technology, Hyderabad-Mani Rathinam Rajamani, Eshwaraiah Punna
  • Technical Paper
  • 2020-01-0009
Published 2020-03-10 by SAE International in United States
An Aircraft’s assembly process plays a vital part in its design, development and production phases and contributes to about half of the Total cost spent in its entire product lifecycle. Design For Assembly (DFA®) principles have been one of the proven effective methodologies in Automotive and Process industries. Use of DFA® principles have resulted in proactively simplifying and optimizing engineering designs with reduced product costs, and improved efficiencies in product design and performance. Standardization of Assembly guidelines is vital for “Design and Build” and “Build-To-Print” manufacturing supplier organizations. However, Standardizing design methodologies, through use of proven tools like Advanced Product Quality Planning, (APQP) are still in the initial stages in Aerospace part and process design processes. Thus, there is a tremendous opportunity for research on the application of the existing DFA® guidelines to optimize Engineering Aerospace Assembly processes aiming to simplify, standardize design methodologies by building on existing industry practices which have a common platform for design communication and are easy to adopt within the existing process/systems. This technical paper is to discuss the framework…
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Model Predictive Automatic Lane Change Control for Intelligent Vehicles

China-Wu Guangqiang
School of Automotive Engineering, Tongji University, China-Ren Meng, Chen Xunjie, Liu Xuyang
  • Technical Paper
  • 2020-01-5025
Published 2020-02-24 by SAE International in United States
As a basic link of driving behavior in urban roads, vehicle lane changing has a significant impact on traffic flow characteristics and traffic safety, and the automation of lane change is also a key issue to be solved in the field of intelligent driving. In this paper, the research on the automatic lane change control for intelligent vehicles is carried out. The main work is to build the overall structure of the vehicle's automatic lane change behavior, of which the planning and tracking are focused. The strategy of Constant Time Headway (CTH) is used in the lane change decision. The lane change trajectory adopts the model of constant velocity offset plus sine function, and the longitudinal displacement is determined by the vehicle speed when changing lanes. Model Predictive Control (MPC) theory is used to track the trajectory, which optimizes tracking accuracy and vehicle stability and constrains the range and rate of change of vehicle speed and steering angle. By using weighted quadratic cost function, linearity matrix inequality constraints and upper and lower bound constraints, the…
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