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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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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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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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MTCNN-KCF-deepSORT:Driver Face Detection and Tracking Algorithm Based on Cascaded Kernel Correlation Filtering and Deep SORT

Hunan University-Jiacai liao, Qiuli Wang, Libo Cao, Jiahao Xia, Yiting Zhang
  • Technical Paper
  • 2020-01-1038
To be published on 2020-04-14 by SAE International in United States
The driver's face detection and tracking method important for Advanced Driver Assistance Systems (ADAS) and autonomous driving in various situations. The deep SORT algorithm has integrated appearance information, the motion model and the intersection-over-union (IOU) distance methods, and has been applied to face tracking, but it depends on detection information in every frame. Once the detection information lacks, the deep SORT algorithm will wait until the target detects bounding boxes appear again, even if the target didn’t disappear or shield. Hence, we propose to use a new tracker that not completely depend on the detection algorithm to cascade with the deep SORT algorithm to realize stable driver's face tracking. At first, the driver's face detection and tracking will be accomplished by the MTCNN-deep-SORT algorithm. Multi-task convolutional neural network (MTCNN) will complete the driver's face detection, and detected face bounding boxes will be transferred into deep SORT tracking algorithm, at this step, we will get the driver's face detection and tracking bounding boxes. Subsequently, the detection of bounding boxes is transferred to the kernel correlation filtering…
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An Augmented around View Monitor System Fusing Depth and Image Information during the Reversing Process

Hunan University-WEI LI, Wenbo Wang, Lu Jiang, Dongjie Xiao, Libo Cao
  • Technical Paper
  • 2020-01-0095
To be published on 2020-04-14 by SAE International in United States
The around view monitor (AVM) system for vehicles usually suffers from the distortion of surrounding objects caused by incomplete rectification and stitching, which seriously affects the driver's judgment of the surrounding environment during the reversing process. In response to solve this problem, an augmented around view monitor (AAVM) system fusing image and depth information is proposed, which highlights the point clouds of persons or vehicles at the rear of the vehicle. First, an around view image is generated from four fisheye cameras. Then, the calibration of multi TOF cameras is conducted to improve their accuracy of depth estimation and obtain extrinsic camera positions. Next, the 2D-driven object point cloud detection method is proposed to localize and segment object point clouds like vehicles or persons. Finally, the around view image, the object point clouds, and the car model are unified in the same vehicle-centric coordinate system, which will be projected at a suitable angle of view so as to easy to observe. The field experiments are conducted using a passenger car with 4 fisheye cameras and…
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Multi-objective discrete robust optimization for vehicle front-end structure design under pedestrian head impact

Hunan University-Fei Lei, Xiaojiang Lv
Geely Automobile Research Institute-Xiaojiang Lv, Heping Yang, Haiyang Zhang, Dayong Zhou, Pengyun Gu
  • Technical Paper
  • 2020-01-0934
To be published on 2020-04-14 by SAE International in United States
Vehicle front-end structures have drawn considerable attention for their significant advantages in the protection of head which is the most vulnerable body part in pedestrian accidents. Optimization design for vehicle front-end structures has proven rather essential and been extensively used to improve the performance of head protection. Nevertheless, an optimal design could become less meaningful or even unacceptable when some uncertainties present. Furthermore, the traditional discrete robust optimization is mostly focused on single objective problems. In fact, the design of front-end structures for pedestrian head impact is indeed a multi-objective discrete optimization problem. This study aimed to explore how to minimize the injury of the head involving uncertain environment and multi-objective discrete optimization problem. For this purpose, the paper proposes a novel multi-objective discrete robust optimization (MODRO) algorithm to minimize the injury of head involving uncertainties in pedestrian-vehicle collisions. MODRO algorithm is achieved by coupling grey relational analysis (GRA) and entropy method with Taguchi approach. Taguchi approach is utilized to perform experiments and analysis of means (ANOM) is used to predict the optimum design. The…
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A primary study on the restraint system of self-driving car

Hunan University-Binhui Jiang, Hongze Ren, Zhonghao Bai
The Johns Hopkins University-Feng Zhu
  • Technical Paper
  • 2020-01-1333
To be published on 2020-04-14 by SAE International in United States
Due to the variation of compartment design and occupant’s postures in the self-driving car, there is a new and major challenge for occupant protection. In particular, the studies on occupant restraint systems used in the self-driving car has significantly delayed compared to the development of the autonomous technologies. In this paper, a numerical study was conducted to investigate the protective effects of the mainstream restraint systems (3-points belt with airbag or 4-points belt with airbag) on the driver in three different scenarios (driving with a seat angle of 110°, half-reclining resting with a seat angle of 135°, and reclining resting with a seat angle of 160°) . It can be found that in the simulation results: 1. All the restraint systems are capable of providing effective protection for the driving driver and the restraint system with 4-points belt has advantages due to its better protective effect on the occupant thorax; 2. When the driver is half-reclining or reclining resting, the head HIC36, neck Nij and chest compression are about 827-958, 0.62-0.88, and 66-68 mm, respectively;…
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Calibration and Stitching Methods of Around View Monitor System of Articulated Multi-Carriage Road Vehicle for Intelligent Transportation

Hunan University-Xiexing Feng, Wei LI, Tianyuan Wei, Yinglin Zhang, Libo Cao
Published 2019-04-02 by SAE International in United States
The around view monitor (AVM) system for the long-body road vehicle with multiple articulated carriages usually suffers from the incomplete distortion rectification of fisheye cameras and the irregular image stitching area caused by the change of relative position of the cameras on different carriages while the vehicle is in motion. In response to these problems, a set of calibration and stitching methods of AVM are proposed. First, a radial-distortion-based rectification method is adopted and improved. This method establishes two lost functions and solves the model parameters with the two-step optimization method. Then, AVM system calibration is conducted, and the perspective transformation matrix is calculated. After that, a static basic look-up table is generated based on the distortion rectification model and perspective transformation matrix. Furthermore, to solve the problem of the variable relative position of cameras, the relative angles of the carriages are collected by the angle sensors and then transmitted to the central processor via the CAN bus. And then a dynamic offset look-up table is generated in real time. With the two look-up tables,…
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An SVM-Based Method Combining AEB and Airbag Systems to Reduce Injury of Unbelted Occupants

Hunan University-Manjiang Hu
Tongji University&Tsinghua University-Zhihua Zhong
Published 2018-04-03 by SAE International in United States
An autonomous emergency braking (AEB) system can detect emergency conditions using sensors (e.g., radar and camera) to automatically activate the braking actuator without driver input. However, during the hard braking phase, crash conditions for the restraint system can easily change (e.g., vehicle velocity and occupant position), causing an out-of-position (OOP) phenomenon, especially for unbelted occupants entering the airbag deployment range, which may lead to more severe injuries than in a normal position. A critical step in reducing the injury of unbelted occupants would be to design an AEB system while considering the effect of deployed airbags on the occupants. Thus far, few studies have paid attention to the compatibility between AEB and airbag systems for unbelted occupants.This study aims to provide a method that combines AEB and airbag systems to explore the potential injury reduction capabilities for unbelted occupants. By dividing the distance between the driver’s head and the top of the steering wheel into five regions, the possible area of head position was obtained by computational investigation for several combinations of braking acceleration and…
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Dynamic Characteristics Analysis of an Ambulance with Hydraulically Interconnected Suspension System

Hunan University-Bohuan Tan, Yang Wu, Bangji Zhang, Hengmin Qi
Hefei University of Technology-Nong Zhang, Minyi Zheng
Published 2018-04-03 by SAE International in United States
The vibration and instability experienced in an ambulance can lead to secondary injury to a patient and discourage a paramedic from emergency care. This paper presents a hydraulically interconnected suspension (HIS) system which can achieve enhanced cooperative control of roll, pitch and bounce motion modes to improve the ambulance's ride comfort and handling performance. A lumped-mass model integrated with a mechanical and hydraulic coupled system is developed by using free-body diagram and transfer matrix methods. The mechanical-fluid boundary condition in the double-acting cylinders is modelled as an external force on the mechanical system and a moving boundary on the fluid system. A special modal analysis method is employed to reveal the vibration characteristics of the ambulance with the HIS. A series of frequency analyses, including free vibration with identified eigenvalues and eigenvectors, vibration transmissibility and force vibration with stochastic road inputs, are performed to evaluate the vehicular performance between an ambulance with a conventional suspension and one with the HIS. The results show that the proposed HIS system is able to reduce the roll and…
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