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Table of Content

    25 September 2023, Volume 45 Issue 9 Previous Issue    Next Issue
    Key Technologies of Brain-Inspired Decision and Control Intelligence for Autonomous Driving Systems
    Shengbo Eben Li,Guojian Zhan,Yuxuan Jiang,Zhiqian Lan,Yuhang Zhang,Wenjun Zou,Chen Chen,Bo Cheng,Keqiang Li
    2023, 45 (9):  1499-1515.  doi: 10.19562/j.chinasae.qcgc.2023.ep.006
    Abstract ( 532 )   HTML ( 36 )   PDF (3942KB) ( 562 )   Save

    As the technical trend of the next generation of high-level autonomous driving, brain-inspired learning is a class of methods that employ deep neural networks (DNN) as the strategy carrier and reinforcement learning (RL) as the training algorithm to realize strategy self evolution through continuous interaction with traffic environments, ultimately obtaining the optimal mapping from the environmental state to execution action. Currently, brain-inspired learning is mainly applied in decision-making and motion control modules of autonomous driving. Its key technologies include how to design its system framework to support interactive training, high-fidelity autonomous driving simulation platform, accurate and flexible representation of environment statues, multiple dimensional evaluation metrics, and effective training algorithm that drives policy updates. This paper systematically summarizes the history and future trends of decision-making and control functionalities in autonomous vehicles, including two main modular architectures (HDC, i.e., hierarchical decision & control and IDC, i.e., integrated decision & control) and three mainstream technical solutions (i.e., rule-based design, supervised learning, and brain-inspired learning). An overview of autonomous driving simulation platforms are briefly introduced, followed by three effective designing methods for representing traffic environment states (i.e., object-based design, feature-based design, and combined design). The paper also introduces multiple dimensional evaluation metrics for autonomous vehicles, which can describe self-driving performances including driving safety, regulatory compliance, driving comfort, travel efficiency, energy efficiency. Typical reinforcement learning algorithms, including their design principles, taxonomy, and algorithm performances, are introduced, as well as their application on brain-inspired autonomous driving systems in the systematic design of road-cloud cooperation.

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    Progress in Simulation Technology of Lithium-ion Battery Manufacturing Process
    Fei Chen,Xiangdong Kong,Yuedong Sun,Xuebing Han,Languang Lu,Yuejiu Zheng,Minggao Ouyang
    2023, 45 (9):  1516-1529.  doi: 10.19562/j.chinasae.qcgc.2023.09.002
    Abstract ( 192 )   HTML ( 23 )   PDF (4043KB) ( 190 )   Save

    The overall performance of lithium-ion batteries not only depends on the innovation of materials and structures, but also is closely related to the progress of manufacturing processes and related equipment technologies. At present, battery manufacturers use the exhaustive method of experimental trial and error to develop battery processes for various systems, and there is still much room for development in process simulation technology. Facing the development trend of high-quality battery manufacturing and digital intelligence upgrading, this paper systematically summarizes the current situation of battery manufacturing process simulation research from the two perspectives of macro battery manufacturing equipment and micro battery electrode structure, analyzes the mechanism research, structure development and application prospect of each process simulation technology, and further points out the shortcomings of current research and future development trend, so as to provide theoretical references for optimizing the manufacturing process of lithium-ion batteries and improving their overall performance.

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    Research Progress on Key Technologies of Basic Software and Hardware for Intelligent New Energy Vehicle Onboard Control
    Zhaolin Li,Huawei Li,Sifa Zheng,Wenwei Wang,Guangcai Zou,Chuang Zhang,Ying Liu,Yongchang Zhang
    2023, 45 (9):  1530-1542.  doi: 10.19562/j.chinasae.qcgc.2023.09.003
    Abstract ( 223 )   HTML ( 13 )   PDF (6274KB) ( 274 )   Save

    The intelligence and networking of new energy vehicles have put forward higher requirements for the basic software and hardware of vehicle on-board control including core control chips, operating systems and networks, which must meet disruptive needs such as high-performance computing, high security control and big data communication. Focusing on the high reliability and safety design requirements of vehicle core control chips, vehicle control operating systems, and high-speed distributed fiber optic communication in vehicles, this paper introduces the latest research on key technologies of the architecture of vehicle control operating systems and vehicle core control chips that support intelligent control algorithms under complex driving conditions, the high reliability design technology and environmental adaptability enhancement technology of vehicle core control chips under harsh working conditions, functional safety design and guarantee technology for vehicle control operating system and onboard core control chip, control signal transmission tool based on high-speed distributed fiber optic communication technology, and communication protocol fault diagnosis and self testing technology. Based on the above research results, the independently developed vehicle core control chip and vehicle control operating system have all passed practical vehicle verification. The established research and development system for technology breakthrough, product development, standard formulation, and practical vehicle verification can provide necessary theoretical and technical support for the complete autonomy and controllability of the basic software and hardware of intelligent new energy vehicle on-board control in China.

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    Tag-Based Vehicle Visual SLAM in Sparse Feature Scenes
    Hongmao Qin,Guoli Shen,Yunshui Zhou,Shengjie Huang,Xiaohui Qin,Guotao Xie,Rongjun Ding
    2023, 45 (9):  1543-1552.  doi: 10.19562/j.chinasae.qcgc.2023.09.004
    Abstract ( 114 )   HTML ( 9 )   PDF (4259KB) ( 135 )   Save

    In the simultaneous localization and mapping of intelligent vehicles, the visual feature point method estimates the vehicle’s pose through extraction and matching of feature points. However, when the environment lacks texture or dynamic changes, due to sparse scene features and poor stability, localization by natural features possibly declines in accuracy or even fails. Adding visual tags in the environment can effectively solve the problem of feature sparsity. But the localization methods based on visual tags highly rely on manual calibration, and the poses often jitter due to perspective changes, which affects the precision of localization. Therefore, this paper proposes a tag-based vehicle visual SLAM method, which makes full use of tag information, introduces in internal and external corner constraints to reduce the pose jitter of the tag and establishes a low drift, globally consistent tag map with the visual odometer. The vehicle pose estimated by tags and the tag map are jointly optimized in localization to build a low-cost and highly robust visual SLAM system. The test results show that the proposed method with internal and external corner constraints effectively reduces the pose jitter of the tag, improves the mapping accuracy by more than 60% and the accuracy of localization by more than 30%, which significantly increases the accuracy and robustness of tag-based localization and is conducive to the safe operation of intelligent vehicles.

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    Quantitative Evaluation and Analysis of On-board Network Components Risk Rate Based on AFC-TARA
    Zheng Zuo,Yunpeng Wang,Bin Ma,Bosong Zou,Yaoguang Cao,Shichun Yang
    2023, 45 (9):  1553-1562.  doi: 10.19562/j.chinasae.qcgc.2023.ep.004
    Abstract ( 100 )   HTML ( 3 )   PDF (2671KB) ( 73 )   Save

    The first step of information security design is threat analysis and risk assessment (TARA), which determines security requirements and objectives, and provides a basis for the forward development of information security and the repair of security vulnerabilities. However, the current TARA can only evaluate the impact of malicious attack and security vulnerabilities, which can’t support quantitative evaluation of the effectiveness of protection strategies. Therefore, an attack and fix combined threat analysis and risk assessment (AFC-TARA) method is proposed in this paper. By converting the security state of the system-level on-board network architecture into a continuous-time Markov chain model, and associating the vulnerability mining, vulnerability repair and security defense strategy with the transition rate, a system-level on-board network architecture security assessment and analysis that comprehensively considers attack variables and defense variables are finally realized.

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    Service-Oriented Architecture and Service Scheduling Mechanism for Intelligent Vehicles
    Jianping Hao,Yanzhao Su,Zhihua Zhong,Jin Huang
    2023, 45 (9):  1563-1572.  doi: 10.19562/j.chinasae.qcgc.2023.09.006
    Abstract ( 202 )   HTML ( 10 )   PDF (2712KB) ( 260 )   Save

    Service-Oriented Architecture (SOA) stands as the core design concept for software-defined intelligent vehicles. This paper presents an analysis and synthesis of the software and hardware layers of SOA in intelligent vehicles, along with a categorization of key environmental factors influencing SOA scheduling. Building upon this analysis, this paper proposes an extended-domain SOA architecture tailored for vehicles, establishes a model for SOA service layers and service response parameters, and devise a service scheduling mechanism for this architecture. The service scheduling mechanism centers around the concept of service confidence, and takes into account multiple factors such as service capability, estimated runtime, resource consumption, and performance stability of sub-services, to make optimal sub-service selections under the current environmental constraints. Simulation tests are performed using a simplified double-layer SOA model in scenarios including highways, congested roadways, and low-light tunnels. Results indicate that compared to scenarios without service scheduling, the proposed SOA architecture with the scheduling mechanism significantly reduces computing load and energy consumption by approximately 36% and decreases the predicted service time by around 30%, all while maintaining comparable service capacity.

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    Research on Delay Compensation Control for Heterogeneous Connected and Automated Vehicle Platoons
    Jizheng Liu,Zhenpo Wang,Fengchun Sun,Lei Zhang
    2023, 45 (9):  1573-1582.  doi: 10.19562/j.chinasae.qcgc.2023.09.007
    Abstract ( 99 )   HTML ( 5 )   PDF (3461KB) ( 116 )   Save

    Multi-vehicle platooning of connected and automated vehicles (CAVs) can effectively reduce vehicle-following distance and improve traffic efficiency of the transportation system. However, platoon control needs to have the ability to accommodate heterogeneous platoons and to ensure the string stability against actuator and communication delays. This paper proposes a delay compensation control method for heterogeneous CAV platooning, which can realize the longitudinal tracking control of the CAV platoon utilizing the acceleration information of other vehicles without obtaining system dynamics characteristics and control input of other vehicles. Furthermore, a Smith-predictor-based delay compensation control scheme is proposed to negate the impact of actuator and communication delay on the string stability. The simulation results of typical working conditions show that the proposed delay compensation controller for heterogeneous CAV platoons can reduce the tracking error by 80.7% and effectively minimize the headway and vehicle-following distance, compared with the common vehicle platooning control mthods.

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    Methodology of Critical Scenarios-Based Dual-Loop Testing and Verification for Safety of the Intended Functionality
    Siyu Wu,Wenhao Yu,Xingyu Xing,Yuxin Zhang,Chuzhao Li,Xueke Li,Xinyu Gu,Yunwei Li,Xiaohan Ma,Wei Lu,Zheng Wang,Zhenmao Hao,Hong Wang,Jun Li
    2023, 45 (9):  1583-1607.  doi: 10.19562/j.chinasae.qcgc.2023.09.008
    Abstract ( 151 )   HTML ( 12 )   PDF (3139KB) ( 534 )   Save

    Safety of the Intended Functionality (SOTIF) is a vital part of autonomous driving and poses a significant challenge for intelligent connected vehicles, which requires comprehensive and high-efficiency testing and verification methodology to effectively assist the safety development process of the system. Based on critical scenarios, this paper proposes a dual-loop framework with close loop verification and dynamic evaluation, summarizes the technologies for critical scenarios construction, and further formulizes a quantitative method for acceptance criterion. Finally, this article looks forward to key researches in the area of SOTIF testing and verification. The paper aims to provide a maneuverable and theoretical reference for the engineering practice on the SOTIF for intelligent connected vehicle.

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    Trajectory Prediction Technology Integrating Complex Network and Memory-Augmented Network
    Gaoshi Zhao,Long Chen,Yingfeng Cai,Yubo Lian,Hai Wang,Qingchao Liu,Chenglong Teng
    2023, 45 (9):  1608-1616.  doi: 10.19562/j.chinasae.qcgc.2023.09.009
    Abstract ( 132 )   HTML ( 7 )   PDF (2915KB) ( 175 )   Save

    The prediction of peripheral target trajectories is an important basis for intelligent vehicle decision-making and planning. Existing modeling methods based on multi traffic agent Euclidean distance cannot effectively describe the complex interaction relationship between multiple targets, which limits the applicability in practical dynamic traffic scenarios. In this paper, complex network and memory-augmented neural network are innovatively integrated to construct a double-layer dynamic complex network model to achieve high reliability and interpretability of multimodal trajectory prediction. This model uses a Gaussian variable safety field to calculate risk weights, taking into consideration of the driving state parameters, shape and size of traffic participants, as well as the interaction between intelligent agents and the road, truly and accurately reflecting the interaction relationship between multiple traffic agents in complex environments. A complex network-coding module composed of attention mechanism and social pool containing risk weights is constructed to realize comprehensive and effective extraction of interaction features between traffic participants and road constraints in dynamic and complex scenes. A trajectory-decoding module based on reference trajectories is constructed, realizing multimodal trajectory output that balances accuracy and interpretability. The validation results on the public dataset nuScenes show that the method proposed in this paper has a minimum average displacement error of 1.37 m and a minimum final displacement error of 8.13 m, with excellent performance and good interpretability.

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    Lightweight Semantic Segmentation Method Based on Local Window Cross Attention
    Zuliang Jin,Hanbing Wei,Liu Zheng,Lu Lou,Guofeng Zheng
    2023, 45 (9):  1617-1625.  doi: 10.19562/j.chinasae.qcgc.2023.09.010
    Abstract ( 79 )   HTML ( 4 )   PDF (2359KB) ( 103 )   Save

    For the environmental perception of autonomous vehicle, the application of circumnavigation cameras in the Bird's Eye View (BEV) coordinate for semantic segmentation of lanes, vehicles and other targets has attracted wide attention. For the problems of linear increase of task inference delay due to the increasing number of cameras as well as difficulty in completing semantic segmentation tasks in real-time in autonomous driving perception, this paper proposes a lightweight semantic segmentation method based on local window cross-attention. The model adopts the improved EdgeNeXt backbone network to extract features. By constructing the local window cross attention between BEV query and image features, the feature query between the cross-camera perspectives is constructed. Then, the fused BEV feature map is decoded by up sampling residual block to obtain the BEV semantic segmentation results. The experimental results on the nuScenes dataset show that the proposed method achieves 35.1% mIoU in the lane static segmentation task of BEV map, which is 2.2% higher than that of HDMapNet. In particular, the inference speed increases by 58.2% compared with that of GKT, with the frame detection rate reaching 106 FPS.

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    Security Access Control for Service-Oriented Multi-domain Electrical and Electronic Architecture
    Zhenyu Yang,Feng Luo,Zitong Wang,Yi Ren,Xiaoxian Zhang
    2023, 45 (9):  1626-1636.  doi: 10.19562/j.chinasae.qcgc.2023.09.011
    Abstract ( 99 )   HTML ( 8 )   PDF (2795KB) ( 156 )   Save

    Under the service-oriented multi-domain electrical and electronic architecture, a large number of heterogeneous services are deployed in the vehicle for purposes such as autonomous driving, safety, comfort, and remote diagnosis. With the increasing interaction with the outside world, there are incremental security risks in the in-vehicle network. In this paper, a secure access control mechanism is proposed to prevent unauthenticated and unauthorized access requests to the in-vehicle domain controllers. Firstly, an access control architecture for attribute-based access control is proposed based on the analysis of security requirements of intelligent connected vehicle, which supports not only fine-grained and flexible authorization but also online permission detection based on per-stream filtering and policing. Secondly, a formal access control model is given in terms of a five-tuple, which mathematically describes the subject, object, policy and request, and proposes a hash-based policy evaluation engine. Finally, the secure access sequence guarantees confidentiality, integrity and availability of the access control process through session establishment and secure communication.

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    Research on Vehicle Control Algorithm Based on Distributed Reinforcement Learning
    Weiguo Liu,Zhiyu Xiang,Weiping Liu,Daoxin Qi,Zixu Wang
    2023, 45 (9):  1637-1645.  doi: 10.19562/j.chinasae.qcgc.2023.09.012
    Abstract ( 161 )   HTML ( 9 )   PDF (2911KB) ( 224 )   Save

    The development of end-to-end autonomous driving algorithms has become a hot topic in current autonomous driving technology research and development. Classic reinforcement learning algorithms leverage information such as vehicle state and environmental feedback to train the vehicle for driving, through trial-and-error learning to obtain the best strategy, so as to achieve the development of end-to-end autonomous driving algorithms. However, there is still the problem of low development efficiency. The article proposes an asynchronous distributed reinforcement learning framework to address the inefficiency and high complexity problems in training RL algorithms in virtual simulation environment, establishes intra and inter process multi-agent parallel Soft Actor-Critic (SAC) distributed training framework on the Carla simulator to accelerate online RL training. Additionally, to achieve rapid model training and deployment, the article proposes a distributed model training and deployment system architecture based on Cloud-OTA, which mainly consists of an Over-the-Air Technology (OTA) platform, a cloud-based distributed training platform, and an on-vehicle computing platform. On this basis, the paper establishes an Autoware-Carla integrated validation framework based on ROS to improve model reusability and reduce migration and deployment cost. The experimental results show that compared with various mainstream autonomous driving methods, the method proposed in this paper has a faster training speed qualitatively, which can effectively cope with dense traffic flow and improve the adaptability of end-to-end autonomous driving strategies to unknown scenes, and reduce the time and resources required for experimentation in actual environment.

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    Ultrasonic Radar Modeling of Automatic Parking System Considering Atmospheric Conditions Effect
    Tianfei Ma,Bo Li,Bing Zhu,Jian Zhao
    2023, 45 (9):  1646-1654.  doi: 10.19562/j.chinasae.qcgc.2023.09.013
    Abstract ( 93 )   HTML ( 7 )   PDF (2284KB) ( 109 )   Save

    The ultrasonic radar is the most commonly used environment sensing sensor in the automatic parking system, and the accurate modeling of the ultrasonic radar is the difficulty of simulation analysis of the automatic parking system. In this paper, a modeling method of ultrasonic radar considering the influence of atmospheric conditions is proposed, including the three atmospheric conditions of air temperature, humidity and atmospheric pressure in the modeling system. Firstly, the working mechanism of ultrasonic radar is analyzed, and it is clarified that the ultrasonic radar model should consist of two parts: the detection range model and the detection distance model. Then the quantitative relationship between atmospheric conditions, target characteristics and ultrasonic absorption energy loss, transmission energy loss is derived, and the detection range model is established. The real sound velocity is calculated according to atmospheric conditions, and the true range value is further modified to the real ultrasonic radar detection value, and the detection range model is established. Finally, the ultrasonic radar model is tested and verified. The results show that the ultrasonic radar model can accurately simulate the detection range and detection distance of the ultrasonic radar in the auto parking scene.

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    Quantitative Evaluation of SOTIF for Control Module of AEBS
    Xianxu Bai,Yu Zuo,Weihan Li,Qin Shi,Chuzhao Li,Shulian Zhao,Jiong Chen
    2023, 45 (9):  1655-1665.  doi: 10.19562/j.chinasae.qcgc.2023.09.014
    Abstract ( 150 )   HTML ( 7 )   PDF (3807KB) ( 212 )   Save

    The establishment of Safety Of The Intended Functionality (SOTIF) evaluation system and SOTIF design are the only way for wide application of the intelligent vehicles. To improve the SOTIF theory and realize the SOTIF design of Autonomous Emergency Braking System (AEBS), safety analysis of the control module of AEBS is conducted by using the method of System Theoretic Process Analysis (STPA) in this paper. Based on the results of the safety analysis, SOTIF evaluation indices of the control module of AEBS are proposed, which are then comprehensively quantified using the CRITIC method and TOPSIS method. In addition, the proposed evaluation methods are used to conduct a SOTIF evaluation of the AEBS control module in a prototype of intelligent vehicle based on real vehicle tests, and the rationality and practicability of the proposed SOTIF evaluation method for the control module of AEBS are verified by the evaluation results. Finally, the evaluation results are analyzed, and further the SOTIF improvement suggestion for the control module of AEBS is put forward according to the proposed SOTIF evaluation indices.

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    Collision Warning Based on Fusion of Millimeter Wave Radar and Vision
    Yongtao Li,Chenxu Sun,Weiguang Zheng,Enyong Xu,Yufang Li,Shanchao Wang
    2023, 45 (9):  1666-1676.  doi: 10.19562/j.chinasae.qcgc.2023.09.015
    Abstract ( 157 )   HTML ( 13 )   PDF (4280KB) ( 194 )   Save

    For the problems of high false alarm rate and missed alarm rate of existing collision warning algorithms of millimeter wave radar and vision fusion, a collision warning method based on millimeter wave radar and vision fusion is proposed in this paper. Firstly, the distance-velocity threshold and life cycle methods are used to pre-process the millimeter wave radar data, and the adaptive extended Kalman filter algorithm based on forgetting factor is proposed to track the target, adding the improved CBAM two-channel attention mechanism YOLOv5 algorithm to improve the accuracy of visual recognition. Then the idea of cross-comparison is applied to realize the decision-level fusion of millimeter wave radar and vision. Finally, a forward collision warning strategy is proposed based on the minimum safe distance model. The results of real-vehicle tests under different scenarios show that the algorithm is more accurate and has better robustness than the single-sensor algorithm.

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    Research on Multi-level Fault Warning Method for Lithium-ion Batteries Driven by Cloud Data
    Wenchao Guo,Lin Yang,Zhongwei Deng,Jilin Li,Zhixian Fan
    2023, 45 (9):  1677-1687.  doi: 10.19562/j.chinasae.qcgc.2023.09.016
    Abstract ( 109 )   HTML ( 9 )   PDF (5628KB) ( 153 )   Save

    At present, there is no effective method for unsupervised fault warning for vehicle cloud data with unspecified fault types. Therefore, this paper proposes a multi-level fault warning method for lithium-ion batteries driven by cloud data. Firstly, the features suitable for the characteristics of cloud data are selected through mechanism analysis, and six types of differential entropy feature sets are constructed for multiple mixed clustering to achieve the score evaluation of battery health. Then, temperature information is introduced in to distinguish heat-related faults and the warning level division criteria are constructed to determine the battery fault status. Finally, five field failure cases are used for validation. The results show that the method can accurately identify faults and distinguish fault types, and is ahead of its time and highly adaptable.

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    Joint Estimation of State of Charge for Lithium-Ion Battery with Kalman Filtering and Gated Recurrent Unit Neural Networks Considering Hysteresis Characteristics
    Minghui Hu,Guangyao Zhu,Changhe Liu,Guofeng Tang
    2023, 45 (9):  1688-1701.  doi: 10.19562/j.chinasae.qcgc.2023.09.017
    Abstract ( 98 )   HTML ( 3 )   PDF (8250KB) ( 122 )   Save

    Due to the existence of hysteresis characteristics, it is difficult for battery management systems to accurately obtain the state relationship between open circuit voltage (OCV) and state of charge (SOC). In order to effectively operate and manage the power battery, this paper investigates a lithium-ion battery model that considers the hysteresis characteristics and selects FFRLS for online identification of parameters. A SOC estimation method combining gated recurrent unit (GRU) neural network and adaptive extended Kalman filter (AEKF) is proposed, using the estimated results of the AEKF and GRU neural network as the model and measured values respectively, and the final SOC estimation results are obtained by Kalman filter (KF) , which is used as the input to the AEKF at the next moment. The results show that the root mean square error (RMSE) of the prediction of voltages by models considering hysteresis characteristics and the SOC estimation by the joint estimation method is within 0.5 mV and 0.64% respectively for the ambient temperature environment. The RMSE for terminal voltage prediction and SOC estimation is within 0.9 mV and 0.72% for low and variable temperature environment respectively. The model considering the hysteresis characteristics and joint estimation method have good accuracy and robustness.

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    Self-adaptive Porous Structure Detection of the Catalyst Layer in PEMFCs Based on GA-PSO-Otsu Algorithm
    Xinjie Yuan,Fang Liu,Zhongjun Hou
    2023, 45 (9):  1702-1709.  doi: 10.19562/j.chinasae.qcgc.2023.09.018
    Abstract ( 72 )   HTML ( 2 )   PDF (4085KB) ( 108 )   Save

    The low efficiency, low accuracy and strict experimental requirements for the detection of the proton exchange membrane fuel cell (PEMFC) catalyst layer porous structure can’t adapt to the increasingly large-scale industry development system. Therefore, to address the problem, this paper innovatively proposes the genetic algorithm-particle swarm optimization-Otsu (GA-PSO-Otsu) algorithm to realize efficient, accurate and self-adaptive identification of pore size distribution and porosity calculation of the scanning electron microscope (SEM) of the catalyst layer. Firstly, Gaussian convolution and binary threshold are combined to maximize the inter-class variance between the foreground and background to effectively reducethe impact of noise and manual adjustment of parameters on accuracy and efficiency, which ensures automatic noise reduction and pore structure detection. Furthermore, the genetic algorithm based particle swarm optimization method is proposed to solve the problem of long time consuming caused by traverse parameters and to avoidlocal optimization, with the advantages of high accuracy and high efficiency. Lastly, the comparative analysis of different algorithms applied on various PEMFC catalyst SEMs with different component ratios and gray scales indicate that the proposed method has high robustness, self-adaptiveness and practicability. Compared with the traditional Otsu approach which traverses all parameters, the porosity error of the proposed method is less than 0.5% and the calculation time is significantly reduced by 26.2%.

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    Simulation Analysis and Test Validation of Fuel Cell System
    Youwei Xu,Guiyin Chen,Lü Ping,Zhenrui Zhao,Yangyang Zhao,Maoxi Sun,Danmin Xing
    2023, 45 (9):  1710-1719.  doi: 10.19562/j.chinasae.qcgc.2023.09.019
    Abstract ( 133 )   HTML ( 10 )   PDF (6090KB) ( 157 )   Save

    The fuel cell system includes stack, air subsystem, hydrogen subsystem, cooling subsystem, involving many components. Therefore, in the early stage of research and development, establishment of a fuel cell system model through system simulation has a guiding role for system development. Firstly, based on the test results and characteristic parameters of components, virtual calibration of components is carried out to establish an accurate component model. Then, according to the system flow chart, a complete fuel cell system simulation model is built. Finally, key output performance parameters of the system are evaluated and predicted through simulation calculation. Comparing the simulation results with the test data, the results show that the maximum average absolute percentage error between the model simulation results and the test data is 4.33%, with a high degree of consistency. It is verified that the simulation model has a high accuracy and can be used to study the performance of the fuel cell system, which has great guiding significance for future research and development of the fuel cell system.

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    Research on Effect of Gas Diffusion Layer Layered Design on the Performance of PEMFC Stack
    Wanteng Wang,Nan Li,Xueyi Bai,Dou Yang,Hang Li,Guijing Li
    2023, 45 (9):  1720-1727.  doi: 10.19562/j.chinasae.qcgc.2023.09.020
    Abstract ( 67 )   HTML ( 0 )   PDF (3304KB) ( 87 )   Save

    In order to improve the uniformity of temperature and reactants between different cells in the stack, thus improving the stack performance and extending the stack life, an improved scheme of setting different gradient porosity in gas diffusion layers of different cell units in the stack is proposed in this paper. A three-dimensional, non-isothermal, single-phase short stack model with five layers of cell units is established for analysis. It is found that the scheme with porosity of 0.4-0.5-0.6-0.5-0.4 can minimize the difference of temperature, oxygen, water molar concentration, membrane current density between the edge layer and the intermediate layer cell unit; thereby improve the internal uniformity of the stack, which is also the same trend under the operating conditions of gas shortage.

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    Abnormal Voltage Detection of Battery for Electric Vehicles Based on Value Rate Model
    Qiquan Liu,Jian Ma,Xuan Zhao,Kai Zhang,Dean Meng,Likang Xiang
    2023, 45 (9):  1728-1739.  doi: 10.19562/j.chinasae.qcgc.2023.09.021
    Abstract ( 117 )   HTML ( 10 )   PDF (6282KB) ( 119 )   Save

    Accurate and efficient abnormal detection of electric vehicle power battery systems is of great significance to ensure safe and reliable operation of vehicles. Based on this, a new power battery voltage abnormality diagnosis method based on voltage variation rate is proposed for detecting abnormal voltage fluctuation faults of individual cells in a battery pack. Further, an evaluation coefficient based on an improved Z-score method is introduced to quantitatively characterize the degree of abnormal voltage fluctuation. On this basis, the validity and reliability of the proposed method is verified based on real-world vehicle data. In addition, a comparative analysis with the commonly used entropy method shows that the method proposed in this paper has reliable fault diagnosis results and high calculation efficiency, with higher value of engineering application. Finally, based on the model, the distribution of the risk of voltage abnormalities in the battery system of this type of vehicle is obtained by statistically analyzing the voltage data of a large number of electric vehicles of the same type. By analyzing the abnormalities hidden beneath the surface, it can provide a reference for vehicle manufacturers for design of the power battery system or the entire vehicle structure.

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    Multi-objective Optimization Design of High Efficiency and High Utilization Magnetic Core of Wireless Charging of Electric Vehicles
    Meng Xiong,Dong Zhang,Guojian You,Tianfei Sun,Kai Sheng,Xuezhe Wei
    2023, 45 (9):  1740-1752.  doi: 10.19562/j.chinasae.qcgc.2023.ep.008
    Abstract ( 119 )   HTML ( 8 )   PDF (8578KB) ( 130 )   Save

    In this paper, based on the asymmetric DD coil and LCC-SP topology of electric vehicle for wireless charging, a novel magnetic core structure is designed and optimized to solve the problem of high magnetic loss and low utilization of the core caused by the non-uniform magnetic flux of the transmitting core. Firstly, the equivalent circuit model and the equivalent magnetic circuit model of the reference coils are established, providing theoretical support for the calculation of magnetic core loss and the layout design of the core structure. Meanwhile, the evaluation index of magnetic flux uniformity CV(B) is proposed, and its quantitative relationship with magnetic core loss and core volume is established, providing the optimization direction and optimization boundary for the magnetic core. Then, based on the coils’ equivalent model, a novel transmitting core structure is proposed, and sensitivity analysis is carried out on its key structure parameters to reduce the complexity of optimization variables. Finally, with the maximum coupling coefficient and the minimum uniformity coefficient as the optimization objectives, the novel core structure optimization based on NSGA-II multi-objective optimization algorithm is completed by the Co-simulation of COMSOL and Matlab. The results show that the utilization rate and efficiency of the optimized core have been improved, with the volume of the optimized core only 60% of the original reference core, the coil transmission efficiency increased to 98.117%, and the core loss reduced by about 10 W, which proves the effectiveness of the proposed optimization method.

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    Research on Modeling of Gear Transmission System and Transfer Characteristics of Typical Interface
    Pu Gao,Hui Liu,Wenjin Bei,Changle Xiang
    2023, 45 (9):  1753-1764.  doi: 10.19562/j.chinasae.qcgc.2023.09.023
    Abstract ( 108 )   HTML ( 2 )   PDF (6108KB) ( 162 )   Save

    With the development of vehicle gear transmission system towards high speed, heavy load and high power, the structure is becoming more and more complex, and the operating conditions are variable, easy to cause damage and failure of parts and components, which affects the reliability of the system. Establishing an accurate gear transmission system model and studying the change law of the transfer characteristics of typical interface are the key technical basis for system fault detection and location. This paper comprehensively considers the key influencing factors such as the gear time-varying meshing stiffness, meshing damping, tooth clearance and bearing support stiffness, establishes a nonlinear dynamic model of the fixed shaft gear transmission system, and conducts vibration characteristics tests, effectively verifying the accuracy of gear transmission dynamics model. For the gear-meshing interface and bearing interface, a typical interface force model is constructed, and the transfer characteristics are quantitatively characterized by the attenuation coefficient of vibration signal transfer. The simulation and experimental research on typical interface vibration transfer are carried out to reveal the essential law of vibration signal transfer in the gear transmission system, which provides a powerful theoretical and technical support for the layout of sensor measuring points in the fault detection of vehicle gear transmission system.

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    Vehicle Handling and Stability Test Type Recognition Method Based on Convolutional Neural Network
    Xin Guan,Zhaohui Zhong,Jun Zhan,Tenglong Xi,Hao Ye,Shenzhen Gao,Jian Cheng,Shihui Liao,Jun Cai
    2023, 45 (9):  1765-1771.  doi: 10.19562/j.chinasae.qcgc.2023.09.024
    Abstract ( 135 )   HTML ( 2 )   PDF (5034KB) ( 164 )   Save

    To meet the need of automatic identification of test types, which is aimed at automatic processing of vehicle handling and stability test evaluation indicators, this paper proposes a vehicle handling and stability test type recognition method based on convolutional neural network. On the basis of analyzing the image characteristics of the test type data, a vehicle handling and stability test type recognition model based on convolution neural network is established, which consists of 1 input layer, 3 convolution layers, 3 batch normalization layers, 2 Max-pooling layers, 5 linear rectification function (ReLU) layers, 3 full connection layers, 2 Dropout layers, 1 Softmax layer and 1 classification layer. The model is trained and verified using 2 250 groups of data collected from the tests. The accuracy of type recognition is 99.33%, and the average recognition time is 0.05 s. The results show that the vehicle handling and stability test type recognition method based on convolutional neural network proposed in this paper can effectively distinguish different test types, which can be used for automatic processing of vehicle handling and stability test results, and can significantly improve the automatic processing level of vehicle handling and stability test.

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    Influence of B-pillar Spoiler on Wind Buffeting Noise and its Mechanism
    Xiaoyong Chen,Lu Yao,Zhengxin Guo,Hao Liu,Ting Luo,Yongliang Wang
    2023, 45 (9):  1772-1778.  doi: 10.19562/j.chinasae.qcgc.2023.09.025
    Abstract ( 110 )   HTML ( 7 )   PDF (103581KB) ( 180 )   Save

    The wind buffeting noise of automobile is one of the important indexes for comfort evaluation. Firstly, the validity of wind buffeting CFD simulation method is verified by road test in this paper. Then, it is explained that the wind buffeting noise is caused by resonance of periodic shedding of turbulent vortex and the interior cavity of the vehicle, and the noise reduction strategy of wind buffeting is proposed. Then the influence of the B-pillar spoiler on the wind buffeting noise and its mechanism are investigated. It is found that reducing the maximum distance of the free shear layer from the outer surface of the B-pillar can reduce the strength of the vortex, thereby reducing the wind buffeting noise. The maximum noise reduction of the spoilers designed in this paper can reach 12.8 dB. Finally, the effectiveness of the B-pillar spoiler is verified by road test. The conclusion of this paper has certain theoretical significance and engineering application value for further understanding and controlling wind buffeting noise.

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