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Table of Content

    25 May 2023, Volume 45 Issue 5 Previous Issue    Next Issue
    Intelligent Vehicle Switching Control Considering Dynamic Stability Constraints
    Yu Zhang,Mingfan Xu,Guangyu Bai,Mingming Dong,Li Gao,Yechen Qin
    2023, 45 (5):  709-718.  doi: 10.19562/j.chinasae.qcgc.2023.05.001
    Abstract ( 294 )   HTML ( 36 )   PDF (3595KB) ( 395 )   Save

    Strengthening active collision avoidance capability is the key to improving driving safety for intelligent vehicles. In particular, efficient and stable implementation of the active collision avoidance function in emergency is the basis for ensuring accurate multi-objective switching of intelligent vehicles. However, current active collision avoidance methods need to be further improved in terms of the collision avoidance ability when facing vehicles cutting in from different directions. To address the above-mentioned problems, a switching control method for the intelligent vehicle is proposed, which quantifies the collision risk, constructs target switching logic and designs a hierarchical system control structure. The proposed method strengthens the active collision-avoidance ability for cut-in vehicles from different directions to realize stable switching among different driving objectives under vehicle stability constraints. Finally, the multi-vehicle experimental platform verifies the effectiveness and correctness of the proposed method.

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    Research on Stability Model Predictive Control of Intelligent Electric Vehicle with Preview Characteristics
    Yilin He,Jian Ma,Shukai Yang,Wei Zheng,Qifan Xue
    2023, 45 (5):  719-734.  doi: 10.19562/j.chinasae.qcgc.2023.05.002
    Abstract ( 161 )   HTML ( 14 )   PDF (9866KB) ( 232 )   Save

    A feedforward and feedback control method with preview characteristics for intelligent electric vehicle stability is proposed. The vehicle preview model is established, and the road curvature is introduced in as a factor influencing vehicle dynamic characteristics according to vehicle preview perception of the environment. Based on the change of vehicle posture guided by the preview information, the desired longitudinal vehicle speed is described according to the road friction condition and the vehicle speed index model and the stability feedforward control method for tire lateral stiffness compensation is established. At the same time, the model prediction control (MPC) is used to design the stability feedback control law, with the preview model and preview time adjusted according to the road information adaptively to eliminate the influence of uncertain factors such as feedforward control error and road disturbance. The research results suggest that the proposed control method has lower vehicle centroid sideslip angle, yaw rate and lateral acceleration, and higher tracking accuracy. In simulation test, compared with no control method, MPC feedback control, and feedforward + MPC feedback control with fixed parameter, the control strategy proposed in this paper reduces the peak mass center sideslip angle by 41.3%, 28.9% and 10.0% respectively under dual shift conditions, and the peak yaw rate by 18.0%, 6.7%, and 2.0% respectively. Under the other dual shift conditions, the peak values of the center of mass sideslip angle decreases by 27.2%, 8.7% and 8.0% respectively, and the peak value of the yaw rate decreases by 16.9%, 12.9% and 8.6% respectively. Compared with MPC feedback control, feedforward + MPC feedback control with fixed parameter, the maximum vehicle sideslip angle decreases by 49.8% and 34.8% respectively, and the maximum yaw rate decreases by 21.8% and 12.7% respectively under the S-shaped condition. Under the other S-shaped condition, the maximum vehicle sideslip angle decreases by 36.6% and 18.6%, and the maximum yaw rate decreases by 17.7% and 12.4% respectively.

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    Semi-active Suspension Control for Intelligent Vehicles Based on State Feedback and Preview Feedforward
    Zixian Li,Shiju Pan,Yuan Zhu,Binbing He,Youchun Xu
    2023, 45 (5):  735-745.  doi: 10.19562/j.chinasae.qcgc.2023.05.003
    Abstract ( 170 )   HTML ( 8 )   PDF (4235KB) ( 296 )   Save

    In order to improve the comprehensive control performance of intelligent vehicle semi-active suspension, a semi-active suspension control method based on state feedback and preview feedforward is proposed. Firstly, an 11-DOF semi-active suspension model is established with an 8-wheeler as the research object, and an LQR state feedback controller is designed. Then, in order to solve the problems of weak road disturbance resistance ability of the state feedback control and poor applicability of preview feedback control based on fixed timing delay, a kind of controller based on state feedback and preview feedforward is proposed, establishing the wheel movement planning model and road preview model to calculate the wheel planning trajectory point number of the suspension control system and the control delay response time. Taking road excitation and vertical acceleration as input and feedforward damping force as output, a fuzzy-like preview feedforward controller is designed, and together with the LQR feedback controller to form the proposed controller. Finally, based on the co-simulation platform of MATLAB/Simulink and Trucksim, the experiments are carried out under the conditions of constant speed steering, variable speed straight line, variable speed steering and constant speed straight line. The results show that the root mean square value of vertical acceleration, pitch angle acceleration and roll angle acceleration is at least reduced by 23.52%, 13.59% and 19.35% compared with the passive suspension under four working conditions. Compared with the pre-view feedback control based on fixed time delay, the proposed control method reduces at least 14.04%, 8.09% and 13.79% under the first three working conditions. Compared with the control method based on state feedback, the proposed control method reduces by 13.20%, 4.96% and 4.12% under the fourth working conditions. The proposed suspension control method can effectively improve vehicle ride comfort under various working conditions.

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    Multi-objective Optimization of In-Vehicle Ethernet Network Architecture for Time-Sensitive Network
    Yuan Zou,Wenjing Sun,Xudong Zhang,Ya Wen,Wanke Cao,Zhaolong Zhang
    2023, 45 (5):  746-758.  doi: 10.19562/j.chinasae.qcgc.2023.ep.007
    Abstract ( 129 )   HTML ( 11 )   PDF (4058KB) ( 200 )   Save

    The network architecture of the vehicle electrical and electronic architecture profoundly affects communication security and certainty. For Zone-Domain based electrical and electronic architectures that use time-sensitive networks (TSN), this paper establishes for the first time the multi-objective optimization framework for network architecture with the optimization objectives of uniform number of ports, balanced load and lowest end-to-end delay of information flows. The end-to-end delay is obtained by solving the TSN traffic scheduling and the traffic scheduling is abstracted as the periodic job-scheduling problem (JSP). The multi-population genetic algorithm (MPGA) applicable to traffic scheduling is proposed, which improves the solution effect by 16% compared with the traditional genetic algorithm. In order to solve the multi-objective optimization problems rapidly, an improved non-dominated sorting genetic algorithm (NSGA-II) is designed in this paper. The optimization efficiency is improved by 25% by introducing in the iteration factor and congestion factor to improve the algorithm with adaptive cross-variance probability. The simulation verifies the effectiveness of the multi-objective optimization framework and provides a design idea for the optimization of in-vehicle Ethernet network architecture with the introduction of TSN.

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    Driver’s Attention Prediction Based on Multi-Level Temporal-Spatial Fusion Network
    Lisheng Jin,Bingdong Ji,Baicang Guo
    2023, 45 (5):  759-767.  doi: 10.19562/j.chinasae.qcgc.2023.05.005
    Abstract ( 125 )   HTML ( 11 )   PDF (3404KB) ( 198 )   Save

    Humanoid driving is one of the important ways to improve the level of vehicle intelligence. It can identify and locate the target and area of interest of the driver, and then quickly and accurately perceive the potential risks in the driving scene or provide the key information required for decision-making, which can effectively enhance the functional understandability and robustness of intelligent vehicles. In this paper, a lightweight multi-level temporal-spatial fusion network is designed based on the hierarchical encoder-decoder architecture, and a lightweight driver attention prediction model is established. Firstly, the MobileNetV2 is used as the backbone network of the encoder to extract the multi-level spatial features on the four scales of the current frame, store them in the memory module, and superimpose them with the multi-level features extracted on the historical frames in the time dimension. Then the temporal-spatial features between consecutive frames are obtained and then transmitted to the decoder. Secondly, the decoder is designed based on the hierarchical decoding structure. The inverse bottleneck 3D convolution module is used to design the temporal-spatial fusion layer to fuse the temporal-spatial features on each independent branch. Finally, the prediction results of different scales information captured on four independent branches are fused. The predicted value of the driver’s attention is obtained as the model prediction output result. The results show that the driver’s attention prediction model proposed in this paper can effectively utilize the time, space and scale information between the current and historical frames of the dynamic scene through encoding and decoding on multiple feature scales. The tests on DADA-2000 and TDV datasets show that it is superior to the current excellent models of the same kind in many indicators. The model size is 19 MB, and the single frame operation speed is 0.02 s, which realizes excellent model lightweight and real-time effect. In summary, this study has solved the problems of large volume and poor real-time performance of the driver’s attention prediction model in the dynamic driving scene under the current complex traffic environment, and has certain theoretical support and application value for the research on humanoid perception and decision-making of intelligent vehicles.

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    Centralized Trajectory Planning in an Unsignalized Intersection Environment Considering Driver Error
    Lijun Qian,Chen Chen,Jian Chen
    2023, 45 (5):  768-776.  doi: 10.19562/j.chinasae.qcgc.2023.05.006
    Abstract ( 90 )   HTML ( 3 )   PDF (3171KB) ( 144 )   Save

    For the hidden collision risk caused by human driving vehicles (HDV) in mixed traffic, a centralized trajectory planning method for an unsignalized intersection considering driver error is proposed. Firstly, a multi-vehicle cooperative trajectory planning method is designed based on the optimal control framework, with the composite optimization objectives established based on motion time, fuel economy and driving delay. Secondly, the operating data sets of different drivers are collected through the real vehicle driving tests, then the Markov chain error transition matrix of acceleration error is established. Finally, the replanning of possible accident situation is calculated based on the results of vehicle collision estimation, and the simulation verification is carried out under different market penetration rate (MPR) conditions of autonomous vehicles. The simulation results show that the incidence of traffic collision and the average number of replanning are negatively correlated with the MPR. Moreover, the success rate of the planning at the intersection by the re-planning method can reach over 90%, with the fuel economy and other traffic indicators improved.

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    An Improved YOLO Algorithm Supporting Anti-illumination Target Detection
    Yujie Yao,Yuhui Peng,Zehui Chen,Weikun He,Qing Wu,Wei Huang,Wenqiang Chen
    2023, 45 (5):  777-785.  doi: 10.19562/j.chinasae.qcgc.2023.05.007
    Abstract ( 118 )   HTML ( 9 )   PDF (4170KB) ( 155 )   Save

    For the problems of unsatisfactory detection accuracy and weak real-time performance in the complicated illumination scenes in the existing deep learning target detection algorithms, an anti-illumination target detection network model YOLO-RLG based on the YOLO algorithm is proposed. Firstly, the RGB data of the input model is converted into HSV data, and the S channel with powerful anti-illumination capability is separated from the HSV data and fused with the RGB data to generate RGBS data so that the input data has anti-illumination capability. Secondly, the backbone network of YOLOV4 is replaced with Ghostnet network, with the model assignment ratio between ordinary convolution and cheap convolution modified to improve the detection efficiency while ensuring the detection accuracy. Finally, the loss function of the model is improved by replacing CIoU with EIoU, which enhances the target detection accuracy and algorithm robustness. The experimental results based on KITTI and VOC datasets indicate that, compared with the original network model, the FPS improves by 22.54 and 17.84 f/s, with the model reduced by 210.3 M, the accuracy (AP) improved by 0.83% and 1.31%, and the algorithm's anti-illumination performance significantly enhanced.

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    Design and Evaluation of Atmospheric Fogging Model for Traffic Image
    He Huang,Zhanyi Li,Lan Yang,Huifeng Wang,Tao Gao,Ting Chen
    2023, 45 (5):  786-795.  doi: 10.19562/j.chinasae.qcgc.2023.05.008
    Abstract ( 80 )   HTML ( 6 )   PDF (9984KB) ( 93 )   Save

    For the problems of weather restriction and insufficient samples due to the difficulty of database acquisition for the collection of traffic haze images in the process of digital twinning, a new atmospheric fogging model is proposed to expand the database of traffic haze images with different concentrations. Firstly, the atmospheric light value is calculated based on the principle of dark feature, and the estimation of atmospheric light is obtained by using the atmospheric light compensation method based on variance fluctuation. Secondly, the color attenuation prior is used to estimate the scene depth, and to solve the initial transmittance. Then, an image atmospheric fogging model is constructed, and the calculated atmospheric light estimation and atmospheric fogging transmission are substituted into the model, and the fogging density is adjusted by the haze coefficient. Finally, several traffic video fogging experiments are designed and evaluated. Experimental results show that with the increase of preset haze coefficient, the proposed algorithm can make the image tend to blur subjectively, and the objective index gradually change accordingly. The image quality degradation law is basically consistent with the real scene containing fog, which can be used to expand haze data set, with good effectiveness and practicability. By evaluating and comparing the fogging images with different defogging algorithms, it can be seen that the effect of the restored image is basically the same as the defogging effect of the actual image, further verifying the effectiveness of the fogging model.

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    A Real-Time Pedestrian Detection Method Based on Improved Gated Context Aggregation Network in Foggy Weather
    Tong Wu,Yuning Wang,Yibo Guan,Shaopeng Tian
    2023, 45 (5):  796-806.  doi: 10.19562/j.chinasae.qcgc.2023.05.009
    Abstract ( 91 )   HTML ( 3 )   PDF (4654KB) ( 117 )   Save

    For the problem that pedestrians are easy to be misdetected or missed by autonomous vehicles in foggy weather, a joint detection method based on improved GCANet defogging network and CenterNet detection network is proposed to effectively detect pedestrians in foggy weather. Firstly, a composite loss function combining the underlying details and global structure is introduced into GCANet to optimize the structural details and image quality of the defogging map. Then, the improved GCANet defogging algorithm is applied to the training image enhancement preprocessing step of the detection algorithm, which is finally sent to the CenterNet for training. The test results show that the average logarithmic missed detection rate of the proposed method on the synthetic Foggy Citypersons dataset reaches 9.65, and the average accuracy value on the real foggy RTTS dataset reaches 86.11. The proposed method reduces the missed detection and false detection of pedestrians in foggy weather, which effectively improves the generalization ability of the detection network in foggy weather.

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    Study on Platformization of Power Batteries Based on Vehicle Platforms
    Yubo Lian,Kai Wu,Dong Zeng,Song Li,Puxi Wang
    2023, 45 (5):  807-813.  doi: 10.19562/j.chinasae.qcgc.2023.05.010
    Abstract ( 190 )   HTML ( 13 )   PDF (1439KB) ( 280 )   Save

    The platformization development of vehicles and the corresponding systems is the consensus and important technology trend of the new energy vehicle industry, which is beneficial for planning each project systematically, sharing more systems and saving the cost. It is necessary for platformization development of battery systems based on vehicle platforms to clarify the relevant variables of vehicles and batteries, which mainly include the space, the weight, the mileage, the power consumption, the power performance of the vehicle, and the size, the weight, the energy, the power property of the battery. In this paper, the development of the battery system of a certain hybrid-vehicle platform is chosen as the case, where the platform solution including two or three types of cells is proposed via summarizing the distribution and boundary of each variable. Moreover, the bandwidth design of the series of the cells and the Y dimension of the pack is also proposed to make it compatible with 16 vehicle types. This study provides the basic reference of strategies for the development of battery solutions for various vehicle platforms of the industry in the future.

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    Battery Safety Risk Prediction for Data-Driven Electric Vehicles
    Jie Hu,Hai Yu,Bowen Yang,Yayu Cheng
    2023, 45 (5):  814-824.  doi: 10.19562/j.chinasae.qcgc.2023.05.011
    Abstract ( 147 )   HTML ( 7 )   PDF (4065KB) ( 243 )   Save

    In order to accurately predict the battery safety risk, a multi-index battery safety risk prediction method based on vehicle-weather-driver is proposed in this paper. Firstly, multi-dimensional information inside and outside the vehicle is extracted, i.e. multi-index characteristics such as weather condition, driving conditions and driving style are extracted by data mining to simulate the actual battery application scenario. Then, features are filtered by random forest and SHAP combination model, which improves the generalization and robustness of the model. Finally, the battery safety risk prediction problem is decoupled into machine learning prediction and time series prediction problems, and XGBoost and random forest models are selected to predict respectively. On this basis, a new Stacking integrated model is established to predict the battery safety risk. According to the predictive effect of the final model and the results of data experiment, the scheme can make a more accurate prediction of the battery safety risk of EV and provide decision-making information for safe and intelligent battery management system.

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    Research on Lithium Ion Battery Life Prediction Method Based on Empirical Aging Model and Mechanism Model for Electric Vehicles
    Haiqiang Liang,Hongwen He,Kangwei Dai,Bo Pang,Peng Wang
    2023, 45 (5):  825-835.  doi: 10.19562/j.chinasae.qcgc.2023.05.012
    Abstract ( 127 )   HTML ( 8 )   PDF (3856KB) ( 235 )   Save

    In order to improve the prediction accuracy of remaining useful life of lithium-ion power battery in practical application, a remaining useful life prediction method of lithium-ion power battery combining the empirical aging model and the battery mechanism model is proposed in this paper. The method uses the SOH prediction value based on the empirical aging model as the prior estimate of the Kalman algorithm, and uses the SOH predicted by estimating the future capacity decline of the battery based on the mechanism model as the posterior correction of the Kalman algorithm, so as to achieve accurate prediction of the remaining useful life of the lithium-ion battery. The validation results of power battery remaining useful life prediction algorithm based on the cell test data show that the remaining useful life prediction error of lithium ion power battery is ≤ 5.83% and the maximum error of remaining useful life prediction of lithium-ion power battery based on real vehicle data is 8.12%, which has achieved good prediction results and enriched the life prediction methods of lithium ion power battery.

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    Experimental Research on Influence of Pressure Fluctuation on Nozzle Flow and Near Field Spray Under Multiple Injections
    Yunpeng Wei,Liyun Fan,Hanwen Zhang,Bo Li,Yuanqi Gu,Xianyin Leng
    2023, 45 (5):  836-844.  doi: 10.19562/j.chinasae.qcgc.2023.05.013
    Abstract ( 52 )   HTML ( 4 )   PDF (5737KB) ( 133 )   Save

    To study the causal relationship between the multi-frequency pressure fluctuations and the characteristics of the internal flow of nozzle, as well as the influence mechanism on the near-field spray, the high-speed microscopic imaging technology is used to carry out visualization experimental study on the real-size tapered hole nozzles during the multiple injection process under different common rail pressures. At the same time, the high-pressure sensor is used to measure the pressure fluctuation data of the nozzle inlet. The research results show that the spray cone angle shows a boot-shaped trend in the main injection process, which consists of the development period, the transformation period, the stable period and the decay period. The overall trend is affected by the injection pressure, and there is a change of cavitation form in the process. In the process of small fuel injection such as pre-injection and post-injection, there are obvious inconsistencies caused by the fluctuation of the needle valve lift. The pressure drop at the nozzle is positively correlated with the level of cycle fuel injection quantity, and the cavitation characteristics affect the frequency characteristics and propagation speed of the pressure fluctuation. When the geometrically induced cavitation forms, the pressure fluctuates at a low frequency.Whenline cavitation forms, a high frequency pressure fluctuation trend occurs.

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    Vibration Characteristic Analysis of Drive Motor Considering Parameter Uncertainty
    Lü Hui,Shuai Jiang,Zhengjun Wei,Yisha Cao
    2023, 45 (5):  845-853.  doi: 10.19562/j.chinasae.qcgc.2023.05.014
    Abstract ( 136 )   HTML ( 6 )   PDF (1469KB) ( 186 )   Save

    To handle the complex situation of uncertain parameters of the drive motor of the electric vehicle, an analysis method for the vibration characteristics of the drive motor considering mixed parameter uncertainty is proposed. Firstly, the response models of the radial electromagnetic force, torque ripple and cogging torque of the drive motor are established based on the neural network surrogate model. Then, the uncertain parameters of drive motor are described by the mixed uncertainty model, where the uncertain parameters with sufficient information are described as random variables, while the uncertain parameters with limited information are described as interval variables. Next, the Taylor series expansion-central difference method( TSE-CDM) is derived to calculate the mixed uncertain responses of the vibration characteristics of drive motor through combining Taylor series expansion and central difference method.Finally, a Monte Carlo method is given as the reference method to verify the effectiveness of TSE-CDM. The numerical analysis results of a drive motor show that the vibration characteristics of the drive motor can be calculated efficiently and accurately based on the 2D finite element model and the neural network model; and the mixed uncertain responses of the vibration characteristics of the drive motor can be effectively solved by TSE-CDM.

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    Research on Accurate Modeling and Simulation Method of Dynamic Characteristics for Automotive Tire Blow-out Process
    Xuefeng Jia,Qizhang Feng,Xiandong Liu,Yingchun Shan
    2023, 45 (5):  854-864.  doi: 10.19562/j.chinasae.qcgc.2023.05.015
    Abstract ( 77 )   HTML ( 6 )   PDF (3694KB) ( 134 )   Save

    The tire blow-out is an extremely dangerous case for a running vehicle, but it is difficult to test and analyze the tire blow-out process accurately. Besides, the current simulation method of tire blow-out process is greatly simplified, making it difficult to describe the transient characteristics of tire blow-out process. To solve these problems, the simulation analysis method for automotive tire blow-out process is proposed in this paper, in which the internal and external air of the tire is simulated respectively, and the failure characteristics of various tire materials and the fluid-structure interaction between the air inside the tire and the tire-wheel assembly are considered. The validity of the simulation model and method is verified by comparing the simulation and theoretical calculation results. At the same time, by calculation the air leakage law inside the tire and the variation characteristics of the radial force on the tire from the road are obtained. The influence mechanism of velocity, pressure and crack size on the deflation time and tire mechanical properties is revealed. This paper focuses on the simulation method, which is of great significance for understanding the transient characteristics of burst tires and studying the dynamics control strategy of the vehicle after tire blow-out.

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    Lightweight Trailer Chassis Based on Roll Punching Integrated Longitudinal Beam
    Chunning Jin,Yan Gao,Shizhe Gao,Tianxia Zou,Yang Liu,Zhiheng Zhang
    2023, 45 (5):  865-872.  doi: 10.19562/j.chinasae.qcgc.2023.05.016
    Abstract ( 117 )   HTML ( 9 )   PDF (3387KB) ( 114 )   Save

    In this paper, roll stamping technology is introduced into the design and manufacture of trailer chassis. Through continuous molding of high strength materials, an integrated chassis rail is constructed, and the corresponding structural improvement is made for a typical trailer chassis. The stress conditions of the two chassis under full load bending and full load braking conditions are compared and analyzed. The results show that because the roller punching process can realize the processing of ultra-long parts with variable section and one punch, the material improvement, structural improvement and the reduction of the number of main components brought by this advantage make the processing of chassis rail significantly improved in terms of production efficiency and assembly efficiency while realizing the lightweight. In addition, the variable section longitudinal beam based on the high strength sheet greatly improves the designability of the structure, which in turn makes it possible to significantly improve the bearing performance. Compared with the base plate with a fixed load mass of 1.4 t, the optimized chassis can bear the load of 2.4 t, and the deformation of the two is similar.

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    Fatigue Study of Tractor Frame Based on Complex Boundary
    Zongyang Zhang,Shuangshuang Xie,Kai Wang,Yupeng Zhang,Tao Bing,Shitao Sun
    2023, 45 (5):  873-879.  doi: 10.19562/j.chinasae.qcgc.2023.05.017
    Abstract ( 79 )   HTML ( 4 )   PDF (3725KB) ( 137 )   Save

    In order to enhance the accuracy of frame fatigue life calculation and accurately predict the frame life in the design stage, it is necessary to consider the influence and coupling effect of the dynamic load on the fatigue of the frame at the outer connection point of the main structure. In this paper, a research method of frame fatigue based on complex boundary is proposed. The whole vehicle load spectrum is collected in the test field to obtain the whole cycle damage value. Based on the damage equivalent principle, the damage value of various surface road combinations is obtained, which is equivalent to the target value of the full cycle, with an accuracy of 99.5%. A finite element frame model with outer points of the main structure is constructed and the unit stress field of the complex boundary is output. The high-precision vehicle dynamics model with saddle and trailer system is established based on the test field load spectrum and the bench test data, to obtain the dynamic load of the outer connection point. The fatigue of the frame is calculated by the fatigue damage theory, with the fatigue analysis results verified by field tests. The results show that the frame model with the complex boundary has high simulation accuracy. Through local optimization and model reconstruction, the frame life can meet the requirements.

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    Study on Aerodynamic Noise Characteristics of SUV Hollow Roof Spoiler
    Ling Qin,Xiaojin Du,Jinyang Feng,Shunqiao Huang,Menghua Duan,Qingyang Wang
    2023, 45 (5):  880-887.  doi: 10.19562/j.chinasae.qcgc.2023.05.018
    Abstract ( 101 )   HTML ( 5 )   PDF (4216KB) ( 131 )   Save

    In the development process of an SUV model, in order to highlight the sense of sportive styling, a hollow roof spoiler is designed in the exterior styling. However, the application of the hollow roof spoiler results in a new aero-acoustics noise source, which seriously deteriorates the interior noise performance. Through the analysis of the wind tunnel test results and the numerical simulation, the mechanism of the noise caused by the hollow roof spoiler is identified in this paper. Firstly, the airflow accelerates in the hollow channel and directly hits the windshield, and secondly, the airflow is separated and coupled in the wake of the roof spoiler to form high turbulence intensity vortex radiation. Based on the noise generation principle, this paper proposes a corresponding optimization scheme: reducing the flux of the air flow passing through the channel; reducing the velocity of the air flow passing through the channel; changing the direction of the air flow passing through the channel. The corresponding optimization schemes are formed and verified by the wind tunnel test. The test results show that the optimization scheme has a significant effect on improving the articulation index in the vehicle and reducing the sound pressure level in the vehicle, with the sound pressure level reduced by 2 dBA at least, and the articulation index improved by 0.7%, 1.5%, 1.7% for each scheme. The research in this paper can provide an important basis for the hollow roof spoiler design and optimization.

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    Construction of An Assessment Model for the Pressure of Foam Materials of the Automobile Seat
    Bing Li,Wenbin Shangguan,Xusheng Huang,Fei Ge,Qiding Li,Xintao Zhu
    2023, 45 (5):  888-895.  doi: 10.19562/j.chinasae.qcgc.2023.05.019
    Abstract ( 88 )   HTML ( 11 )   PDF (6714KB) ( 99 )   Save

    The property of foam materials is one of the key factors affecting automobile seat comfort. In this paper, the tensile and compression testing machine is used to measure sitting pressure of the seat foam materials and three single factor experiments are designed, i.e. the sitting pressure vs. foam density, the sitting pressure vs. foam hardness and the sitting pressure vs. foam rebound rate to analyze the correlation and the signification between the sitting pressure and different physical parameters are. Based on the 40 sets of experimental data, the evaluation model of the sitting pressure for foam materials is obtained by applying the least square regression method in the multidisciplinary optimization software HyperStudy. With this model the sitting pressure can be calculated to assess the seat comfort in the product design stage.

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