Table of Content

25 September 2022, Volume 44 Issue 9 Previous Issue    Next Issue

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Key Technologies to Ensure the Safety of the Intended Functionality for Intelligent Vehicles Wenbo Shao,Jun Li,Yuxin Zhang,Hong Wang 2022, 44 (9):  1289-1304.  doi: 10.19562/j.chinasae.qcgc.2022.09.001 Abstract ( 758 )   HTML ( 76 )   PDF (3585KB) ( 9647 )   Save The limitations on performance， insufficient specifications or reasonably foreseeable misuse lead to the issues related to the safety of the intended functionality （SOTIF） emerging one after another， seriously hindering the rapid development of intelligent vehicles. This paper focuses on the key technologies to ensure the SOTIF， and systematically summarizes the related state of art of research from system development， functional improvement， and operation three phases. Finally， the research prospect is foreseen from the perspectives of basic theory， risk prevention and update mechanism. The review can provide an important reference for the research on the safety of the intended functionality for intelligent vehicles. Figures and Tables | References | Related Articles | Metrics

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The Design of the Safety of the Intended Functionality of the Control Strategies for Vehicle Automatic Emergency Braking System Shunchang Duan,Xianxu Bai,Qin Shi,Weihan Li,Guannan He 2022, 44 (9):  1305-1317.  doi: 10.19562/j.chinasae.qcgc.2022.09.002 Abstract ( 353 )   HTML ( 29 )   PDF (2063KB) ( 506 )   Save The safety risks the autonomous vehicles face not only come from the deficiencies of functional safety and information safety， but also stem from the insufficiencies of the safety of the intended functionality （SOTIF）. As an important part of autonomous driving system， the automatic emergency braking （AEB） system has SOTIF insufficiencies in control strategies. In this paper， the system theoretical process analysis method is adopted to analyze the safety of AEB system， find out the trigger events that may cause harm and put forward the corresponding safety objectives. Aiming at the safety objectives， a control strategy for AEB system based on detailed scenes are proposed. The control strategy proposed for AEB system is then verified in CarSim-MATLAB/Simulink environment. The results show that after functional corrections in both the event acceptance criterion and total risk acceptance criterion， the risk level of the system becomes much lower and the safety level of the system is apparently enhanced. Figures and Tables | References | Related Articles | Metrics

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Surrounding Multi-Target Trajectory Prediction Method Based on Monocular Visual Motion Estimation Zihao Wang,Yingfeng Cai,Hai Wang,Long Chen,Xiaoxia Xiong 2022, 44 (9):  1318-1326.  doi: 10.19562/j.chinasae.qcgc.2022.09.003 Abstract ( 255 )   HTML ( 13 )   PDF (2064KB) ( 233 )   Save Based on a low-cost monocular visual perception system， a multi-target trajectory prediction method considering the influence of vehicle motion is proposed in this paper. Firstly， the ego vehicle motion estimation model composed of the depth estimation network and the position and orientation estimation network is established to achieve effective calculation of ego vehicle visual odometer in image sequence. Then， a prediction model is built by using the historical position and orientation sequences of ego vehicle， and a normalization processing on the historical positions of surrounding targets is fulfilled under the current perspective of ego vehicle camera. Finally， the prediction network is constructed based on the historical trajectory information and regional image information to realize the effective prediction of surrounding multi-target trajectories around intelligent vehicles. The innovation points of this paper are combining visual SLAM method with trajectory predictive model and putting forward the new motion estimation model and ConvLSTM-based multi-target trajectory predictive network. The model proposed overcomes the adverse influence of existing research on the trajectory prediction accuracy of the surrounding target caused by ignoring the ego vehicle motion state， and achieves a better prediction results under the condition of using monocular vision perception only. The results of test on public data sets show that with a prediction time step of 1.5s， the model proposed has a MSEcenter of 321， i.e. a 52% lower than that of the existing baseline model， with an excellent performance also in the long-time-step trajectory prediction in the future. Figures and Tables | References | Related Articles | Metrics

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Cross-Domain Object Detection Algorithm Based on Multi-scale Mask Classification Domain Adaptive Network Jie Hu,Boyuan Xu,Zongquan Xiong,Minjie Chang,Di Guo,Lihao Xie 2022, 44 (9):  1327-1338.  doi: 10.19562/j.chinasae.qcgc.2022.09.004 Abstract ( 210 )   HTML ( 12 )   PDF (3315KB) ( 263 )   Save Aiming at the problems of multi-scale and domain negative transfer caused by the contradiction between domain discriminability and invariance in unsupervised domain adaptive object detection， a multi-scale mask classification domain adaptive network （MMCN）， that can alleviate the negative transfer of domain， is proposed in this paper. Firstly the adversarial training of image-level domain is performed on multiple intermediate layers on backbone network. Then a region proposal mask is added to the image-level feature map as a supplementary information to supplement instance features. Finally a sub-category instance-level domain classifier is put forward to enable the network to extract effective domain-invariant information as much as possible on the premise of ensuring domain discriminability. The results of verification on both Cityscapes and FoggyCityscapes datasets show that the mean average precision of domain classification with MMCN proposed is 13.2 percentage points higher than that with DA-FasterRCNN， significantly enhancing the domain adaptive capability of network. Figures and Tables | References | Related Articles | Metrics

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Determination Method of Forward Collision Warning Indicator and Threshold Based on Drivers’ Car-Following Characteristics Wenmin Long,Guangquan Lu,Xi Shi,Haitian Tan 2022, 44 (9):  1339-1349.  doi: 10.19562/j.chinasae.qcgc.2022.09.005 Abstract ( 174 )   HTML ( 10 )   PDF (3039KB) ( 311 )   Save In order to more reasonably select the forward collision warning indicator and set the personalized warning threshold for different drivers， a comprehensive evaluation method of forward collision warning indicator is proposed based on signal detection theory and rank sum ratio method， achieving the on-line identification and updating of driver’s response time based on vehicle following data. Natural driving experiments are carried out to collect driving behaviors data in urban traffic environment for verifying the effectiveness of on-line identification of driver’s response time. Furthermore， the personalized warning thresholds for different drivers are obtained through the statistical analysis and identification. The comprehensive comparison and analysis on the different warning indicator thresholds obtained show that among 6 forward collision warning indicators， safety margin is the best， risk perception factor the next， the rank sum ratio follows the order of reciprocal time to collision > time headway > warning coefficient， while the evaluation results of time margin fluctuate greatly. Figures and Tables | References | Related Articles | Metrics

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Discrete Platoon Control at an Unsignalized Intersection Based on Q-learning Model Lijun Qian,Chen Chen,Jian Chen,Xinyu Chen,Chi Xiong 2022, 44 (9):  1350-1358.  doi: 10.19562/j.chinasae.qcgc.2022.09.006 Abstract ( 145 )   HTML ( 13 )   PDF (3359KB) ( 172 )   Save In order to enhance the driving efficiency of connected and automated vehicles （CAVs） at traffic bottlenecks， a platoon cooperative control strategy at an unsignalized intersection is proposed. Firstly， a control framework for the allocation of the right of way for platoons is put forward based on the traffic flow model and occupied time of platoons at the intersection. Then， a Q-learning model is designed to conditionally select platoon sizes， with instantaneous efficiency and travel delays as compound indicators. Finally， an online trajectory planning simulation is carried out for the grouped vehicles based on vehicle following model. The results show that the Q-learning model can flexibly allocate the platooning commands according to different working conditions and ensure the overall safety of platoons during driving process. Compared with the nonplatoon scheme， the traffic capacity of the intersection is increased by around 36.1%. Figures and Tables | References | Related Articles | Metrics

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Modeling and Cooperative Control of Mixed Vehicle Platoon Under Multi-time Delay Manjiang Hu,Lingkun Bu,Hongmao Qin,Yan Zhou,Yougang Bian,Ning Sun,Xunjia Zheng 2022, 44 (9):  1359-1371.  doi: 10.19562/j.chinasae.qcgc.2022.09.007 Abstract ( 201 )   HTML ( 4 )   PDF (6233KB) ( 252 )   Save The modeling and cooperative control method of mixed vehicle platoon consisting of both human-driven vehicle （HDV） and connected and automated vehicle （CAV） under multi-delay condition is studies in this paper. Firstly， a generalized model for mixed vehicle platoon system is constructed to characterize the number and spatial distribution of CAVs， with the time delay of driver’s response introduced into the model. Then， with consideration of V2V communication time delay and sensor measurement time delay， a state feedback controller is designed， the characteristic equation of the closed-loop system is derived， and the sufficient conditions for the closed-loop stability of the system are determined according to the Routh Hurwitz criterion to guide the parameter design of the controller. Finally， numerical simulation is conducted to verify the effectiveness of the controller design， quantitatively exhibiting the role of CAV in attenuating traffic fluctuation， with the effects of various time delays on traffic flow fluctuation analyzed. Figures and Tables | References | Related Articles | Metrics

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Integrated Dynamic Control Strategy for Extreme Maneuvers of 4WIDEVs Cheng Lin,Sheng Liang,Xinle Gong,Xiao Yu,Bowen Wang 2022, 44 (9):  1372-1385.  doi: 10.19562/j.chinasae.qcgc.2022.09.008 Abstract ( 430 )   HTML ( 25 )   PDF (5184KB) ( 705 )   Save In order to improve the active safety of four-wheel independent drive electric vehicles under extreme conditions such as low adhesion road driving and high-speed steering， a predictive control-based dynamic integrated control method is proposed in this paper. Firstly， in order to balance the modeling accuracy of the prediction model and the computational burden of the controller， the nonlinear yaw dynamic model is simplified by a piecewise affine approximation， and then the prediction model of the hybrid system is established. Secondly， the instability mechanism of the multi-time-varying parameter system is analyzed. The maneuvers with bifurcation are defined as the extreme conditions， and the unified vehicle stability judgement method for different extreme conditions such as low adhesion and high speed is developed to determine the switching mechanism of the control mode. Then， the integrated dynamic control strategy based on the robust hybrid predictive control algorithm is proposed， which systematically considers the vehicle speed variation and tire nonlinear lateral deflection characteristics under the extreme conditions， and coordinately optimizes the anti-skid performance， yaw stability and other safety indexes. The processor-in-the-loop test shows that the proposed integrated dynamic control strategy can meet the control requirements of low adhesion road driving and high-speed steering conditions， and significantly improve the active safety of the vehicle under extreme conditions. Figures and Tables | References | Related Articles | Metrics

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Analysis of Key Influencing Factors on Rotor Critical Speed of Centrifugal Air Compressor for Fuel Cell Vehicles Zhiming Zhang,Jiaqi Pan,Tong Zhang 2022, 44 (9):  1386-1393.  doi: 10.19562/j.chinasae.qcgc.2022.09.009 Abstract ( 126 )   HTML ( 7 )   PDF (3417KB) ( 176 )   Save In view of demand of the high-pressure ratio and large flow air of centrifugal air compressor for domestic fuel cell vehicle， a rotor-bearing system model with compound cross-section is established to study the resonance instability problem of the rotor stability design for ultra-high-speed air compressor with rated speed of 100 000 r/min. The paper analyzes the critical speed increase by increasing the bearing stiffness and reducing the bearing span， and the decrease of critical speed by the rotor hollow structure and the temperature rise， and proposes different shock absorption measures for rigid and flexible rotors. In addition， the impeller with large moment of inertia significantly improving the high-order critical speed due to the influence of the rotary effect is discussed. The conclusions can provide theoretical guidance and design reference for the rotor and bearing design of ultra-high speed centrifugal air compressor of fuel cell vehicle. Figures and Tables | References | Related Articles | Metrics

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Experimental Study on the Effect of Fuel Injection Control Strategy Under Different Coolant Temperatures for a Hybrid Engine Bowen Yan,Tianyu Ma,Yunping Pu,Tiegang Hu,Wei Deng,Ping Jiang,Xianghong Nie 2022, 44 (9):  1394-1399.  doi: 10.19562/j.chinasae.qcgc.2022.09.010 Abstract ( 152 )   HTML ( 6 )   PDF (1380KB) ( 148 )   Save An experimental study is conducted on a Changan 1.5TGDI dedicated hybrid engine， mainly to investigate the effect of fuel injection strategy on the performance under different coolant temperatures.The results show that under 1 000 r/min working condition， multi-injections can achieve lower fuel consumption and PN emissions than single injection， at the low coolant temperature of 30 ℃， with the advantageous area extending below 0.5 MPa BMEP. As the water temperature increases to be above 50 ℃， its fuel consumption benefit can be seen mainly at medium to high load conditions， with BMEP above 0.7 MPa， while the soot emissions become worse gradually. At 2 000 and 3 000 r/min，multiple injection shows a lower fuel consumption only under medium to high load conditions， and this advantage will be further reduced as the temperature and speed increase， in addition， the soot emission of single injection is equivalent to or better than that of multi-injections under low to medium load， but shows a significant deterioration as speed and load increase. Therefore， at the low water temperature of 30 ℃ ， for 2 000 and 3 000 r/min， multi-injections can be used at the loads greater than 0.8 and 1.0 MPa BMEP respectively. As the temperature increases to be above 50 ℃， it can be used at the loads greater than 1.0 and 1.3 MPa BMEP. Figures and Tables | References | Related Articles | Metrics

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Energy Management Strategy Based on TD3-PER for Hybrid Electric Tracked Vehicle Bin Zhang,Yuan Zou,Xudong Zhang,Guodong Du,Wenjing Sun,Wei Sun 2022, 44 (9):  1400-1409.  doi: 10.19562/j.chinasae.qcgc.2022.09.011 Abstract ( 158 )   HTML ( 8 )   PDF (6901KB) ( 210 )   Save To optimize the fuel economy and traction battery performance of series hybrid electric tracked vehicle （SHETV）， an energy management strategy （EMS） based on twin delayed deep deterministic policy gradient with prioritized experience replay （TD3-PER） is proposed. The TD3 algorithm can achieve more precise continuous control and prevent training from falling into over-assessment. The PER algorithm can accelerate strategy training and obtain higher optimization performance. Based on the model of the SHETV including longitudinal and lateral dynamics， the framework construction and simulation verification of EMS based on TD3-PER is completed. The results show that compared with deep deterministic policy gradient algorithm， the strategy proposed reduces the fuel consumption of SHETV by 3.89%， making its fuel economy reaching 95.05% of DP algorithm as a benchmark， with a better battery SOC retention ability and working condition adaptability. Figures and Tables | References | Related Articles | Metrics

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Research on Wheel Biaxial Fatigue Accelerated Test Method Tie Wang,Cheng Tian,Xudong Li,Hongwei Zhao 2022, 44 (9):  1410-1415.  doi: 10.19562/j.chinasae.qcgc.2022.09.012 Abstract ( 215 )   HTML ( 6 )   PDF (4962KB) ( 200 )   Save In view of the long period and high cost of wheel biaxial fatigue test， a novel wheel biaxial fatigue accelerated test method is proposed. Based on the strain measurement results on the key positions of wheel rim under biaxial load condition， with considerations of the apparent rotation cycle characteristics of wheel rim stress， the linear relationship between the cyclic changing stress magnitude and external load intensity and the effects of biaxial load proportion on the direction of wheel rim principal stress， the biaxial loads with similar proportion are merged and reduced based on the principle of damage equivalence. The feasibility and rationality of the wheel biaxial fatigue accelerated test method proposed are verified by tests. The use of the method can greatly reduce the test period and cost. Figures and Tables | References | Related Articles | Metrics

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Study on the Design and Parameter Matching of Integrated Electro-Hydraulic Braking System Zhaoyong Liu,Yiming Long,Yihang Li,Xiaoqiang Tan,Guangqiang Wu 2022, 44 (9):  1416-1424.  doi: 10.19562/j.chinasae.qcgc.2022.09.013 Abstract ( 152 )   HTML ( 7 )   PDF (2397KB) ( 358 )   Save In this paper, an integrated electro-hydraulic braking system is designed through theoretical research and structural analysis, and the working characteristic and performance parameters of key components of the system are preliminarily determined by the analysis and calculation of the hydraulic system and its auxiliary mechanical system. A simulation model of the brake system is built by using AMESim software, and a simulation is conducted to verify the basic functions of the system. Furthermore, the influence of motor powers on the dynamic characteristics of the braking system is studied to obtain the best parameters of drive motor. Finally, a co-simulation on the overall performance of the braking system is carried out. The results show that the integrated electro-hydraulic braking system designed fully meets the braking requirements of intelligent driving vehicles, with all the indicators reaching and even exceeding the national standard. Figures and Tables | References | Related Articles | Metrics

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Estimation Method of Longitudinal Vehicle Speed Under Emergency Braking Condition Xiaohua Zeng,Qifeng Qian,Dafeng Song,Haoming Gao,Jiajun Wu 2022, 44 (9):  1425-1436.  doi: 10.19562/j.chinasae.qcgc.2022.09.014 Abstract ( 210 )   HTML ( 16 )   PDF (2722KB) ( 289 )   Save In view of that the rotational speed of wheel can no longer reflect the longitudinal speed of vehicle due to the large slip of all four wheels in the vehicle state of emergency braking， an estimation method of vehicle longitudinal speed combined with a slip controller is proposed. The method can directly influence the control logic of wheel slip to ensure there always exist one of the four wheels staying at the state of weak braking force control and maintain the stable change of speed， and hence enabling the accurate estimation of longitudinal vehicle speed in emergency braking conditions. The results of simulations under the both straight driving and curve turning conditions on both high and low adhesive roads verify the braking efficacy of slip controller and the robustness of estimation method of vehicle longitudinal speed. Figures and Tables | References | Related Articles | Metrics

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Research on Fracture Failure Simulation of Auto Headlights in a Vehicle-pedestrian Crash Hao Chang,Hao Zheng,Yongzhou Cai,Fen Luo,Li Sun,Zhourui Pan 2022, 44 (9):  1437-1446.  doi: 10.19562/j.chinasae.qcgc.2022.09.015 Abstract ( 168 )   HTML ( 12 )   PDF (5501KB) ( 224 )   Save Auto headlights may cause great damage to pedestrians’ legs in a vehicle-pedestrian crash. This paper aims to enhance the simulation accuracy of headlight fracture failure by studying the failure behavior of headlights in a vehicle-pedestrian crash condition， so as to accurately predict the pedestrian protection performance of vehicle in design stage. With the material of headlight housing PP-GF30 as the object， its elastic-plastic property and fracture failure behaviors are characterized based on static， dynamic and fracture failure material mechanical tests. The fracture failure model is verified through the simulation on PP-GF30 material fracture failure model established based on MAT_SAMP-1 constitutive， the headlight impact subsystem test and the vehicle-pedestrian leg impactor collision test，. The results show that the PP-GF30 fracture failure model built has a high simulation accuracy and can accurately predict the fracture failure behavior of auto headlights in vehicle-pedestrian collision. The research can also provide a reference for the establishment of failure simulation models of other related plastic materials. Figures and Tables | References | Related Articles | Metrics

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Study on Quantification of Driver’s Subjective Risk Perception in Curve Driving Condition Zibin Guo,Hui Chen,Taokai Xia,Wei Ran,Yosuke Nishimura,Jianzhen Wang 2022, 44 (9):  1447-1455.  doi: 10.19562/j.chinasae.qcgc.2022.09.016 Abstract ( 203 )   HTML ( 18 )   PDF (3606KB) ( 262 )   Save In order to in-depth understand driver’s behavior， a quantitative exploration on the subjective risk perception of driver in curve driving condition is conducted in this paper. Firstly， a method to quantify drivers’ subjective risk perception in curve driving is proposed based on 1/CTLC， 1/STLC， and 1/TAD indicators. Then， the subjective evaluation experiments are devised for latent and overt risk perception characteristics respectively， the driver’s risk estimate is obtained by using the magnitude estimation method， and the results are fitted according to Stevens’ power law to construct a driver’s subjective risk perception model in curve driving. Finally， the driver’s natural driving data are analyzed based on the model. The results show that the risk perception model constructed can reflect the risk perception characteristics of drivers in curve driving condition. Figures and Tables | References | Related Articles | Metrics

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Evaluation and Management Method of Vehicle Driving Safety on Cross-Sea Bridge Under Strong Wind Environment Zhiqun Yuan,Yufeng Liu,Li Lin 2022, 44 (9):  1456-1468.  doi: 10.19562/j.chinasae.qcgc.2022.09.017 Abstract ( 121 )   HTML ( 6 )   PDF (9456KB) ( 132 )   Save In view of that the traffic capacity of cross-sea bridge under strong wind environment is the key to ensuring the traffic safety and efficiency of bridges， and the existing bridge traffic management mode of adopting speed limit or traffic restriction can not meet the requirements of the development of intelligent transportation in the future， taking van trucks and cars as the research objects， an evaluation and management method of the vehicle driving safety on cross-sea bridge under strong wind environment is proposed in this paper. The interaction of aerodynamic relationship of "wind-vehicle-bridge" and its influence on vehicle crosswind stability are studied and the quantitative co-evaluation on the multi-factors of wind speed， vehicle speed and road surface etc. are conducted by using vehicle dynamic responses under the action of strong wind. Finally， some suggestions on the vehicle driving organization and driving speed control regulation related to driving safety on cross-sea bridge under different conditions are put forward. Figures and Tables | References | Related Articles | Metrics