Table of Content

25 March 2022, Volume 44 Issue 3 Previous Issue    Next Issue

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Control Strategies Design of Intelligent and Connected Vehicle Platoon Under Emergency Conditions Pengfei Li,Yugong Luo,Chang Liu,Weiwei Kong 2022, 44 (3):  299-307.  doi: 10.19562/j.chinasae.qcgc.2022.03.001 Abstract ( 360 )   HTML ( 32 )   PDF (3918KB) ( 372 )   Save At present， few researches focus on control strategies of intelligent and connected vehicle platoon under emergency conditions. In order to tackle with the safety and stability control problems of vehicle platoon on the highway under emergency conditions， this article studies the control strategy under the two conditions of platoon emergency braking and merging of other vehicles. Firstly， a hierarchical structure of the control system is established， consisting of a strategy layer and a control layer. The control layer activates the vehicle’s longitudinal and lateral controllers according to the output of the strategy layer； the strategy layer is designed with control strategies for the two kinds of emergency conditions and mode-switch strategies between different conditions. Then， a joint simulation platform for highway platoon control is built with PreScan and Simulink. A complex verification scenario including multiple emergency conditions is designed and a five-vehicle platoon simulation test is carried out. Furthermore， the effect of communication delay on control performance is discussed. The simulation results show that the proposed control system can ensure safety and stability of platoon under these two emergency conditions， and can realize the switching control of different operating conditions. Figures and Tables | References | Related Articles | Metrics

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Research on Brake-by-Wire System and Pressure Control Algorithm for Advanced Automatic Driving Liang Chu,Cheng Chang,Xu Wang,Di Zhao,Yanwu Xu 2022, 44 (3):  308-318.  doi: 10.19562/j.chinasae.qcgc.2022.03.002 Abstract ( 331 )   HTML ( 26 )   PDF (3602KB) ( 349 )   Save For the functional requirements of advanced automatic driving， this paper proposes a brake-by-wire system， including two operating modes： conventional braking and redundant braking. The system decouples the brake pedal and brake pressure and realizes active braking by wire in both modes. And for the conventional braking that accounts for most of the working intervals， a variable equivalent piston cross-sectional area control method is used to ensure pressure control accuracy while reducing the performance requirements of hydraulic cylinder motor and extending its service life. Meanwhile， to achieve accurate pressure control， pressure control algorithms based on p-V characteristics of wheel cylinders and solenoid valve overflow characteristics are proposed respectively according to the different hardware structure characteristics of the two working modes. Finally， the simulation analysis and hardware-in-the-loop test are carried out. The results show the feasibility and effectiveness of the proposed brake by wire system and pressure control algorithms. Figures and Tables | References | Related Articles | Metrics

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Model-free Adaptive Sliding Mode Predictive Control Algorithm for Vehicle Longitudinal Control Haobin Jiang,Zhangqi Feng,Yangke Hong,Qizhi Wei,Jian Pi 2022, 44 (3):  319-329.  doi: 10.19562/j.chinasae.qcgc.2022.03.003 Abstract ( 390 )   HTML ( 31 )   PDF (4048KB) ( 361 )   Save In view of that the vehicle longitudinal dynamics system is a typical nonlinear discrete system with time-varying parameters and multiple disturbances， so the control algorithm based on accurate mathematical model is hard to achieve ideal results， an algorithm merely based on input/output data without model is adopted in this paper. Firstly， based on the compact-format dynamic linearization model， the model-free adaptive controller （MFAC） algorithm is combined with sliding-mode control （SMC） algorithm and model predictive control （MPC） algorithm to design a model-free adaptive controller. Then its stability is proved by theoretical analysis. Finally， a comparative simulation is conducted to compare the control algorithm proposed with the feedforward + feedback algorithm commonly used in longitudinal control and MFASMC （MFAC+SMC） algorithm， with a hardware-in-the-loop test carried out to verify the effectiveness of the algorithm proposed. The results show that the control algorithm proposed has fast response， strong robustness and smoother output， and can be better applied to the longitudinal dynamics control of intelligent vehicles. Figures and Tables | References | Related Articles | Metrics

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Parallel Parking Trajectory Planning for Autonomous Vehicles Jie Hu,Minchao Zhang,Wencai Xu,Ruinan Chen,Xinkai Zhong,Linglei Zhu 2022, 44 (3):  330-339.  doi: 10.19562/j.chinasae.qcgc.2022.03.004 Abstract ( 295 )   HTML ( 27 )   PDF (3028KB) ( 377 )   Save Based the analysis on the parallel parking scenes of autonomous vehicles， a parallel parking trajectory planning method based on sampling is proposed， which decouples the parallel parking trajectory planning of autonomous vehicles into path planning and speed planning. By sampling the parking starting point region， a series of parking path curves with continuous curvature and meeting the path constraint are generated， and the optimal parking path is selected by using multi-objective evaluation function. Then on the basis of the optimal parking path， the S-t curve with the shortest selecting time and meeting the constraint is selected by time sampling to generate the trajectory. Finally， simulation and real vehicle test verify the feasibility and effectiveness of the method proposed and the parallel parking of autonomous vehicles is successfully realized. Figures and Tables | References | Related Articles | Metrics

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Real-time Detection of 3D Objects Based on Multi-Sensor Information Fusion Desheng Xie,Youchun Xu,Feng Lu,Shiju Pan 2022, 44 (3):  340-349.  doi: 10.19562/j.chinasae.qcgc.2022.03.005 Abstract ( 275 )   HTML ( 15 )   PDF (4776KB) ( 356 )   Save Aiming at the 3D objects detection based on multi-sensor information fusion， a high-accuracy real-time two-stage deep neural network PointRGBNet is proposed. In the first stage with regional proposal network， 3D point clouds are firstly projected onto 2D image to generate 6D RGB point clouds， then feature extraction is performed on the 6D RGB point clouds input to obtain low-dimensional feature map and high-dimensional feature map which are then fused for generating a large number of proposals with high confidence. In the second stage with object detection network， the proposals generated in the first stage are used for RoI pooling to obtain the feature collection corresponding to each proposal from feature map， and more accurate 3D object detection is achieved by targetedly learning the feature collection of proposals. The results of open test on KITTI dataset show that PointRGBNet is not only better than the object detection networks using only 2D images or 3D point clouds in detection accuracy， even better than some advanced multi-sensor information fusion networks， but also has a high object detection speed of the entire network up to 12 frame/s， meeting the real-time requirements. Figures and Tables | References | Related Articles | Metrics

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Tightly Coupled SLAM System Based on Multi-Sensor Fusion Yingfeng Cai,Ziheng Lu,Yicheng Li,Long Chen,Hai Wang 2022, 44 (3):  350-361.  doi: 10.19562/j.chinasae.qcgc.2022.03.006 Abstract ( 285 )   HTML ( 28 )   PDF (4931KB) ( 311 )   Save Simultaneous localization and mapping （SLAM） is an essential part of autonomous vehicles. Its existing algorithms are mainly based on lidar or visual-inertial odometer， which do not make full use of the respective advantages of multi-mode sensors， leading to insufficient robustness to featureless scenes. In view of these， a multi-sensor tightly coupled SLAM system using lidar， camera and inertial measurement unit is proposed in this paper. Firstly， the system improves the schemes of the feature extraction of lidar point cloud and plane fitting and enhances the efficiency and accuracy of the depth information optimization of visual feature points by using lidar point cloud. Secondly， the tightly coupled state estimation framework proposed directly adds lidar odometer constraints onto visual inertial system， so enhancing the system stability and accuracy without increasing the complexity of algorithm. Finally， the coarse-to-fine visual-lidar coupled loop framework further reduces the long-term cumulative drift of the system. The results of massive tests for validation on the open-source dataset KITTI show that compared with other commonly used algorithms， the proposed algorithm achieves higher accuracy and environmental adaptability. In addition， the real vehicle test on the self-built autonomous vehicle test platform also demonstrates its adaptability to the long-time and large scene environment. Figures and Tables | References | Related Articles | Metrics

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A Multi-time Scale Joint State Estimation Method for Lithium-ion Batteries Based on Data-driven Model Fusion Ping Wang,Xiangyuan Peng,Ze Cheng,Ji’ang Zhang 2022, 44 (3):  362-371.  doi: 10.19562/j.chinasae.qcgc.2022.03.007 Abstract ( 218 )   HTML ( 11 )   PDF (4271KB) ( 241 )   Save This paper proposes a multi-time scale joint state estimation method for lithium-ion batteries based on the fusion of data driven method （DDM） and equivalent circuit model （ECM）. Firstly， the internal resistance is extracted as the health factor （HF）， and the least squares support vector machine （LSSVM） is used to establish the battery aging model to estimate state of health （SOH）. Subsequently， the battery state space equation is established according to the RC parameter identification values and the capacity estimation values， and then the Unscented Kalman Filter （UKF） algorithm is used to estimate state of charge （SOC）. Then， Gaussian process regression （GPR） is used to map the change of HF with the number of cycles to predict the trend of HF change， and long-term remaining useful life （RUL） prediction is realized combined with the LSSVM model. The experimental results show that the proposed method has high accuracy and robustness. Figures and Tables | References | Related Articles | Metrics

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A P-C-C-P Equalizer and Its Control Methods for Lithium-ion Batteries in Series Hongrui Liu,Donghua Gu,Hairui Li,Bin Zhang,Jing Qian 2022, 44 (3):  372-378.  doi: 10.19562/j.chinasae.qcgc.2022.03.008 Abstract ( 147 )   HTML ( 8 )   PDF (3079KB) ( 92 )   Save In view of the problem that there is often an inconsistency in capacity between single cells in a lithium-ion battery pack of electric vehicles， leading to the reduction of the available capacity of battery pack and even greatly shorten its service life， a P-C-C-P equalizer based on flyback transformer is proposed. The equalizer is simple in structure and easy to control. Flyback transformer transmits energy within battery pack， enhancing equalization efficiency. In the process of charging， discharging and stewing of battery pack， three equalization strategies， i.e. pack to cell （P-C）， cell to cell （C-C） and cell to pack （C-P） can be freely selected according to the situations. Each equalization strategy only needs to carry out PWM control on one MOSFET， so the energy loss is small. In this paper， the basic principle and control method of equalizer are presented in detail， and an experimental platform is built to carry out equalization experiments. The results show that the equalizer proposed is feasible. Figures and Tables | References | Related Articles | Metrics

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An Analysis on the Effects of Operating Conditions on the Performance and Water Content of PEMFC Xin Zhao,Guang Chen,Yanyi Zhang 2022, 44 (3):  379-384.  doi: 10.19562/j.chinasae.qcgc.2022.03.009 Abstract ( 135 )   HTML ( 13 )   PDF (2151KB) ( 135 )   Save In this paper， the visualized test platform of single fuel cell and the water balance model are used to investigate the relationship between the performance and the water content of proton exchange membrane fuel cell and their influencing factors. Firstly， the water balance model of fuel cell is given. Then， the visualized test platform for single fuel cell is constructed. Finally， the effects of the temperature and humidity of inlet air and the stoichiometric ratio of hydrogen and air on the electrochemical impedance spectroscopy， voltage and water content of fuel cell are tested with their influencing factors analyzed. Figures and Tables | References | Related Articles | Metrics

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Effects of Neck Muscle’s Active Force on Head Injury in Pedestrian Collision Accidents Fan Li,Mingjie Ye,Wei Huang,Jin Nie,Minggang Tan 2022, 44 (3):  385-391.  doi: 10.19562/j.chinasae.qcgc.2022.03.010 Abstract ( 299 )   HTML ( 8 )   PDF (3923KB) ( 142 )   Save This paper aims to investigate the effects of active force of neck muscle on pedestrian head injury under different impact speeds and pedestrian gaits. Firstly， the head-neck part of LSTC pedestrian model is replaced by HHNM III head-neck model developed by Hunan University to form a hybrid pedestrian dummy model， whose effectiveness is then verified by cadaver test data. Then a simulation is conducted to analyze the effects of pedestrian gaits， i.e. struck leg backward （SLB） and struck leg forward （SLF） on pedestrian head injury under different impact speeds. The results show that in low-speed collisions， the neck muscles will reduce the amplitude of head movement， but increase the risk of head injury， the pedestrian head injury with a gait of SLB is severer than that with SLF， and the neck muscles have smaller effects on head injury in high-speed collisions. Figures and Tables | References | Related Articles | Metrics

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A Method for Predicting Frontal Crash Grade Hongbin Tang,Junyuan Zhang,Guojun Liu 2022, 44 (3):  392-398.  doi: 10.19562/j.chinasae.qcgc.2022.03.011 Abstract ( 1075 )   HTML ( 41 )   PDF (2820KB) ( 33117 )   Save Through the statistics and summing-up of real frontal crash test data in NHTA and IIHS and analytical solving， an evaluation method for the impact waveform and intrusion in 100% overlap frontal rigid barrier （FRB） crash and 50% overlap moveable progressive deformable barrier （MPDB） offset crash evaluated by C-NCAP， and frontal small overlap barrier （SOB） offset crash evaluated by C-IASI （China insurance automobile safety index） is established， which can lay down a good foundation for the matching of occupant restraint system and provide assurance for vehicles to obtain excellent star grade. Figures and Tables | References | Related Articles | Metrics

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Study on Dynamic Test Method of Rear Impact of School Bus Seat Lei Lou,Hongbin Liu,Qingxiang Guo 2022, 44 (3):  399-402.  doi: 10.19562/j.chinasae.qcgc.2022.03.012 Abstract ( 111 )   HTML ( 3 )   PDF (959KB) ( 80 )   Save By means of literature research and simulation analysis， the condition input of seat rear impact dynamic test is determined， and the corresponding requirements of seat strength and dummy injury are proposed in this paper. The test methods and requirements proposed can be applied to the revision of the national standard for school bus seats and the static anti-backward-pitching test is upgraded to a dynamic one， so solving the problem that the static test cannot reflect the seat performance in actual traffic accidents and meeting the requirements of technological development. Figures and Tables | References | Related Articles | Metrics

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Injury Assessment of Three-Year-Old Child Occupant in Frontal 100% Overlap Rigid Barrier Crash Test Simulation Shijie Ruan,Hangjie Su,Haiyan Li,Shihai Cui,Lijuan He,Lü Wenle 2022, 44 (3):  403-411.  doi: 10.19562/j.chinasae.qcgc.2022.03.013 Abstract ( 130 )   HTML ( 5 )   PDF (4998KB) ( 143 )   Save According to the requirements of C-NCAP （2021 version）， the validated biomechanical model of Chinese three-year-old child occupant with detailed anatomical structure is used to establish a model for frontal 100% overlap rigid barrier crash test with a simulation conducted so as to compare the kinematic and biomechanical responses of three-year-old child occupant’s head and chest in different restraint systems in this paper. The results show that the use of safety seat belts can reduce the injury risks of child occupants in vehicle crash with high probability， the five-point seat belt has better child protection performance than three-point seat belt， and the application of biomechanical model for three-year-old child occupant with good bio-fidelity can use biomechanical evaluation parameters to analyze in-depth the injury mechanism of child occupant and hence to conduct all-around and multi-layer assessment on child protection devices and tested vehicle model. Figures and Tables | References | Related Articles | Metrics

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Detection of Driver’s Abnormal Behavior Under Emergent Collision Avoidance Conditions Zhiguo Zhao,Yuan Li,Haorui Hu,Peng Wang,Xiaorong Chen 2022, 44 (3):  412-425.  doi: 10.19562/j.chinasae.qcgc.2022.03.014 Abstract ( 138 )   HTML ( 12 )   PDF (7617KB) ( 94 )   Save In the scene of emergent collision avoidance， driver is prone to abnormal driving behavior due to panic and misjudgment. Therefore， detecting the abnormal behavior of driver in advance is of great significance to ensure the safety of the driver himself and the surrounding traffic. In view of this， a detection method of abnormal driving behavior that integrates the steering wheel angle residual sequence and the phase plane diagram judgment is proposed in this paper. Firstly， vehicle stability boundary is determined by using phase plane method. Then， the driver model is established based on model predictive control and the steering wheel angle residual sequence between the actual driving operation and the driver model reference input is constructed. Finally， the abnormal behavior factor and evaluation function of the driver are calculated to detect the abnormal behavior of the vehicle deviating from the expected driving trajectory. The results of simulation and hardware-in-the-loop test show that the abnormal driving behavior detection method proposed can detect the abnormal behavior of driver at least 0.5 s before the vehicle deviates from the desired trajectory. Figures and Tables | References | Related Articles | Metrics

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Research on Compensation Algorithm for Load Simulation Accuracy of Electric Drive System Test Bench Guanfeng Wang,Qiang Song,Lukai Zhao 2022, 44 (3):  426-433.  doi: 10.19562/j.chinasae.qcgc.2022.03.015 Abstract ( 144 )   HTML ( 9 )   PDF (3370KB) ( 121 )   Save In order to ensure the accuracy of road load simulation and realize the hardware-in-the-loop test of electric drive system， a dynamic compensation algorithm of bench test is proposed in this paper. Firstly， based on the analysis on load simulation problem， the test bench inverse model algorithm is adopted. Then， for improving torque dynamic response， Kalman filter is adopted to achieve accurate compensation of model errors. Finally， on the basis of the analysis on bench accuracy， accuracy coupling compensation algorithm is put forward and verified by bench test. The results show that compensation algorithm can well achieve speed following in cycle conditions and enhance the accuracy of bench test in starting condition. Figures and Tables | References | Related Articles | Metrics

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Chinese Traffic Sign Recognition Based on Two-stage Classification Algorithm Runze Feng,Kun Jiang,Weiguang Yu,Diange Yang 2022, 44 (3):  434-441.  doi: 10.19562/j.chinasae.qcgc.2022.03.016 Abstract ( 159 )   HTML ( 11 )   PDF (2311KB) ( 205 )   Save Autonomous driving technology plays an important role in alleviating traffic congestion and reducing transportation cost. Advanced driver assistance systems （ADAS） can effectively increase the comfort and safety of car driving. Traffic signs contain rich semantic information， which provides important constraints for decision-making of autonomous vehicles and ADAS. Therefore， development of traffic sign recognition algorithms is very important. Based on the characteristics of traffic scenes in China and the high accuracy requirements of automatic driving and ADAS on traffic sign detection， this paper proposes a traffic sign recognition algorithm framework based on two-stage classification. The algorithm consists of two stages of recognition and classification. In the recognition stage， traffic signs in the image are detected. And in the classification stage， traffic signs are divided into categories and subcategories. By refining the task， the algorithm improves the performance of each algorithm module independently， thus improving the recognition accuracy of the whole algorithm. In this paper， the single-stage recognition algorithm is improved to be used as the recognition module of the algorithm. The experimental results show that the proposed algorithm is better than the benchmark single-stage recognition algorithm in accuracy， with an average increase of 8.52% in mAP. In addition， with the detection speed better than the traditional two-stage recognition algorithm Faster-RCNN， the mAP is improved by 40%. Figures and Tables | References | Related Articles | Metrics

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An Experimental Study on Active Noise Control System of Automotive Engine Ningning Liu,Yuedong Sun,Yansong Wang,Pei Sun,Hui Guo 2022, 44 (3):  442-448.  doi: 10.19562/j.chinasae.qcgc.2022.03.017 Abstract ( 167 )   HTML ( 8 )   PDF (2818KB) ( 214 )   Save Different from the idea of the majority of existing variable step-size active noise control algorithms， i.e. establishing the nonlinear function between step-size parameters and errors， a novel iterative variable step-size FxLMS （IVS-FXLMS） algorithm is proposed based on the arc-tangent function in this paper. Then， reference signals are constructed according to engine speed signal， and by using the IVS-FxLMS algorithm a simulation on the effects of active control of the second， fourth and sixth order engine noises at driver’s ear is conducted. Finally， the hardware and software of the active noise control system are designed and constructed for a domestically produced vehicle to carry out real vehicle experiment for verifying the simulation results. Experimental results show that the in-vehicle engine order noise is effectively suppressed， reducing engine booming noise. Figures and Tables | References | Related Articles | Metrics