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25 December 2022, Volume 44 Issue 12 Previous Issue    Next Issue

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Human-Like Behavior Decision-Making of Intelligent Vehicles Based on Driving Behavior Generation Mechanism Dongjian Song,Bing Zhu,Jian Zhao,Jiayi Han,Yanchen Liu 2022, 44 (12):  1797-1808.  doi: 10.19562/j.chinasae.qcgc.2022.12.001 Abstract ( 455 )   HTML ( 45 )   PDF (3666KB) ( 505 )   Save In this paper， a human-like behavior decision-making strategy （HBDS） is established by analyzing drivers’ driving behavior generation mechanism. HBDS has a framework that matches the driving behavior generation mechanism， obtains the human-like reward function through maximum entropy inverse reinforcement learning， and adopts the Boltzman noisily-rational model to build the mapping relationship between behavior probability and its cumulative reward. By discretizing the expected trajectory space， the curse of dimensionality in the integration of continuous high-dimensional space is avoided， and based on statistical law and safety constraint， the expected trajectory space is compressed and pruned， enhancing the sampling efficiency of HBDS. The strategy is trained and tested on NGSIM dataset， and the results show that HBDS can make behavior decisions that conform to the driver’s personalized cognitive and behavioral characteristics. Figures and Tables | References | Related Articles | Metrics

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Distributed Multi-vehicle Collaborative Visual SLAM System Chaoyang Jiang,Tianran Lan,Xiaoni Zheng,Jiulong Gao,Xuetong Ye 2022, 44 (12):  1809-1817.  doi: 10.19562/j.chinasae.qcgc.2022.12.002 Abstract ( 345 )   HTML ( 19 )   PDF (3230KB) ( 304 )   Save Reliable localization and navigation are prerequisites for autonomous driving. Single-vehicle visual simultaneous localization and mapping（SLAM） enables vehicle localization in GNSS denial environment. However， the cumulative error will gradually increase with the running time， which leads to a great challenge of continuous and accurate localization. Therefore， localization can be improved by multi-vehicle collaborative visual SLAM. In this paper， a robust and lightweight distributed multi-vehicle collaborative visual SLAM system is proposed. The system uses ORB-SLAM2 as visual odometry， and uses global image descriptors NetVLAD for multi-vehicle place recognition and data association. A method based on data similarity and structural consistency is proposed to solve multi-vehicle loop-closure outlier rejection. Moreover， a distributed pose graph optimization method is proposed， which can enhance the accuracy of multi-vehicle collaborative localization. The system has been tested on our datasets collected by autonomous platform and KITTI datasets. The experiment results show that the proposed system outperforms the existing visual SLAM and collaborative SLAM. Figures and Tables | References | Related Articles | Metrics

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Semantic Segmentation Method of Autonomous Driving Images Based on Atrous Spatial Pyramid Pooling Dafang Wang,Lei Liu,Jiang Cao,Gang Zhao,Wenshuo Zhao,Wei Tang 2022, 44 (12):  1818-1824.  doi: 10.19562/j.chinasae.qcgc.2022.12.003 Abstract ( 100 )   HTML ( 4 )   PDF (2439KB) ( 142 )   Save If a vehicle can accurately and quickly understand the semantics of people and vehicles on the road， it can guide the obstacle avoidance and path planning to a large extent. The existing semantic segmentation methods based on deep learning need a tradeoff between segmentation speed and segmentation accuracy. In this paper， based on the existing semantic segmentation network， the multi-scale semantic information of image can be obtained by adding an atrous spatial pyramid pooling structure after the reference network of feature extraction. Experimental results show that modules A_ASPP_1 and A_ASPP_2 proposed can effectively segment images of common people and various vehicles in automatic driving scenes. Compared with BiSeNet， two corresponding improved network structures have 2.1 and 1.2 percentage points higher mean intersection over union of training results respectively， though with a little lower segmentation speed. Figures and Tables | References | Related Articles | Metrics

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Modeling of Traffic Vehicle Interaction for Autonomous Vehicle Testing Yuande Jiang,Bing Zhu,Xiangmo Zhao,Jian Zhao,Bingbing Zheng 2022, 44 (12):  1825-1833.  doi: 10.19562/j.chinasae.qcgc.2022.12.004 Abstract ( 208 )   HTML ( 11 )   PDF (3598KB) ( 199 )   Save In order to meet the requirements of autonomous vehicle testing on the realness of the test scenes， a coupled feature modeling method is proposed， aiming at the interaction relationship between traffic vehicles. The dataset of traffic vehicle behaviors is established by combining the virtual data built based on mechanism model and the real scene data. Deep learning is adopted to set up the behavior decision model， following model and lane change model of traffic vehicles with local information response. The single model with relatively simple structure can enhance the expandability of scene simulation. In view of the high requirements of autonomous vehicle testing on model robustness， a framework of distributed execution and centralized adversarial training is constructed to conduct traffic vehicle model optimization for enhancing its robustness to input disturbance. The simulation environment for traffic vehicle interaction is created with a simulation on the model performed， and the effectiveness of the model is verified by comparing simulation data distribution with real data one and quantifying evaluation indicators. Figures and Tables | References | Related Articles | Metrics

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Interference Suppression Characteristics of Vehicle Platoon with Periodic Type Control Structure Xiujian Yang,Xinyu Yin,Jin Gao 2022, 44 (12):  1834-1843.  doi: 10.19562/j.chinasae.qcgc.2022.12.005 Abstract ( 99 )   HTML ( 3 )   PDF (5004KB) ( 98 )   Save Enlightened by that the vibration can be suppressed by periodic structure， a periodic type control structure for vehicle platoon is proposed in this paper， with its interference suppression characteristics emphatically studied. First of all， the vehicle platoon model with periodic type control structure is established， and the external interference is introduced into the acceleration control input to construct the spacing error equation matrix of the whole platoon. Then the transfer function equations from external interference and leading vehicle disturbance to spacing following error are derived. Finally， the interference suppression characteristics of the vehicle platoon with periodic type control structure are analyzed by the maximum singular value of the spacing error transfer function matrix. The results show that the rational design of periodic type control structure can effectively reduce the peak of the maximum singular value of the transfer function matrix from interference to spacing error， and enhance the interference suppression capability of vehicle platoon， even for a heterogeneous one. In addition， the vehicle platoon with periodic type control structure also exhibits a good scale expandability. Figures and Tables | References | Related Articles | Metrics

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Model Predictive Path Following Control of Intelligent Vehicles Considering System Complex Disturbances Longxin Guan,Zufei Gu,Chao Zhang,Aichun Wang,Chenruo Peng,Huihua Jiang,Xiaojian Wu 2022, 44 (12):  1844-1855.  doi: 10.19562/j.chinasae.qcgc.2022.12.006 Abstract ( 193 )   HTML ( 13 )   PDF (5056KB) ( 233 )   Save Intelligent vehicle path tracking control is faced with disturbances such as system model simplification， parameter uncertainty， the delay of actuator and sensor signals， and road curvature changes， which will generate system disturbance errors， resulting in reduced tracking accuracy. A model predictive control （MPC） method that considers the complex disturbance of the tracking system is proposed in this paper. Firstly， a model prediction tracking system is established based on the single-track vehicle dynamics model， and a dynamic adjustment method of the preview distance based on real-time path planning and speed information is designed to obtain the best preview point to improve the delay disturbance of the actuators and sensor signals of the intelligent vehicle chassis. Then， an extended state observer （ESO） is introduced to estimate the unknown disturbance to the system due to the simplified vehicle model in real time and use it for feed-forward compensation. At the same time， considering the steady-state disturbance error caused by the change of the road reference curvature to the system， a feed-forward control （FFC） method with curvature constraints is designed to eliminate this disturbance； and finally the steering angle control law of the superposition of the feedback input of the MPC controller， the ESO anti-interference compensation input and the FFC input is formed. Finally， real vehicle test and comparison analysis are carried out in a low-speed park scene with a certain brand of intelligent vehicle platform， which verifies the feasibility and superiority of the improved MPC method of integrating disturbance compensation. Figures and Tables | References | Related Articles | Metrics

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Backoff Mechanism and Verification of Adaptive Primary and Secondary Windows Based on IEEE 802.11p Xingkai Zhou,Zufang Dou,Xijuan Yang,Qiaoli Yang 2022, 44 (12):  1856-1865.  doi: 10.19562/j.chinasae.qcgc.2022.12.007 Abstract ( 113 )   HTML ( 5 )   PDF (4129KB) ( 139 )   Save In traffic intensive scenarios， the existing DSRC and C-V2X technologies can not ensure efficient data transmission. Firstly， this paper introduces the network architecture of the Internet of vehicles. Secondly， the design of an IEEE 802.11p mechanism based on adaptive primary and secondary window partition is proposed， in order to reduce the collision rate of vehicle nodes and then increase the data transmission rate. Then， by establishing a two-dimensional Markov model， analytical expressions of transmission delay and other performance indexes are obtained. Finally， the improved mechanism is numerically verified. The simulation results show that compared with the classical mechanism， the improved mechanism can obtain better network performance in both sparse and dense traffic scenes. At the same time， a multi-objective optimization model with minimum delay and highest reliability is established to optimize the proposed mechanism so as to obtain balanced system performance. Figures and Tables | References | Related Articles | Metrics

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Research on Energy Management of Hybrid Electric Vehicle Based on Time-Varying Chassis Configuration Junqiu Li,Jiwei Liu,Chaofeng Zhu 2022, 44 (12):  1866-1876.  doi: 10.19562/j.chinasae.qcgc.2022.12.008 Abstract ( 127 )   HTML ( 14 )   PDF (3891KB) ( 176 )   Save This paper aims to study the time-varying configuration energy management strategy for hybrid distributed drive heavy vehicles based on real vehicle test data. Firstly， based on the real vehicle test data and by using the dynamic programming algorithm， the chassis configuration with optimal energy consumption is found， and the long short-term memory （LSTM） neural network is trained to complete the configuration optimization in three typical scenes. Then， the RULE_LSTM algorithm is proposed based on rule judgment. Its matching accuracy is 11.76% higher than that using LSTM network configuration with optimal energy consumption， and its frequency of configuration switching is reduced by 33.3%. Next， based on traffic flow the prediction on long-scale operating condition information is completed and the optimal chassis configuration matching and reference SOC trajectory generation are fulfilled. Based on radial basis function neural network， a short-scale operating condition prediction sequence is generated as the input of the subsequent algorithm. Finally， time-varying configuration is adopted to optimize the control variables， meanwhile the strong speed change rate constraint and SOC reference trajectory guidance are also introduced to implement the guided multi-APU predictive energy management strategy. The results show that with above-mentioned measures taken， the fuel consumption is reduced by 10.60%， 3.95%， and 2.06% respectively. Figures and Tables | References | Related Articles | Metrics

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Research on the Optimal Dynamic Coordinated Control of Power Split Hybrid Electric Vehicles with Dual-Clutch Collaboration Dehua Shi,Xiangwei Rong,Shaohua Wang,Kaimei Zhang,Long Chen,Chun Li 2022, 44 (12):  1877-1888.  doi: 10.19562/j.chinasae.qcgc.2022.12.009 Abstract ( 170 )   HTML ( 6 )   PDF (1850KB) ( 186 )   Save For the power split hybrid electric vehicle integrated with multi-clutch， the transient mode switching behavior and optimal dynamic coordinated control strategy from pure electric mode to hybrid driving mode involving the state collaboration of two clutches are studied. Based on the lever analogy and the matrix method， the dynamic models of the system at different switching stages are established. The feasibility analysis of the dual-clutch working sequence is conducted according to the engine start-stop control and transient mode switching requirements， and the mode switching logic is further formulated. On this basis， for the mode switching quality degradation caused by the collaboration slipping of the two clutches， the weighted sum of the vehicle longitudinal jerk， clutch friction work and mode switching time is taken as the optimization objective， and the simulated annealing algorithm is applied to optimize the slipping behavior of different clutch engagement and disengagement processes. In order to address the problem that the fixed engine speed adjustment strategy is difficult to adapt to the requirements of different acceleration conditions， the adaptive engine speed adjustment strategy in hybrid driving mode is constructed to realize adaptive torque regulation of motor MG1 according to the driving torque requirements under different conditions. Simulation and hardware-in-the-loop （HIL） test results show that the proposed optimal dynamic coordinated control can not only reduce the mode switching jerk of the power split HEV effectively for the dual clutch collaboration process， but also enables good working condition adaptability， which can ensure good transient mode switching quality under different acceleration conditions. Figures and Tables | References | Related Articles | Metrics

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Research on the Influence of Key Structural Parameters of Ejectors for a 170 kW Fuel Cell System Zihui Pang,Jiquan Han,Ping Chen,Yunmei Liu,Jianmei Feng,Xueyuan Peng 2022, 44 (12):  1889-1895.  doi: 10.19562/j.chinasae.qcgc.2022.12.010 Abstract ( 138 )   HTML ( 5 )   PDF (2093KB) ( 140 )   Save Hydrogen re-circulation driven by ejectors in high-power fuel cell systems is promising in the future. However， the outstanding problem is that the performance of ejectors is significantly poor under low power conditions， which results in the inefficiency of the ejector working in the wide power range of fuel cell systems. In this paper， a three-dimensional numerical model is established for the ejector used in a 170 kW fuel cell system. The influence of two key geometric parameters including throat diameter of the primary nozzle （Dt） and mixing chamber diameter （Dm） is analyzed under a wide range of working conditions. Moreover， the optimal combination of geometric parameters applicable for a wide power range is discussed. The results show that a large pressure difference is generated in the ejector due to a small Dm， thereby preventing the backflow of the secondary flow. Hence the performance of the ejector can be improved under low power conditions. Furthermore， the best performance is obtained when Dm / Dt is 2.5~3.0， which leads to an increase in the power range from 70~170 kW to 40~70 kW （i.e. an increase of nearly 43%）. The research results provide an important reference for the design of ejectors used in fuel cell systems with power above 170 kW. Figures and Tables | References | Related Articles | Metrics

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Study on Coupling Dynamics of Electric Drive System of Pure Electric Vehicle Changzhao Liu,Tie Zhang,Jian Song,Xiansong Yin,Shuaishuai Ge 2022, 44 (12):  1896-1909.  doi: 10.19562/j.chinasae.qcgc.2022.12.011 Abstract ( 243 )   HTML ( 21 )   PDF (9572KB) ( 275 )   Save In order to study the dynamic characteristics of electric drive system of pure electric vehicle， considering spatio-temporal electromagnetic excitation and system structure flexibility， an electromechanical coupling dynamic model of integrated electric drive system suitable for variable speed conditions is proposed and verified by simulation. By means of dynamic analysis， the effect of motor torque fluctuation， gear error and housing flexibility on the dynamic characteristics of electric drive system is studied under steady-state and acceleration conditions. The study shows that the influence of motor torque fluctuation on the bearing force is not obvious under the steady-state condition， the gear error will significantly increase the amplitude of gear dynamic meshing torque and bearing reaction force， and the influence of housing flexibility on gear dynamic meshing torque is slight. Under the acceleration condition， the gear error is easy to stimulate the system high-frequency resonance， and the low-order resonance related to rotating frequency is also easy to be excited after coupling the housing. Figures and Tables | References | Related Articles | Metrics

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Fusion Estimation of Vehicle State Parameters Based on Dichotomy Yunfei Zha,Lü Xiaolong,Xinye Liu,Fangwu Ma 2022, 44 (12):  1910-1918.  doi: 10.19562/j.chinasae.qcgc.2022.12.012 Abstract ( 121 )   HTML ( 6 )   PDF (3422KB) ( 143 )   Save In order to enhance the accuracy and reliability of vehicle state parameters estimation， a vehicle state fusion estimation method based on dichotomy is proposed. Firstly， an extended Kalman filtering （EKF） algorithm based on the vehicle 3-DOF dynamic model and the data-driven radial basis function （RBF） neural network estimation algorithm are designed. Then for further raising the reliability of the estimation algorithm and reducing the estimation error of single algorithm， a fusion estimation method is proposed with model-driven estimation algorithm and data-driven estimation algorithm compensating each other. The weights of the estimation results of EKF and RBF neural network are assigned based on dichotomy and the fusion of algorithms enhances the estimation accuracy. Finally， the co-simulation of MATLAB/Simulink and CarSim， and the real vehicle in-the-loop experiment are performed to verify the effectiveness of the fusion method. The results show that the change trend of the estimation result is consistent with the real one， and the estimation accuracy of fusion algorithm proposed is significantly enhanced， compared to RBFNN and single EKF algorithms. Figures and Tables | References | Related Articles | Metrics

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Combustion Control Strategy of Active Jet Ignition of Natural Gas Engine Wei Wang,Ziqing Zhao,Kaiyuan Cai,Yi Liu,Shang Liu,Wei Liu,Zhi Wang 2022, 44 (12):  1919-1925.  doi: 10.19562/j.chinasae.qcgc.2022.12.013 Abstract ( 103 )   HTML ( 7 )   PDF (2837KB) ( 86 )   Save In this paper， the impact of injection pressure and injection duration on the combustion characteristics of a natural gas engine using active jet ignition mode is studied. The test conditions are selected under conditions where the intake air pressure is maintained at 0.08 MPa while the injection duration of natural gas at the inlet is kept at 18 ms. The active injection pressure of natural gas in the jet chamber is adjusted to increase from 0.5 MPa to 3.0 MPa with an increment interval of 0.5 MPa and the injection duration increases from 1 ms to 5 ms， with an increment interval of 1 ms. The engine speed is kept at 800 r/min and the spark timing is fixed at -24°CA ATDC for all the conditions. The experimental results show that the active jet ignition mode can increase the peak heat release rate and accelerate the combustion rate compared with the passive jet ignition mode. Large COV is observed with too low active injection pressure and too short injection duration while the COV decreases （COV<1.5%）with the increase of injection pressure or injection duration. The combustion stability is insignificantly impacted by the injection pressure or injection duration once the COV is below 1.5%. Besides that， the peak in-cylinder pressure and peak heat release rate increase as the injection pressure or injection duration increases. Under such conditions， the combustion rate in the initial stage is accelerated while the overall combustion duration becomes longer. Higher indicated thermal efficiency is realized under lower injection pressure and shorter injection duration at fixed ignition time. The highest indicated thermal efficiency is realized when the injection pressure is 0.5 MPa and the injection duration is 2~5 ms， with an increase of 2. 8% of the optimized indicated thermal efficiency. Figures and Tables | References | Related Articles | Metrics

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Experimental Study on Performance of China VI Diesel Engine at Different Altitudes Renxin Xiao,Daping Liang,Guisheng Chen,Shuang Liu 2022, 44 (12):  1926-1935.  doi: 10.19562/j.chinasae.qcgc.2022.12.014 Abstract ( 111 )   HTML ( 6 )   PDF (1469KB) ( 141 )   Save Based on the plateau environment simulation test bench， the power， economy and emission characteristics of the China VI diesel engine at different altitudes under full load and 40% load conditions are studied， and the possibility of the diesel particulate filter （DPF） blocking under 4 000 m altitude with the engine running continuously at low speed and high load conditions is also explored. The results show that the intake flow rate， air-fuel ratio， brake thermal efficiency， exhaust oxygen concentration and exhaust pressure of the engine decrease nonlinearly with the increase of altitude at full load and 40% load， while the brake specific fuel consumption rate， exhaust temperature and NO x emission increase by different degrees； the power and economy decrease significantly and the emission performance deteriorates. The full load operating condition is more sensitive to the change of altitude， especially the performance at low and high speed decreases more. When the China VI diesel engine operates continuously at 4 000 m altitude at low speed under high load conditions， a large amount of particles is deposited in the DPF but regeneration is difficult， and it is blocked within a short time. Figures and Tables | References | Related Articles | Metrics

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Vibration Comfort Evaluation of Vehicle Seat Based on Body Pressure Distribution Kaizhan Gao,Qiao Luo,Zhifei Zhang,Zhongming Xu 2022, 44 (12):  1936-1943.  doi: 10.19562/j.chinasae.qcgc.2022.12.015 Abstract ( 144 )   HTML ( 11 )   PDF (3769KB) ( 158 )   Save For using the body pressure distribution on the human-seat contact surface to characterize the vibration comfort of vehicle seat， the subjective and objective test of seat vibration comfort are conducted with 12 test participants under low-frequency vertical excitation with six different magnitudes to find the body pressure distribution indicator. The test results of vibration acceleration and body pressure distribution are analyzed to extract the objective evaluation indicators， including the root-mean-square （RMS） of weighted acceleration， the means of average pressure and maximum pressure， and the RMSs of average pressure changing rate and normal force changing rate. A correlation analysis is carried out on subjective and objective indicators by applying non-parametric statistics method. The results show that the means of average pressure and maximum pressure have rather weak correlation with subjective discomfort score （β=0.26， 0.10 respectively）， while the RMSs of average pressure changing rate and normal force changing rate have strong correlation with subjective discomfort score （β=0.83， 0.85 respectively）. Finally， the relationship between the objective parameters and subjective discomfort rating is analyzed by using Stevens’ power law. The results indicate that compare with the RMS indicator of weighted acceleration， the RMSs of both average pressure changing rate and normal force changing rate are highly correlated （R2 >99.0%） with subjective discomfort score， hence can be taken as body pressure distribution indicators to characterize vibration comfort. Figures and Tables | References | Related Articles | Metrics

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The Application of the Injury Bionic Model of Chinese Three-year-old Child Occupant to the Simulation of C-NCAP Frontal Crash Tests Haiyan Li,Hangjie Su,He Zhu,Chong Liu,Yanxin Wang,Shihai Cui,Lijuan He,Yida Wang,Lü Wenle 2022, 44 (12):  1944-1953.  doi: 10.19562/j.chinasae.qcgc.2022.12.016 Abstract ( 91 )   HTML ( 5 )   PDF (5652KB) ( 126 )   Save In this paper， the validated TUST injury bionic model of Chinese three-year-old child occupant （TUST IBMs 3YO-O） with detailed anatomical structure features is used to build a simulation model， according to two dynamic frontal crash test specifications specified in C-NCAP （2001 version）. A simulation is conducted to analyze the kinematic and biomechanical responses of the head， neck and chest and study the injury mechanism and the injury discrepancy of three-year-old child occupant in different conditions during frontal crash evaluation test. The results show that in the aspect of kinematic response， the injury risk of three-year-old child occupant in the frontal 50% overlap mobile progressive deformable barrier （MPDB） crash test is higher than that in the frontal 100% overlap rigid barrier （FRB） crash test， and the child farther away from the impact point has more serious injuries. In the aspect of biomechanical response， the three-year-old child occupant may suffer a mild concussion due to the lower jaw contacting the chest in the FRB crash test， while in the MPDB crash test， the child moves transversely toward left with the lower jaw contacting the right side of chest， leading to a larger peak biomechanical response， and may inducing minor concussion， rib fracture， lung contusion and other injuries. Figures and Tables | References | Related Articles | Metrics

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Research on Noise Source Locating for Car Door Rattle Based on Time Reversal Method Weidong Zhao,Xinwei Xu,Rui Song,Mingliang Yang,Chao Qi 2022, 44 (12):  1954-1970.  doi: 10.19562/j.chinasae.qcgc.2022.12.017 Abstract ( 107 )   HTML ( 8 )   PDF (3544KB) ( 92 )   Save For locating the noise sources of common car door rattle， a mathematical model is established first based on the Lamb wave propagation theory， Morlet wavelet transform and time reversal focusing positioning principle， and a method for locating the noise source of car door rattle is proposed. Then through thin plate impact simulation， the cause of the aliasing of the vibration signal wave packet is explored， and the principle of narrowband signal extraction is determined. Finally a noise source locating test for car door rattle is conducted， and the influencing rule of the issuing moment of abnormal noise signal on the positioning imaging is revealed， with a signal image judgment method for the moment put forward. The test results show that the maximum and average locating error of noise source of car door rattle is 3.16 cm and 2.01 cm respectively， verifying the feasibility and engineering application value of the rattle source locating method based on time reversal technique proposed. Figures and Tables | References | Related Articles | Metrics