Table of Content

25 August 2019, Volume 41 Issue 8 Previous Issue    Next Issue

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Subjective and Objective Driveability Evaluation ofTCU Shift Strategy Driven by Driving Simulator Zhan Jun, Liu Rong, Chen Haodong, Guan Xin, Wang Zhangu 2019, 41 (8):  859-864.  doi: 10.19562/j.chinasae.qcgc.2019.08.001 Abstract ( 587 )   PDF (1352KB) ( 686 )   Save The influence of TCU shift strategy on vehicle driveability is mostly tested and validated by subjective evaluation. For the problem that the subjective evaluation of TCU shift strategy cannot be realized by software-in-the-loop and hardware-in-the-loop simulation methods, a subjective driveability evaluation method of TCU shift strategy by driving simulator is proposed. Firstly, in this paper, the evaluation platform of human-vehicle-environment closed loop TCU shift strategy with embedded driving simulator AutoBox is built, the TCU shift strategy model which can identify driving intention and road environment is established. and the subjective and objective evaluation forms of driveability related to TCU shift strategy are proposed. Then, the subjective and objective evaluation of the established TCU shift strategy is carried out by using the built platform, and the subjective score results and objective evaluation index are obtained. Through analysis and evaluation, the feasibility of drivability evaluation platform on TCU shift strategy with the driving simulator and the research method are verified. The platform and method can be used for the rapid subjective and objective evaluation of driveability of the TCU shift strategy, which effectively reduces the the workload of real vehicle test and evaluation, cuts development costs, and shorten the development cycle References | Related Articles | Metrics

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ACC Method Considering Driving State of Front and Rear Vehicles Li Yayong, Cai Yingfeng, Chen Long, Sun Xiaoqiang, He Youguo, Zhang Yunshun 2019, 41 (8):  865-871.  doi: 10.19562/j.chinasae.qcgc.2019.08.002 Abstract ( 533 )   PDF (2294KB) ( 641 )   Save In order to enhance traffic efficiency and road utilization ratio, a new artificial potential field is applied to the intelligent control of vehicles under congestion conditions. The both front and rear vehicles are regarded as the centers of two potential fields and a vehicle control system is designed to enable the vehicle to automatically find the best following distance according to the positions and speeds of front and rear vehicles. Based on the research of artificial potential field and vehicle control, a new artificial potential field function and a 3 DOF vehicle dynamics model are used to construct an error preview-based mathematical model for vehicle control, which is then applied to the control of single or multiple vehicles, to achieve automatical adjustment of the distance between vehicles according to the positions and speeds of front and rear vehicles. The time histories of the operation parameters and the resulting force in artificial potential field of vehicle are obtained by simulation, verifying the effectiveness of adaptive cruise control scheme proposed References | Related Articles | Metrics

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A Study on Higher-order Fractional Derivative Dynamic Model of Rubber Bushing Gao Qi, Feng Jinzhi, Zheng Songlin, Lin Yang 2019, 41 (8):  872-879.  doi: 10.19562/j.chinasae.qcgc.2019.08.003 Abstract ( 260 )   PDF (2750KB) ( 565 )   Save Taking a vehicle swing arm rubber bushing as the research carrier, the axial frequency correlation and amplitude correlation of the bushing are studied through the dynamic loading test. A rubber bushing model based on parallel connection of an elastic unit, a friction unit and a higher-order fractional derivative viscoelastic unit is established. Based on the dynamic neighbor and generalized learning particle swarm optimization algorithm, a higher-order fractional derivative viscoelastic unit parameter identification method is proposed. Then the model parameters are identified combined with the test results. Furthermore, the fractional derivative coefficients are fitted to the functions of the loading amplitudes, which improves the overall prediction accuracy and applicability of the model. It is verified by test results that the established model can accurately describe the axial dynamic characteristics of the suspension rubber bushing. The model is of great significance for improving the accuracy of dynamic simulations of suspension system and the vehicle References | Related Articles | Metrics

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Effect of Diesel Exhaust Process on Particle Size and Surface Functional Groups Li Ruina, Wang Zhong, Sun Bo 2019, 41 (8):  880-884.  doi: 10.19562/j.chinasae.qcgc.2019.08.004 Abstract ( 233 )   PDF (1876KB) ( 305 )   Save The particulates in different positions of the exhaust pipe of the 186F diesel engine were collected by using the engine exhaust particle size (EEPS), and the effect of the exhaust transport process on the particle size is analyzed. The fourier infrared spectrometer and X ray photoelectron spectrometer were used to detect the particulates collected at different positions of the exhaust pipe, and the effect of the exhaust transport process on the surface functional groups of the particulates was studied. The results show that the average particle size of the particulates was increased gradually along the flow direction of the exhaust gas in the process of diesel exhaust transportation, and the proportion of the nuclear particulates was reduced gradually. In the process of exhaust transport, the chemical composition of the particulate surface was basically the same. With the process of exhaust transport, the aliphatic hydrocarbon content of the particulates was increased, the content of C=O and C-OH in the particulates was increased, and the oxidation activity of the particulates was increased. The study showed that, along the flow direction of diesel exhaust transportation, the oxidation activity of the particulates was increased which was beneficial to the regeneration of the diesel engine post treatment device DPF References | Related Articles | Metrics

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A Multi-objective Lightweight Optimization Study on FullLife Cycle of Electric and Conventional Vehicles Xu Jianquan, Yang Yanping 2019, 41 (8):  885-891.  doi: 10.19562/j.chinasae.qcgc.2019.08.005 Abstract ( 537 )   PDF (1128KB) ( 613 )   Save Although automobile lightweight can effectively reduce energy consumption and emissions during the usage stage, when the full life cycle of vehicles from material acquisition, material processing, parts processing and manufacturing, assembly, to use and recycling is taken into account, lightweight may not necessarily save energy and reduce emission and the overall costs may even increase. Previous evaluations of the lightweight effect of automotive products focus on the operation and use stages of automobiles, but fail to comprehensively consider the various stages of the entire vehicle life cycle and there is no multi-objective lightweight optimization research on the whole life cycle of automobiles. To address this problem, this paper proposes to consider comprehensively energy consumption, environmental emissions and costs of the full life cycle during the lightweight design phase, and conducts a lightweight life cycle multi-objective optimization study to achieve weight reduction, while reducing energy consumption, environmental emissions and costs throughout the whole life cycle of the automobiles. The conventional gasoline vehicle produced by a company and the pure electric vehicle developed on the same platform are selected as the empirical research objects. Based on the static life cycle evaluation model, the steel weight reduction ratio, the aluminum weight increase ratio and magnesium weight increase ratio are selected as design variables. Full life cycle energy consumption, greenhouse effect (GWP) and production cost are selected as three objectives. Through multi-objective optimization, when the steel weight of the pure electric vehicle and conventional gasoline vehicle decreases respectively by 6.44% and 6.41% ; the aluminum weight increases by 1% in both types of vehicles and the magnesium weight increases by 0.44% and 0.41%, respectively, the energy consumption for whole life cycle decreases by 3.20% and 3.21% and GWP decreases by 2.84% and 2.88%, respectively; and the production cost doesn't increase References | Related Articles | Metrics

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An Analysis on the Limit of Lightweighting Existedin Automotive Structural Design Liu Yuting, Hu Daijun, Liu Xiandong, Shan Yingchun, Lu Hongzhou 2019, 41 (8):  892-895.  doi: 10.19562/j.chinasae.qcgc.2019.08.006 Abstract ( 463 )   PDF (773KB) ( 482 )   Save In view of the existing blindness of one-sidedly pursuing the use of high-strength and low-density materials in the practice of attempting lightweighting of vehicle structure at present, the maximum deflection and the strength limit of the beam structures with three different cross sections, following different mass reduction modes are studied by theoretical analysis and calculation under a condition of uniformly-distributed loading with a fixed support on one end and a roller support on the other end, to obtain the lightweighting limit of beam structures with different cross sections, providing references for the lightweight design of structure References | Related Articles | Metrics

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A Research on Control of Horizontally InterconnectedAir Suspension System Based on Agent Theory Li Zhongxing, Guan Xiaoxing, Jiang Hong 2019, 41 (8):  896-904.  doi: 10.19562/j.chinasae.qcgc.2019.08.007 Abstract ( 249 )   PDF (5556KB) ( 495 )   Save To alleviate the contradiction between ride comfort and handling stability of laterally horizontally interconnected air suspension vehicles, an intelligent system for interconnecting state control agent system of laterally horizontally interconnected air suspension is constructed based on the agent theory. Firstly, a horizontally interconnected air suspension vehicle model is established and its accuracy is verified through experiments. Then, based on the structure of traditional BDI (belief-desire-intention) agent, Thompson sampling is adopted to build the imitated skyhook interconnecting state control agent with online self-learning ability. The environmental state information is sensed from the sensor information acquisition module firstly, and then self-learning is performed through the internal BDI reasoning process and learning behavior, and finally the key parameters of imitated skyhook interconnecting state control adapted to different environmental states are output (hysteresis range to the interconnected state control module). The simulation is carried out under the mixed condition and the results show that the system balances the ride comfort and handling stability of vehicles References | Related Articles | Metrics

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Lateral Stability Control Based on Regional Pole Placementof In-wheel-motored Electric Vehicle Huang Caixia, Lei Fei, Hu Lin, Zhang Zhiyong 2019, 41 (8):  905-914.  doi: 10.19562/j.chinasae.qcgc.2019.08.008 Abstract ( 326 )   PDF (2610KB) ( 492 )   Save For the opportunities and challenges brought by the distributed drive structure on vehicle dynamics control, how to reliably realize lateral stability control is the key technology. Considering the uncertainty of vehicle parameters, a lateral stability control strategy of an in-wheel-motored electric vehicle based on the regional pole placement is proposed, and the influence of guaranteed weight parameters on control performance is analyzed. In order to make maximum use of the adhesion ability of the road, the yaw moment is generated by the driving forces and braking forces of the in-wheel-motors together and a rule-based torque allocation control strategy is proposed combined with the switch of the driving model. The performance analysis the control system is carried out by numerical simulation and hardware-in-loop simulation. The results show that the proposed upper strategy based on regional pole placement can not only improve vehicle handling stability, but also has strong robustness to the parameter uncertainties such as tire lateral stiffness. At the same time, the lower level strategy can reliably allocate wheel torques on low attachment road References | Related Articles | Metrics

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Simulation and Experimental Study on the Influencing Factorsof Collision Test Deviations for Child Safety Seat Zhang Xuerong, Yin Wenqian 2019, 41 (8):  915-921.  doi: 10.19562/j.chinasae.qcgc.2019.08.009 Abstract ( 245 )   PDF (3635KB) ( 391 )   Save Aiming at the cases that the child safety seat is fixed with car three-point seat belt and the child dummy is restrained by a five-point seat belt, the effects of the initial tension of seat belt, the initial position of five-point harness, the overall position of child safety seat and the image recognition method of head displacement on the results of dynamic collision test are quantitatively analyzed by the combination of simulation analysis and test verification. The results indicate that the forward and backward shifts of child safety seat have the most significant effects, leading to a maximum deviation of 4.3% in chest resultant acceleration and 37.7% in chest vertical acceleration. The correction formula proposed reduce the image recognition deviation of head displacement by a wide margin, and the control schemes and measures formulated effectively lower the test errors and ensure the consistency of test data References | Related Articles | Metrics

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Improvement of Coach Crashworthiness Based onTopology Optimization of Substructure Wu Changfeng, Na Jingxin, Qin Guofeng, Lu Linzhao, Yuan Zheng, Yang Jiazhou 2019, 41 (8):  922-926.  doi: 10.19562/j.chinasae.qcgc.2019.08.010 Abstract ( 240 )   PDF (2833KB) ( 412 )   Save An improved design method of coach body skeleton crashworthiness based on the topology optimization of substructure is proposed. Firstly, the crashworthiness evaluation of a monocoque coach is carried out by test and simulation, and the crux of body structure deformation is analyzed. The skeleton of front driving area is extracted as the sub-structure, and its crashworthiness is analyzed for improvement with the same crash energy absorption as the equivalence condition. Then in order to control the local deformation instability of sub-structure, a topology optimization is conducted on the spatial region of sub-structure, with the peak collision force of the energy absorbing box as loading condition. Eight groups of improvement schemes are comparatively analyzed, with the up-to-the-standard scheme having the lightest mass selected for sled test verification. Finally, the scheme is incorporated into the whole vehicle structure for validating its crashworthiness improvement. The results show that the crashworthiness of vehicle is effectively improved References | Related Articles | Metrics

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Optimization of Aluminum Honeycomb Energy-absorbingStructure for Pedestrian Leg Protection Zhang Zhifei, Jin Wei, Xu Zhongming, Chen Zhao, Shi Dengren, He Yansong 2019, 41 (8):  927-933.  doi: 10.19562/j.chinasae.qcgc.2019.08.011 Abstract ( 257 )   PDF (2873KB) ( 411 )   Save The finite element model for the collision between the front-end of a car and the lower legs of a pedestrian is established, and a simulation on which reveal that as the injury indicators of pedestrian legs, the peaks of the tibial acceleration at the center of the bumper (Y0), the tibial acceleration and the knee bending angle near the energy absorption box (Y390) all exceed safety threshold. In order to improve the pedestrian leg protection performance of vehicle, thirty sets of aluminum honeycomb energy-absorbing structures with six different honeycomb cell lengths and five different honeycomb cell thicknesses are designed according to energy-absorbing space and analyzed with LS-DYNA to get the changing trend of the corresponding mean square evaluation (MSE) and specific energy absorption (SEA) of pedestrian legs at Y0, with the relative optimum 14 mm of honeycomb cell length determined. Then an optimization is conducted by using software Hyperstudy and LS-DYNA integrated optimization technique with minimizing the MSE of pedestrian legs at Y390 as objective and the thicknesses of the front cover plate and honeycomb cell as variables. After optimization, all three injury indicators of pedestrian legs at both Y0 and Y390 reduce significantly and meet the requirements of safety threshold. The aluminum honeycomb energy-absorbing structure optimized effectively improves the pedestrian leg protection performance of vehicle References | Related Articles | Metrics

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Predictive Control for Lane Departure Prevention with Two-stage WarningBased on Coordination of Active Steering and Differential Braking Wei Zhenya, Wang Qidong, Wang Huiran, Chen Wuwei, Liang Xiutian 2019, 41 (8):  934-943.  doi: 10.19562/j.chinasae.qcgc.2019.08.012 Abstract ( 288 )   PDF (1416KB) ( 432 )   Save In order to make full use of differential braking control and active steering control with concurrent consideration of vehicle driving safety and the driving freedom of driver in designing lane departure prevention system, a lane departure prevention strategy with two-stage warning is proposed, utilizing coordinated control of active steering and differential braking. When the vehicle is in low risk, only differential braking control is used to ensure driver's control on steering wheel, and when the vehicle is in high risk, predictive control is adopted to achieve the coordination control of active steering and differential braking systems, so that the vehicle can quickly return back to the center-line of the lane. The time to lane crossing is selected to design the lane departure warning algorithm, with two warning thresholds set according to the response of the steering system of the vehicle respectively for low and high risk. To ensure vehicle stability, model predictive control with appropriate constraints is used to design the differential braking controller and coordinated controller of active steering and differential braking. The results of simulation and hardware-in-the-loop test show that the lane departure prevention control strategy designed based on the coordination of active steering and differential braking gives the driver full driving freedom while ensuring the premise of vehicle driving safety References | Related Articles | Metrics

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A Novel Robust UKF Algorithm for SOC Estimation of Traction Battery Tan Faming, Zhao Junjie, Wang Qi 2019, 41 (8):  944-952.  doi: 10.19562/j.chinasae.qcgc.2019.08.013 Abstract ( 265 )   PDF (1612KB) ( 477 )   Save In view of the interference of outliers appearing in observed voltage data during the process of SOC estimation of traction battery, an improved UKF algorithm is proposed, which corrects the observed noise model into the scaled-contaminated normal distribution model and utilizes Bayesian theorem to calculate the posterior probability of outliers, which can be used as weighting coefficients to adaptively adjust the filter gain and state covariance. This method can effectively overcome the problem of outlier interference, but when there are errors in initial SOC setting, it may mistakenly regard the normal value of observed voltage data as the outliers and only adjust it with small filter gain control quantity, leading to the slow convergence or even divergence of the algorithm. Therefore, a sub-optimal fading factor based on the strong tracking principle is introduced in the initial stage of the algorithm to track the target quickly, remedying the inadequacies of the simple anti-outlier method mentioned above. The test results show that the improved UKF algorithm has strong robustness, good tracking speed and accuracy, providing a new method for outlier interference resistance in estimating the SOC of traction battery References | Related Articles | Metrics

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A Research on Path Tracking of Intelligent Vehicle Based on Fuzzy Neural Network Zhang Bingli, Li Zilong, Shen Gan, Fang Tao, Cao Congcong, Zheng Pingping 2019, 41 (8):  953-959.  doi: 10.19562/j.chinasae.qcgc.2019.08.014 Abstract ( 400 )   PDF (3202KB) ( 628 )   Save Based on the research of the traditional dynamics model and preview model, a kind of path tracking controller is designed in view of the theory of neural network and fuzzy control. Utilizing the self-learning and self-adjusting characteristics of neural network, combined with the advantages of fuzzy control, a kind of network is designed to predict the speed of vehicle and its output and lateral deviation are taken as the input of the fuzzy network to control the steering angle. Finally, the joint simulation by CarSim and Matlab/Simulink software is carried out and the actual vehicle experiment is done, having verified the effectiveness and accuracy of the designed controller References | Related Articles | Metrics

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Traffic Light Detection Based on Genetic Optimization and Deep Learning Xiong Hui, Guo Yu'ang, Chen Chaoyi, Xu Qing, Li Keqiang 2019, 41 (8):  960-966.  doi: 10.19562/j.chinasae.qcgc.2019.08.015 Abstract ( 575 )   PDF (2808KB) ( 858 )   Save Traffic light detection is one of the key techniques of advanced driver assistance system and an important research direction for the on-board environment perception in autonomous vehicles. In view of the problem that general object detection algorithms are not suitable for small objects like traffic lights and the lack of real-time sliding window detection algorithms, a novel traffic light detection method is proposed in this paper, covering the generation of the candidate regions of traffic lights based on genetic optimization and the locating and classification of traffic lights based on deep neural network, in which the former, as the focus of the study, includes three parts: the common feature region extraction of traffic lights, the parameter sampling of the candidate region of traffic lights based on importance sampling and the parameter optimization of the candidate region of traffic lights based on genetic algorithm. Compared with existing traffic light detection methods, the method proposed can effectively detect and classify the horizontal rows and vertical columns of traffic lights with red and green colors, and round and arrow shapes. The comparative experiments on a public traffic light dataset show that the proposed method has a high recall rate for traffic lights, and can effectively distinguish different types of traffic lights References | Related Articles | Metrics

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Obstacle Avoidance Trajectory Planning for Intelligent VehicleBased on Derived State Lattice from Obstacle Hu Yanping, Tian Bo, Chen Wuwei, Zhang Ruichen 2019, 41 (8):  967-974.  doi: 10.19562/j.chinasae.qcgc.2019.08.016 Abstract ( 258 )   PDF (3295KB) ( 471 )   Save The obstacle avoidance process of intelligent vehicle is studied, a concept of derived state lattice is proposed, and on this basis, a trajectory planning algorithm for obstacle avoidance is determined. The algorithm combines the movement state and location information of target vehicle and obstacles, and converts the problem of seeking the desired obstacle avoidance trajectory in complex road environment into a trajectory planning one between target vehicle and state lattice. The obstacle avoidance trajectory generated by the corresponding algorithm is suitable for multi-obstacle environment with pertinent consideration of the state of obstacles, another concept of state lattice cost is also put forward, and the Dijkstra search algorithm is used to find the optimum from several feasible obstacle avoidance trajectories. The results of simulation show that both the yaw rate and lateral acceleration of vehicle meet the requirements of stability in its obstacle avoidance maneuver, verifying the feasibility of the algorithm. Finally, a CarSim/LabView hardware-in-the-loop test is also conducted to further verify the method proposed, with a conclusion basically agrees with simulation results References | Related Articles | Metrics

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Design and Test of Novel Vehicle Retarder Based onMagnetorheological and Eddy-current Effects Zheng Xiangpan, Wang Cheng 2019, 41 (8):  975-981.  doi: 10.19562/j.chinasae.qcgc.2019.08.017 Abstract ( 241 )   PDF (2730KB) ( 490 )   Save With motor vehicle developing toward heavy and large-size, its braking safety issue becomes increasingly prominent. Additionally installing auxiliary braking device is one of the important ways to achieve the safety braking for heavy-duty vehicles. Magnetorheological (MR) brake has advantageous features of stable braking torque, low noise and small volume and mass etc., so is able to remedy the inadequacies of traditional auxiliary braking devices, e.g. the poor performance at low speeds. A new idea of combined retarding braking by utilizing both MR and eddy-current effects is put forward, the working principle of novel MR retarder is analyzed, the double-disk symmetric structure of novel retarder is designed and developed, the mathematical model for its braking torque is established and the effects of different parameters on braking performance are theoretically analyzed. According to the working features of high-power braking in heavy-duty vehicles, a testing platform for braking performance is constructed, and a test on braking torque characteristics is conducted. The theoretical analysis and test results show that the novel MR retarder has the features of stable braking performance at low speed and large braking torque at high speed, with its braking torque characteristics meeting the braking requirements of heavy-duty vehicles References | Related Articles | Metrics