Table of Content

25 November 2019, Volume 41 Issue 11 Previous Issue    Next Issue

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Trajectory Tracking of Skid Steer Unmanned Vehicle Based on Backstepping Yu Zhuoping, Hou Yuye, Xiong Lu, Chen Suqin 2019, 41 (11):  1229-1234.  doi: 10.19562/j.chinasae.qcgc.2019.011.001 Abstract ( 1099 )   PDF (1895KB) ( 982 )   Save To meet the tracking requirements under the condition of high speed and large lateral acceleration, the dynamics characteristics and related stabilization problem of a skid steer unmanned vehicle are studied, and the course angle tracking error and the dynamics stability of path tracking of vehicle are analyzed in this paper. The dynamics controller, which is designed based on backstepping and saturation control techniques, tracks the given signal of course angle while stabilizing the internal dynamic state of vehicle. Simulation results demonstrate the reliability of proposed control scheme and the outstanding tracking performance of system under the condition of zero or constant 1st-order derivative of course angle. Meanwhile, the stability of the interconnection between controllers guarantees good system performance in tracking target path under general conditions. References | Related Articles | Metrics

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A Research on Design Principles for Electric Drive Assembly Mounts of Pure Electric VehiclesKang Qiang, Gu Pengyun, Zuo Shuguang 2019, 41 (11):  1235-1242.  doi: 10.19562/j.chinasae.qcgc.2019.011.002 Abstract ( 1546 )   PDF (6630KB) ( 2093 )   Save Different from the mechanical noise and the combustion noise of low-frequency order ignition in internal combustion engine, the noise of electric drive assembly in electric vehicles is mainly the high-frequency whistling generated by electromagnetic force and gear meshing. Noise below 2000-2500 Hz of electric drive assembly propagates into vehicle cabin mainly through structural paths. In view of the high torque of the driving motor of electric vehicles, the vibration isolation performance of electric drive assembly mounts should be as high as possible while ensuring their torsion resistant performance. In this paper, the powertrain vibration characteristics of electric vehicle and traditional fuel vehicle as well as the angular displacement around transverse axis and forces of mounts in different mount layout schemes are compared, and the main factors affecting the vibration isolation rates of electric drive assembly are analyzed. Finally, the general design principles for the drive assembly mounts of electric vehicle are summarized. References | Related Articles | Metrics

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Interaction Analysis on Cycle Fuel Injection Quantity Fluctuation for High Pressure Common Rail System Bai Yun, Lan Qi, Sha Haonan, Fan Liyun, Ma Xiuzhen 2019, 41 (11):  1243-1250.  doi: 10.19562/j.chinasae.qcgc.2019.011.003 Abstract ( 470 )   PDF (3058KB) ( 417 )   Save The fuel injection quantity stability of high pressure common rail system is influenced by the variation of electronic controlled injector parameters, which affects the working consistency and reliability of the diesel engines. In this paper, a numerical model including common rail, high pressure fuel pipeline and injector is proposed based on bond graph theory. The experimental results show that the model can predict the fuel injection quantity fluctuation accurately. The investigation scheme is formulated using experiment design method, and the fuel injection quantity fluctuation response surface model is obtained which can predict the fuel injection quantity fluctuation well. The influence of interaction between parameters on fuel injection quantity fluctuation is analyzed based on response surface method. The results indicate that the interaction between inlet orifice diameter and nozzle hole diameter, inlet orifice diameter and needle lift, nozzle hole diameter and control valve reset spring pre-tightening force, nozzle hole diameter and needle lift, control valve reset spring pre-tightening force and needle lift has significant effect on fuel injection quantity fluctuation, which can provide theoretical guidance for the numerical modeling and optimal design of high pressure common rail system. References | Related Articles | Metrics

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A Research on Power Splitting Strategy for Hybrid Energy Storage System Based on Driving Condition Prediction Wang Feng, Luo Yutao 2019, 41 (11):  1251-1257.  doi: 10.19562/j.chinasae.qcgc.2019.011.004 Abstract ( 476 )   PDF (3398KB) ( 459 )   Save In this paper, an adaptive neural fuzzy control power splitting strategy for hybrid energy storage system is proposed based on driving condition prediction. Markov chain model is adopted to predict the future driving conditions of vehicle, the vehicle speed predicted is used as one of the inputs of adaptive neural fuzzy controller, and the processing by which will get the results of power splitting. The results of experiment show that the adoption of proposed power splitting strategy with adaptive neural fuzzy control for hybrid energy storage system can significantly extend the service life of battery and reduce the overall operation cost of energy storage system. References | Related Articles | Metrics

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Takeover Safety Evaluation Model for Level 3 Automated Vehicles Lin Qingfeng, Wang Zhaojie, Lu Guangquan 2019, 41 (11):  1258-1264.  doi: 10.19562/j.chinasae.qcgc.2019.011.005 Abstract ( 1190 )   PDF (1966KB) ( 1256 )   Save To evaluate the safety of takeover in Level 3 automated vehicles, the takeover scenario on a two-way six-lane highway is designed to conduct driving simulation experiments based on driving simulator. Drivers carry out the secondary tasks in vision all along during automated driving. The secondary tasks are watching arrowhead charts with three different-degrees of difficulty and the takeover scenario is that ago vehicle comes across a broken-down vehicle in front on the same lane, with a take-over request time of 7 s and an automated vehicle speed of 110 km/h. A total of 49 testees (30 males, 19 females) are recruited for experiment with an average age of 31.06 years (standard deviation: 7.10 years). After the vehicle sends auditory and visual request signals for takeover, testee should push the switch button on steering wheel to take back vehicle control. Bivariate logistic regression is used to build the evaluation model for takeover safety, with the group of minimum TTC taken as dependent variable: minimum TTC ≤ 1s is set as dangerous group and minimum TTC > 1s is set as safe group. The results show that in the condition of 7s takeover request time, the factors affecting takeover safety are takeover reaction time and secondary task, and the prediction accuracy of the takeover safety evaluation model built reaches 85.5%. References | Related Articles | Metrics

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Design and Implementation of Mental Workload Calculation System for Drivers Pei Yeqing, Jin Xiaoping, Song Zhenghe, Liu Longcan 2019, 41 (11):  1265-1272.  doi: 10.19562/j.chinasae.qcgc.2019.011.006 Abstract ( 565 )   PDF (992KB) ( 381 )   Save With the popularity of motor vehicles, traffic accidents frequently occur, and high mental workload during driving becomes an important cause of accidents. Multiple resource theory holds that mental workload stems from information processing process, which can be described by essential behavioral factors such as vision, audition, cognition and psychomotor. The design and implementation of driver's mental workload calculation system are studied in this paper. Firstly, based on multiple resource theory, the analysis methods of typical driving tasks are summed up and the calculation model for mental workload is established. Then the task of “intersection green-light straight crossing” is selected for case analysis, and according to the driving task, mental workload value is calculated by using calculation system. Finally, the pupil diameter and skin electrical signal of testees are measured by experiments and compared with the mental workload value calculated, demonstrating the correctness and usability of the system. The method proposed can handily calculate and predict the mental workload of drivers in executing typical driving task, find out the causes of high mental workload and hence reduce the occurrence of traffic accidents. References | Related Articles | Metrics

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A Study on Thermal Equilibrium of Cylindrical Lithium-ion Battery Pack Cui Xing, Li Da, Liu Zenghui, Wei Zhen, Guo Liwei, Dong Haotian, Wang Dafang 2019, 41 (11):  1273-1280.  doi: 10.19562/j.chinasae.qcgc.2019.011.007 Abstract ( 478 )   PDF (4009KB) ( 539 )   Save Firstly, the layout scheme and 3D model of water cooling system are established. Then the cooling effect and thermal equilibrium of cylindrical lithium-ion battery 18650 in water-cooled mode with different arrangements are comparatively analyzed. Finally, the temperatures at different points of battery module in discharge process are measured. Heat ratio is defined to quantitatively describe the thermal equilibrium of battery module. The results of simulation analysis and test verification show that when the geometric model and cell number of the battery module are the same, the cooling effect and thermal equilibrium of the battery module with staggered arrangement are better than that with parallel arrangement. Under 1C discharge rate, the highest temperature rise of the battery module with staggered arrangement is 2.26 K lower than that with parallel arrangement, with thermal equilibrium improved by 33.9%. In the same arrangement, the more the number of battery cells, the worse the thermal equilibrium of the module. When the number of cells in the module increases from 15 to 60, its thermal equilibrium with parallel arrangement lowers by 5.1%, while that with staggered arrangement lowers by 6.3%, and geometric model and discharge rate have little effects on thermal equilibrium. References | Related Articles | Metrics

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A Study on Calculation Accuracy of Turbulent Pressure Fluctuation on Vehicle Surface Wang Jun, Chen Ruyi 2019, 41 (11):  1281-1285.  doi: 10.19562/j.chinasae.qcgc.2019.011.008 Abstract ( 567 )   PDF (3602KB) ( 412 )   Save CFD analysis on the models with two kinds of mesh size and two kinds of geometric details are carried out by using detected eddy simulation method to obtain turbulent fluctuating sound pressure level on side window surface, which is then compared with wind tunnel test results. The results show that the accuracy of 1 mm mesh is higher while the 2 mm mesh has apparent error when frequency higher than 2 000 Hz. The error of styling model is slightly larger than vehicle model at low frequency range (below 100 Hz), but is basically the same as that of vehicle model at middle and high frequency range. Q-criterion shows that 1 mm mesh can capture smaller vortex cores with larger vorticity, which is just the reason why 1 mm mesh is more accurate at high frequency range. With consideration of computational efficiency, it is recommended to use styling model for the calculation of turbulent pressure fluctuation with finer mesh (1 mm) in side window area. References | Related Articles | Metrics

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Simulation and Evaluation on the Crosswind Stability of Vehicles Yuan Xiayi, Chen Lin, Li Shuai, Wang Wenyuan 2019, 41 (11):  1286-1293.  doi: 10.19562/j.chinasae.qcgc.2019.011.009 Abstract ( 669 )   PDF (2755KB) ( 867 )   Save This paper aims to study the driving stability issue of vehicle caused by trajectory deviation due to the action of sudden or sustained sidewind on high-speed driving vehicle. Firstly, the aerodynamic characteristics of the vehicle under crosswind conditions are obtained by CFD simulation and compared with the results of wind tunnel test. Then, the six aerodynamic component forces obtained by CFD simulation are loaded on the vehicle dynamics model to predict the yaw rate and lateral deviated displacement of vehicle under crosswind conditions. Finally, a real vehicle road test is conducted to compare the stability of two vehicles subjected to the same pattern of crosswind by means of subjective evaluation. The results show that the simulated maximum yaw rate and lateral deviated displacement of vehicle A and vehicle B with a driving speed of 100 km/h and after 0.5 s action of crosswind with a windspeed of 80 km/h are 2.69°/s, 265 mm and 3.79°/s, 374 mm respectively, and their subjective evaluation results are “good” and “relatively good” respectively. Finally, an evaluation criterion is established to provide a guidance for crosswind stability development at the detailed design stage of new model program. References | Related Articles | Metrics

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An Analysis on Torsional Characteristics of Dual Mass Flywheel and Vehicle Test Study Chen Long, Shi Wenku, Chen Zhiyong, Liu Guozheng, Liu Helong 2019, 41 (11):  1294-1300.  doi: 10.19562/j.chinasae.qcgc.2019.011.010 Abstract ( 647 )   PDF (2609KB) ( 449 )   Save This paper studies the performance of dual mass flywheel by bench and vehicle tests. Firstly, the influence of torsion angle on the static torsional stiffness of dual mass flywheel is analyzed. Secondly, the bench test of the dual mass flywheel sample is carried out to verify the validity of the theory and prove its stiffness value meeting the design requirements of torsional stiffness. Finally, the road test of the dual mass flywheel is carried out to obtain the torsional vibration damping performance of the dual mass flywheel in the transmission system under idle, constant speed, acceleration and deceleration conditions. The test results show that the dual mass flywheel has obvious damping effect on torsional vibration of the transmission system under various working conditions. Under steady-state conditions (idle, constant speed), the torsional vibration attenuation of the dual mass flywheel is about 50%; under unsteady conditions (acceleration and deceleration), the torsional vibration attenuation of the dual mass flywheel is about 80%. References | Related Articles | Metrics

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A Study on Safety Performance Optimization of Seat Subsystem Based on Kriging Model Zheng Jianzhou, Chen Yousong, Lü Binbin, Yin Haoqing 2019, 41 (11):  1301-1307.  doi: 10.19562/j.chinasae.qcgc.2019.011.011 Abstract ( 598 )   PDF (3933KB) ( 412 )   Save This paper aims to study the parameters optimization of seat subsystem which plays the role of occupant protection in frontal crash. Firstly, a simulation model of driver‘s seat subsystem in a commercial vehicle for a frontal impact sled test is established and verified by sled test. Then, a sensitivity analysis is conducted on 11 design parameters with the design of experiment of optimal Latin hypercube, and 6 relatively most sensitive parameters are selected to construct a Kriging model for analyzing the influence of seat parameters on occupant protection effect in frontal crash. Finally, NSGA-II genetic algorithm is adopted to perform multi-objective optimization with minimizing the forward displacement and submergence of dummy’s H-point as objective. The results show that after optimization the forward displacement and submergence of dummy‘s H-point is reduced by 2.98% and 10.47% respectively, demonstrating the apparent effects of optimized seat subsystem in occupant protection. References | Related Articles | Metrics

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Leader-follower Joint Topological Optimization for the Crashworthiness of Energy Absorption and Re-direction Anti-collision Structure Lei Zhengbao, Huang Min, Gou Mingxing 2019, 41 (11):  1308-1312.  doi: 10.19562/j.chinasae.qcgc.2019.011.012 Abstract ( 530 )   PDF (2061KB) ( 379 )   Save The traditional anti-collision structure only needs to meet the requirements of safety indicator, though which requires both peak collision acceleration and maximum deformation are small, the conflicting requirements has intersection set in feasible domain. With the perfection of national standards, the re-directive performance indicator newly added requires very high stiffness. As a result, the requirements on both safety and re-directive performance leads to an empty set in feasible domain, and this issue can't be solved by the existing methods available. In view of this, a leader-follower joint topology optimization scheme is proposed in this paper for the crashworthiness of the anti-collision structures with both energy absorbing and re-directive performances. Firstly, the safety follower model is established according to the safety indicator. Then, based on the force transfer path of safety follower model, a re-directive stiffness compensation device is introduced, by combining which with safe follower model the leader model is built. Subsequently, a topology optimization is carried out, with its topology configuration obtained. Finally, the applicability of the scheme proposed is verified by real examples and the results show that the vehicle has excellent re-directive performance in 25% overlap collision and superb energy absorbing effects in 100% overlap crash, providing a new way for the optimal design of anti-collision structures. References | Related Articles | Metrics

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A Research on the Design and Optimization of Multi-chamber Side Airbag Ge Ruhai, Chen Yuhang, Hong Liang, Cai Chaoyang, Cui Yizhong 2019, 41 (11):  1313-1319.  doi: 10.19562/j.chinasae.qcgc.2019.011.013 Abstract ( 404 )   PDF (2089KB) ( 425 )   Save In view of that the single-chamber side airbag of a vehicle made in China ‘broke down’ during side collision process, a multi-chamber side airbag with multi-chamber independent control and secondary buffering function is proposed and simulated. The results show that the novel multi-chamber side airbag has good protection effects of occupant’s thorax and abdomen with ‘break down’ phenomenon eliminated. Then orthogonal experiment is conducted to optimize the parameters related to the protection effect of airbag. After optimization the value of comprehensive injury indicator C reduces by 14.77% and is 31.35% lower than the original airbag, enhancing the protection effect of side airbag. References | Related Articles | Metrics

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Cascaded Anti-lock Brake Control Strategy Based on Electro-booster Brake Chen Zhicheng, Zhao Jian, Zhu Bing, Wu Jian 2019, 41 (11):  1320-1326.  doi: 10.19562/j.chinasae.qcgc.2019.011.014 Abstract ( 542 )   PDF (3184KB) ( 578 )   Save Electro-booster brake system (Ebooster) achieves master cylinder pressure regulation via servo motor control, and can provide some redundant function for anti-lock brake system (ABS). In this paper, a three-layer cascade anti-lock brake redundant control architecture based on non-decoupled Ebooster is proposed, including sliding mode variable structure control layer, pressure-servo control layer and motor control layer, which will work in case the traditional solenoid valve type of ABS fails. A hardware-in-the-loop test based on dSPACE is carried out to verify the algorithm. The results show that when the faults in ABS occur, the Ebooster-based anti-lock brake redundant control strategy can effectively fulfill slip-rate control, enhancing the braking stability of vehicle. References | Related Articles | Metrics

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Simulation Analysis and Control of High Frequency Noise in Commercial Vehicles Considering Leakage Tang Rongjiang, Tong Zhe, Zheng Weiguang, Li Shenfang, Huang Li 2019, 41 (11):  1327-1334.  doi: 10.19562/j.chinasae.qcgc.2019.011.015 Abstract ( 418 )   PDF (3610KB) ( 379 )   Save In order to simulate the acoustic environment in the cab more truly and improve the interior noise prediction accuracy, the leakage is applied to SEA modeling and a commercial vehicle SEA model considering leakage is established. Bernoulli equation is used to derive the equivalent leakage area. The equivalent total leakage area is divided by the leakage contribution and added to the model for simulation. In contrast with the SEA model without considering leakage ,the results show that the simulation accuracy is improved and the error is reduced by about 1.5 dB (A) with the absolute error less than 2 dB(A), which meets the engineering requirement of high frequency noise analysis and prediction in vehicle product development and design stage. The SEA model considering leakage is fully validated. Under different leakage values, the interior noise is simulated and the curve of effect of leakage on the noise value is obtained. Combined with the influence curve and many other factors, the suitable leakage value of 150 SCFM is determined. The main leakage points are targeted for optimization and the leakage value drops from 268.5 to 149.1 SCFM. The interior noise after optimization is measured and the results show that the noise values are reduced by 1.82 and 1.31 dB(A) respectively under two working conditions compared with those before optimization. References | Related Articles | Metrics

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An Experimental Research on Indoor Pass-by Noise Measurement of Vehicles Based on the Replacement of Tyre/Road Noise Liu Ce, Chen Jian, Zhang Yongbin, Li Jiazhu 2019, 41 (11):  1335-1340.  doi: 10.19562/j.chinasae.qcgc.2019.011.016 Abstract ( 452 )   PDF (2644KB) ( 425 )   Save The outdoor pass-by noise tests of vehicles are subject to environmental factors, driving skill and test sites, and the international standard ISO 362—1∶2007 has more stringent requirements on outdoor pass-by noise tests, which makes the success rate of pass-by noise test is significantly reduced. In order to establish an efficient platform for pass-by noise tests, the indoor measurement methods for pass-by noise tests have become an urgent need. In view of the key problem of vehicle pass-by noise indoor measurement methods that there are differences between indoor and outdoor tyre/road noise in the pass-by noise tests, the experimental research on indoor and outdoor pass-by noise tests for a certain vehicle is carried out. Based on indoor coast-by method, the indoor tyre/road noise coefficients are obtained and the indoor tyre/road noise is extracted, which is then replaced by outdoor tyre/road noise based on the energy superposition principle of sound pressure. The absolute error between the indoor pass-by noise measurement result and outdoor measurement result is within ±1 dB(A) , which verifies the effectiveness of the method. References | Related Articles | Metrics

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Pressure Field Analysis in Leak Monitoring of EVAP System Based on Fluent-Simulink Collaborative Simulation He Ren, Fang Yanyue 2019, 41 (11):  1341-1346.  doi: 10.19562/j.chinasae.qcgc.2019.011.017 Abstract ( 674 )   PDF (2438KB) ( 540 )   Save This paper aims to analyze the effect of the position of leak hole on the pressure and flow field characteristics in vapor space of vehicle evaporative control system when adopting vacuum decay method in leak monitoring. Firstly, the numerical model for total pressure in vapor space is built to obtain the boundary conditions of transient models. Then transient models with 1 mm leak hole for upward and sideward leaks are analyzed. Finally, verification test with 1 mm reference hole is conducted. Results show that in decay time 30-39 s the pressure in vapor space is basically equal everywhere except in the vicinity of leak hole and pipeline. The maximum pressure in the pipeline with valves is higher than that in circulating pipe. Vacuum decay rate in upward leak is higher than that in sideward leak. Decay time 30-39 s is the preferred leak monitoring period. References | Related Articles | Metrics