Table of Content

25 September 2019, Volume 41 Issue 9 Previous Issue    Next Issue

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Active Fault-Tolerant Control Based on MFAC for 4WID EV Driving System Hu Yun, Jiang Fachao, Chen Rui & Luo Yugong 2019, 41 (9):  983-989.  doi: 10.19562/j.chinasae.qcgc.2019.09.001 Abstract ( 542 )   PDF (1432KB) ( 569 )   Save To solve the problem of the existing active fault-tolerant control of four-wheel independent drive (4WID) electric vehicles (EV), which mostly relies on complex and non-linear vehicle model and accurate fault diagnosis information, a multi-input and multi-output model free adaptive active fault-tolerant control method is proposed. The method only uses multiple input and output information of vehicle system in the design of the control system. The coordinated fault-tolerant control of the driving system and the steering system ensures that the vehicle can maintain the desired speed and not deviate from the set trajectory under various failure conditions. The controller monotonic convergence and boundary input and output are proved by theoretical derivation. Based on the joint simulation of MATLAB/Simulink and CarSim, the validity of the control algorithm is verified. Under typical working conditions, the vehicle longitudinal speed error is maintained within 3%, with lateral stability and non-deviation, which ensures driving safety. On this basis, the real-time performance of the control algorithm is verified by the driving simulator experiment. References | Related Articles | Metrics

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Sensitivity Analysis on Energy Consumption ofPHEV Based on Real Vehicle Road Data Xia Hongpu, Wang Bin, Wu Guangyao, Li Tie & Tong Ronghui 2019, 41 (9):  990-997.  doi: 10.19562/j.chinasae.qcgc.2019.09.002 Abstract ( 407 )   PDF (1152KB) ( 337 )   Save In order to evaluate the energy consumption level of plug-in hybrid vehicles (PHEV) in actual driving process and study the essential factors affecting the energy consumption level of PHEV, this paper explores the relationship between the vehicle driving status and driving behavior and the overall energy consumption of PHEV based on the driving record data of 180 drivers. Firstly, principal component analysis (PCA) method is employed to decouple the characteristics of parameter matrix of driving conditions, and the first 5 PCs contributing accumulatively 84% to the overall information are extracted. The principle components are also defined according to the numerical distribution of the influence coefficient matrix. Then, based on kinematics fragments, the K-means algorithm is used to constrain the principal components in turn to form target real vehicle road conditions, which is put into vehicle power flow model to calculate the comprehensive energy consumption level. Finally, Pearson correlation coefficient and covariance value between each principle component and comprehensive energy consumption level are calculated and clustering and sensitivity definitions are given. The results show that the three significant factors representing human-vehicle-road extracted in this paper have a strong sensitivity relationship with energy consumption. The conclusions of this paper have important guiding significance for the selection of PHEV design and control parameters. References | Related Articles | Metrics

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The Application of Proper Orthogonal Decomposition in the Researchof In-Cylinder Flow Field Coherent Structure Qin Wenjin, Qi Guanchao, Wang Tao, Zhou Lei, Jia Ming & Xie Maozhao 2019, 41 (9):  998-1005.  doi: 10.19562/j.chinasae.qcgc.2019.09.003 Abstract ( 223 )   PDF (1791KB) ( 489 )   Save In this paper, large eddy simulation method is used to calculate 100 continuous cycle cold flow fields for a four-valve single-cylinder optical engine. The calculation results are verified by PIV experiments, and a reliable database is constructed for the study of the coherent structure of the turbulent flow field in the cylinder. Then, the orthogonal decomposition method is used to process the in-cylinder turbulent flow field database, and in-cylinder turbulent flow field is decomposed according to the vortex structure energy.The large scale coherent structures and small scale random vortices are effectively separated, which is benefit for studying the characteristic of different scale vortices. The calculation results also show that the intake jet in the intake stroke stage dominates the early overall flow pattern, and the resulting large-scale coherent structures are broken into small-scale vortices in the subsequent process, accompanied by the energy cascade phenomenon, and then the flow field gradually becomes isotropic References | Related Articles | Metrics

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A Study on CFD Simulation and Wind Tunnel Test on Aerodynamic Effectsof Wheel Rotation and Drag Reduction Optimization Fang Jian & Wang Fuliang 2019, 41 (9):  1006-1012.  doi: 10.19562/j.chinasae.qcgc.2019.09.004 Abstract ( 319 )   PDF (3758KB) ( 341 )   Save In this paper, with two Shanghai GM vehicles as study object, the multi-reference frame (MRF) scheme of moving reference frame (MRF) method is applied to the simulation of wheel rotation, both CFD simulation and wind tunnel test are conducted on the aerodynamic characteristics of vehicle under both conditions of the standstill and rotation of wheel, and by comparing the results of simulation and wind tunnel test, the correctness of MRF method in simulating aerodynamic effects of wheel rotation is verified. Based on the analysis on the flow-field simulation results, the generation mechanism of aerodynamic resistance of rotating wheel and the effects of wheel rotation on wake structure and rear-end pressure are analyzed, and the flow-field action mechanism of the change in Cd caused by wheel rotation is explored. According to the features of flow-field distribution, optimization schemes for reducing wheel resistance are proposed and the results of simulation show that the optimal scheme can significantly reduce Cd. The study provides the flow-field simulation scheme with CFD for simulating the aerodynamic effects of wheel rotation and analyzes the mutual action mechanism of complex flow-field related to wheel rotation, providing helpful reference for the aerodynamic optimization development of wheels and rear-end. References | Related Articles | Metrics

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A Safe Lane-change Model for Vehicle EmergentCollision Avoidance on Curved Section of Highway Peng Tao, Su Lili, Guan Zhiwei, Zhang Ronghui, Zong Changfu & Li Junkai 2019, 41 (9):  1013-1020.  doi: 10.19562/j.chinasae.qcgc.2019.09.005 Abstract ( 301 )   PDF (898KB) ( 446 )   Save Aiming at the safety problem of vehicle lane change on the curved section of highway, a lane-change model for emergent collision avoidance is established based on the normal distribution fitting of vehicle lateral velocity, with consideration of human-vehicle-road interaction, and according to the location relation of vehicle collision avoidance, the safety constraint conditions of lane change on curved road are proposed, and the minimum safe distance for vehicle collision avoidance is obtained under the condition of lane change with braking. The results of simulation compared with those with traditional model and 2 DOF vehicle dynamics model show that the model established can accurately describe the lane-change trajectory on curved section and calculate the minimum safe distance for vehicle collision avoidance. The safe lane-change model set up for collision avoidance fully considers the cooperative relationship among human, vehicle and road, providing valuable reference for the research on intelligent vehicle and assisted driving. References | Related Articles | Metrics

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Trajectory Tracking Method for Intelligent Vehicles Based on Tracking-error Model Pan Shiju, Li Hua, Su Zhiyuan & Xu Youchun 2019, 41 (9):  1021-1027.  doi: 10.19562/j.chinasae.qcgc.2019.09.006 Abstract ( 495 )   PDF (1400KB) ( 1580 )   Save In order to improve intelligent vehicle trajectory tracking accuracy, a trajectory tracking method based on linear time-varying model predictive control is proposed based on vehicle dynamics model. The method linearizes and discretizes the nonlinear tracking-error model of vehicle dynamics as the predictive model of the controller. The objective function of the system control increment is established with the constraints of the state, control and control increment designed. Then the objective function is solved by the quadratic programming problem with constraints and the first control volume of the optimal sequence is applied to the system. The experimental results show that the maximum lateral error is less than 0.52 m and the maximum heading error is less than 0.067 rad when the vehicle speed is less than 15 m/s under double lane-changing conditions. References | Related Articles | Metrics

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A Research on Connected Cruise Control with Consideration of Merging Zhang Tao, Zou Yuan, Zhang Xudong, Liu Xiantao & Wang Wenwei 2019, 41 (9):  1028-1035.  doi: 10.19562/j.chinasae.qcgc.2019.09.007 Abstract ( 449 )   PDF (2097KB) ( 518 )   Save In view of the problem that human-drivers on adjacent lane are prone to enter the fleet during the process of connected vehicle driving, a follow-up strategy with consideration of the merging maneuver of vehicle on adjacent lane is proposed and a hierarchical control system for distributed application is designed in this paper. Firstly, the rationality of the follow-up strategy proposed is analyzed, and a connected cruise control (CCC) system considering delay and error feedback is constructed. Then the influences of different control gain parameters on system stability in frequency domain are analyzed, and the simulation results verify the stability of multi-vehicle platooning driving. Finally, a test platform is constructed and a real vehicle test is conducted with a result showing that the CCC control system designed can quickly fulfill vehicle braking and ensure the stability of platooning driving during the merging of vehicle on adjacent lane. The follow-up strategy proposed can enhance the ride comfort of vehicle and the safety of traffic system. References | Related Articles | Metrics

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A Research on Vehicle Trajectory Prediction Method Based onBehavior Recognition and Curvature Constraints Xie Feng, Lou Jingtao, Zhao Kai & Qi Yao 2019, 41 (9):  1036-1042.  doi: 10.19562/j.chinasae.qcgc.2019.09.008 Abstract ( 499 )   PDF (1729KB) ( 689 )   Save In order to make a reasonable and effective prediction of vehicle's trajectory in the environment around the intelligent vehicle, a vehicle trajectory prediction method based on behavior recognition and curvature constraints is proposed. Firstly, it receives the perceived obstacle information and performs behavior recognition on vehicle combined with the lane line information provided by the high-precision map. Then the s-l coordinate system is established to decompose the vehicle motion into the motion along the lane line direction (longitudinal direction) and the motion perpendicular to the lane line direction (lateral direction). According to the behavior recognition result, the polynomial equation of the vehicle in the horizontal and vertical motion is obtained. Then the curvature of the lane line in the high-precision map is used as a constraint to select an optimal prediction trajectory. The actual vehicle experiment results show that under the three basic behaviors of lane keeping, lane changing and turning, the average vehicle trajectory prediction error within 4 s is 0.52, 0.51 and 1.03 m respectively, which is reduced by 1.81, 4.48 and 5.49 m compared with the prediction error of the CTRA model, and the average time of single vehicle trajectory prediction is 0.103 ms, which verifies the validity, accuracy and real-time of the proposed method. References | Related Articles | Metrics

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A Research on Vehicle Rollover Prevention Based on Combined Controlwith Active Anti-Roll Bar and Differential Braking Chen Song, Zhang Hongdang, Wu Haidong, Zhang Fengjiao & Jiang Xiaoying 2019, 41 (9):  1043-1049.  doi: 10.19562/j.chinasae.qcgc.2019.09.009 Abstract ( 321 )   PDF (1495KB) ( 570 )   Save In view of the problem that the high-speed driving vehicle is prone to rollover in sharp turning or obstacle avoidance maneuver, a rollover control strategy with the combination of differential braking and active anti-roll bar is put forward. For enhancing rollover control effect, on one hand, all-wheel differential braking is adopted to enhance the yaw stability of vehicle, prevent the vehicle from tripping rollover due to instability, and reduce the probability of vehicle rollover; on the other hand, taking into account the nonlinearity and time variability of vehicle under emergency conditions, an active anti-roll bar is applied and a second-order sliding mode super-twisting controller is designed to dynamically track the ideal roll angle of the vehicle for achieving accurate judgment of the inclination of vehicle rollover, preventing the mal-operation of driver and further enhancing the anti-rollover capability of vehicle. Finally, a hardware-in-loop test is conducted to validate the effectiveness of the combined control strategy with active anti-roll bar and differential braking. References | Related Articles | Metrics

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Modeling and Control of Active Pneumatic Braking System for Tractor-Semitrailer Combination Zhu Bing, Zhang Peixing, Wang Zhen, Zhao Jian, Wu Jian & Feng Yao 2019, 41 (9):  1050-1055.  doi: 10.19562/j.chinasae.qcgc.2019.09.010 Abstract ( 276 )   PDF (970KB) ( 432 )   Save In order to enhance the active safety of tractor-semitrailer combination, an active pneumatic brake control system is built in this paper. A set of active pneumatic brake actuators, compatible with traditional pneumatic braking system, are designed with corresponding hardware system constructed. The pressure boost and relief models of the system and the on-off process model for solenoid valve are set up, and the model parameters are identified with particle swarm algorithm based on experimental data. On this basis, a model-based active pneumatic brake control strategy is established and verified by tests. The results show that the active pneumatic brake control system proposed for tractor-semitrailer combination can achieve accurate control of active pneumatic brake. References | Related Articles | Metrics

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Simulation and Experimental Study on the Drag TorqueCharacteristics of Wet Clutches in High Speed Condition Zhou Xiaojun, Wu Penghui, Yang Chenlong, Xu Jin, Shang Xiaobo & Wang Zhaoshuai 2019, 41 (9):  1056-1064.  doi: 10.19562/j.chinasae.qcgc.2019.09.011 Abstract ( 233 )   PDF (3017KB) ( 521 )   Save In order to study the characteristic rule of wet clutch, i.e. the drag torque rises again in high speed range, which traditional model cannot predicts, a mathematical model with gaseous and liquid two phases is established with consideration of the effects of grooves and temperature, and the analyses on the model reveal that the drag torque shows a certain rise trend again when the speed reaches specific value due to the reduction of oil film thickness in the gap between frictional linings and steel disks. Meanwhile two-phase volume of fluid model is also set up to simulate the distribution rule of the volume fraction of air and oil two phases. Finally, tests on different conditions are conducted to analyze the effects of factors such as speed, drag gap, oil flow rate, oil temperature, frictional material and grooves on drag torque. References | Related Articles | Metrics

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An Analysis on the Effects of Tire Nonlinearity on Autonomous Platoon Stability Li Ling, Yao Xigui & Shi Shuming 2019, 41 (9):  1065-1072.  doi: 10.19562/j.chinasae.qcgc.2019.09.012 Abstract ( 225 )   PDF (1948KB) ( 451 )   Save Aiming at the problem that existing autonomous platoon model cannot reflect the effects of tire nonlinearity on the stability of vehicle, a 5 DOF (the longitudinal and lateral speeds and yaw rate of vehicle and the rotational angular speeds of front and rear wheels) vehicle model is utilized, combined with linear and nonlinear tire models respectively to analyze the dynamics characteristics and stability of autonomous platoon system. The results show that the nonlinearity of tires significantly affects the stability of autonomous platoon system in high-speed following driving and leads to the instability of the following vehicles. References | Related Articles | Metrics

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Rigid-flexible Coupling Modelling and Experimental Study of Drive Axle Assembly Shi Hui, Shi Wenku, Liu Guozheng, Zhang Henghai & Chen Zhiyong 2019, 41 (9):  1073-1079.  doi: 10.19562/j.chinasae.qcgc.2019.09.013 Abstract ( 271 )   PDF (1978KB) ( 406 )   Save In order to more accurately analyze the dynamics characteristics of the gear transmission system of a drive axle for guiding the design of drive axle for vibration and noise reduction, the rigid-flexible coupling modelling and experimental study on drive axle assembly are conducted in this paper. Firstly, the models for the gears, axle housing and final drive housing are established by finite element method. Then, combined with the bearing, spline and the intermediate support of propeller shaft, which are simulated by multi-body connection elements, a complete rigid-flexible coupling model of drive axle is constructed. Finally, modal tests of drive axle in both free state and vehicle installation state are carried out. The results show that the vibration modes of drive axle in free state cannot reflect its actual vibration modes under constraints. Therefore, drive axle cannot be taken alone as the research object, and it is essential to perform modal test of drive axle in vehicle installation state with components such as propeller shaft and leaf springs connected. And using multi-body connection elements to simulate components like bearings and splines can significantly increase computation speed while ensuring the calculation accuracy of model with the relative error of modal simulation against modal test is less than 7%, which demonstrates the reasonableness of the rigid-flexible coupling model for drive axle, having a certain practical engineering significance for studying the vibration and noise characteristics of drive axle. References | Related Articles | Metrics

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A Bench Test Method for Suspension Durability Based on Virtual Load Fan Lu, Chen Weibo & Liu Ligang 2019, 41 (9):  1080-1087.  doi: 10.19562/j.chinasae.qcgc.2019.09.014 Abstract ( 379 )   PDF (2041KB) ( 806 )   Save For speeding up vehicle test and validation cycles and reducing test cost, a virtual load generation method based on multi-body dynamics and its data processing procedure are adopted, a test bench for road simulation of suspension system is built, and durability tests based on both virtual load and the real load of proving ground are conducted respectively. The comparative analysis on the mode and occurring time of suspension part failures in durability tests verifies the effectiveness of suspension road simulation test method based on virtual load. References | Related Articles | Metrics

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Modified RMS Calculation Formulae for Vehicle VibrationResponses and Their Engineering Application Yu Yuewei, Zhao Leilei & Zhou Changcheng 2019, 41 (9):  1088-1095.  doi: 10.19562/j.chinasae.qcgc.2019.09.015 Abstract ( 562 )   PDF (2543KB) ( 498 )   Save In order to effectively solve the problem of over-estimation of the existing formulae for calculating the root mean square (RMS) of vehicle vibration responses in practical engineering applications, the filtered white noise road spectrum is used as the road input model of vehicle system, and by using the random vibration theory and the integral solving method of complex variable function and based on quarter vehicle model, the RMS calculation formulae for the car body vertical vibration acceleration, the suspension dynamic deflection, and the wheel dynamic load are derived and verified by real vehicle test. The comparative analysis with the calculation results of traditional white-noise road spectrum input model indicates that the calculation formulae derived can more truly reflect the actual vibration of vehicle, while the traditional calculation model overestimates the vehicle vibration responses under high-speed operation. The formulae can be effectively applied to the estimation of vehicle driving vibration responses, the prediction of road grade, and the estimation of suspension damping ratio in vehicle initial design. References | Related Articles | Metrics

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Matching Design Method for Connection Structures of Composite Leaf Spring Ke Jun, Shi Wenku, Yuan Ke & Zhou Gang 2019, 41 (9):  1096-1101.  doi: 10.19562/j.chinasae.qcgc.2019.09.016 Abstract ( 221 )   PDF (1867KB) ( 395 )   Save In order to fulfill the matching design for the connection structures of the composite leaf spring in a light bus, the ultimate loads of the connection structures along different directions are obtained through multi-body dynamics simulation, and the parameter matching design method for the connection structure of composite leaf spring is proposed. According to the failure mode of connection structures, the design principle for the layup scheme of connection structure is proposed with the layup scheme optimized. Both fatigue bench test and real vehicle reliability test on the connection structures optimized are carried out. The results indicate that the designed connection structures of composite leaf spring can meet the requirements for installation on vehicles, having a great significance to ensure the reliability of composite leaf spring assembly and promote its popularization and application. References | Related Articles | Metrics

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Multi-objective Lightweight Optimization of Parametric FrontendBIW Structure Based on Analysis-driven Design Zhang Shuai, Guo Zhijun & Wang Chuanqing 2019, 41 (9):  1102-1107.  doi: 10.19562/j.chinasae.qcgc.2019.09.017 Abstract ( 278 )   PDF (1742KB) ( 559 )   Save The parametric frontend model built with SFE-CONCEPT software and the finite element model for the rest part of body-in-white (BIW) are put together to form a complete BIW model, and the complete model of vehicle is composed by all subassemblies using modularization technique. A frontal crash safety simulation on vehicle model is conducted and its results are compared with that of real vehicle test, verifying the effectiveness of frontal crash safety simulation. The frontal crash safety parameters including acceleration peak are extracted by editing batch script file, truly embodying the concept of “analysis driven design”. Six shape variables and seven panel thicknesses in parametric frontend BIW are chosen as design variables for lightweight optimization. The optimal Latin hypercube scheme in the design of experiment is chosen to generate sample points, fulfilling the automatic construction and accuracy verification of Kriging metamodel. NSGA-II algorithm is adopted to perform optimization with compromised solution set obtained, from which the one with the minimum mass of frontend BIW is finally selected as the optimum solution. After optimization the mass of frontend BIW reduced by 7.02%, with its performances almost remain unchanged, the acceleration peak on left and right side lowers by 0.99% and 1.31%, while the average acceleration on left and right side increases by 15.41% and 8.67% respectively, and among four doors, some deformations increase and some deformations decrease with a maximum changing ratio of 10.6%. References | Related Articles | Metrics