Table of Content

25 February 2020, Volume 42 Issue 2 Previous Issue    Next Issue

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Sliding Mode Active Disturbance Rejection Control for Dynamic Load Emulation of the Electric Braking System Ma Ruihai, Wang Lifang, Zhang Junzhi, He Chengkun 2020, 42 (2):  141-148.  doi: 10.19562/j.chinasae.qcgc.2020.02.001 Abstract ( 410 )   PDF (1160KB) ( 466 )   Save To accurately emulate the nonlinear mechanical loads of the electric braking system with consideration of the backlash and elasticity in a transmission system, a dynamometer control algorithm based on an adaptive fuzzy sliding mode active disturbance rejection control is proposed. Firstly, the mechatronics model for a front axle drive electric vehicle and the test bench with the integrated induction motor model is established, and the typical normal braking and anti-lock braking control strategies are introduced as the test objects. Then, an extended state observer is constructed to estimate the unmodelled dynamics of the test bench system, and the adaptive fuzzy sliding mode control is adopted as the dynamometer regulator to emulate the highly nonlinear mechanical loads. Finally, simulations of bench tests on the braking control strategies are carried out. The results show that the proposed method can accurately simulate the dynamic load of the electric braking system and effectively improve the bench test accuracy of the braking control algorithm References | Related Articles | Metrics

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Research on Control Strategies of Two-stage Turbocharging System with Turbo By-pass Valves at Variable Altitudes Zhang Zhongjie, Liu Ruilin, Yang Chunhao, Zhang Junyi, Jiao Yufei 2020, 42 (2):  149-156.  doi: 10.19562/j.chinasae.qcgc.2020.02.002 Abstract ( 249 )   PDF (2394KB) ( 413 )   Save In order to solve the boost pressure control problems of regulated two-stage turbocharged diesel engine under whole operating conditions at varying altitudes, the working process model of a two-stage turbocharged diesel engine at high altitudes is established by GT-POWER and verified by experimental data. The control scheme of the regulated two-stage turbocharging system at different altitudes is designed, and the optimal opening of high-pressure turbo-valve, low-pressure turbo-valve and boost pressure are obtained by optimization calibration. The effect of PID closed-loop control based on boost pressure and open-loop control based on turbo by-pass valve opening on the transient performance of diesel engine at high altitude is compared by simulation and test. The results show that, compared with the plain, the time when the boost pressure first reaches 90% of the target value at the altitudes of 3 000 and 5 000 m increases by 0.11 and 0.19 s respectively based on PID closed-loop control. Compared with PID closed-loop control, the time when the boost pressure first reaches the target value under open-loop control shortens by 0.09,0.197 and 0.14 s at the altitudes of 0,3 000 and 5 000 m, but there exists a certain deviation between actual boost pressure value and target boost pressure value. Based on this, the control algorithm combining the PID closed-loop feedback control of boost pressure with the open-loop control of turbo bypass valve can take into consideration of the robustness and accuracy of the transient process of the two-stage boost system at the same time. It is an ideal control algorithm for the transient process of the two-stage boost system at high altitude in the future References | Related Articles | Metrics

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Multiple Injection Distribution of Electronically Controlled Injector in Typical Working Conditions of Diesel Engine Wang Jun, Jin Yi, Zhang Youtong, Ding Xiaoliang, Han Shu 2020, 42 (2):  157-163.  doi: 10.19562/j.chinasae.qcgc.2020.02.003 Abstract ( 240 )   PDF (754KB) ( 812 )   Save To improve the effect of energy-saving and emission-reduction of diesel engine, the brief analysis of the form and function of multiple injection is firstly made. Six typical working conditions of diesel engine for vehicle are determined based on operation in different road conditions, and then the distribution method of multiple injection is proposed based on the working condition emission limit. The emission limit value of typical working conditions is determined by the emission-sharing rate of the working condition and the injection times and injection combination solutions are optimized. Finally, combined with the bench test of 4JB1 high-pressure common rail diesel engine, taking NOx and smoke as the evaluation parameters and taking into consideration of the change of fuel consumption rate, the influence of different injection combinations on the emission of diesel engine is analyzed. The results show that it is advisable to use two injections for idle speed and medium speed and heavy load conditions, triple injections for low speed and small load conditions and medium speed and medium load conditions, quadruple injections for medium speed and light load conditions, one injection for high speed and heavy load conditions, which shows that the distribution method of multiple injection based on the restriction of emission value is valid References | Related Articles | Metrics

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Experimental Research on Nozzle Fuel Cavitation and the Influencing Factors Gao Yongqiang, Zhong Bing, Tao Lili, Liu Yonghui, Wang Xibo, Zhang Kesong 2020, 42 (2):  164-171.  doi: 10.19562/j.chinasae.qcgc.2020.02.004 Abstract ( 214 )   PDF (5357KB) ( 396 )   Save Atomization of diesel engine fuel injection is not only influenced by the turbulence and aerodynamic force effect of ambient gas,but also related to the cavitation in the nozzle. Therefor, it is of great importance to study the fuel cavitation in the nozzle and the influencing factors. A transparent nozzle is designed to replace the original injector of the diesel engine. With a nanosecond level flash lamp as the exposure light source, the high speed digital camera and the high-magnification, high-resolution long-distance micro imaging technology, the experimental images with high resolution and clarity are obtained. The generation, development and distribution of fuel cavitation in the nozzle of diesel engine are observed. The fuel cavitation in the nozzle and its influence law are visually presented and a direct understanding of the process of fuel cavitation is obtained. The results show that the cavitation flow in the nozzle is complex and has many influencing factors, among which the geometry of the nozzle has the most significant influence on the cavitation process. The cavitation in the nozzle first appears near the needle valve of the pressure chamber, and then the cavitation area spreads and extends to the outlet of the nozzle. For the gradually shrinking nozzle, the cavitation formation is inhibited, while the gradually expanding nozzle is conducive to the cavitation formation. Reducing the diameter of the nozzle is not conducive to cavitation. The environment pressure has inhibiting effect on cavitation and the increase of environmental pressure is not conducive to the formation of cavitation. In addition, the cavitation intensity in the nozzle is described quantitatively, and the image obtained from the experiment is analyzed quantitatively through the cavitation intensity References | Related Articles | Metrics

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Study on Adaptive Decoupling Control Algorithm for Air Supply System of Vehicle Proton Exchange Membrane Fuel Cell Zhou Su, Hu Zhe, Xie Fei 2020, 42 (2):  172-177.  doi: 10.19562/j.chinasae.qcgc.2020.02.005 Abstract ( 385 )   PDF (1224KB) ( 583 )   Save When the performance of air compressor degrades or its static characteristics change, the control quality of the air supply system in proton exchange membrane fuel cell by using feedforward compensation decoupling closed-loop control algorithm will deteriorate. In view of this, an adaptive table-lookup algorithm is added onto the feedforward compensation decoupling closed-loop control algorithm, to enhance the speed adjustment capability of air compressor. The results of hardware-in-the-loop simulation show that the improved adaptive decoupling control algorithm can online and adaptively update the air compressor speed calibration table, thus effectively eliminating the phenomenon of integral saturation in PI regulator, speeding up the response of air compressor and improving the control effect of inlet air flow References | Related Articles | Metrics

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A Multi-Objective Optimization Method for the Spherical Hinge of a Thrust Rod Based on the Finite Element Method and Genetic Algorithm Ke Jun, Zu Hongfei, Shi Wenku 2020, 42 (2):  178-183.  doi: 10.19562/j.chinasae.qcgc.2020.02.006 Abstract ( 277 )   PDF (1807KB) ( 419 )   Save In order to optimize the structure of the spherical hinge of a thrust rod and improve its fatigue life, a multi-objective optimization method for the spherical hinge of a thrust rod based on the finite element analysis (FEA) and genetic algorithm (GA) is proposed. The strain distribution characteristics of the rubber bushing and the stiffness parameters of the thrust rod are obtained at different precompression values and spherical hinge structures using FEA. Moreover, the relationships among the stiffness of the thrust rod, the precompression value of the rubber bushing, and the key structural parameters of the spherical hinge are obtained. On this basis, the multi-objective optimization model for the thrust rod spherical hinge is established using the genetic algorithm. The optimum scheme of the spherical hinge is obtained by using the multi-objective optimization model. The sample bench test results show that the fatigue life of the thrust rod spherical hinge is increased by seven times with the optimum scheme. The proposed multi-objective optimization method not only enriches the design theory of variable cross-section rubber-metal composite structure, but also provides a theoretical basis for the optimal design of thrust rods References | Related Articles | Metrics

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Coordinated Control of Vehicular Platooning Based on Nonlinear Model Predictive Control Yang Xiujian, Li Jinyu 2020, 42 (2):  184-190.  doi: 10.19562/j.chinasae.qcgc.2020.02.007 Abstract ( 340 )   PDF (1042KB) ( 568 )   Save For the problem of the lack of connection between the upper and lower control of vehicular platoon based on hierarchical control, this paper puts forward the idea of coordinated control of vehicle platoon following and individual vehicle dynamics stability. The basic idea is to realize the objective of vehicle following control as much as possible while ensuring the safe and stable driving of the individual vehicles. A coordinated control scheme is designed by the nonlinear model predictive control (NMPC) method, and the optimization objective function consisting of three sub-objectives of the spacing error and the velocity error between two adjacent vehicles, and the difference of vehicle speed and wheel circumferential speed is designed. Hence, the coordinated control scheme is transformed into an optimal control problem with constraints, which is solved based on the sequential quadratic programming (SQP) method and the braking/driving torques of the front and rear axles are obtained to achieve the desired following acceleration of the upper decision-making output. The simulation analysis of the proposed control scheme is carried out based on the nonlinear platoon model composed of three vehicles. The results show that the proposed NMPC based coordinated control scheme can well realize vehicle following control while simultaneously ensuring safe and stable driving of the individual vehicle in a broad range of operating conditions References | Related Articles | Metrics

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Stability Control of Vehicle with Active Front Steering Under Extreme Conditions Li Shaosong, Guo Konghui, Qiu Tao, Chen Hong, Wang Guodong, Cui Gaojian 2020, 42 (2):  191-198.  doi: 10.19562/j.chinasae.qcgc.2020.02.008 Abstract ( 452 )   PDF (1187KB) ( 761 )   Save Tire has an important influence on vehicle stability. Studying and utilizing the nonlinear characteristics of tire is conducive to expanding the stability region of vehicle. In this paper, a modified linear time-varying model predictive control (LTV-MPC) method is proposed based on nonlinear tire model. The proposed method can expand the stability region of the vehicle with active front steering and enhance vehicle stability under extreme conditions. Simulation results show that the proposed method has better control effects than the traditional LTV-MPC References | Related Articles | Metrics

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Estimation of In-wheel Motor Driven Electric Vehicle Speed and Road Gradient Chen Hao, Yuan Liangxin, Sun Tao, Zheng Sifa, Lian Xiaomin 2020, 42 (2):  199-205.  doi: 10.19562/j.chinasae.qcgc.2020.02.009 Abstract ( 380 )   PDF (1317KB) ( 630 )   Save Aiming at the estimation of vehicle speed and road gradient, a first-order extended state observer based on longitudinal non-linear dynamic equation is designed to jointly estimate the vehicle speed and road gradient with the steady-state error of estimation analyzed. Meanwhile, the recursive least squares estimation algorithm with forgetting factor is used to separate the gradient information from acceleration sensor signals, and the proportional coefficients are set to fuse two-types of gradient information and finally obtain the estimation value of road gradient. The MATLAB/Simulink-Carsim co-simulation platform is built to conduct a simulation on variable gradient road, and a real vehicle test is also carried out on a slope. The results of simulation and real vehicle test show that the proposed method is simple and feasible References | Related Articles | Metrics

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Research on Hierarchical Control Strategy for Automatic Emergency Braking System with Consideration of Time-to-collision Lan Fengchong, Yu Meng, Li Shicheng, Chen Jiqing 2020, 42 (2):  206-214.  doi: 10.19562/j.chinasae.qcgc.2020.02.010 Abstract ( 371 )   PDF (1028KB) ( 807 )   Save In order to enhance the active safety of the vehicle, the control strategy for the vehicle automatic emergency braking system is studied. The control strategy is modeled with the idea of hierarchical control. The upper controller is a time-to-collision model for determining vehicle braking deceleration, which analyze the braking deceleration of brake system based on the drivers' emergency braking data of the vehicle rear-end accident depth investigation to determine the time-to-collision threshold with consideration of comfort. The lower controller analyzes the relationship between the tire model and the brake system according to the braking deceleration output from upper controller, and controls the vehicle by adjusting the braking pressure through PID control. The reliability of control strategy is verified under the standard condition of safety evaluation specifications and the effectiveness of the control strategy is validated through the reconstruction of rear-end accident scene. The results of simulation show that the control strategy devised can effectively avoid collisions with a relative speed lower than 65 km/h and can reduce the collision speed to the maximum extent with a relative speed higher than 65 km/h, reducing the severity of damage References | Related Articles | Metrics

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Design and Test of Integrated Performance Test System for Pneumatic Antilock Braking System in Commercial Vehicles Xia Xiaojing, Zhang Xiaolong, Feng Qifei, Wu Yanpeng, Jing Mei, Ding Wenjun 2020, 42 (2):  215-221.  doi: 10.19562/j.chinasae.qcgc.2020.02.011 Abstract ( 230 )   PDF (1475KB) ( 406 )   Save For solving the problems of low efficiency and inaccuracy in the performance test of the pneumatic antilock braking system (ABS) of commercial vehicles cause by the difficulty in accurately controlling brake pipeline pressure, an integrated performance test system for the pneumatic ABS of commercial vehicle is constructed based on virtual instrument technology. The brake pipeline pressure regulation device is designed according to the real brake pipeline structure, and the software developed based on NI LabVIEW platform is adopted to accurately regulate the brake pipeline pressure. Finally, both the test for pressure regulation device and the real vehicle field test for pneumatic ABS performance are conducted, verifying the accurate regulation effects on the brake pipeline pressure of commercial vehicle and the working reliability of the test system constructed References | Related Articles | Metrics

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Optimization Design of Vehicle Structural Crashworthiness with Consideration of Robustness Zhang Haiyang, Lü Xiaojiang, Zhou Dayong, Xia Liang, Gu Xianguang 2020, 42 (2):  222-227.  doi: 10.19562/j.chinasae.qcgc.2020.02.012 Abstract ( 390 )   PDF (2216KB) ( 519 )   Save Based on the condition of 40% overlap offset crash against deformable barrier in C-NCAP, the structural crashworthiness of a car is optimized in this paper. In order to enhance the predicted accuracy of output responses, the support vector regression model based on particle swarm optimization algorithm is employed to simulate the relationship between output responses and design variables, and the Pareto front of the proposed optimization problem is obtained by using non-dominated sorting multi-objective genetic algorithm II. On the basis of deterministic optimization with consideration of the fluctuation of product performance under the influence of uncertain factors, an optimization design for robustness is conducted. Finally, the results of optimization are verified by finite element simulation. The results show that after optimization the mass of structure is reduced, the crashworthiness is obviously enhanced, and the stable product performances are ensured References | Related Articles | Metrics

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Analysis on Child-head Protection Effects of Energy-absorbing Foam Filled in Safety Seat Li Haiyan, Li Jian, Cui Shihai, He Lijuan, Ruan Shijie, Lü Wenle 2020, 42 (2):  228-233.  doi: 10.19562/j.chinasae.qcgc.2020.02.013 Abstract ( 261 )   PDF (2490KB) ( 549 )   Save The deceleration curve, as a provision in regulation ECE R129, is applied on a validated 6-year-old child finite element model to simulate the head injury of rear-row child occupant in a side crash incident of vehicle by using software Pam-Crash. The child head protection effects of energy-absorbing foam blocks filled in the head-rest of the side wing of safety seat in a side impact are studied in terms of a series of indicators including the resultant acceleration of head mass center, head performance criterion, the Von Mises stress of brain tissue, intracranial pressure, shear stress and the contact force between foam and head. The results indicate that the foam filled in child safety seat can effectively reduce head injury in side impact, and in which the protective effect of PU foam is better than that of EPS foam References | Related Articles | Metrics

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Analysis on Thermal Comfort in Car Passenger Compartment Based on Flow Field and Temperature Field Lü Hongbin, Chen Bo, Gao Tianyuan, Li Yuanyuan, Shi Junye, Chen Jiangping 2020, 42 (2):  234-239.  doi: 10.19562/j.chinasae.qcgc.2020.02.014 Abstract ( 296 )   PDF (1578KB) ( 617 )   Save Based on flow field and temperature field, the effects of different inlet air temperatures on the thermal comfort of passenger compartment are analyzed in this paper. The simulation results well agree with experimental results, showing that under extreme hot conditions, increasing inlet air volume to the vicinity of critical one is conducive to rapid heat dissipation and avoiding excessive blowing sensation. High inlet air temperature will significantly deteriorate the cooling effect of occupants, but the air freshness in the compartment has little change. It is suggested that in designing air conditioning system, sufficient consideration should be given to the flow and cooling of air in the compartment, including the vicinity of passenger's feet, and by adjusting the grille angle of duct to avoid poor cooling due to the appearance of dead speed zone References | Related Articles | Metrics

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NVH Performance Analysis and Optimization of Automobile Drive Axl Jiao Dongfeng, Liu Zhifeng 2020, 42 (2):  240-249.  doi: 10.19562/j.chinasae.qcgc.2020.02.015 Abstract ( 409 )   PDF (1557KB) ( 780 )   Save In order to realize the analysis and optimization of NVH performance of automobile drive axle, the process and method of NVH performance analysis and optimization of drive axle are established. The methods of finite element, vibration response, acoustic simulation and topology optimization analysis used in the analysis process are comprehensively studied. Appropriate analysis methods, calculation methods and analysis software are selected. The noise problem of a bus in 60~65 km/h acceleration driving condition is analyzed and optimized as an example. Finally, the NVH test of the optimized driving axle is carried out to verify the validity of the established analysis process and method References | Related Articles | Metrics

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Research on Merging Prediction and Cruise Control for Connected Vehicles Zhang Tao, Zou Yuan, Zhang Xudong, Wang Wenwei 2020, 42 (2):  250-256.  doi: 10.19562/j.chinasae.qcgc.2020.02.016 Abstract ( 498 )   PDF (1265KB) ( 516 )   Save For detecting the driver's merging intention of the vehicle in adjacent lane and enhance the cruising active safety of connected vehicles,an iterative loop prediction algorithm based on nonlinear autoregressive(NAR)neural network learning is proposed. The training samples of NAR neural network are obtained from the merging data of vehicles in real traffic environment, the trained network is used to predict the lateral trajectory of the adjacent vehicle in a certain time-segment of future, and the cut-in probability of adjacent vehicle is calculated according to the designated monitoring area. Meanwhile, a follow-up distance strategy considering merging probability is also proposed and applied to the connected vehicle CACC system. The results show that the merging prediction algorithm proposed can accurately calculate the lateral lane change trajectory of adjacent vehicle, and the follow-up strategy proposed can enhance the follow-up safety of vehicle References | Related Articles | Metrics

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Lightweight Design of Carbon Fiber Reinforced Composite Battery Box Chen Jing, Peng Bo, Wang Dengfeng, Tang Aotian, Chen Shuming 2020, 42 (2):  257-263.  doi: 10.19562/j.chinasae.qcgc.2020.02.017 Abstract ( 338 )   PDF (1771KB) ( 517 )   Save The lightweight design of the battery box of an electric vehicle is conducted. Since the uppercase is mainly for sealing, structural optimization is taken as its lightweighting scheme; while the lowercase acts as a load-bearing component, thus its lightweighting scheme is using carbon fiber to replace original material. In the lightweight design of lowercase, multi-objective optimization algorithm is introduced. The results of simulation show that the lightweighting schemes adopted not only reduce the mass of battery box, but also effectively increase its stiffness and modal frequency References | Related Articles | Metrics

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Structural Optimization of Carbon Fiber Reinforced Plastic Crossbeam in Twist Beam Suspension Jiang Rongchao, Liu Yue, Liu Dawei, Wang Dengfeng, Sun Haixia 2020, 42 (2):  264-269.  doi: 10.19562/j.chinasae.qcgc.2020.02.018 Abstract ( 266 )   PDF (1457KB) ( 470 )   Save In view of the features of lightweight and high-strength of carbon fiber reinforced plastic (CFRP), the original steel crossbeam of twist beam suspension is substituted with CFRP one, and the structural optimization design of CFRP crossbeam is carried out. Firstly, the material mechanical parameters are obtained through the mechanical properties test on CFRP laminates. The finite element model of suspension twist beam is established, and a modification of the cross section of CFRP crossbeam is proposed. On this basis, with concurrent consideration of the mass, stiffness and process constraints of crossbeam, a multi-stage optimization is conducted on the thickness, orientation angle and laying sequence of the plies of CFRP crossbeam. After optimization, compared with the original steel crossbeam, the CFRP crossbeam gets a mass reduction of 79.34%, achieving a remarkable effect in mass reduction while meeting the requirements of performance indicators References | Related Articles | Metrics

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Research on Economic Speed Planning of Intelligent Vehicle for Starting Stage Jin Hui, Zhang Jun 2020, 42 (2):  270-277.  doi: 10.19562/j.chinasae.qcgc.2020.02.019 Abstract ( 333 )   PDF (1237KB) ( 438 )   Save The speed profile of an intelligent vehicle affects the fuel economy. To optimize the fuel economy of the vehicle under the acceleration condition in the starting stage, the transient fuel consumption model is established and the economic shift schedule method based on this model is proposed. Based on the longitudinal dynamic equation, the vehicle speed recursive equation based on the forward Euler discrete method is established, and the initial/final constraints and boundary conditions are given. Based on the principle of optimality of dynamic programming (DP), an economic speed planning method for the starting stage of intelligent vehicle is proposed, and correspondingly a speed search strategy is developed. Based on the joint simulation experiment of Matlab/Simulink and CarSim, the fuel consumption level of typical driver speed following mode is compared. The results show that the optimized economic speed profile and corresponding gear sequence by DP algorithm have good fuel-saving characteristics, which can provide guidance for the speed planning and gear planning of intelligent vehicle's eco-driving References | Related Articles | Metrics