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One Step Positive Approach for Sheet Metal Forming simulation Based on Quasi-conjugate-gradient Method

Chinese Journal of Mechanical Engineering 2013年第4期26卷 730-736页

作者： NA Jingxin CHEN Wei State Key Laboratory of Automotive Simulation and Control Jilin University

In one step inverse finite element approach, an initial blank shape is normally predicted from the final deformed shape. The final deformed shape needs to be trimmed into a final part after stamping, the trimmed area, therefore, needs to be compensated manually before using one step inverse approach, which causes low efficiency and in consistency with the real situation. To solve this problem, one step positive approach is proposed to simulate the sheet metal stamping process. Firstly the spatial initial solution of one step positive method is preliminarily obtained by using the mapping relationship and area coordinates, then based on the deformation theory the iterative solving is carried out in three-dimensional coordinate system by using quasi-conjugate-gradient method. During iterative process the contact judgment method is introduced to ensure that the nodes on the spatial initial solution are not separated from die surface. The predicted results of sheet metal forming process that include the shape and thickness of the stamped part can be obtained after the iterative solving process. The validity of the proposed approach is verified by comparing the predicted results obtained through the proposed approach with those obtained through the module of one step inverse approach in Autoform and the real stamped part. In one step positive method, the stamped shape of regular sheet can be calculated fast and effectively. During the iterative solution, the quasi-conjugate-gradient method is proposed to take the place of solving system of equations, and it can improve the stability and precision of the algorithm.

关键词： positive approach deformation theory quasi-conjugate-gradient method

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Dual Extended Kalman Filter for Combined Estimation of Vehicle state and Road Friction

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Chinese Journal of Mechanical Engineering 2013年第2期26卷 313-324页

作者： ZONG Changfu HU Dan ZHENG Hongyu State Key Laboratory of Automotive Simulation and Control Jilin University

Vehicle state and tire-road adhesion are of great use and importance to vehicle active safety control systems. However, it is always not easy to obtain the information with high accuracy and low expense. Recently, many estimation methods have been put forward to solve such problems, in which Kalman filter becomes one of the most popular techniques. Nevertheless, the use of complicated model always leads to poor real-time estimation while the role of road friction coefficient is often ignored. For the purpose of enhancing the real time performance of the algorithm and pursuing precise estimation of vehicle states, a model-based estimator is proposed to conduct combined estimation of vehicle states and road friction coefficients. The estimator is designed based on a three-DOF vehicle model coupled with the Highway Safety Research Institute（HSRI） tire model; the dual extended Kalman filter （DEKF） technique is employed, which can be regarded as two extended Kalman filters operating and communicating simultaneously. Effectiveness of the estimation is firstly examined by comparing the outputs of the estimator with the responses of the vehicle model in CarSim under three typical road adhesion conditions（high-friction, low-friction, and joint-friction）. On this basis, driving simulator experiments are carried out to further investigate the practical application of the estimator. Numerical results from CarSim and driving simulator both demonstrate that the estimator designed is capable of estimating the vehicle states and road friction coefficient with reasonable accuracy. The DEKF-based estimator proposed provides the essential information for the vehicle active control system with low expense and decent precision, and offers the possibility of real car application in future.

关键词： vehicle state road friction coefficient estimation dual extended Kalman filter (DEKF)

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Identification of Maximum Road Friction Coefficient and Optimal Slip Ratio Based on Road Type Recognition

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Chinese Journal of Mechanical Engineering 2014年第5期27卷 1018-1026页

作者： GUAN Hsin WANG Bo LU Pingping XU Liang State Key Laboratory of Automotive Simulation and Control Jilin University

The identification of maximum road friction coefficient and optimal slip ratio is crucial to vehicle dynamics and ***,it is always not easy to identify the maximum road friction coefficient with high robustness and good adaptability to various vehicle operating *** existing investigations on robust identification of maximum road friction coefficient are *** this paper,an identification approach based on road type recognition is proposed for the robust identification of maximum road friction coefficient and optimal slip *** instantaneous road friction coefficient is estimated through the recursive least square with a forgetting factor method based on the single wheel model,and the estimated road friction coefficient and slip ratio are grouped in a set of samples in a small time interval before the current time,which are updated with time *** current road type is recognized by comparing the samples of the estimated road friction coefficient with the standard road friction coefficient of each typical road,and the minimum statistical error is used as the recognition principle to improve identification *** the road type is recognized,the maximum road friction coefficient and optimal slip ratio are *** numerical simulation tests are conducted on two typical road friction conditions（single-friction and joint-friction）by using CarSim *** test results show that there is little identification error between the identified maximum road friction coefficient and the pre-set value in *** proposed identification method has good robustness performance to external disturbances and good adaptability to various vehicle operating conditions and road variations,and the identification results can be used for the adjustment of vehicle active safety control strategies.

关键词： maximum road friction coefficient optimal slip ratio road type recognition recursive least square

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control of water contamination on side window of road vehicles by A-pillar section parameter optimization

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Journal of Hydrodynamics 2020年第6期32卷 1138-1150页

作者： Li Xin Xing-jun Hu Jing-yu Wang State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun130025China

The water contamination on the side windows of moving vehicles is a crucial issue in improving the driving safety and the *** this paper,an effective optimization method is proposed to reduce the water contamination on the side windows of *** accuracy and the efficiency of the numerical simulation are improved by using the lattice Boltzmann method,and the Lagrangian particle tracking *** parameters are constructed on the basis of the occurrence of the water deposition on a vehicle’s side *** water contamination area of the side window and the aerodynamic drag are considered simultaneously in the design process;these two factors are used to form the multi-objective optimization function in the genetic algorithm(GA)*** approximate model,the boundary-seeded domain method,and the GA method are combined in this study to enhance the optimization *** optimization,the optimal parameters for the A-pillar section are determined by setting the boundary to an area of W=7.77 mm,L=1.27 mm and H=11.22 *** side window’s soiling area in the optimized model is reduced by 66.93%,and the aerodynamic drag is increased by 0.41%only,as compared with the original *** is shown that the optimization method can effectively solve the water contamination problem of side windows.

关键词： Water contamination aerodynamic drag A-pillar section parameters multi-objective optimization approximate model genetic algorithm

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Target Vehicle Selection Algorithm for Adaptive Cruise control Based on Lane-changing Intention of Preceding Vehicle

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Chinese Journal of Mechanical Engineering 2021年第5期34卷 390-407页

作者： Jun Yao Guoying Chen Zhenhai Gao State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130022China

To improve the ride comfort and safety of a traditional adaptive cruise control(ACC)system when the preceding vehicle changes lanes,it proposes a target vehicle selection algorithm based on the prediction of the lane-changing intention for the preceding ***,the Next Generation simulation dataset is used to train a lane-changing intention prediction algorithm based on a sliding window support vector machine,and the lane-changing intention of the preceding vehicle in the current lane is identified by lateral position ***,according to the lane-changing intention and collision threat of the preceding vehicle,the target vehicle selection algorithm is studied under three different conditions:safe lane-changing,dangerous lane-changing,and lane-changing ***,the effectiveness of the proposed algorithm is verified in a co-simulation *** simulation results show that the target vehicle selection algorithm can ensure the smooth transfer of the target vehicle and effectively reduce the longitudinal acceleration fluctuation of the subject vehicle when the preceding vehicle changes lanes safely or cancels their lane change *** the case of a dangerous lane change,the target vehicle selection algorithm proposed in this paper can respond more rapidly to a dangerous lane change than the target vehicle selection method of the traditional ACC system;thus,it can effectively avoid collisions and improve the safety of the subject vehicle.

关键词： Lane-changing intention Target vehicle selection Support vector machine Adaptive cruise control

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A reduced combustion mechanism of ammonia/diesel optimized with multi-objective genetic algorithm

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Defence Technology（防务技术） 2024年第4期34卷 187-200页

作者： Wanchen Sun Shaodian Lin Hao Zhang Liang Guo Wenpeng Zeng Genan Zhu Mengqi Jiang State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130025China

For the deep understanding on combustion of ammonia/diesel,this study develops a reduced mechanism of ammonia/diesel with 227 species and 937 *** sub-mechanism on ammonia/interactions of N-based and C-based species(N—C)/NOx is optimized using the Non-dominated Sorting Genetic Algorithm II(NSGA-II)with 200 *** optimized mechanism(named as 937b)is validated against combustion characteristics of ammonia/methane(which is used to examine the accuracy of N—C interactions)and ammonia/diesel *** ignition delay times(IDTs),the laminar flame speeds and most of key intermediate species during the combustion of ammonia/methane blends can be accurately simulated by 937b under a wide range of *** for ammonia/diesel blends with various diesel energy fractions,reasonable predictions on the IDTs under pressures from 1.0 MPa to5.0 MPa as well as the laminar flame speeds are also achieved by *** particular,with regard to the IDT simulations of ammonia/diesel blends,937b makes progress in both aspects of overall accuracy and computational efficiency,compared to a detailed ammonia/diesel *** kinetic analysis reveals that the reaction pathway of ammonia during the combustion of ammonia/diesel blend mainly differs in the tendencies of oxygen additions to NH_2 and NH with different equivalence ratios.

关键词： Ammonia Diesel Combustion Kinetic mechanism Multi-objective optimization

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MPC‑Based Coordinated control of Gear Shifting Process for a Power‑split Hybrid Electric Bus with a Clutchless AMT

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Chinese Journal of Mechanical Engineering 2022年第6期35卷 377-389页

作者： Tong Liu Xiaohua Zeng Dafeng Song State Key Laboratory of Automotive Simulation and Control Jilin UniversityChangchun 130025China

Two-speed clutchless automated manual transmission(AMT)has been widely implemented in electric vehicles for its simple structure and low *** contrast,due to the complex response characteristics of powertrain,utilizing clutchless AMT in a hybrid power system comes with complex coordination control *** order to address these issues,a power-split hybrid electric bus with two-speed clutchless AMT is studied in this paper,and a coordinated control method based on model predictive control(MPC)is used in gear shifting control strategy(GSCS)to improve gear shifting quality and reduce system ***,the dynamic model of power sources and other main powertrain components including a single planetary gear set and AMT are established on the basis of data-driven and mechanism modeling ***,the GSCS is put forward using the segmented control idea,and the shifting process is divided into five phases,including(I)unloading of drive motor,(II)shifting to neutral gear,(III)active speed synchronization by drive motor,(IV)engaging to new gear,and(V)resuming the drive motor’s power,among which the phases I and V have evident impact on the system ***,the MPC-based control method is adopted for these phases,and the fast compensation of driving torque is realized by combining the prediction model and quadratic programming *** simulation results show that the proposed GSCS can effectively reduce shift jerk and improve driving *** research proposes a coordinated control strategy of two-speed clutchless AMT,which can effectively improve the smoothness of gear shifting and provides a reference for the application of two speed clutchless AMT in power-split hybrid powertrains.

关键词： Power-split hybrid electric bus Shift jerk Model predictive control

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Estimation of vehicle states and tire-road friction using parallel extended Kalman filtering

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2011年第6期12卷 446-452页

作者： Chang-fu ZONG Pan SONG Dan HU State Key Laboratory of Automotive Simulation and Control Jilin University Changchun 130025 China

A model-based estimator design and implementation is described in this paper to undertake combined estimation of vehicle states and tire-road friction *** estimator is designed based on a vehicle model with three degrees of freedom(3-DOF) and the dual extended Kalman filter(DEKF) technique is *** of the estimation is examined and validated by comparing the outputs of the estimator with the responses of the vehicle model in CarSim in three typical road adhesion conditions(high-friction,low-friction,and joint-friction roads).simulation results demonstrate that the DEKF estimator algorithm designed is able to obtain vehicle states(e.g.,yaw rate and roll angle) as well as road friction coefficients with reasonable accuracy.

关键词： Vehicle dynamics state estimation and system identification Active safety and passive safety

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Water medium retarders for heavy-duty vehicles:Computational fluid dynamics and experimental analysis of filling ratio control method

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Journal of Hydrodynamics 2017年第6期29卷 1067-1075页

作者：郑宏鹏雷雨龙宋鹏翔 State Key Laboratory of Automotive Simulation and Control College of Automotive EngineeringJilin UniversityChangchun 130022China

The water medium（WM） retarder is an auxiliary braking device that could convert the kinetic energy of the vehicle to the thermal energy of the coolant, and it is used instead of the service brake under non-emergency braking conditions. This paper analyzes the flow distribution based on a mathematical model and analyzes the key factors that could affect the filling ratio and the braking torque of the WM retarder. Computational fluid dynamics（CFD） simulations are conducted to compute the braking torque, and theresults are verified by experiments. It is shown that the filling ratio and the braking torque can be expressed by the mathematical model proposed in this paper. Compared with the Reynolds averaged Navier-Stokes（RANS） turbulent model, the shear stress transport（SST） turbulent model can more accurately simulate the braking torque. Finally, the flow distribution and the flow character in the WM retarders are analyzed.

关键词： Heavy duty vehicle braking system water medium retarder computational fluid dynamics filling ratio control method

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Challenges and developments of automotive fuel cell hybrid power system and control

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Science China(Information Sciences) 2019年第5期62卷 50-74页

作者： Jinwu GAO Meng LI Yunfeng HU Hong CHEN Yan MA State Key Laboratory of Automotive Simulation and Control Jilin University Department of Control Science and Engineering Jilin University

Fuel cells are emerging as promising power sources and have attracted increasing attention from industries and academics worldwide. In particular, automotive manufacturers are replacing internal combustion engines in vehicles with fuel cell systems, which are advantaged by zero emissions, high efficiency,and various clean routes that generate pure hydrogen. However, current fuel cell systems are costly, and their corresponding infrastructures are not fully qualified to meet current market demand. This paper reviews the challenges and developments of automotive fuel cell hybrid power systems and their controls. It briefly summarizes the model, control, and optimization issue associated with the research and application of fuel cells in hybrid power systems. After presenting the basic knowledge and discussing the trending size and structure of fuel cells for automotive usage, the review describes models of automotive fuel cell systems,focusing on the electrochemical reaction dynamics and the key parameters influencing their efficiency and lifetime. The control problems associated with automotive fuel cell systems as well as the optimization issue associated with hybrid energy systems(comprising fuel cells, batteries, and ultra-capacitors) are elaborately analyzed. The review concludes with current problems and challenges faced by the energy control systems of fuel cell vehicles.

关键词： fuel cell system automotive fuel cell control optimization issue hybrid energy system

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