Volume 45,Issue 10,2022 Table of Contents

1 Numerical simulation and experimental verification of shearing brittle materials

PU Jingyu , WANG Shilong , ZHOU Jie , YANG Bo , YI Lili , DONG Jianpeng , ZHOU Keyuan

2022, 45(10):1-10. DOI: 10.11835/j.issn.1000-582X.2021.13

[Abstract](446) [HTML](576) [PDF 3.97 M](1157)

Abstract:
The shearing of spent fuel assembly is a key step in the spent fuel reprocessing process. Due to the high radioactivity of spent fuel assembly, simulating assembly often combines brittle materials with stainless steel in shearing test research. In this study, Drucker-Prager model and Shear Damage model were combined to establish the shear constitutive model. As the typical representative of brittle materials, the mortar was chosen to be tested and the model was verified at the speed of 5, 20, 30, 40, and 50 mm/s. The experimental results matched with simulation well. Moreover, the shearing process of brittle materials were analyzed, including the elastic deflection, the plastic deflection and the breaking of the mortar. The results show that the shear force fluctuates in a certain range with shear speed increases from 5 mm/s to 50 mm/s, and the shear force first increases and then decreases with the increase of the tool clearance.

2 Prediction of long-term extreme response of offshore floating wind turbine based on environmental contour method

CHAI Ziyuan , ZHU Caichao , TAN Jianjun , SONG Chaosheng , WANG Ye

2022, 45(10):11-24. DOI: 10.11835/j.issn.1000-582X.2021.116

[Abstract](350) [HTML](548) [PDF 6.93 M](687)

Abstract:
To ensure the normal service of offshore floating wind turbine under complex environmental loads, such as wind and wave, it is necessary to evaluate the long-term extreme response of offshore floating wind turbine. Through the joint probability distribution of measured wind and wave, the combination of environmental conditions is obtained by the environmental contour methods based on the IFORM and the ISORM, and the short-term response is obtained by simulations. Combined with the Gumbel extreme value, the long-term extreme response of the wind turbine is calculated, and the extreme response analysis of the 50-year return period of the offshore floating wind turbine is realized. The results show that under the combined effect of wind and wave, with the increase of the mean wind speed, platform surge motion, bladed root out-of-plane bending moment, and tower base fore-aft bending moment first increase and then decrease; as the significant wave height increases, the maximum and mean values of platform surge motion and the maximum value of tower base fore-aft bending moment also increase. Compared with the environmental contour method based on IFORM, the environmental contour method based on ISORM can cover more combinations of environmental conditions and obtain greater long-term extreme response, which improves the safety of the wind turbine structure design.

3 Research on ADRC for pitch control of offshore floating wind turbine

WANG Shiqi , DU Xuesong , ZHU Caichao , TAN Jianjun , SONG Chaosheng , LIU Bin

2022, 45(10):25-37. DOI: 10.11835/j.issn.1000-582X.2021.15

[Abstract](344) [HTML](552) [PDF 2.70 M](601)

Abstract:
In order to effectively suppress the power fluctuations of the offshore floating wind turbine caused by the random wind and wave loads, a pitch active disturbance rejection control (ADRC) strategy was proposed. Considering aerodynamics, hydrodynamics, structure flexibility and pitch control, an aero-elastic-hydro-servo coupling dynamic model for the 5 MW offshore floating wind turbine was established. Pitch ADRC controller was designed based on the target of the constant torque control, in which the bandwidth setting method and BP neural network were used to set controller parameters. The suppression effects of the pitch ADRC on the power fluctuations were analyzed. The results show that the pitch ADRC based on bandwidth tuning and BP neural network tuning can effectively improve the pitch sensitivity and suppress the power fluctuation, and the fluctuation amplitude is reduced compared with the traditional PID control.

4 Modeling and optimization of hydrogen fast filling process with cascade storage system

BAI Yunfeng , ZHANG Caizhi , JIANG Shangfeng , ZHOU Zhiming

2022, 45(10):38-47. DOI: 10.11835/j.issn.1000-582X.2021.16

[Abstract](306) [HTML](492) [PDF 3.40 M](1052)

Abstract:
Due to the rapid compression and the Joule-Thompson effect of hydrogen during fast filling process, the internal temperature of the cylinder rises sharply, which may lead to hidden safety hazards. In this study, a mathematical model of a cascade storage system was developed to analyze the temperature rise in hydrogen cylinders under different working conditions. Results show that the pressure switching coefficient of the cascade storage system has a significant effect on the filling time, and the pre-cooling of hydrogen has a significant impact on the final temperature and the states of charge (S_OC) of the cylinder. Based on these results, a multi-objective optimization algorithm was proposed to optimize the above two controllable variables, taking filling time, energy consumption and S_OC within cylinders as optimizing objectives. The results show that the optimized method can significantly decrease the energy consumption, improve S_OC and allow acceptable refueling time.

5 Design and simulation analysis of the whole vehicle thermal management system for fuel cell vehicles

LU Chihua , WANG Liangxu , LIU Zhien , LIU Jianguo , ZHOU Jianjun

2022, 45(10):48-61. DOI: 10.11835/j.issn.1000-582X.2021.10

[Abstract](487) [HTML](645) [PDF 3.76 M](1250)

Abstract:
Taking a fuel cell vehicle as the research object, considering the vehicle layout environment and thermal management requirements comprehensively, a complete thermal management system of hydrogen fuel cell vehicle is designed. The key components are selected and designed to match the performance. At the same time, AMESim software is used to build a one-dimensional simulation model of thermal management system and verify its credibility. Using the coolant input flow rate, components’ inlet and outlet temperatures and temperature difference as the evaluation indicators, the simulation analysis of the thermal management system of hydrogen fuel cell vehicle under different working conditions is carried out. The results show that the system works well and meets the design requirements except that when the outlet water temperature of the stack and intercooler reaches the limit value under the peak condition, it is not suitable to work for a long time. The proposed thermal management system can provide some design ideas for the future research and development of the thermal management system of fuel cell vehicles.

6 Analysis of lubrication characteristics of plunger pair of pressure compensation pump in deep water

CAO Xuepeng , JU Jianyang , TIAN Fuyaun , WEI Changchen , DING Kai , WANG Deshuo , HE Zhanrui

2022, 45(10):62-76. DOI: 10.11835/j.issn.1000-582X.2021.026

[Abstract](333) [HTML](344) [PDF 2.07 M](564)

Abstract:
The pressure-compensated plunger pump can better adapt to the extreme deep water environment, but the extreme deep water environment will change the lubrication characteristics of the plunger pair, affecting its underwater working performance and application. Taking the lubrication characteristics of the auxiliary oil film of the pressure compensated pump as the research object, and considering the influence of environmental factors, such as deep water temperature and pressure, on the viscosity, density and other properties of the medium, a numerical model of the auxiliary oil film of the plunger in the deep water environment is established. The parameters that characterize the lubrication features, such as the thickness, pressure, leakage and axial friction of the plunger pair, are obtained by combining coordinate rotation optimization and finite difference discretization in the eccentric direction. The results show that when the water depth is 1 000 m and the rotation angle of the main shaft is about 90°, the auxiliary oil film of the plunger appears in an extremely thin area less than 1 μm, and the pressure difference reaches 80 MPa. When changing the spindle speed and the inclination angle of the swash plate, the leakage and axial friction changes more significantly under air conditions. Under different water depths, there is a positive correlation between the axial friction and the water depth, but the change in leakage is the opposite. This study can provide a useful reference for the design and development of pump plunger pairs in deep water environments.

7 Variable-step double-arc interpolation algorithm based on cycloid roller female mold matrix

XIAO Xiang , HUANG Jian , CHEN Jiahao , CHEN Bingkui

2022, 45(10):77-85. DOI: 10.11835/j.issn.1000-582X.2021.114

[Abstract](225) [HTML](776) [PDF 1.07 M](605)

Abstract:
The machining accuracy of the female mold matrix is a key factor affecting the manufacturing accuracy of the cycloid diamond roller. In order to improve the machining accuracy of the cycloidal roller female mold on the CNC (computer numerical control) machine tool, firstly, the basic curve equation of the cycloidal roller female mold is solved. Then, based on the double arc interpolation method, a mathematical model of the variable-step double-arc interpolation of the cycloidal roller female mold is established. The interpolation node data are obtained by using numerical analysis method, and the interpolation error can be adjusted by controlling the step length expansion. The feasibility of the algorithm is verified by calculation examples. The results show that the double-arc interpolation error is less than 0.01 μm, which is 75% lower than the linear interpolation error. By controlling the step length expansion, the number of fitting arc segments is reduced by 55% under the same tolerance, and the processing efficiency is improved. Moreover, the machining simulation curve fitted by the interpolation data is smooth and flat, and the tool path has G1 continuity.

8 Fault diagnosis of centrifugal blowers based on multi-source information fusion and ADCNN

ZHANG You , LI Congbo , LIN Lihong , WANG Rui

2022, 45(10):86-96. DOI: 10.11835/j.issn.1000-582X.2021.08

[Abstract](266) [HTML](738) [PDF 10.79 M](623)

Abstract:
The fault information of the single sensor signal is limited in the process of centrifugal blower fault recognition, and the traditional convolutional neural network (CNN) has poor feature extraction abilities when processing multi-source high-dimensional data. To address these problems, this paper proposes a fault diagnosis method based on multi-source information fusion and adaptive deep convolutional neural network (ADCNN) for centrifugal blowers. Firstly, data-level fusion of multi-source homogeneous information of the centrifugal blower is realized based on correlation variance contribution rate method, and a multi-source information fusion framework is established. Then, ADCNN is used to adaptively extract the features of heterogeneous information and complete feature fusion, and an ADCNN fault diagnosis model that integrates multi-source information is constructed. Finally, the proposed method is applied to the fault diagnosis of the centrifugal blower rotor and compared with the traditional fusion method, as well as CNN, BPNN, and SVM. The experiment results show that the proposed method has superior diagnosis accuracy and robustness than other methods.

9 Coordinated control of torque distribution and acceleration slip regulation for front- and rear-independent-drive electric vehicles

GUO Cong , FU Chunyun , ZHAI Jun , CAO Kaibin , LUO Ronghua , LIU Yang , PAN Hongwei , QIAO Shuaipeng

2022, 45(10):97-112. DOI: 10.11835/j.issn.1000-582X.2021.121

[Abstract](386) [HTML](451) [PDF 11.37 M](590)

Abstract:
In order to improve the overall performance of front- and rear-independent-drive electric vehicles, a coordinated control strategy (CCS) is proposed to integrate the control actions of front-rear torque distribution controller and acceleration slip regulation controller. Firstly, an economy-oriented torque distribution controller and an acceleration slip regulation controller based on sliding mode control theory are designed. Then, a coordinated control strategy integrating the effects of the two controllers is proposed. Different from the existing integrated control strategies, instead of a simple combination of front-rear torque distribution and acceleration slip regulation control, the proposed strategy is a reasonable and effective integration which takes into consideration of vehicle safety, economy and dynamic performance. Under normal driving conditions, the vehicle operates in an economic mode by default, and the proposed CCS monitors the slip ratio of each wheel in real time. When the road condition deteriorates and economic driving cannot be sustained, appropriate torque compensation is applied without jeopardizing vehicle safety. By this means, road adhesion is made full use of and vehicle dynamic performance is optimized. Finally, the proposed CCS is verified through simulation studies in the MATLAB/CarSim environment. The simulation results show that when the opening of the accelerator pedal is 10%, 30% and 50%, the proposed CCS improves the vehicle dynamic performance by 15.3%, 35.6% and 4.5%, respectively, compared to traditional integrated control strategy (TICS).

10 Reinforcement learning NSGA-II for multi-objective flexible job shop scheduling

YIN Aijun , YAN Wentao , ZHANG Houwang

2022, 45(10):113-123. DOI: 10.11835/j.issn.1000-582X.2021.19

[Abstract](526) [HTML](757) [PDF 4.91 M](1070)

Abstract:
Non-dominated sorting genetic algorithm II (NSGA-II) has the shortcomings of insufficient diversity, prematurity and local convergence in solving the multi-objective optimal scheduling problem in flexible job shop. In this study, an improved NSGA-II algorithm based on reinforcement learning (RLNSGA-II) is proposed. To avoid NSGA-II to fall into the problem of local convergence, a two-population evolution strategy is introduced. The sex determination method is used to split the population into two populations, and different cross mut-ation operators are used in the evolution process to increase the local and global search capabilities of the algorithm. In order to solve the problem of insufficient diversity caused by the NSGA-II elite strategy, multiple diversity metrics are integrated, and reinforcement learning is used to dynamically optimize the split ratio parameters in the population iteration process to maintain diversity and improve algorithm convergence performance. Finally, simulation experiments and performance analysis are carried out through Kacem standard calculation examples, verifying the effectiveness and superiority of RLNSGA-II.

11 Prioritized multi-task method of iteratively successive projection

WANG Chuoyun , TANG Xianzhi , JIANG Pei , WANG Yan , LI Huaqiang

2022, 45(10):124-133. DOI: 10.11835/j.issn.1000-582X.2021.17

[Abstract](240) [HTML](336) [PDF 4.77 M](693)

Abstract:
The insertion and removal of tasks in the task priority hierarchy always cause the problem of the joint velocity discontinuity. In this paper, an iteratively successive projection multi-task priority method is proposed based on the iteratively successive projection mechanism. Based on Lyapunov’s stability theory, the stability of the proposed method is verified under the condition that iteration times tend to infinity. Taking the obstacle avoidance task as the primary task and the trajectory tracking task as the secondary task, the performance of the iteratively successive projection multi-task priority method is simulated and compared with the traditional augmented projection multi-task priority method. Simulation results show that obstacle avoidance tasks are inserted into the priority hierarchy when approaching obstacles, and the iteratively successive projection multi-task priority method can ensure the joint velocity continuity. In addition, within the ability of redundancy, the end trajectory tracking task is performed as much as possible, and the convergence of the tracking error is guaranteed.

12 Application of improved NSGA2 algorithm in aero piston engine assembly

LI Chunlin , PANG Xiaoping , ZHANG Guo

2022, 45(10):134-144. DOI: 10.11835/j.issn.1000-582X.2021.20

[Abstract](276) [HTML](836) [PDF 3.94 M](708)

Abstract:
In the selective assembly of complex mechanical products, there is the replication phenomenon of individual components and parts. This paper proposes an improved multi-objective optimization NSGA2(non-dominated sorting genetic algorithm-2) based on an elite reserved strategy of the offspring combining population evenness and crowding degree. With assembly qualified rate and assembly precision as the quality evaluation index, a multi-objective optimization model for selective assembly is established. The deficiencies of the local search capability of the NSGA2 algorithm is overcome by introducing the nearest neighbor search operator. Taking the assembly of a certain type of aircraft piston engines as an example with the optimization result represented by the Pareto boundary set, the results show that the diversity and astringency of the non-dominated solution sets (non-dominated solution sets) are obtained after the algorithm is improved.

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