Table of Content

10 December 2020, Volume 31 Issue 23

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Integrated Design of Vibration Isolation and Anti-shock for Complex System Reconstruction by Using System Emergence

WU Chongjian;YAN Xiaojie;DU Kun;CHEN Zhigang;HUANG Xichun;FU Aihua;ZHENG Lijie

2020, 31(23):  2773-2779.  DOI: 10.3969/j.issn.1004-132X.2020.23.001

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A concept of emergence was introduced, and the optimization of system was carried out through reconstruction by utilizing the inherent logical relationship between system elements and architecture and the external expression of architecture and form, so as to equip system with more positive emergence instead of negative emergence. A concept of reconstruction pole was put forward, and the method of comprehensive evaluation across systems was established through the comparison of reconstruction pole elements, thus the problem of complex giant system optimization was broken. The integrated case of vibration isolation and anti-shock shows that system reconfiguration may bring great benefits, and “two in one” reconstruction model may have a wide application prospect in optimization design of complex systems such as naval vessels and airplanes, etc.

Status and Development Trend of Domestic Heavy-duty CNC Machine Tools

GUI Lin;LI Sheng

2020, 31(23):  2780-2787,2797.  DOI: 10.3969/j.issn.1004-132X.2020.23.002

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Heavy-duty CNC machine tools were the machine tools for overweight and oversized components in energy, transportation industries and so on, which restricted the development of these industries. Combining the challenges of the design and manufacture of heavy-duty CNC machine tools in China, the technological breakthroughs and innovations of heavy-duty CNC machine tools were introduced with the example of a CNC seven-axis five-link propeller machining heavy-duty turning and milling machine tool CKX5680. The on-service domestic heavy-duty CNC machine tools and the encountered problems in the machining prosesses were proposed.Future development trends of heavy-duty CNC machine tools were prospected.

Development of High-light Optical Element Processing Technology

DAI Yifan;ZHONG Yaoyu;SHI Feng;TIAN Ye

2020, 31(23):  2788-2797.  DOI: 10.3969/j.issn.1004-132X.2020.23.003

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In order to realize low-defect fabrication of optical elements, detection and characterization methods of damage precursors related to laser damage performance were summarized herein. It was proposed that nanoscale damage precursors and chemical structural defects were the focus in low damage fabrication. Combined with the development of optical elements, methods for mitigating nanoscale damage precursor were discussed to effectively decrease nanoscale contaminations and chemical structural defects based on chemical-assisted magnetorheological polishing and ion beam sputtering cleaning technology. Three challenges in low-defect fabrication of optical elements in high fluence were introduced, which might be a reference for the clean manufacturing of optical elements.

Review on Hybrid Flow Shop Scheduling Problems

LI Yingli;LI Xinyu;GAO Liang

2020, 31(23):  2798-2813,2828.  DOI: 10.3969/j.issn.1004-132X.2020.23.004

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Hybrid flow shop scheduling problems (HFSP), one of popular research topics in the field of shop scheduling, several alternative parallel machines in all or part of stages of the flow-shop were introduced, and production capacity and flexibility of the shop were improved. Hybrid flow-shop scheduling methods were reviewed according to the number of stages and machine characteristics herein. Related extension problems in background of practical engineering were systematically summarized, and the existing problems and possible solutions were pointed out. Combined with development trend of operations research, application prospect of HFSP in emerging fields was discussed. Finally, some possible research directions in future were pointed out.

Experimental Study on Influence Factors of Friction Noises for Rotating Sliding Friction Pairs

WU Yuhou;ZHANG Jiayi;ZHANG Lixiu;WANG Junhai

2020, 31(23):  2814-2821.  DOI: 10.3969/j.issn.1004-132X.2020.23.005

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In order to explore the influence factors of sliding friction noises, a single factor experimental method was used to analyze the influences of surface roughness, relative velocity, load, friction pair material, and mass fraction of graphene in lubricating oil on sliding friction noises. Friction noises measured during the experiments were roughly divided into early stage, middle stage, and stable stage. The lower the surface roughness, the lower the friction noises. When rotation speed increases, the friction noises increase gradually. With the increases of rotation speeds, the growth rate declineds. Appropriate increases of loads are helpful to noise reduction. Graphene has excellent noise reduction effectiveness. Ceramic friction pairs have more advantages than bearing steel friction pairs.

Electrode Morphology in Dielectrophoresis Abrasive Flow Polishing

DENG Qianfa;ZHENG Tao;YUAN Julong;WANG Xu;ZHANG Xueliang;LYU Binghai

2020, 31(23):  2822-2828.  DOI: 10.3969/j.issn.1004-132X.2020.23.006

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A method of dielectrophoresis abrasive flow polishing was proposed for internal surface polishing of thin-walled ceramic workpieces. A non-uniform electric field was arranged on outer surfaces of the ceramic workpieces to be polished, and the abrasive particles were polarized to implement efficient polishing of the ceramic workpiece inner surfaces. Simulation results show that when electrode gap ratio is as 2, SiC abrasive particles have the best dielectrophoresis effectiveness and the most abrasive particles involved in polishing. When initial internal surface roughness value of workpiece Ra is as (208±5)nm, after 10 h polishing, the internal surface roughness value Ra of the workpiecess is as 51nm without dielectrophoresis effectiveness, and that of the workpieces is as 23 nm with dielectrophoresis effectiveness.

Early Fault Diagnosis Method of Rolling Bearings Based on DTD Transform-SCS Method

WAN Shuting;PENG Bo;WANG Xiaolong

2020, 31(23):  2829-2836.  DOI: 10.3969/j.issn.1004-132X.2020.23.007

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Aiming at the weak early fault characteristics of rolling bearings which were difficult to extract under interference of noise and harmonics, a fault diagnosis method was proposed based on DTD transform and SCS. Firstly, original signals were transformed by DTD transform, and the diagonal series of DTD spectrum was used as reconstructed signals. Secondly, the reconstructed signals were handled by SCS method to suppress the interference of noises and low-frequency harmonics. Finally, denoised signals were analyzed by envelope spectrum to extract fault characteristic frequency, judge fault type, and realize fault diagnosis. Analyzed results of simulation signals, experimental signals, and engineering signals show that the proposed method may effectively extract weak fault characteristics in the early fault signals of rolling bearings and accurately judge the fault type.

Design and Research of Multifunctional Dexterous Hands Based on Parallel Finger Structure

GONG Junshan;FANG Yuefa;JIN Xiaodong

2020, 31(23):  2837-2846.  DOI: 10.3969/j.issn.1004-132X.2020.23.008

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In order to meet requirements for the dexterity and carrying capacity of robot end grippers in industrial productions, a multifunctional dexterous hand was designed based on parallel finger structure. Firstly, kinematics, working spaces, and singularity of finger mechanisms were analyzed. Then, the carrying capacity of the dexterous hands was optimized and verified by ADAMS simulation. Prototype experiments show that the dexterous hands have ideal working spaces and good adaptability, and may realize conformable grasping of objects with different shapes, which makes the dexterous hands adapt to the requirements of flexible industrial productions.

Detection of Brake Requests Using Neural Network and Fuzzy Control

LIU Yanyu;YU Fan;SONG Juanjuan;PANG Jisu;KAKU Chuyo

2020, 31(23):  2847-2855.  DOI: 10.3969/j.issn.1004-132X.2020.23.009

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Aiming at ensuring the brake safety of vehicles, approaches for detecting driver brake requests weres investigated by applying neural network and fuzzy control. Firstly, neural network algorithm and fuzzy control algorithm were used to complete preliminary judgment of drivers braking demands. And then, completion degree of braking actions of the braking systems was predicted by feedback signals of the master cylinder pressure. Then the recognition results of braking demands were continuously fed back to track and modify in order to ensure the braking system of vehicles to achieve expected braking efficiency. The control algorithms were compared and validated by MATLAB/Simulink simulation tests and bench tests. The results show that the method may quickly and accurately identify the drivers braking demands and provide guarantee for vehicle braking safety.

Decision-making Method for Energy-saving Control of CNC Machine Tools Based on Transfer Learning

ZHANG Chaoyang;JI Weixi;PENG Wei

2020, 31(23):  2855-2863.  DOI: 10.3969/j.issn.1004-132X.2020.23.010

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In order to reduce energy consumption of machine tools in waiting processes, a energy-saving control decision-making method for CNC machine tools was proposed based on transfer learning. By analyzing energy-saving control conditions of machine tools, 5 energy-saving control strategies of the machine tools in waiting processes were proposed. Considering diversity and complexity of production data, an energy-saving decision-making method was established based on deep belief networks and transfer learning. Through analyzing a case of elevator part manufacturing workshops, it is found that energy saving decision errors of this method are as 3.2%, and the total energy consumption in machine tools waiting processes is reduced by 52.5%.

Dispersive Analysis and Accaracy Verification of Yield Strength Online Recognition

DUAN Yongchuan;QIAO Haidi;ZHANG Fangfang;LIU Yu;YANG Liu;GUAN Yingping

2020, 31(23):  2864-2873.  DOI: 10.3969/j.issn.1004-132X.2020.23.011

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Window vector method and standardized fitting residual method were constructed to identify yield parameters of sheet metals on line, and a yield response significance evaluation method was given. Influence mechanism of die sizes on yield recognition dispersion was analyzed from geometric point of view. Window vector method has better effectiveness and may eliminate dispersion of yield recognition brought by different hardening indices. The proposed two methods both use fitting algorithm and have certain anti-noise interference ability. Relative errors of real material yield strength which is predicted based on the window method are within 15%.

Vehicle Emergency Lane-changing Behavior Prediction Method Based on GMM-HMM and ANN

YU Yang;LIANG Jun;CHEN Long;CHEN Xiaobo;ZHU Ning;HUA Guodong

2020, 31(23):  2874-2882,2890.  DOI: 10.3969/j.issn.1004-132X.2020.23.012

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In order to effectively reduce the traffic incidents caused by drivers’ emergency lane-changing behaviors and improve the blocking efficiency of chains of road traffic incidents, a method of predicting emergency lane-changing behaviors was proposed based on GMM-HMM and ANN. First, GM-HMM was utilized to identify the intention of lane-changing based on the continuous observation sequences of vehicle states and the driving behaviors. ANN was utilized to predict the driving behaviors in the next interval, and then lateral acceleration rate during lane-changing was predicted to judge the dangerous degree of emergency lane-changing. The results of driver in-the-loop simulations and real vehicle experiments show that the predictive risk avoidance success rate is as 92.83% and the experiment risk avoidance success rate is as 90.32%. The method may effectively warn and intervene the emergency lane-changing behaviors.

Parameter Analysis of Electronic Stability Controller Matching Mechanical Elastic Wheels

ZHENG Xin;ZHAO Youqun;WANG Qiuwei;ZHANG Chenxi

2020, 31(23):  2883-2890.  DOI: 10.3969/j.issn.1004-132X.2020.23.013

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In order to improve the stability of an off-road vehicle with MEWs, a robust feedback control for electronic stability controller(ESC) was designed by considering uncertainty perturbation of MEW and traditional radial tire cornering characteristics based on Lyapunov stability theorem. Norm bounded model with the uncertainty of tire cornering stiffness was introduced herein, and the feedback matrix was solved by Schur complement lemma and LMI. Finally, fish hook tests with different vehicle speeds and road adhesion were carried out on CarSim/Simulink platform. Simulation results show that the ESC matched with MEW may ensure the stability of the vehicles, the yaw velocity and the center of mass sideslip angle tracking errors were maintained in the ranges of 0.03~0.3 rad/s and 0.06~0.1 rad respectively, and the control algorithm may keep good robustness in the range of 05 times lateral stiffness of ordinary inflatable wheels, which provides a theoretical reference for the whole vehicle active safety control matching with MEWs.