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Research Review of Error Compensation Technology for Ultra-precision Machining CHEN Qidi, HU Xiaolong, LIN Min, SUN Xiaoxia, ZHANG Tao, ZHOU Zhixiong China Mechanical Engineering    2023, 34 (03): 253-268.   DOI: 10.3969/j.issn.1004-132X.2023.03.001 Abstract （1759）      PDF （8557KB）（529）       Knowledge map    Save  Ultra-precision machining technology was a key technology in high-end manufacturing fields. At present, ultra-precision machining has entered the nano scale. Mastering the key technology of ultra-precision machining error control, ensuring and improving the machining accuracy of CNC machine tools, become a hot research point to improve the machining and manufacturing levels. This paper systematically summarized the research status and development trend of ultra-precision machining error compensation technology, and focused on the geometric errors, force induced errors, thermal induced errors and their compensation methods, which had the greatest impact on ultra-precision machining. Then, a series of problems of ultra-precision machining in geometric error separation, cutting force, thermal induced error measurement and compensation were deeply discussed, and it is further pointed out that the ultra-precision machining error compensation technology should also pay attention to the development direction of high efficiency, high precision, generalization, modularization, intelligence and flexibility. Reference | Related Articles | Metrics

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Industrial Engineering and Lean Management for Smart Manufacturing QI Ershi, HUO Yanfang, LIU Hongwei China Mechanical Engineering    2022, 33 (21): 2521-2530.   DOI: 10.3969/j.issn.1004-132X.2022.21.001 Abstract （1518）      PDF （4622KB）（1085）       Knowledge map    Save This paper reviewed the development routes of developed countries such as the United States， Japan， and Germany since the emergence of industrial engineering for more than 100 years， discussed the regular characteristics of enterprise management innovation， and drew the conclusion that smart manufacturing also needed IE/LM to provide management support. According to the smart manufacturing project cycle， the functions of IE/LM in smart manufacturing engineering were analyzed from the perspectives of basic preparation， scheme selection， and integration development. The framework of lean smart management system for smart manufacturing transformation of Chinese enterprises was given， and the improvement ideas and methods of smart-lean integration were explained based on a case. Finally， some key technologies of smart manufacturing management facing transformation and upgrading of Chinese enterprises were presented based on the actual needs of China.  Reference | Related Articles | Metrics

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Tool Wear and Remaining Useful Life Estimation of Difficult-to-machine Aerospace Alloys：a Review LUO Huan, ZHANG Dinghua, LUO Ming China Mechanical Engineering    2021, 32 (22): 2647-2666.   DOI: 10.3969/j.issn.1004-132X.2021.22.001 Abstract （927）      PDF （2230KB）（757）       Knowledge map    Save  Due to the special application requirements, such as light weight designs, strength,in aeronautical manufacturing field, a large number of difficult-to-machine materials such as titanium alloy and nickel-based alloy were used, and the cutting tools wore fast. Excessive tool wear would affect product quality. Under the premise of ensuring product quality, it was urgent to monitor tool wear states and to predict tool remaining useful life in order to make full use of the cutting tools. The definition, classification and models of the cutting tool remaining useful life estimation were described herein. Meanwhile tool wear monitoring was the basis and prerequisite of tool life prediction, the main steps and common models were briefly described. The remaining useful life prediction models might be categorized into physics-based models, data-driven models and hybrid models. The advantages and disadvantages of different prediction methods and their application scenarios were summarized , and the future research directions were discussed. Reference | Related Articles | Metrics

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Development Status and Prospect of Key Rail Grinding Equipment and Technology of Grinding Stone ZHANG Wulin, FANXiaoqiang, ZHU Minhao, DUAN Haitao China Mechanical Engineering    2022, 33 (19): 2269-2287.   DOI: 10.3969/j.issn.1004-132X.2022.19.001 Abstract （854）      PDF （17216KB）（700）       Knowledge map    Save  The rail grinding strategies and techniques were reviewed， and the key equipment of the grinding methods using grinding wheels（active grinding and high-speed passive grinding）and the milling and grinding compound process were summarized. Meanwhile， the research status of rail grinding stone（grinding wheel， equipped with rail grinding train and used for cutting tools）were reviewed from ingredients， forming processes， structural design and grinding performance evaluation criterions， etc. It was concluded that the fine formula design, scientific evaluation criterions, etc. were the main challenges for the development of high-performance grinding stones. Finally， it was pointed out that the greenization， standardization， and intelligence were the important directions for future development of grinding stone technology.  Reference | Related Articles | Metrics

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Research Progresses of Robot Grinding and Polishing Force Compliance Controls GE Jimin, DENG Zhaohui, LI Wei, LI Chongyang, CHEN Xi, PENG Deping China Mechanical Engineering    2021, 32 (18): 2217-2230,2238.   DOI: 10.3969/j.issn.1004-132X.2021.18.011 Abstract （851）      PDF （6054KB）（762）       Knowledge map    Save Low-cost and high-dexterity robots were used in field of grinding and polishing more and more widely. Compliance control of grinding and polishing forces for robots were the key to reduce surface roughness of workpieces and obtain high shape accuracy and surface integrity. Main research results of at home and abroad scholars in robots grinding and polishing force active compliance control strategies, passive compliance control devices, active-passive compliance control methods were summarized. Principles and implementation processes of various typical control methods were analyzed, and the advantages and disadvantages of each method were compared. Problems existing in current researches were pointed out. Finally, the key technical difficulties were summarized, and development trend was looked forward. Reference | Related Articles | Metrics

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Development Status and Perspective Trend of Motor Cooling Systems TANG Yong, SUN Yalong, GUO Zhijun, ZHANG Shiwei, YUAN Wei, TANG Heng, LIANG Fuye China Mechanical Engineering    2021, 32 (10): 1135-1150.   DOI: 10.3969/j.issn.1004-132X.2021.10.001 Abstract （838）      PDF （15987KB）（535）       Knowledge map    Save Cooling systems with high heat dissipation efficiency were the important foundations of restraining motor temperature rise, improving motor operation stability and prolonging motor life. The development status of air cooling, liquid cooling and evaporative cooling was introduced, which were commonly used in the cooling systems for motors. The advantages, disadvantages and application ranges of various motor cooling systems were analyzed and discussed. The research progresses in improving the cooling efficiency of motor heat dissipation system at home and abroad were reviewed. By combining the additional thermal circuit enhanced motor cooling system and the phase change heat dissipation technology, a new scheme to improve the heat dissipation efficiency of motors using phase change heat transfer devices was proposed. Finally, the development trend of the motor heat dissipation systems was predicted and prospected scientifically.  Reference | Related Articles | Metrics

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Bearing Fault Diagnosis Method Based on Small Sample Data under Unbalanced Loads#br# HE Qiang, TANG Xianghong, LI Chuanjiang, LU Jianguang, CHEN Jiadui China Mechanical Engineering    2021, 32 (10): 1164-1171,1180.   DOI: 10.3969/j.issn.1004-132X.2021.10.004 Abstract （836）      PDF （6051KB）（503）       Knowledge map    Save Aiming at the problems that the bearing vibration signals were easily disturbed by unbalanced load and the small number of bearing fault samples, a bearing fault diagnosis method based on WGAN-GP and SeCNN was proposed. The bearing vibration signals were processed by short-time Fourier transform to get the time-spectrum samples that were easy to be processed by WGAN-GP, which were divided into training set, validation set and test set. Then the training set was inputted into WGAN-GP for adversarial training, new samples were generated with similar distribution to the training samples, and added to the training set to expand the training set. The expanded training set was input into SeCNN for learning, and the trained model was applied to the test set and output the fault recognition results. The analysis of the CUT-2 platform unbalanced load bearing data was carried out, and the experimental results show that the proposed method may accurately and effectively classify the bearing faults. Reference | Related Articles | Metrics

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State-of-the-art of Key Maritime Rescue and Salvage Equipment and Technology ZHAO Jiechao, JIN Hao, CHEN Jian, PAN Changcheng, ZHANG Yingxiang, WANG Jiwu, WENG Datao China Mechanical Engineering    2022, 33 (04): 432-451,458.   DOI: 10.3969/j.issn.1004-132X.2022.04.007 Abstract （751）      PDF （3281KB）（481）       Knowledge map    Save  To promote the modernization of the national emergency management systems and capabilities， combined with the current development of maritime emergency rescue capabilities in China， the key issues exposed in some typical maritime emergency rescue cases in recent years were deeply analyzed， and the conclusion that “systematic construction” was the core issue that urgently needed to be strengthened in the construction of Chinese maritime rescue and salvage equipment and technology was pointed out. From the perspective of the land-sea-air-space integrated， aiming at the four major Chinese rescue and salvage missions of life rescue， environmental rescue， property rescue， and emergency rescue and salvage， this paper systematically divided the key equipment technology of maritime rescue and salvage into 7 types according to the dimensions of space-based， air-based， water surface， and underwater. Aiming at the current development of each type of key equipment technology， the Delphi method， brainstorming method and bibliometric method were used to carry out research and judgment on the development of key maritime rescue and salvage equipment and technology. The results of the study selected 13 key equipment technologies that require urgent attention from the 7 categories of key equipment technologies. Meanwhile， the current challenges faced by each key equipment technology were systematically analyzed， and recommendations for the development goals and core construction tasks in the next 5~15 years were given as well.  Reference | Related Articles | Metrics

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Review on Management at Mechanical Design and Manufacturing Discipline of NSFC in 2022 YE Xin, ZHU Mingliang, HUANG Zhiquan, China Mechanical Engineering    2023, 34 (04): 379-386.   DOI: 10.3969/j.issn.1004-132X.2023.04.001 Abstract （747）      PDF （2658KB）（331）       Knowledge map    Save The applications， evaluations and funding of projects at mechanical design and manufacturing discipline （division Ⅱ of engineering science） of the NSFC in 2022， as well as the research progresses and achievements of the executing and finished projects were reviewed. Specific measures of mechanical design and manufacturing discipline were illustrated， such as the reform of scientific fund， talent cultivation and future research. Finally， a short prospect of the work in 2023 was introduced.  Reference | Related Articles | Metrics

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Related Parallel Machine Online Scheduling Method Based on LSTM-PPO Reinforcement Learning HE Junjie, ZHANG Jie, ZHANG Peng, WANG Junliang, ZHENG Peng, WANG Ming China Mechanical Engineering    2022, 33 (03): 329-338.   DOI: 10.3969/j.issn.1004-132X.2022.03.009 Abstract （738）      PDF （6559KB）（565）       Knowledge map    Save To solve the related parallel machine online scheduling problems, the total weighted completion time was taken into account, and an online scheduling method was proposed based on LSTM-PPO reinforcement learning. A LSTM-integrated agent was designed to record the historical variations of workshop states and the corresponding scheduling policy adjustment, and then online scheduling decision was made according to the state information. Meanwhile, the workshop state matrix was designed to describe the problem constraints and optimization goals, additional machine waiting was introduced in scheduling action space to expand solution space, and the reward function was designed to decompose the optimization goal into step-by-step rewards to achieve scheduling decision evaluation. Finally, the model updating and global optimization of parameters was achieved by PPO algorithm. Experimental results show that the proposed method has competitive solutions than the existing heuristic rules, and the proposed algorithm is applied to the production scheduling of the actual workshops, which effectively reduces the total weighted completion time. Reference | Related Articles | Metrics

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Rebound Law and Precision Compensation Method of Three-dimensional Laser Cutting of High Strength Steel Hot Stamping Structural Parts LI Shougang, LIU Peng, LIU Xiang, HU Zhili, China Mechanical Engineering    2022, 33 (22): 2741-2747.   DOI: 10.3969/j.issn.1004-132X.2022.22.012 Abstract （734）      PDF （7408KB）（108）       Knowledge map    Save In order to reduce the influences of springback defects on the cutting accuracy in the three-dimensional laser cutting of high-strength steel body structures, the rebound characteristics was studied by applying three-dimensional laser cutting of hot stamped high-strength steel body components.For high-strength steel car body structure A-pillar, hot stamping and laser cutting finite element models were established respectively by the finite element simulation software AUTOFORM and ABAQUS respectively. The rebound value distribution diagram was obtained through numerical simulation, and the rebound law of the contour of the body structures after cutting was found. The optimal cutting contour was determined according to the direct compensation method based on rebound prediction. The compensation method was validated by cutting the A-pillar semi-finished products. The results show that the contour may be controlled within the tolerance range, the contour errors are decreased by about 28.5%, and the profile rebound is decreased by about 38.3%，by the proposed compensation method,which verify the effectiveness of the compensation method. Reference | Related Articles | Metrics

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Modeling of Material Removal Depth in ABFW Polishing Based on Modified Preston Equation ZHANG Junfeng, SHI Yaoyao, LIN Xiaojun, WU Xiaojun China Mechanical Engineering    2022, 33 (22): 2711-2716.   DOI: 10.3969/j.issn.1004-132X.2022.22.008 Abstract （729）      PDF （4289KB）（169）       Knowledge map    Save Due to the elasticity of ABFW, the actual material removal depth was not consistent with the nominal polishing depth, which directly affected the control of polishing efficiency and surface quality. Based on the Hertz elastic contact theory, the distribution function of polishing pressure and cutting speed in the contact area was established, and the material removal depth model was established according to the modified Preston equation. Based on this, the key processing parameters that affected the material removal depthi.e、abrasive particle size, spindle speed, ABFW deformation and feed rate were determined. Then, the distribution of material removal depth in contact areas and the influences of key polishing process parameters on the material removal depth were obtained. Finally, the correctness of the model and the influence law were verified by simulation and polishing experiments, the results show that the model may better predict the material removal depth of ABFW polishing.  Reference | Related Articles | Metrics

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Overview of Micro Friction to Macro Dynamics for Bolted Connections CAO Junyi, LIU Qinghua, HONG Jun China Mechanical Engineering    2021, 32 (11): 1261-1273.   DOI: 10.3969/j.issn.1004-132X.2021.11.001 Abstract （689）      PDF （7675KB）（487）       Knowledge map    Save As a typical mechanical assembly method, bolted connections played an important role in the design and operation of key mechanical equipment in the field of aerospace, military weapons, energy and chemical equipment and transportation industry. Moreover, due to the introduction of the nonlinear factors of stiffness and damping by bolted connections, new challenges in performance predictions and operation reliability were come into being to propel us to comprehensively understanding the characteristics of bolted connections from interface micro friction to macro structural dynamics. Therefore, the micro-macro dynamics of bolted connections reviewed and the fractal characterization modeling, statistical summation modeling and Iwan modeling methods of bolt joint friction constitutive model were summarized. Several experimental benchmarks for testing the friction energy consumption of bolted connections in the world were analyzed in detail. The latest research progresses of nonlinear modeling, parameter identification, numerical simulation and structural health monitoring in the macro dynamics of bolted connections were discussed, and the development trend of this field was prospected. Reference | Related Articles | Metrics

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Research Status and Prospect of CMG Technology REN Yinghui, ZHOU Jiaheng, LI Wei, ZHOU Zhixiong, LI Chenfang China Mechanical Engineering    2021, 32 (18): 2143-2152.   DOI: 10.3969/j.issn.1004-132X.2021.18.001 Abstract （673）      PDF （6455KB）（506）       Knowledge map    Save At present, the CMG technology was widely applied in fields of optics and semiconductors manufacturing, because it might achieve ultra-precision, high quality and low damage processing for hard-brittle materials such as monocrystalline silicon and quartz glass through chemo-mechanical synergistic processes. Current CMG research status around material removal mechanism, grinding processes and compound processes was reviewed, and these existing problems for related researches were summarized. Factors affecting the quality and processing efficiency of CMG were discussed furtherly. The analyses show that revealing the mechanism of CMG from the perspective of solid-solid phase chemical reaction and chemo-mechanical synergistic effect is helpful to innovate feasible methods to improve the processing efficiency of this technology from the perspectives of material removal mechanism, grinding tool structure design and compound processing development. Furthermore, the probable development trend of CMG technology in the direction of diversified processing materials, more complicated structure processing, multi-energy field compound processing, and related intelligent machining databases were forecasted.  Reference | Related Articles | Metrics

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Digital Transformation Mode and Strategy of SMEs in China WANG Baicun, ZHU Kailing, XUE Yuan, BAI Jie, ZANG Jiyuan, XIE Haibo, YANG Huayong, China Mechanical Engineering    2023, 34 (14): 1756-1763.   DOI: 10.3969/j.issn.1004-132X.2023.14.013 Abstract （671）      PDF （5220KB）（489）       Knowledge map    Save Promoting the digital transformation of SMEs was of great significance for Chinas manufacturing industries to improve quality and increase efficiency. SMEs were facing problems in digital transformation, such as high cost, fuzzy path, talent shortage, and lacking analytical framework and reference paradigm for digital transformation. The key factors to achieve digital transformation were clarified by building an analytical framework for SMEs digital transformation herein. Through case studies, 4 basic path models of digital transformation of SMEs were summarized and proposed. Based on the above researches, targeted suggestions were proposed for SMEs digital transformation in China, so as to promote the digital and intelligent development of SMEs. Reference | Related Articles | Metrics

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Optimization of Gear Grinding Parameters with Worm Grinding Wheel WANG Liting, ZHAO Xiuxu, LI Jiao China Mechanical Engineering    2021, 32 (17): 2136-2141.   DOI: 10.3969/j.issn.1004-132X.2021.17.015 Abstract （668）      PDF （1083KB）（285）       Knowledge map    Save Taking the 20CrMnTi gear grinding processes with worm grinding wheels as the research object, the uniform design test method was selected to study influences of the grinding parameters（i. e. grinding wheel linear speed vs， grinding wheel along the gear axial feed speed vw， grinding thickness ap）on the tooth surface roughness. The regression model of grinding parameters and tooth surface roughness was established by using two-level stepwise regression method， and the optimization model with multiple goals was established with the machining efficiency and tooth surface roughness as the optimization objectives. The particle swarm optimization algorithm was used to optimize the grinding parameters. The experimental results show that the optimized grinding parameters may improve the machining efficiency and reduce the tooth surface roughness.  Reference | Related Articles | Metrics

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A Review of Force Sensing Technology in Robot-assisted Laparoscopic Surgery ZHANG Jianxun, YAO Bin, DAI Yu, XIA Guangming, China Mechanical Engineering    2021, 32 (21): 2521-2531.   DOI: 10.3969/j.issn.1004-132X.2021.21.001 Abstract （667）      PDF （4488KB）（620）       Knowledge map    Save In order to promote the further research and clinical applications of force sensing technology in robot-assisted laparoscopic surgery， the research progresses were reviewed. Sensor force sensing was divided into two categories：electrical signal-based sensing and optical signal-based sensing. Some key indicators were analyzed， such as sensor position distribution on surgical instruments， mechanical structure， measurement range， measurement accuracy and electromagnetic compatibility. Sensors advantages and disadvantages were discussed. Sensorless force sensing was divided into two categories：vision-based sensing and dynamic model-based sensing. And the realization method， technical obstacle and error sources were analyzed. Finally， the development trend of force sensing technology in robot-assisted laparoscopic surgery was prospected.  Reference | Related Articles | Metrics

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Research Progresses of Basic Equipment Manufacturing and High-grade Integrated CNC Machine Tools HU Lai, ZHA Jun, ZHU Yongsheng, WEI Wenming, LI Dongya, LUO Ming, NIU Wentie, CHEN Yaolong China Mechanical Engineering    2021, 32 (16): 1891-1903.   DOI: 10.3969/j.issn.1004-132X.2021.16.001 Abstract （651）      PDF （26502KB）（602）       Knowledge map    Save In order to solve the key problems faced by the aerospace manufacturing fields and improve the service capability for the industries，the machine tool industry proposed to build an innovative capability platform for high-grade CNC machine tools in the field of aerospace manufacturing. The research progresses in four aspects of basic assembly manufacturing and high-grade CNC machine tools were summarized about the innovation platform, including: motorized spindle unit technology(dynamic analysis of high-speed spindle—tool handle—tool system, digital simulation and prototype modal verification analysis); machine tool design(rigid-flexible coupling—electromechanical coupling dynamics of linear axis feed system, verification and analysis of electromechanical coupling dynamic model of multi-axis linkage and high-speed five-coordinate hybrid machining equipment and swing/rotary feed system, innovative structural design of MTC1000 boring, milling and grinding composite machining center); machine tool control(verification and analysis of high-speed start-stop residual vibration suppression technology) and machine tool verification(analysis of field data acquisition, mapping and storage technology for high-speed machining of aerospace structural parts). Finally, the future research trends were prospected. Reference | Related Articles | Metrics

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Development of Gear Measurement Technology during Last 20 Years SHI Zhaoyao, YU Bo, SONG Huixu, WANG Xiaoyi China Mechanical Engineering    2022, 33 (09): 1009-1024.   DOI: 10.3969/j.issn.1004-132X.2022.09.001 Abstract （651）      PDF （72652KB）（573）       Knowledge map    Save There were two forces that promoted the development of gear measurement technology. One was the continuous new requirements for gear measurement put forward by industrial development, and the other was the penetration of continuously improving related technologies in the field of gear measurement. Since the 21st century, the convergence of these two forces promoted the rapid development of gear measurement technology. Based on a brief review of the evolution of gear accuracy theory and gear measurement technology in the 20th century, the basic framework of gear generalized accuracy theory was put forward. The gear measurement technology during the last 20 years was systematically summarized from the aspects of gear full-information measurement technology, in-site rapid gear sorting and detection technology, extreme measurement technology for extra-large gears and micro gears, high-precision gear artifacts and traceability, etc. There is more than 100 years since the beginning of gear precision measurement, and it is currently in the critical stage of the transition from the 3rd generation to the next-generation of gear measurement. The overall technical concept of next-generation of gear measurement was presented, the basic theory and key technical problems that must be overcome were listed for realizing the next-generation of gear measurement, and the research focus and scientific issues of gear measurement in the next 10 years were prospected. Reference | Related Articles | Metrics

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Online Monitoring Method for NC Milling Tool Wear by Digital Twin-drivenLI Congbo SUN Xin, HOU Xiaobo, ZHAO Xikun, WU Shaoqing China Mechanical Engineering    2022, 33 (01): 78-87.   DOI: 10.3969/j.issn.1004-132X.2022.01.009 Abstract （633）      PDF （11516KB）（572）       Knowledge map    Save In order to solve the problems of large errors of tool wear prediction model caused by continuous aging of CNC milling machines and difficulties of on-line acquisition of dynamic data during machining, a digital twin-driven online tool wear monitoring method was proposed. Firstly, a neural network was used to extract features from multi-source data in the machining processes, and a quantitative model of tool wear time varying deviation was established considering machine aging. Based on this, an on-line prediction method of tool wear in CNC milling was proposed. Then, a numerical control milling digital twin system for tool wear was developed to online sense the dynamic data and simulate the tool wear processes in real time. Finally, this method was applied to actual machining and compared with other prediction methods. The results show that this method may reduce the prediction errors and realize the accurate prediction of tool wear value. Reference | Related Articles | Metrics

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Research Status of Key Technologies for Energy Management System of Marine Hybrid Propulsion Systems SUN Xiaojun, SONG Enzhe, YAO Chong China Mechanical Engineering    2022, 33 (04): 469-481,495.   DOI: 10.3969/j.issn.1004-132X.2022.04.010 Abstract （631）      PDF （4818KB）（388）       Knowledge map    Save In the face of energy shortage and strict emission regulations， the use of new hybrid power system would become an important direction of ship development in the future. Firstly， the challenges were analyzed by the shipping industries， and the advantages and necessity of marine hybrid power were expounded. The topology and implementation framework of energy management systems were presented. Secondly， the research status of energy management strategy was analyzed, and the development route of hybrid system multi energy coupling energy management strategy was put forward. The challenges faced by the research and development of energy management strategies for marine hybrid power systems were explored ， and  the future development trends and in-depth research directions were looked forward. The paper provides the research and development directions for the green and intelligent development of marine hybrid powers.  Reference | Related Articles | Metrics

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State-of-the-art on MQL Synergistic Technologies and Their Applications YANG Jianzhang, WANG Chengyong, YUAN Yaohui, YUAN Songmei, WANG Xibin, LIANG Cile, LI Weiqiu China Mechanical Engineering    2022, 33 (05): 506-528.   DOI: 10.3969/j.issn.1004-132X.2022.05.001 Abstract （628）      PDF （22261KB）（441）       Knowledge map    Save MQL technology had the advantages of low cutting fluid consumption and high lubrication efficiency. However, there were more problems such as inadequate lubrication and low cooling performance under the specific conditions. MQL synergistic technology, such as cryogenic air or liquid carbon dioxide et.al. which combines the advantages of cooling and lubrication, might effectively solve the machining problems of difficult-to-cut materials. The latest research of principle, key devices and technology applications of various types of MQL synergistic technology were summarized. The performance of various devices and their parameter regulation characteristics were analyzed in details. Combining with the applications and the mechanism of MQL synergistic technology, the machinability in titanium alloy, nickel alloy, stainless steel and other difficult-to-cutting materials were analyzed. In addition, a sustainable analysis of various types of MQL synergistic technology was provided. The purpose is to provide technical support and reference for the engineering applications of clean cutting technologies. Reference | Related Articles | Metrics

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Chip Formation and Tool Wear in High-speed Cutting of Hardened Steels under Cryogenic Liquid Nitrogen Cooling WU Shixiong, ZHANG Wenfeng, LIU Guangdong, WANG Chengyong China Mechanical Engineering    2022, 33 (05): 551-559.   DOI: 10.3969/j.issn.1004-132X.2022.05.003 Abstract （628）      PDF （7443KB）（113）       Knowledge map    Save In view of the lack of relevant research on chip formation and tool wear mechanism in high-speed cutting of hardened steel under cryogenic liquid nitrogen cooling, a high-speed cutting of hardened steels under liquid nitrogen cooling was studied and compared with dry cutting. The cutting force, cutting temperature, characteristics of chip and tool wear were analyzed, and the mechanism of cooling and lubrication, chip formation and tool wear were discussed. The results show that compared with dry cutting, the cutting temperature of cryogenic liquid nitrogen cooling cutting is reduced by 6.9%-9.9%, and the cutting force is increased by 10.1%-12.8% due to material hardening. Compared with dry cutting, chip serration increases obviously under cryogenic liquid nitrogen cooling, which is related to the larger stress and strain in the first deformation zone and the transition from thermoplastic shear instability to periodic brittle fracture in chip formation. Cryogenic liquid nitrogen reduces cutting heat generation in cutting interfaces, the strong jet of liquid nitrogen blows away the chips, and the strong heat transfer capacity quickly take away the heat in the cut areas. Compared with the dry cutting, cryogenic liquid nitrogen may significantly reduce the adhesive wear, alleviate the tool micro-spalling by cooling and strengthen the tool, and improve the tool life by 28.6%-47.1%. Under cryogenic liquid nitrogen cooling conditions, adhesion is no longer one of the main wear mechanism, abrasive wear and impact wear are the main wear mechanism, and flank flaking and micro collapse blade are the main tool damage forms. Reference | Related Articles | Metrics

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Two-way Fluid-Solid Coupling Simulation and Experimental Research of Sealing Rings Based on MpCCI Method GONG Ran, ZHANG Zhenyu, CHENG Zhigao, XU Yi, ZHANG He China Mechanical Engineering    2021, 32 (14): 1639-1646.   DOI: 10.3969/j.issn.1004-132X.2021.14.001 Abstract （622）      PDF （5466KB）（496）       Knowledge map    Save To predict the fluid-solid coupling characteristics of sealing systems in transmission of heavy-duty off-road vehicles, the stress state of sealing rings in small confined spaces and the flow characteristics in flow fields of rotating sealing gaps were taken into account, and then the numerical models of two-way fluid-solid coupling for sealing systems were established and the solving methods were presented. The multi physics code coupling tool MpCCI was combined with FLUENT and Abaqus to carry out the numerical calculations of two-way fluid-solid coupling of rotary sealing systems. According to the fluid-solid coupling calculations, the flow states of oil in flow fields of rotary sealing gaps were obtained. The effective characteristics of sealing ring deformations on the leakage of rotary sealing systems and the friction torques of sealing rings were studied. The influences of transmission system working conditions on sealing ring performances were explored by two-way fluid-solid coupling dynamic simulation. Experimental investigations were performed in sealing performance test rig for sealing rings of vehicle transmission systems. Comparisons of numerical and experimental results show a good consistency of their change rules, which verifies the correctness of sealing fluid-solid coupling numerical models and calculation results. Reference | Related Articles | Metrics

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Research on Mode Switching Control Strategy of Marine Diesel/Natural Gas Dual Fuel Engines SONG Enzhe, JIANG Zhongzhou, YAO Chong, ZHAO Guofeng China Mechanical Engineering    2022, 33 (04): 388-396.   DOI: 10.3969/j.issn.1004-132X.2022.04.002 Abstract （616）      PDF （4803KB）（242）       Knowledge map    Save In the actual operations of marine diesel/natural gas dual-fuel engines， switching between pure diesel mode and dual-fuel mode might easily cause large engine speed fluctuations and unstable operations， which endanger the normal operations of the engines. In addition， in some emergencies（such as insufficient natural gas fuel， sudden load unloading， et al）， the engine needed to switch between different modes quickly and smoothly. In response to the demands， a rule-based dual-fuel engine mode switching control strategy was designed based on the operating requirements and mechanism of the dual-fuel engine under the premise of the same control system hardware. Among them， the diesel-to-dual-fuel mode adopted the reverse control method， and the dual-fuel-to-diesel mode was divided into active switching and passive switching to respond to different control requirements. The designed switching control strategy realized the mutual switching of different fuel modes based on experimental calibration data and software algorithms. Finally， an experimental platform was built to verify different operating conditions mode switching control performance based on the YC6K dual-fuel engine. The results show that the designed switching strategy satisfies the switching control requirements under various working conditions， and improves the running performance of the whole machine.  Reference | Related Articles | Metrics

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Navigation Trajectory Prediction Method of Inland Ships Based on Multi-model Fusion ZHANG Yang, GAO Shu, HE Wei, CAI Jing China Mechanical Engineering    2022, 33 (10): 1142-1152.   DOI: 10.3969/j.issn.1004-132X.2022.10.002 Abstract （615）      PDF （2807KB）（314）       Knowledge map    Save  Inland waterway navigation was an important part of the modern comprehensive transportation systems. The real-time and high-precision ship trajectory prediction method was helpful to effectively avoid water traffic accidents and enhance the ability of automation and intelligent supervision. Aiming at the problems that the accuracy of the existing inland ship trajectory prediction was not high， in order to improve the short-term prediction accuracy of ship trajectory， comprehensively using the recent AIS (automatic identification system) data and historical AIS data of the ships， and based on the relationship among trajectory and speed， course， and the characteristics of inland waterway， the temporal convolutional network model for speed and course prediction， ship trajectory dynamics equation model and adaptive double-hidden layer RBF network were constructed. The ship trajectory prediction method based on multi-model fusion was proposed. Experimental results show that the proposed method has obvious improvement in trajectory prediction accuracy and may meet the real-time requirements.  Reference | Related Articles | Metrics

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Research on Forming Manufacturing Technology and Equipment of Composite Preforms SHAN Zhongde, LIU Yang, FAN Congze, WANG Jun China Mechanical Engineering    2021, 32 (23): 2774-2784，2931.   DOI: 10.3969/j.issn.1004-132X.2021.23.001 Abstract （605）      PDF （13069KB）（290）       Knowledge map    Save The revolutionary history of composite preforms forming technique was summarized from the standpoints of manufacturing technology and equipment development.The technical characteristics of the composite preform forming manufacturing technology were analyzed.The status of typical technology and equipment of composite preform forming manufacturing at home and abroad as well as existing challenges and gaps were listed.Finally，the future development directions and trends of composite preform forming technique were discussed prospectively.The development of digital precision forming manufacturing technology and equipment for high-performance composite components may promote the technical progresses of composites in China better，and achieve more extensive promotions and applications. Reference | Related Articles | Metrics

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Research on Accelerated Life Test Method of Harmonic Reducers WANG Qiao, DU Xuesong, SONG Chaosheng, ZHU Caichao, SUN Jianquan, LIAO Delin China Mechanical Engineering    2022, 33 (19): 2317-2324.   DOI: 10.3969/j.issn.1004-132X.2022.19.005 Abstract （596）      PDF （5879KB）（308）       Knowledge map    Save At present， there was an urgent need for an accelerated life test method of harmonic reducer in engineering to replace the full life test in order to reduce the test cycles and costs. Based on the principles of accelerated life test， a constant stress accelerated life test program  was proposed based on the failure characteristics of the harmonic reducer. The flexible wheel that was most likely to fail in the harmonic reducers was taken as the object， and the definite failure judgment， acceleration stress， acceleration factor， method of accelerating model were pointed out. In the small sample test data processing， a more accurate Weibull distribution parameter estimation was obtained by using the maximum likelihood method and Markov Monte Carlo method. The experimental results of the prototype show that the scheme may effectively describe the life of the harmonic reducers. The reliability evaluation standard of the basic rated life is 62% higher than that of the evaluation standard of the median life. The life index of the harmonic reducers was effectively evaluated. The research results have certain engineering application values.  Reference | Related Articles | Metrics

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Hybrid Flow Shop Scheduling Problems with Unrelated Parallel Machine Solved by Improved Adaptive Genetic Algorithm(IAGA) with ITPX ZHENG Kun, LIAN Zhiwei, GU Xinyan, ZHU Changjian, XU Hui, FENG Xueqing China Mechanical Engineering    2023, 34 (14): 1647-1658，1671.   DOI: 10.3969/j.issn.1004-132X.2023.14.002 Abstract （591）      PDF （4458KB）（140）       Knowledge map    Save Aiming at the hybrid flow-shop scheduling problems, an adaptive genetic algorithm with ITPX was proposed. Firstly, the solution performance of two-points crossover（TPX） was improved by exacting point taking method. Secondly, adaptive selection probability was demonstrated based on hormonal regulation guiding convergence trend of populations. Then, a pool of high-quality chromosomes and a memory factor were established to record the high-quality chromosomes during population evolution, and two different regional crossovers were implemented. Experimentsal results show that ITPX may save optimization time and improve solution performance; the adaptive probability may enhance convergence; ITPX-IAGA may reduce solution time by more than 40% and improve solution performance. Reference | Related Articles | Metrics

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A Wafer Cycle Processing Time Prediction Method Incorporating Double Attention Mechanism and Parallel GRU DAI Jiabin, ZHANG Jie, WU Lihui China Mechanical Engineering    2023, 34 (14): 1640-1646.   DOI: 10.3969/j.issn.1004-132X.2023.14.001 Abstract （590）      PDF （4600KB）（179）       Knowledge map    Save Low efficiency and low prediction accuracy were caused by the large scale of production feature data, complex correlation among features, and strong correlation of feature samples in wafer fabrication processes, so a wafer processing cycle prediction method integrating double attention mechanism and parallel GRU was proposed. Firstly, Relief-F algorithm was used to reduce the dimensionality of production feature data. Secondly, a fuzzy C-mean algorithm was used to cluster the process similarity of data samples and design a parallel GRU network to explore the strong correlation among wafer feature samples. Finally, a double attention mechanism was designed to learn the complex correlation information within key features and among features and processing cycle. The experimental results show that the proposed method may effectively reduce the prediction training time and improve the prediction accuracy. Reference | Related Articles | Metrics

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Design and Adsorption Performance Optimization of Non-contact Variable Magnetic Gap Type Permanent Magnet Absorption Mechanisms of Pipe Climbing Robots GUO Denghui, CHEN Yuan China Mechanical Engineering    2021, 32 (14): 1659-1668.   DOI: 10.3969/j.issn.1004-132X.2021.14.004 Abstract （588）      PDF （3267KB）（640）       Knowledge map    Save A non-contact variable magnetic gap type climbing robot was designed, which was adaptive adsorb tubes with different diameters. A magnetic field distribution model and magnetic adsorption force model of adsorption mechanisms were established by vector magnetic position method and finite element method. Based on equilibrium equation of space force system, the mechanics model of the robot was established and the minimum magnetic adsorption force was obtained. Based on the theoretical model of magnetic field and magnetic adsorption force and Maxwell simulation, the optimal magnet width and magnetic adsorption force were obtained by discrete combination method. After comparing different magnetic fields and magnetic adsorption forces, when the optimal magnet width is as 80 mm, the magnetic attraction force per unit volume of approximate circular arc mechanisms is as 0.0078 N/mm3, which is larger than 0.0047 N/mm3 of rectangular magnet. The magnetic adsorption force satisfies the load requirements of the minimum magnetic adsorption force of 2100 N. Finally, the magnetic adsorption force characteristics of the magnetic adsorption mechanisms were obtained by experiments. The results prove the feasibility of the optimization design of magnetic adsorption mechanisms. Reference | Related Articles | Metrics

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Research on Backlash Elimination Method of Dual-motor Precision Transmission Mechanisms ZHENG Jieji, CHEN Lingyu, FAN Dapeng, XIE Xin China Mechanical Engineering    2022, 33 (22): 2684-2692.   DOI: 10.3969/j.issn.1004-132X.2022.22.005 Abstract （582）      PDF （6537KB）（333）       Knowledge map    Save Aiming at the problems of large speed fluctuation and impact caused by the gaps between the two transmission chains of the dual-motor precision transmission mechanisms, the method of eliminating the gaps of the system was studied. First, a mechanism dynamics model including the meshing clearances between the output gear of the planetary reducer and the large ring gear was established. Through the model simulation, the influences of the gap size on the system characteristics were analyzed. Then, a compound anti-backlash method was proposed combining dynamic bias torque based on speed command and cross-coupling synchronous control based on differential negative feedback. An experimental device for dual-motor precision transmission mechanisms was built, and the verification experiments of the anti-backlash method were carried out. The experimental results show that in the case of closed-loop speed, the proposed compound anti-backlash method may ensure the complete elimination of the system gaps, and may improve the system speed tracking accuracy by 73.38%, and the shock amplitude in the start-up phase may be attenuated by 76.35%. The research results lay a certain foundation for the research of the high-precision control method of the double-motor precision transmission mechanisms, and provide a reference scheme for the elimination of the gaps in the gear transmission systems.  Reference | Related Articles | Metrics

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Feature Line Extraction for Point Cloud Based on Normal Vector Region Clustering Segmentation SHI Hongxia, WANG Jianmin China Mechanical Engineering    2021, 32 (21): 2552-2561.   DOI: 10.3969/j.issn.1004-132X.2021.21.004 Abstract （573）      PDF （7172KB）（178）       Knowledge map    Save In oder to solve the problems of incomplete extraction of transition lines and detail feature lines of scattered point cloud models in reverse engineering, a method of extracting feature lines was proposed based on normal vector region clustering. Principal component analysis of adaptive neighborhood was used to estimate the normal vector of the model, and the FA optimized FCM clustering algorithm was introduced to cluster the normal vectors for realizing the effective segmentation of the model. The candidate feature points were extracted from the boundary points of each block by constructing the rule of eliminating and merging point sets, and then the feature points were extracted based on the principal axis direction of local neighborhood. Experimental results show that the feature lines of simple models may be extracted accurately and completely, and the extraction rate of the number and the length of feature lines of some complex models may reach 90% and 85%, respectively. The algorithm has good adaptability and accuracy, and may extract sharp features and detail features from the point cloud model, meanwhile getting transition features as much as possible. Reference | Related Articles | Metrics

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Research Progresses on Surface Integrity of Bearing Grooves WANG Dongfeng, YUAN Julong, WANG Yanshuang, CHENG Yongjie, LYU Binghai China Mechanical Engineering    2022, 33 (18): 2143-2160.   DOI: 10.3969/j.issn.1004-132X.2022.18.001 Abstract （570）      PDF （5702KB）（464）       Knowledge map    Save Improving the surface integrity of bearing grooves was an important solution to solve technical problems such as low reliability life, high friction power consumption and unstable vibrations and noises of bearings. On the basis of comprehensive research of generalized surface integrity by domestic and foreign scholars, the definition and connotation of characteristic parameters of bearing groove surface integrity were proposed, and the significance of characteristic parameters and the influence mechanism on bearing performance were expounded. The influences of different processing processes such as forging, turning, heat treatment, grinding and ultra-precision on the surface characteristic parameters of bearing raceways were analyzed in details, and the corresponding control measures were given. The new technologies, new processes, and new methods for improving surface integrity were briefly introduced. Finally, the summary and prospect of improving the surface integrity of bearing grooves were made to provide some references for improving the contact fatigue lifes of bearings. Reference | Related Articles | Metrics

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Key Technologies of Design and Performance Improvement of Heavy-duty and High Precision Machining Robot Bodies for Large-scale Components FENG Fei, YANG Haitao, TANG Lina, DING Han, China Mechanical Engineering    2021, 32 (19): 2269-2287.   DOI: 10.3969/j.issn.1004-132X.2021.19.001 Abstract （568）      PDF （16780KB）（330）       Knowledge map    Save According to the summary and analysis of the application background and development status of mobile robot machining for the typical large-scale components， the basic performance requirements of large-scale component processing robot bodies such as the large workspace， high rigidity， high precision， heavy-duty， light-weight， high dynamic response and high load-to-weight ratio were proposed. Furthermore， focusing on the basic performance requirements， the optimization design and robot performance improvement method of heavy-duty and high-precision machining robot bodies were demonstrated， from the aspect of the optimization design of robot body configurations and mechanisms， the development of the high-performance dedicated and professional controller and the open source operating system of machining robots， dynamic calibration of kinematic parameters and real-time prediction and dynamic compensation of pose errors， dynamics modeling of rigid-flexible coupling multibody system， as well as the robot dynamics control and active vibration suppression control. And then， the conceptual design of the configurations and mechanisms of the machining robot bodies utilized on the large-scale components was completed. The innovative design and development of the robot bodies for the large-scale component processing robots may provide high-performance and super flexible robot machining system for the typical large-scale components in aerospace and other fields， and help to promote the improvement of key performance of domestic industrial robots.  Reference | Related Articles | Metrics

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Design of a Kind of Multi-dimensional Attitude Adjustment and Vibration Isolation Platform Based on 4-UPS/CPC Parallel Mechanisms#br# ZHANG Ying, SUN Hao, MA Shuaishuai China Mechanical Engineering    2021, 32 (13): 1513-1522,1529.   DOI: 10.3969/j.issn.1004-132X.2021.13.001 Abstract （567）      PDF （9410KB）（271）       Knowledge map    Save  A kind of multi-dimensional attitude adjustment and vibration isolation platform （MDAA&VIP） was presented for the wheel legged robot carriers. With 4-UPS/CPC parallel mechanisms as the main body and spring damping module as supplementary， the functions of attitude adjustment and vibration isolation were combined in the proposed MDAA&VIP to meet the needs of attitude adjustment and vibration isolation during the working processes of the carriers. Taking the combination of working space， static stiffness and dexterity as the objectives， and the structural parameters of the 4-UPS/CPC parallel mechanisms were optimized. The road spectrum model was established and the length of each limb needed to keep the upper platform horizontal was predicted by using the differential prediction algorithm when the carriers walked on the C-level roads. The effectiveness of the attitude adjustment function of the designed platform was verified by simulations. The vibration model of multi-dimensional vibration isolation system was established， and the vibration response of the system was studied by theoretical and simulation methods under forced vibrations. The results show that the isolation rates of the platform in five degrees of freedom directions are above 57%. The prototype of vibration isolation platform was designed and the experimental system was set up， and the vibration isolation experiments in X， Y and Z directions were carried out. The experimental results show that the designed MDAA&VIP has good vibration isolation performance， and the vibration isolation rates in the three test directions are more than 50%. Reference | Related Articles | Metrics

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Binocular Camera Calibration Based on BP Neural Network Optimized by Improved Genetic Algorithm#br# ZHANG Fengfeng, ZHANG Xin, CHEN Long, SUN Lining, ZHAN Wei China Mechanical Engineering    2021, 32 (12): 1423-1431.   DOI: 10.3969/j.issn.1004-132X.2021.12.005 Abstract （566）      PDF （7128KB）（206）       Knowledge map    Save The BP neural network has the problems of low accuracy and poor convergence in the binocular camera calibration processes. A method was proposed to solve these problems to complete the calibration of binocular camera based on BP neural network optimized by improved genetic algorithm. First, the Trajkovic operator with multi-lattice fusion algorithm was proposed for corner detection. A matching algorithm of homonymous corner combining point-to-point spatial mapping and grid motion statistics was proposed. Then, the pixel value of the homonymous corner was extracted and the actual 3D coordinate value was calculated, and the crossover and mutation probability and selection operator of genetic algorithm were improved. Finally, the improved genetic algorithm was used to optimize the BP neural network, and the pixel value and the 3D coordinate value were used as the input and output of the BP neural network respectively, so as to complete the calibration of binocular camera. The results show that average calibration prediction errors before and after optimization are as 0.66 mm and 0.08 mm respectively, and the average calibration prediction error was reduced by 88%. The number of calibration test iterations before and after optimization is as 736 and 169 respectively, and the iteration speed is increased by 3.4 times after optimization. The improved genetic algorithm optimizes the BP network and achieves good results, which basically meets the requirements of binocular camera calibration.  Reference | Related Articles | Metrics

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Research on Dry Etching Processes on PSSs HOU Xiang, LIU Yixin, ZHONG Mengjie, LIN Sai, LIU Yang, LUO Ronghuang, LUO Xuetao, ZHANG Sa, China Mechanical Engineering    2021, 32 (24): 3001-3007.   DOI: 10.3969/j.issn.1004-132X.2021.24.014 Abstract （564）      PDF （4253KB）（253）       Knowledge map    Save In order to shorten the etching time and improve the luminescence performance of the light-emitting diodes(LEDs), the dry etching processes of adding etching auxiliary gas trifluoromethane(CHF3) were studied. The effects of the bias power, the CHF3 flows and the degree of throttle butterfly pendulum auto pressure control valve（abb. APC） on the etch selectivity and the etch rate were investigated by orthogonal experiments during the inductively coupled plasma(ICP) dry etching processs. The experimental results show that the process has higher etch selectivity and etch rate when the bias power, the CHF3 flows and the APC is as 350 W, 15 sccm and 55%, respectively. The PSSs with large size, high pattern-sapphire ratio and small radian were obtained, compared with the conventional PSSs, the height and the pattern-sapphire ratio of optimized PSSs are improved by 5.6% and 4.6%, respectively. Reference | Related Articles | Metrics

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A Collision Detection Method of Heavy-duty CNC Machine Tools Based on Digital Twin JIANG Xuemei, YUAN Zihang, LOU Ping, ZHANG Xiaomei, YAN Junwei, HU Jiwei, China Mechanical Engineering    2022, 33 (22): 2647-2654，2663.   DOI: 10.3969/j.issn.1004-132X.2022.22.001 Abstract （563）      PDF （10716KB）（229）       Knowledge map    Save At present, the collision detection of CNCMTs usually used the basic simulation function of the CNC system to detect machining G codes, which only considered whether there were collisions between the tool and the ideal workbench, or the tool and fixtures on the tool path during the processes. It was difficult to meet the actual dynamic processing environments, clamping mode and fixture change of open heavy-duty machine tools. So the digital twin was introduced into the collision detection of open heavy-duty CNCMTs, and a perception-evolutionary prediction-feedback collision detection framework was constructed. By constructing digital twin of CNCMTs and dynamically sensing machining elements such as workpieces ，fixtures and cutting tools, the evolution of the digital twin should be driven by perception data, and the potential interference phenomenon would be predicted in the machining processes. Thus, the efficiency of the CNCMTs was improved, and the potential harm was avoided. The method was applied to the collision detection of heavy-duty CNC gantry boring and milling machine ZK5520, and the effectiveness and feasibility of the proposed method were proved. Reference | Related Articles | Metrics

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Multi-scene Motion Planning of Manipulators Based on Improved RRT*FN Algorithm FANG Lijin, WU Zhenghan, WANG Huaizhen China Mechanical Engineering    2021, 32 (21): 2590-2597.   DOI: 10.3969/j.issn.1004-132X.2021.21.008 Abstract （558）      PDF （7704KB）（168）       Knowledge map    Save Aiming at the problems of low precision, poor environmental adaptability of RRT*FN algorithm, an improved RRT*FN motion planning algorithm for manipulators was proposed. Firstly, in the iteration processes, combining the advantages of target biased random sampling and ellipsoid subset sampling, a new heuristic method was constructed to constrain the sampling areas, so as to ensure better search paths. Then, in expanding node processes, the preset values of total number of nodes in the tree were configured, and the leaf nodes in the tree were deleted by weighting method, which avoided the infinite growth of tree sizes. Finally, under the dynamic environment, a heuristic replanning method of node pruning and connection was adopted to effectively improve the adaptability of dynamic environment. Experimental results show that the algorithm herein has faster convergence speed and higher efficiency in planning processes, and has strong environmental adaptability. Reference | Related Articles | Metrics