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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）（490）       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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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 （591）      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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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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Time-series Correlation Prediction of Quality in Process Production Processes Based on Deep TCN and Transfer Learning YIN Yanchao, SHI Chengjuan, ZOU Chaopu, LIU Xiaobao China Mechanical Engineering    2023, 34 (14): 1659-1671.   DOI: 10.3969/j.issn.1004-132X.2023.14.003 Abstract （552）      PDF （13154KB）（126）       Knowledge map    Save  To address the problems which were difficult to accurately predict production quality due to the temporal coupling of multiple processing parameters in process production, a fast and efficient production quality prediction method was proposed based on deep TCN networks and migration learning. With a sequence-to-sequence learning structure, a deep TCN and a temporal attention mechanism formed the encoding component for extracting key temporal features from multiple sources, while a residual long short term memory network formed the decoding component for simultaneous extraction of quality temporal information, and migration learning was introduced to address the adaptability of the prediction model to online production quality prediction. The experiments show that the proposed method has significant advantages in prediction accuracy and stability, and has high prediction accuracy and computational efficiency in predicting small sample data. Reference | Related Articles | Metrics

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Human Factor Engineering for Human-Cyber-Physical System Collaboration in Intelligent Manufacturing YANG Xiaonan, FANG Haonan, LI Jianguo, XUE Qing China Mechanical Engineering    2023, 34 (14): 1710-1722,1740.   DOI: 10.3969/j.issn.1004-132X.2023.14.008 Abstract （516）      PDF （5740KB）（291）       Knowledge map    Save The theoretical system of intelligent manufacturing for HCPS confirmed the central position of human in the intelligent manufacturing system. Starting from the demand of human-machine collaboration in the intelligent manufacturing system, the emphases of human factors in HCIM were discussed from three levels such as behavior, intention, and cognition, based on the theory of gulf. Focusing on virtual-real fusion scenarios, multimodal human-machine interaction, cognitive quantification and other methods, the importance of human factor engineering in promoting the integration of human-computer intelligence was expounded. Finally, research direction and development suggestions of human-centered intelligent manufacturing from the implementation of HCPS intelligent manufacturing systems were put forward. Reference | Related Articles | Metrics

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Robot Welding Trajectory Planning and High Frequency Control for Curved Seams WU Chaoqun, ZHAO Song, LEI Ting China Mechanical Engineering    2023, 34 (14): 1723-1728.   DOI: 10.3969/j.issn.1004-132X.2023.14.009 Abstract （491）      PDF （6070KB）（241）       Knowledge map    Save In a robotic real-time seam tracking system, the trajectory planning and control delay affected the tracking accuracy and welding quality. To solve this problem, a piecewise real-time trajectory planning and control method for curved seams was proposed by combining B-spline curve interpolation algorithm and EGM module. Firstly, the trajectory was segmented according to the principle of optimal interpolation time. Secondly, three times non-uniform B-spline was used to interpolate each trajectory to obtain the interpolation points. Finally, the high-frequency controller of the robot was designed. The interpolation points were sent to the robot by EGM module in a cycle of 4 ms to guide the robot movements. The experimental results show that this method may complete the planning of sine curve weld and guide the robot welding in 100 ms, and the tracking errors were controlled within ±0.2 mm, which realizes the rapid trajectory planning and high-frequency control. Reference | Related Articles | Metrics

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A Robotic Multi-directional Polishing Trajectory Generation Method Based on Preston-PSO Algorithm LI Jiaxuan, LI Lun, ZHOU Bo, ZHAO Jibin, ZHU Guang, WANG Zhengjia, China Mechanical Engineering    2023, 34 (14): 1729-1740.   DOI: 10.3969/j.issn.1004-132X.2023.14.010 Abstract （464）      PDF （13506KB）（138）       Knowledge map    Save Aiming at the texture phenomenon in robotic polishing processes, a multi-directional trajectory generation method used for robotic polishing was proposed based on Preston equation and particle swarm optimization algorithm，and the generated multidirectional polishing path was smooth, evenly distributed and without corners. Simulations and experiments show that compared with the polishing effectiveness of parallel trajectory, the trajectory generated by this algorithm may effectively inhibit the generation of surface polishing texture, reduce the roughness of polished surfaces, improve the surface quality, and obtain good mirror polishing effectiveness. Reference | Related Articles | Metrics

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Evolution of Concept of Machine Composition from the 19th Century to Modern Time ZHANG Ce, YANG Tingli, LIU Jianqin China Mechanical Engineering    2023, 34 (10): 1135-1139.   DOI: 10.3969/j.issn.1004-132X.2023.10.001 Abstract （423）      PDF （2405KB）（423）       Knowledge map    Save  With increasing of productivity and development of machines， the concept of “machine composition” also evolved. The requirements of modern society for machines were gradually increasing， and complex machines came from the transformation of traditional machines. Understanding the evolution of machines was a necessary process for the transformation of traditional machines. Marx first described the composition of machines in his Das Kapital， which coincided with the start of the Second Industrial Revolution. However， within only a few years， the control system joined a machine， and Marxs “concept of machine composition” began to be broken through. In the second half of the 20th century， in the Third Scientific and Technological Revolution， the concept of mechatronics emerged， and electronic technology， control technology and sensor technology were integrated into mechanical systems. The evolution processes of the concept of machine composition were explained through the history of the development of machines herein. By analyzing the evolution of the concept of machine composition， a more accurate definition of modern mechanical systems was put forword. It may enlighten people， increase their understanding of the machine itself， which has guiding significance for modern mechanical product designers.  Reference | Related Articles | Metrics

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Job-shop Scheduling Problems Considering Similar Learning Effect in One-worker and Multiple-machine Partterns ZHANG Weicun, GU Hongyu China Mechanical Engineering    2023, 34 (14): 1701-1709.   DOI: 10.3969/j.issn.1004-132X.2023.14.007 Abstract （411）      PDF （4248KB）（153）       Knowledge map    Save  A multi-objective job shop scheduling model was established considering the effects of job similarity and personnel learning under the one-worker multiple-machine production mode, and a grid filtering external archive genetic algorithm(GFEAGA) was designed to solve the scheduling problems. In order to improve solution efficiency, a two-stage coding and decoding approach was adopted, and an improved N6 neighbor structure search method was applied. The personnel selection method was designed to balance personnel workload. Non-dominant individuals were filtered based on grid sorting to enhance the diversity of the solution sets. The experiments verified the high efficiency and superiority of GFEAGA solution, and the sensitivity of the similarity and learning rate in the model were analyzed. Reference | Related Articles | Metrics

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Online Diagnostic Inspection and Prediction of Product Quality in Injection Molding Intelligent Factories Based on Data Mining CHEN Yu, XIANG Wei, GONG Chuan China Mechanical Engineering    2023, 34 (14): 1749-1755.   DOI: 10.3969/j.issn.1004-132X.2023.14.012 Abstract （395）      PDF （1793KB）（142）       Knowledge map    Save The dimensional accuracy of injection products was related to the injection processing parameters, and the real-time conditions of each stage in the injection processes and the changes of real-time working conditions. A workpiece quality diagnosis model was developed herein based on data mining. The real-time data collected by high-frequency sensors such as temperature, pressure, and displacement etc. in mold were used to construct the high-dimensional time series feature set. A three-stage feature selection method was used to determine the key feature subset, which was used to train the online quality detection model based on LightGBM classifier. The future values of each features were predicted based on the CNN-LSTM temporal prediction model, and the product quality was forecasted in advance with the classifier. The results show that the average recall rate of the macros is as 89.1%, and the average recall rate of the macros is as 81.6%. Reference | Related Articles | Metrics

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Calibration Parameter Optimization and Accuracy Evaluation of Complex Visual Measurement Systems SUN Jiale, LUO Chen, ZHOU Yijun, WANG Wei, ZHANG Gang China Mechanical Engineering    2023, 34 (14): 1741-1748,1755.   DOI: 10.3969/j.issn.1004-132X.2023.14.011 Abstract （383）      PDF （3739KB）（106）       Knowledge map    Save There were many calibration errors in complex visual measurement systems， and the coupling between errors directly affected the accuracy of system measurement， so the accuracy improvelment of system calibration parameters was the key to ensure the system measurement accuracy. Thus， a calibration parameter optimization method was proposed based on multi-dimensional angular point error compensation. Firstly， a multi-dimensional angular point error function was defined， and the corresponding optimization model whose parameters were solved by LM algorithm was established. Then， the effects of the parameter optimization method on the system calibration optimization were evaluated by the optimization rate of the system calibration errors. Experimental results show that the optimization rate of the system calibration errors may reach 48%， the system measurement accuracy is high and meets the measurement requirements.  Reference | Related Articles | Metrics

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Supply Chain Inventory System Optimization Model under Demand Disturbances WU Yingnian, ZHANG Jing, LI Qingkui, JIAO Shuai, China Mechanical Engineering    2023, 34 (14): 1672-1682，1700.   DOI: 10.3969/j.issn.1004-132X.2023.14.004 Abstract （368）      PDF （7177KB）（82）       Knowledge map    Save  Aiming at the supply chain inventory systems under demand disturbances, a supply chain inventory system optimization model was designed combining improved sliding mode controller and disturbance observer. A dynamic inventory model of a three-echelon networked supply chain system was established based on the product operation logic of the supply chain system. An optimization model combining improved sliding mode controller was designed based on adaptive exponential reaching law and disturbance observer. The model could suppress the influences of demand disturbances on the supply chain inventory system under the premise of ensuring system stability. Simulation comparison experiments verified the effectiveness of the optimization model. Reference | Related Articles | Metrics

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Finite Element Analysis for Extrusion, Assembly and Loosening Processes of Hi-lock Nuts ZHANG Jingdong, DENG BoGUI Xuewen, LI Jian, LIAO Ridong China Mechanical Engineering    2023, 34 (12): 1387-1394，1406.   DOI: 10.3969/j.issn.1004-132X.2023.12.001 Abstract （364）      PDF （12625KB）（269）       Knowledge map    Save  The FE（finite element） modeling method of UNJ threaded hi-lock nuts was investigated, and a modeling program was written to generate structured meshes, through which the fine FE meshed model was established. The extrusion process, assembly process and loosening behavior under transverse loads of hi-lock nuts were simulated by finite element method（FEM）, and the simulated locking torque was verified by tightening tests. The simulation results show that within a certain range, the maximum radial displacement and the locking torque of the hi-lock nuts are linearly related to the extrusion amount approximately. With the extrusion amount increases, the maximum radial displacement and the locking torque both increase. The higher the locking torque of the hi-lock nuts, the better the anti-loosening performance. However, there is an optimal value of the extrusion amount for the anti-loosening performance. Once the extrusion amount exceeds the optimum value, increasing the amount of extrusion does not have a significant effect on the improvement of the anti-loosening performance. Reference | Related Articles | Metrics

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Mechanism and Influencing Factors of Shape Warpage of TA2/Q235B Composite Plates during Stress Relief Annealing WANG Rui, ZHAO Zhimin, HUANG Jing, LIU Xin, JI Xiangyun, SU Chunjian China Mechanical Engineering    2023, 34 (10): 1230-1240.   DOI: 10.3969/j.issn.1004-132X.2023.10.013 Abstract （339）      PDF （11513KB）（76）       Knowledge map    Save In order to explore the mechanism and influencing factors of shape warping during stress relief annealing of TA2/Q235B composite plates， a Gleeble thermal simulation experiment was carried out to obtain the true stress and strain of TA2 and Q235B materials under different working conditions. The JC constitutive model parameters of TA2 and Q235B were determined by numerical method， and the finite element simulation model of stress relief annealing was established by combining boundary conditions such as temperature and external load. The heat treatment experiments verified the accuracy of the model. The results show that a certain tensile load may improve the strain distribution， excessive tensile load results in local concentration of residual strain， and the composite ratio and the total thickness affect the stress distribution， which will affect the strain states.  Reference | Related Articles | Metrics

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Failure Mechanism on Touchdown Bearings of Heavy Maglev Rotor Drop LI Zilin, SHI Zhengang, TIE Xiaoyan, YANG Guojun, REN Wenliang, YAO Jiakang, WANG Yuming, WANG Zixi China Mechanical Engineering    2023, 34 (09): 1009-1018.   DOI: 10.3969/j.issn.1004-132X.2023.09.001 Abstract （334）      PDF （11267KB）（146）       Knowledge map    Save For the national key R&D program “high-speed precision suspension bearing”, the requirements for the drop capacity of TDBs were: rotor mass ≥3000 kg, drop speed ≥3000 r/min, and successful drops ≥10 times. Based on this, the research and development of TDBs drop failure mechanism were carried out. Two hybrid TDBs with ceramic balls suitable for drop conditions were proposed: full complement ball without cage scheme and non-full complement ball with cage scheme. A rotor drop simulation model was built including dynamics and thermal. The force and heating processes of the drop processes were simulated. The effectiveness of the simulation model was verified by mounting the TDBs in the test bench for experiments. TDBs without cage are found to have failed severely. The damages of the failed bearing are detected, and it is observed that due to the large friction coefficient between the rolling elements, the rolling elements are seized up, resulting in continuous dry friction between the rolling elements and the raceways, and between the inner ring and the rotor, and serious burns and wear of the inner rings. Reference | Related Articles | Metrics

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Patent Data Driven Product Innovation Design Based on SAO LIN Wenguang, LIU Xiaodong, XIAO Renbin China Mechanical Engineering    2023, 34 (15): 1765-1777.   DOI: 10.3969/j.issn.1004-132X.2023.15.001 Abstract （324）      PDF （5241KB）（318）       Knowledge map    Save The patent data-driven product innovation design method was proposed based on SAO using big data mining technology. Firstly， semantic dependency parsing was used to mine the SAO structure and interaction relationships among product components from patent text databases. Subsequently， a complex network knowledge model was constructed for product systems， and the constraint coefficients of components in the complex network were calculated by using structural hole theory to identify the innovative target components. Then， the semantic similarity coefficients of components were calculated using Word2Vec， and the functional similarity coefficients were calculated using SAO similarity algorithm. And the recommendation algorithm and combination matrix were integrated to achieve structural innovation， functional innovation， and functional optimization. Finally， a typical bathroom shower product was taken as an example to demonstrate the method in detail， which fully verifies the effectiveness and progressiveness of the method.  Reference | Related Articles | Metrics

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Multi Tooth Meshing Characteristics and Load Bearing Contact Analysis Method of Cycloidal-pin Wheels WANG Yongqiang, WEI Bingyang, XU Jiake, YANG Jianjun China Mechanical Engineering    2023, 34 (10): 1151-1158.   DOI: 10.3969/j.issn.1004-132X.2023.10.003 Abstract （314）      PDF （4467KB）（247）       Knowledge map    Save  The tooth profile equations of cycloidal gear were derived by the envelope methods， and the tooth surface contact parameters were obtained. An accurate algorithm for the geometry analysis of the backlash was proposed， which solved the defects that the traditional backlash algorithm might only be used for the constant displacement modification. The tooth by tooth clearance elimination methods were used to solve the deformation compatibility equation， which avoided the error and uncertainty of conventional meshing analysis and improved the calculation accuracy and efficiency of load-bearing contact analysis. The complete calculation flow from tooth surface contact analysis to load contact analysis was given， and the accurate load parameters of any angle position and different modification methods were obtained.  Reference | Related Articles | Metrics

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Research Progresses of Superhydrophobic Surface Processing Technology and Abrasion Resistance HUANG Yun, HUANG Jianchao, XIAO Guijian, LIU Shuai, LIN Ouchuan, LIU Zhenyang China Mechanical Engineering    2024, 35 (01): 2-26.   DOI: 10.3969/j.issn.1004-132X.2024.01.001 Abstract （314）      PDF （50387KB）（453）       Knowledge map    Save The abrasion resistance of currently prepared superhydrophobic surfaces is generally poor, which limite the applications in various fields. Studied results found that micro-nano structure and low surface energy were the key factors to achieve superhydrophobic properties. Firstly, based on the mechanism of superhydrophobic surface, the superhydrophobic surface texture was summarized, aiming to solve the wear-prone challenge of micro-nano structures by optimizing the surface texture. Secondly, the superhydrophobic surface processing technology was summarized, and measures to reduce surface energy were analyzed in terms of cost and efficiency which might provide ideas for expanding the superhydrophobic surface processing system. Then, the means of analyzing the abrasion resistance of superhydrophobic surfaces were concluded in detail and the methods of improving the abrasion resistance of superhydrophobic surfaces were described. Finally, the future development prospects of abrasion resistant superhydrophobic surfaces was prospected, with a view to promote the large-scale applications of superhydrophobic surfaces in engineering. Reference | Related Articles | Metrics

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Molecular Dynamics Simulation for Effect of Nanoparticle Additives on Boundary Lubrication PAN Ling, LIN Guobin, HAN Yuqing, YU Hui China Mechanical Engineering    2023, 34 (10): 1140-1156.   DOI: 10.3969/j.issn.1004-132X.2023.10.002 Abstract （306）      PDF （12614KB）（178）       Knowledge map    Save The boundary lubrication behavior of Cu nanoparticles in n-hexadecane was investigated under different loads by experiments and simulations herein. Boundary lubrication model with sinusoidal rough peaks was established. The density distribution of the lubricant along the film thickness with and without Cu nanoparticles were simulated at different loads using MD respectively. The shear velocity in the opposite direction was applied to the upper and lower solid walls of the system， and the stress between the wall atoms and the copper particle atoms， the friction force of the solid-liquid interface， the normal pressure and the friction coefficient were calculated. The friction coefficient of the lubricant containing nano-copper particles was measured with a micro-nano scratch meter. The results show that the base oil n-hexadecane in the two lubrication systems is stratified under different pressures. There are still a small amount of n-hexadecane molecules at the contact interface when the nano-rough peaks are directly contacted， and the arrangement direction of the molecular main chain is the same as the shear direction. Cu nanoparticles may reduce the maximum stress of solid wall by 35.3% and improve the bearing capacity of lubrication system at 200 MPa. The lubricating oil film of lubrication system without Cu nanoparticles breaks at 50 MPa， while that of lubrication system with Cu nanoparticles breaks at 200 MPa. The friction coefficient of two lubrication system under boundary lubrication is simulated， which is in accordance with the experimental measurement.  Reference | Related Articles | Metrics

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Research on Underwater Gliders Path Tracking Based on Reinforcement Learning Algorithm SHI Qingqing, ZHANG Runfeng, ZHANG Lianhong, , LAN Shiquan, China Mechanical Engineering    2023, 34 (09): 1100-1110.   DOI: 10.3969/j.issn.1004-132X.2023.09.011 Abstract （304）      PDF （6340KB）（308）       Knowledge map    Save Aiming at the large deviations between the actual paths and the predetermined ones of underwater gliders affected by ocean current, a neural network ocean current prediction model with long-term and short-term memory and attention mechanism was established based on the traditional long-term and short-term memory network model.The dynamic Q-table of underwater glider motions was generated by depth neural network, and the optimal motion attitude was selected by reinforcement learning algorithm. Considering the influences of ocean current, an underwater glider path tracking algorithm was constructed based on depth reinforcement learning. The results show that the long-term and short-term memory network based on attention mechanism has less mean square errors and root mean square errors in ocean current prediction than that of the traditional integrated moving average autoregressive model and long-term and short-term memory network.Compared with the traditional PID control, the deep reinforcement learning model may reduce the root mean square errors of the underwater glider trajectory by 50.9%, and significantly improve the path tracking accuracy. Reference | Related Articles | Metrics

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High Rigidity and Lightweight Design of Purlins in Photovoltaic Tracker Bracket DONG Xiaohu, WANG Shitao, ZHOU Dechun China Mechanical Engineering    2023, 34 (10): 1207-1213.   DOI: 10.3969/j.issn.1004-132X.2023.10.010 Abstract （302）      PDF （5559KB）（250）       Knowledge map    Save In the intelligent photovoltaic tracker brackets， cold-formed purlins were used to support the photovoltaic panels， and located spannig the horizontal single-axis and the module frame. Firstly， the minimum compliance of the structures was taken as the target and relative densities of elements were taken as the design variables， and the topology optimum design models were constructed under the given volume and the first natural frequency constraints. Optimal material distributions of the purlins were obtained based on SIMP (solid isotropic material with penalization) method， and this topology optimization structure was engineering designed and manufactured. Then， test load conditions were designed according to the practical environment where the photovoltaic tracker brackets were applied under different wind loads. The static and dynamic finite element analyses of the original and optimized purlins were carried out respectively， the simulation results show that the optimized purlins are improved in terms of bending resistance， torsion resistance， and natural frequency. Thus， the effectiveness of the optimization design method is verified. After that， the optimal purlins whose mass is reduced by 8.8% were also manufactured by engineering methods， and the mechanics performances were verified by the experiments.  Reference | Related Articles | Metrics

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Ultrasonic Impact Strengthening of Titanium Alloys：State-of-the-art and Prospectives ZHA Xuming, YUAN Zhi, QIN Hao, XI Linqing, ZHANG Tao, JIANG Feng China Mechanical Engineering    2023, 34 (19): 2269-2287.   DOI: 10.3969/j.issn.1004-132X.2023.19.001 Abstract （292）      PDF （36447KB）（221）       Knowledge map    Save This review started with the introduction to the principles and research progresses of the ultrasonic impact strengthening technology for titanium alloys. The influences of the properties of titanium alloys were investigated, which was associated with the different parameters of ultrasonic impact strengthening processes（static pressure， ultrasonic amplitude and numbers of rolling）. Results show that the optimization of different processing parameters has a significant improvement on the performance strengthening of the titanium alloys. However， there is a critical value of the different processing parameters. Once the critical values are exceeded， continuing to increase the parameter values will reduce the service performance of the titanium alloys. Finally， the difficulties of ultrasonic impact strengthening technology which used in the engineering applications were summarized. Combined with the development of intelligent manufacturing， the future development of ultrasonic impact strengthening technology was prospected.  Reference | Related Articles | Metrics

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High-precision Microsphere Radius Measurement Model and Comparation among Roundness Evaluation Methods LI Ruijun, DUAN Liuhui, ZHAO Wenkai, CHENG Zhenying, FAN Guangzhao China Mechanical Engineering    2023, 34 (10): 1159-1163,1171.   DOI: 10.3969/j.issn.1004-132X.2023.10.004 Abstract （281）      PDF （3444KB）（148）       Knowledge map    Save A high-precision microsphere radius measurement model was proposed based on the principle of rotary axis method and two-point method， and the microsphere roundness evaluation was realized based on the amount of radius changes. A model was established that might separate the spindle runout errors and calculate the corresponding radius of each measurement points. Using the microsphere roundness measurement system developed by the authors group based on a high-precision air-bearing rotary table and two Michelson interferometers， the equatorial circular cross section of a ruby sphere with a nominal diameter of 300 μm and a roundness of 250 nm was scanned and measured. The roundness of the measured microsphere was evaluated by the minimum zone circle method， based on the measured radius by the proposed model and the calculated radius by the diameter. The results show that the roundness of the microspheres obtained by the proposed model and the conventional diameter evaluation method are as 280 nm and 403 nm with standard deviations of 2 nm and 23 nm， respectively， the proposed radius measurement model is accurate and reliable， and the roundness of the microspheres evaluated by the proposed model and the minimum zone circle method is more accurate and reliable. The proposed method may be used to obtain the radius of the measured microspheres easily and accurately， and may be applied to the accurate evaluation of the roundness of microspheres. Reference | Related Articles | Metrics

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Design and Experimental Study of a Flexible Winding Forming System for Carbon Fiber Reinforced Carbon/Carbon Crucible Preform WANG Zheng, DONG Jiuzhi, CHEN Yunjun, JIANG Xiuming, China Mechanical Engineering    2023, 34 (10): 1184-1190,1198.   DOI: 10.3969/j.issn.1004-132X.2023.10.007 Abstract （272）      PDF （5668KB）（306）       Knowledge map    Save In order to solve the problems of product consistency and low production efficiency caused by manually reinforced carbon/carbon crucible preforms， a flexible winding forming system of carbon fiber reinforced crucible preform was proposed. The line type design process of crucible core die for special rotary body structure with one end plane head and one end ellipsoid head was presented based on the non-geodesic method. Each module and implementation method of computer aided line type design were introduced， and the design line type was simulated. A special winding machine with four degrees of freedom was designed according to the winding characteristics. The control system of four-axis winding machine was designed based on programmable controller and touch screen， and the winding tests were carried out. It is indicated that the winding machine runs stably and the fiber may be wound continuously and stably on the surfaces of the core die， and the system may realize automatic winding of carbon fiber reinforced carbon/carbon crucible preforms.  Reference | Related Articles | Metrics

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Research on Path Tracking Control Method of Distributed Drive Electric Vehicles with Integrated Stability WANG Shu, ZHANG Haichuan, ZHAO Xuan, SONG Hankun China Mechanical Engineering    2023, 34 (09): 1035-1044.   DOI: 10.3969/j.issn.1004-132X.2023.09.003 Abstract （272）      PDF （7528KB）（129）       Knowledge map    Save  A path tracking control strategy with integrated vehicle stability was proposed to improve the path tracking precision and vehicle stability of distributed drive electric vehicles under dangerous driving conditions such as high speed and low adhesion conditions. The hierarchical structure path tracking control strategy with vehicle stability, including the path tracking control layer, the stability controller decision layer and the drive wheel torque distribution layer. To solve the problem of the lower accuracy of LQR path tracking controller under high-speed and large curvature conditions, a closed loop PID correction driver model was used to compensate the front wheel angle of the vehicles. In addition, the stability controller was designed to track the ideal reference model of the vehicles. The controller developed the model predictive control algorithm to generate additional yaw moment. Meanwhile, the controller realized the optimal distribution of the wheel drive torques with the objective of minimizing tire load rate. Based on the independently designed distributed drive electric test vehicle, the double lane change tests were carried out on high-speed high adhesion road surfaces and high-speed low adhesion road surfaces respectively. The results show that, when driving on dry concrete pavement at 90 km/h speed, the lateral root mean square errors of the path tracking precision with integrated dynamics stability reduce by 29.7%, compared to the LQR path tracking controller using only closed-loop PID correction for path tracking. When driving on wet asphalt pavement at 70 km/h speed, the lateral root mean square errors reduce by 10.3%. Therefore, the proposed path tracking control strategy with integrated vehicle stability of distributed drive electric vehicles may improve path tracking accuracy, ensuring yaw stability under extreme conditions effectively.  Reference | Related Articles | Metrics

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Study on Design of Wheel-leg Deformable Wheel and Vehicle Control GENG Xueqing, WU Mengwu, HUA Lin, China Mechanical Engineering    2023, 34 (12): 1446-1452.   DOI: 10.3969/j.issn.1004-132X.2023.12.007 Abstract （271）      PDF （6422KB）（254）       Knowledge map    Save  In view of the demands of vehicle mobility and obstacle-crossing ability in complex terrain and road conditions, a deformable wheel structure was designed with the characteristics of switching between wheeled and legged states under different terrain and road conditions. The design principle of the deformable wheel was introduced and the structural parameters were calculated and optimized, the maximum diameter ratio of the wheel-leg deformable wheel was obtained. A set of simple and effective wheel-leg deformation control system was also designed. And then the vehicle layout design and movement process analysis was carried out. Finally, a prototype vehicle platform was made to verify the mobility and obstacle-crossing ability by physical experiments. The results show that the deformable wheel may be quickly and intelligently switched between wheeled and legged types, which enables the vehicle to run stably on both structured and unstructured roads, resulting in a high mobility and obstacle-crossing ability of the vehicle system. Reference | Related Articles | Metrics

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Assessment Method of Environmental Impact of Casting Processes Based on Digital Twin GU Zhenyu, HE Yi, LI Dongyang China Mechanical Engineering    2023, 34 (12): 1465-1475.   DOI: 10.3969/j.issn.1004-132X.2023.12.009 Abstract （268）      PDF （4109KB）（200）       Knowledge map    Save Focusing on the new needs of foundry enterprises to carry out process environmental impacts and carbon emission evaluations, and addressing the issues of consistent management of dynamic data in dynamic evaluations of processes, the casting processes were taken as the research object and the digital twin technologies were introduced into the assessments of the environmental impacts and carbon emissions of the casting processes. A digital twin model of the casting processes for environmental impact assessments was constructed and integrated into the basic process of LCA evaluation, and a digital twin-based method for environmental impact assessments of the casting processes was proposed. By evolving from twin models to instance models and instance twins, the consistency of the process data structure was ensured, while the dynamic scene data carrying was realized by generating instance twins of different stages, and the management of dynamic process data was realized. Finally, the application of the proposed method in the environmental impact assessments of the processes was illustrated by the example of the 3.5-ton carrier V-normal casting processes in a foundry. Reference | Related Articles | Metrics

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Optimization of Multi-objective Grinding Process Parameters to Suppress Chatter Marks LI Guolong, ZHU Guohua, JIANG Lin, TAO Yijie, JIA Yachao China Mechanical Engineering    2023, 34 (09): 1086-1092.   DOI: 10.3969/j.issn.1004-132X.2023.09.009 Abstract （265）      PDF （2038KB）（144）       Knowledge map    Save Aiming at the problems of chatter marks frequently occurring in gear grinding with worm-shaped grinding wheel, the effects of grinding process parameters (linear speed of grinding wheel, axial feed speed of abrasive wheel, radial feed of grinding wheel) on machining vibrations and tooth surface roughness were investigated by orthogonal design experiments of helical gears used in a certain type of new energy vehicles. A multi-objective optimization mathematical model was established with multiple quadratic regression method to reduce vibrations and tooth surface roughness, and genetic algorithm was used to optimize grinding parameters. The results show that the optimized processing parameters may greatly reduce the vibrations in grinding while maintaining the stable roughness value of tooth surfaces, effectively prevent the generation of chatter marks and prolong the working life of the machine tools. Reference | Related Articles | Metrics

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Research on Compliant Legs of Bionic Hexapod Robots WANG Wei, WEI Lang, LIU Fusheng, WANG Guoshun China Mechanical Engineering    2023, 34 (17): 2089-2094.   DOI: 10.3969/j.issn.1004-132X.2023.17.008 Abstract （263）      PDF （6492KB）（172）       Knowledge map    Save In order to explore the specific influences of the curved legs with compliance on the motion performance of the bionic hexapod robots， firstly， the PRB model was used to describe the deformation features of the curved legs， and the mathematical expression of the stiffness was given.  Then， based on the stiffness model， a virtual prototype was built in the Webots simulation environment， and the changes in velocity and energy consumption rate of the bionic hexapod robots were analyzed by setting different stiffnesses of the curved legs.  Finally， the curved legs with different stiffness were fabricated and verified in the physical prototype.  The results show that the compliance of the curved legs may be more accurately described by the PRB model， which improves the velocity of the bionic hexapod robots and reduces the energy consumption.  Reference | Related Articles | Metrics

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Research Progresses of Super-hard Abrasive Grain Controllable Arrangement Grinding Wheels CHEN Bing, GUO YeDENG Zhaohui China Mechanical Engineering    2023, 34 (09): 1019-1034.   DOI: 10.3969/j.issn.1004-132X.2023.09.002 Abstract （261）      PDF （16342KB）（140）       Knowledge map    Save In the grinding processes, the distribution and arrangement of the abrasive grains on the grinding wheel affected the form of interaction between the abrasive grains and the workpiece materials, the order of grinding trace distribution and the material removal characteristics, which determined the grinding surfaces, sub-surface quality, grinding forces, et al. Compared with the grinding wheel with random distribution of abrasive grains, the ordered grinding wheel helped to reduce the grinding forces and grinding temperature during processing and improve the life and grinding performance of the grinding tools by reasonably adjusting the positions and distribution modes of abrasive grains on the grinding wheel surfaces, which helped the abrasive grains on the grinding wheel surfaces to have uniform forces and reasonable size of chip holding spaces. At present, the research on super-hard grain ordered grinding wheels was a relatively mature research direction with earlier development and more related theories than that on ordered grinding wheels such as abrasive clusters and structured grinding wheels. The research status of super-hard abrasive ordered arrangement wheel preparation was reviewed herein. Then, the theory and application status of super-hard abrasive wheel with directional arrangement, phyllotactic arrangement and other arrangement were discussed. Finally, the future research directions of super-hard abrasive grain controllable arrangement grinding wheels was discussed. Reference | Related Articles | Metrics

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Adaptive Fractional Order Sliding Mode Control for PMSMs Based on NDO ZHAO Ximei, WANG Chao, JIN Hongyan China Mechanical Engineering    2023, 34 (09): 1093-1099,1119.   DOI: 10.3969/j.issn.1004-132X.2023.09.010 Abstract （260）      PDF （3665KB）（123）       Knowledge map    Save The feed system of CNC machines driven by PMSM servo system was susceptible to parameters variation, external disturbances and other uncertain factors, an AFOSMC scheme was designed based on NDO. First, the dynamic mathematical model of PMSM with uncertainties was established. Then, FOSMC and adaptive control were combined to suppress the chattering phenomenon of integer order sliding mode control, and the switching gain might be adjusted in real time to improve the control accuracy of the system. However, external disturbances would have a great impact on the system. Therefore, NDO was used to identify the external disturbances in real time, and the observed values were introduced into AFOSMC as feedforward compensation to improve the anti-interference ability of the controller. Finally, the experimental results show that the designed AFOSMC may weaken the chattering phenomenon effectively based on NDO, improve tracking performance and anti-interference ability of the feed systems. Reference | Related Articles | Metrics

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Pivot Steering Control of Off-road Vehicles Driven by In-wheel Motors FU Xiang, LIU Zexuan, , LIU Daoyuan, LI Dongyuan, China Mechanical Engineering    2023, 34 (10): 1251-1259.   DOI: 10.3969/j.issn.1004-132X.2023.10.015 Abstract （260）      PDF （6293KB）（327）       Knowledge map    Save In order to solve the problems of large minimum turning radius and inadequate steering maneuverability of Ackermann steering-based off-road vehicles， a road adaptive pivot steering control strategy was developed by taking advantages of the independent control of vehicle torque driven by in-wheel motors. A seven-degree-of-freedom pivot steering dynamics model was constructed to explain the evolution of the longitudinal and transverse coupled motion tire forces during pivot steering， and a quantitative model was established to quantify the pivot steering resistance moment and transverse sway moment with wheel slip rate and road adhesion coefficient. The desired trajectory of transverse sway angular velocity under different adhesion conditions was designed with steering power responsiveness as the optimization objective， and the safety threshold of each wheel slip rate was used as the stability constraint to reduce the steering center offset. The executive layer tracked the transverse angular velocity based on the model prediction algorithm， while the adaptive sliding mode controller was introduced to adjust the wheel slip rate to ensure the stability of the longitudinal and transverse motions. Simulation tests and real vehicle tests show that the developed pivot steering control strategy achieves accurate tracking of the desired pivot steering trajectory under high， medium and low adhesion surfaces， and limits the steering center offset to within 500 mm， which improves the pivot steering flexibility and lateral stability of the off-road vehicles and realizes "fast and stable" pivot steering.  Reference | Related Articles | Metrics

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Collaborative Optimization of Stacking Sequence and Material Distribution for Wing Skins PENG Xiang, JIANG Haohao, GUO Yuliang, LI Jiquan, YI Bing, JIANG Shaofei, China Mechanical Engineering    2023, 34 (12): 1415-1424,1435.   DOI: 10.3969/j.issn.1004-132X.2023.12.004 Abstract （259）      PDF （11856KB）（85）       Knowledge map    Save To realize the lightweight and shock absorption design of the wing skins, the hybrid composite materials were introduced into the design of wing skins, and a collaborative optimization design method of stacking sequences and materials distribution was proposed for wing skins. The stacking sequences and material distribution of the wing skins were taken as the optimization design variables, the collaborative optimization model with cost as constraint, minimization of skin mass and displacement, and frequency maximization as objectives was established. The multi-objective collaborative optimization problem of the wing skins was carried out by using the NSGA-Ⅱ based on the developed optimization design framework of the wing skins. Compared with the performance of aluminum alloy wing skins and initial structure scheme, the optimized stacking sequences and material distributions may significantly improve the comprehensive performance of the wing skins without increasing the costs, which verifies the effectiveness of the proposed method. Reference | Related Articles | Metrics

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Open Shop Scheduling Problems Considering Equipment Preventive Maintenance  ZHU Chuanjun, FENG Shijian, ZHANG Chaoyong, JIN Liangliang, WANG Linlin China Mechanical Engineering    2023, 34 (14): 1693-1700.   DOI: 10.3969/j.issn.1004-132X.2023.14.006 Abstract （258）      PDF （2203KB）（139）       Knowledge map    Save Based on the actual operations of a production workshop, an open shop scheduling model with equipment preventive maintenance was established, and a hybrid genetic taboo search algorithm was designed to solve the problems. According to the characteristics of the problems, the genetic coding, decoding, improved crossover, and mutation operations of the hybrid algorithm, and the neighborhood structure of the taboo search algorithm were designed to achieve an balance between centralized searches and decentralized searches. The proposed algorithm was applied to the Taillard benchmark instance of open shop scheduling and the open shop scheduling case with preventive maintenance, which verifies the efficiency and effectiveness of the proposed hybrid algorithm. Reference | Related Articles | Metrics

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Study on Unbalanced Meshing Loads of Planetary Gear Transmission under Heavy-load Conditions TAN Jianjun, LI Hao, YANG Shuyi, ZHU Caichao, SONG Chaosheng, SUN Zhangdong China Mechanical Engineering    2023, 34 (13): 1513-1524.   DOI: 10.3969/j.issn.1004-132X.2023.13.001 Abstract （255）      PDF （24327KB）（250）       Knowledge map    Save  To study the gear tooth load distribution affected by the multi-flexible body deformations of planetary gear transmission under heavy-load conditions， a coupled dynamics modeling method of planetary gear transmission that taken into account the structural flexibility and dynamic contact of gear pair was proposed. Taking a certain type of megawatt-class wind turbine gearbox planetary gear train as the research object， according to the ring gear， carrier， and their boundary characteristics， the finite element reduction theory was used to establish the correlations between the ring gear teeth， carriers coupling points and the corresponding elastic supports， and the dynamic load-contact of the gear pair was used as the interface coordination condition to couple these components， to establish the planetary gear transmission coupling dynamics model. The phenomenon of unbalanced meshing loads and the effects of structural parameters on the meshing characteristics were analyzed. The results show that the comprehensive bending moment acting on the planet gear and the asymmetric structural deformations of the carrier pin are the main causes of the unbalanced meshing loads， and the resonance of the system will aggravate this phenomenon. In the resonance region， the dynamic meshing stiffness differs greatly from the static meshing stiffness. Increasing the carrier pin stiffness and the helix angle may improve the meshing condition and reduce the system vibration in the resonance region. But in low-speed region, that is not good for system vibration absorption. Increase of the rigidity of the carriers connecting plate may keep the systems vibration state in the low-speed region， and reduce the system vibration in the resonance region.  Reference | Related Articles | Metrics

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Analysis and Test on Dynamic Transmission Errors of RV Reducers under Load Conditions XU Lixin, XIA Chen, YANG Bo China Mechanical Engineering    2023, 34 (18): 2143-2152.   DOI: 10.3969/j.issn.1004-132X.2023.18.001 Abstract （254）      PDF （8485KB）（191）       Knowledge map    Save  For the current RV reducer transmission accuracy factory calibration value was detected under no-load conditions, it was difficult to reflect the real accuracy performance under torque loading conditions, in order to effectively reveal the dynamic transmission error characteristics of the RV reducers under the action of the load, a theoretical dynamic model of contact multi-body system of standard RV reducer with two crankshafts was proposed, which took the multi-error factors of geometry and position of key transmission parts into consideration. In order to effectively reveal the dynamic transmission error characteristics of RV reducers under load, during modeling, firstly, the parametric model of the whole reducer was designed and completed for the RV reducer transmission structure characteristics. Secondly, a detailed dynamic contact analysis method was proposed considering involute gear drive of the first stage, cycloidal-pin drive of the second stage, and multiple sets of turning-arm bearings and support bearings. Thus, the dynamic transmission error characteristics of reducer under torque load were discussed taking RV20E as the object. The results show that with the increase of load torque, the transmission error amplitudes of reducer are increasing, but the amplitude growth rate is decreasing. Compared with no-load conditions, the increase of theoretical transmission errors of the reducers under rated torque is as 73.1%, and the increase of experimental transmission errors under rated torque is as 58.9%. Reference | Related Articles | Metrics

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Correction Model and Experimental Study of Removal Rate in Tangential Cylindrical Grinding Based on Grinding Thermal Deformation Analysis CHI Yulun, WU Zixuan China Mechanical Engineering    2023, 34 (15): 1778-1788.   DOI: 10.3969/j.issn.1004-132X.2023.15.002 Abstract （252）      PDF （13452KB）（174）       Knowledge map    Save In order to solve the problem in plunge type cylinder grinding caused by the traditional grinding removal efficiency model of grinding thermal deformation is different from the actual grinding， the traditional grinding removal efficiency model was modified based on the analysis of grinding thermal deformation mechanism. By analyzing the grinding thermal deformation and thermal deformation rate of grinding wheel and workpiece， the correction function was determined， the material removal efficiency correction model based on the thermal deformation was established. The model was verified by grinding experiment， and the results show that the model has higher accuracy.  Reference | Related Articles | Metrics

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Yaw Rate Calculation and Vehicle Stability Control Considering Tire Nonlinearity MIN Delei, TONG Ruting, WEI Yintao China Mechanical Engineering    2023, 34 (21): 2521-2530.   DOI: 10.3969/j.issn.1004-132X.2023.21.001 Abstract （250）      PDF （7794KB）（211）       Knowledge map    Save Based on the nonlinear tire model， an accurate yaw rate calculation method was proposed to calculate the accurate yaw rate and applied to vehicle stability control. Tire nonlinearity was characterized by the brush model. The equivalent stability factor was obtained by perturbation analysis， and the accurate analytical solution of the yaw rate was obtained. The analysis of the existence of analytical solutions indicates that tire nonlinearity may impact vehicle stability. Real vehicle tests and control simulations based on vehicle models show that considering tire nonlinearity may effectively improve the calculation accuracy of the steady-state yaw rate as the target parameter， and improve the effect of vehicle stability control.  Reference | Related Articles | Metrics

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Numerical Analysis Method and Test for Contact Stress of Cycloidal Gear in RV Reducer HUANG Xiangmao China Mechanical Engineering    2023, 34 (24): 3015-3023.   DOI: 10.3969/j.issn.1004-132X.2023.24.013 Abstract （249）      PDF （8857KB）（144）       Knowledge map    Save The effective contact area and circumferential load distribution of cycloid gear tooth surfaces under specific loads were calculated by taking into account the elastic deformations and backlash of cycloid tooth surfaces. A mathematical model of contact stress in the tooth width direction of cycloidal gears was established by using force balance equation and deformation coordination equation, and the calculation procedure and flow chart were given. The mathematical model was a nonlinear equation set, by solving the nonlinear equations, the stress distribution and contact width in the tooth width direction of cycloidal gears were obtained. The mathematical model of contact stress and computational procedures were given to simulate the contact tooth width and contact stress distribution of cycloidal gear under ideal conditions and alignment errors. And the correctness and feasibility of the proposed method were verified by combined with testing and simulation results. Reference | Related Articles | Metrics

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Experimental Study of Laser Assisted Water Jet Micromilling of Single Crystal β-Ga2O3 Substrates TIAN Long, HUANG Chuanzhen, LIU Dun , YAO Peng , LIU Hanlian, LIU Xuefei China Mechanical Engineering    2023, 34 (13): 1559-1567.   DOI: 10.3969/j.issn.1004-132X.2023.13.005 Abstract （249）      PDF （7739KB）（178）       Knowledge map    Save  Gallium oxide （β-Ga2O3） was a new type of high performance semiconductor material. Due to the characteristics of easy cleavage， high brittleness， poor thermal conductivity and anisotropy， the micro cracks would be easily generated in traditional precision machining and laser machining, which greatly restricted the applications of gallium oxide single crystal. Laser-assisted water jet machining might combine the advantages of high efficiency and high precision of laser machining and no thermal damages of water jet machining， which might realize the near thermal damage free machining of hard and brittle materials， thus a good application prospect was obtained in the field of semiconductor wafer processing. All-factor experimental study of laser assisted water jet micro-milling of single crystal β-Ga2O3 substrates was carried out herein. Results show that the processing parameters have significant influences on the depth and the surface roughness of the bottom of the micro-groove. By optimizing the processing parameters， the micro-groove with low surface damage， flat bottom and low surface roughness （Ra<1 μm） may be obtained by the laser assisted water jet machining.  Reference | Related Articles | Metrics