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A Comparative Study on Asperity Peak Modeling Methods

Chinese Journal of Mechanical Engineering 2021年第4期34卷 137-150页

作者： Wei Zhou Daiyan Zhao Jinyuan Tang Jun Yi Hunan Provincial Key Laboratory of High Efficiency and Precision Machining of Difficult-to-Cut Material Hunan University of Science and TechnologyXiangtan 411201China State Key Laboratory of High Performance Complex Manufacturing Central South UniversityChangsha 410083China

The peak identification scheme based method(three-point definition)and the spectral moments based method(spectral moment approach)are both widely used for asperity peak modeling in *** discover the differences between the two methods,a great number of rough surface profile samples with various statistical distributions are first randomly generated using *** the distribution parameters of asperity peaks are calculated for the generated samples with both *** obtained results are compared and verified by *** variation rules of the differences between the two methods with statistical characteristics of rough surfaces are *** explain for the discovered differences,the assumptions by spectral moment approach that the joint distribution of surface height,slope and curvature is normal and that the height distribution of asperities is Gaussian,are *** results show that it is unreasonable to assume a joint normal distribution without inspecting the correlation pattern of[z],[z′]and[z′′],and that the height distribution of asperities is not exactly Gaussian before correlation length of rough surface increases to a certain extent,20 for instance.

关键词： Surface topography Roughness Surface analysis Asperity peak Random process model

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Interfacial stress characterization of GaN epitaxial layer with sapphire substrate by confocal Raman spectroscopy

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Nanotechnology and precision Engineering 2021年第2期4卷 9-19页

作者： Zengqi Zhang Zongwei Xu Ying Song Tao Liu Bing Dong Jiayu Liu Hong Wang State Key Laboratory of Precision Measuring Technology and Instruments Centre of MicroNano Manufacturing TechnologyTianjin UniversityTianjin 300072China State Key Laboratory of Separation Membranes and Membrane Processes School of Materials Science and EngineeringTianjin Polytechnic UniversityTianjin 300387China

As an important wide-bandgap semiconductor,gallium nitride(GaN)has attracted considerable *** paper describes the use of confocal Raman spectroscopy to characterize undoped GaN,n-type GaN,and p-type GaN through depth profiling using 405-,532-,and 638-nm wavelength *** Raman signal intensity of the sapphire substrate at different focal depths is studied to analyze the depth *** on the shift of the E2 H mode of the GaN epitaxial layer,the interfacial stress for different types of GaN is characterized and *** results show that the maximum interfacial stress appears approximately at the junction of the GaN and the sapphire *** interfacial stress analysis between the GaN epitaxial layer and the substrate will be very helpful in furthering the applications of GaN devices.

关键词： Confocal Raman spectroscopy Gallium nitride Heteroepitaxial growth Interfacial stress

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Calculation method of product similarity based on modern algorithm

Calculation method of product similarity based on modern alg...

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2023 International Conference on Automation Control, Algorithm, and Intelligent Bionics, ACAIB 2023

作者： Lv, Fuheng Ge, Xiaohong Chen, Yi Wang, Jinhuo Huang, Yuanfang Chen, Bin Key Laboratory of Functional Materials and Application of Fujian Province Xiamen University of Technology Xiamen361024 China Xiamen Engineering and Technology Research Center of High Efficiency and Precision Intelligent Manufacturing School of Materials Science and Engineering Xiamen University of Technology Xiamen361024 China Solex Technology Co. Ltd. Xiamen361024 China

ISBN: (纸本)9781510667662

Make the existing product data as a new production factor to enable intelligent design. Based on the historical data of various shower ontology and molds in a sanitary ware company, this paper presents a method to calculate the similarity of case data for shower handle products, and uses similar products for mold reuse design. By combining the structural characteristics of shower ontology and molds, the shower design data is transformed into a characteristic information model, and Hierarchical clustering combining K-means algorithm is then studied to improve the accuracy of clustering results. Euclidean similarity algorithm is used to calculate the similarity between shower bodies. The experimental verification shows that the case data is divided into three categories and the similarity threshold of 0.7 can retrieve the product design with high similarity. The correlation algorithm provides the judgment basis for realizing the reuse design of product mold. © 2023 SPIE.

关键词： Molds

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Collaborative Motion Planning for Multiple Tractor-Trailer Vehicles Based on Local Conflict Search and Priority Game Inheritance

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IEEE Robotics and Automation Letters 2025年第7期10卷 7500-7507页

作者： Su, Longfei Yue, Ming Sun, Xu Wang, Heyang Zhao, Xudong Dalian University of Technology School of Mechanical Engineering Dalian 116024 China Dalian University of Technology State Key Laboratory of High-performance Precision Manufacturing Dalian 116024 China Dalian University of Technology School of Control Science and Engineering Dalian 116024 China

This paper introduces a novel approach for efficiently planning collision-free optimal trajectories for multiple tractor-trailer vehicles (TTVs) in environments with dense obstacles. The approach employs a hierarchical planning strategy to generate the initial homotopy path: at the higher level, it integrates body collision model and enhances conflict resolution through local priority strategy. At the lower level, the TractorTrailer Spatiotemporal Hybrid State A* (TT-SHA*) is employed, combining joint expansion with heuristic methods to efficiently generate paths for individual agents, while accounting for underactuated and nonholonomic constraints. To resolve priority deadlock issues, the concept of priority inheritance and backtracking is integrated into conflict search, which significantly improves the success rate and solving speed. Finally, it refines the path solution into smooth trajectories using nonlinear optimization based on corridor and relative safety distance constraints. Experimental results show that the proposed method outperforms existing TTVimproved Multi-Agent Motion Planning algorithms in scalability when handling large-scale TTV scenarios, providing a solution that is applicable for practical implementation. © 2016 IEEE.

关键词： Autonomous vehicle navigation collision avoidance path planning for multiple mobile robots or agents

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Effect of partial recrystallization on microstructure and tensile properties of NiFeCoCrMn high-entropy alloy

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Transactions of Nonferrous Metals Society of China 2022年第3期32卷 947-956页

作者： Hui DU Jia-hong CAI Ya-song WANG Jun-qing YAO Qiang CHEN Yu CUI Xin-wang LIU Key Laboratory of Metallurgical Equipment and Control Technology Ministry of EducationWuhan University of Science and TechnologyWuhan 430081China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and TechnologyWuhan 430081China Precision Manufacturing Institute Wuhan University of Science and TechnologyWuhan 430081China State Key Laboratory of Materials Processing and Die&Mould Technology School of Materials Science and EngineeringHuazhong University of Science and TechnologyWuhan 430074China Southwest Technology and Engineering Research Institute Chongqing 400039China

To obtain a balance between strength and ductility in NiFeCoCrMn high-entropy alloy, the degree of dislocation strengthening was tuned via partial recrystallization during traditional thermomechanical processing(cold rolling and recrystallization). The tensile properties in each state were then examined. Significant improvements in uniform elongation and work hardening rate, with decrease in yield strength and ultimate tensile strength, are associated with increase in the recrystallized fraction, i.e., reductions in the degree of strain hardening. In particular, recrystallized fractions of 37% and 74% are obtained by annealing at 650 ℃ for 10 min and 15 min, respectively, which results in yield strengths of 1003 MPa and 742 MPa and uniform elongations of 4% and 24%, respectively. The strengthening is due to the unrecrystallized grains with a high density of dislocations, whereas the ductility benefits from the presence of recrystallized strain-free grains.

关键词： high-entropy alloy partial recrystallization microstructure tensile property strengthening mechanism

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Belt conveyor roller bearing fault diagnosis based on CGM-MobileNet

Belt conveyor roller bearing fault diagnosis based on CGM-Mo...

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Electronic Communication and Artificial Intelligence (IWECAI), International Workshop on

作者： Fei Zeng Xiaochuan Zhang Sheng Feng Yukai Liu Key Laboratory of Metallurgical Equipment and Control of Ministry of Education Wuhan University of Science and Technology Wuhan China Precision Manufacturing Institute Wuhan University of Science and Technology Wuhan China

ISBN: (数字)9798350386943

ISBN: (纸本)9798350386950

Aiming at the problem of multiple working conditions and high noise of belt conveyor in the actual working environment, which leads to the low accuracy of roller bearing fault diagnosis, a CGM-MobileNet belt conveyor roller bearing fault diagnosis method based on CGM-MobileNet is proposed. Firstly, the original one-dimensional vibration signals are obtained from two-dimensional time-frequency image by Continuous Wavelet Transform(CWT), Gramian Angular Field(GAF) and Markov Transition Field(MTF) respectively, and spliced into three-channel two-dimensional time-frequency image; secondly, a lightweight convolutional neural network MobileNet is used as the fault classification network to ensure the diagnostic efficiency; and finally, the CBAM attention mechanism is introduced to improve the stability and accuracy of the network. Using the proposed method for several experiments, the average accuracy rate reaches 99.6%, and the proposed method can meet the high efficiency and accuracy of roller bearing fault diagnosis.

关键词： Fault diagnosis Vibrations Employee welfare Time-frequency analysis Accuracy Noise Rolling bearings

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Developed of special CNC system for dental implant based on spiral trajectory smooth compression 5

Developed of special CNC system for dental implant based on ...

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5th International Conference on Mechatronics and Computer technology Engineering, MCTE 2022

作者： Xu, Qingping Zhao, Gang Huang, Bo Shao, Hua He, Kai Key Laboratory of Metallurgical Equipment and Control Technology Ministry of Education Wuhan University of Science and Technology Wuhan430081 China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and Technology Wuhan430081 China Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen518005 China Shenzhen Key Laboratory of Precision Engineering Shenzhen518005 China

ISBN: (纸本)9781510661073

The demand for dental implants has grown rapidly in recent years, but they are expensive. One of the prime reasons is its manufacturing costs. In order to realize low cost and high efficiency of dental implant processing, this paper presents a seven-axis machine tool and develops a special numerical control system of the machine tool. Firstly, the structure of machine designed by us is introduced. Then, the hardware structure and software function of the control system were designed according to the processing technology of dental implant, including turning-milling conversion and back processing. In addition, a spiral path smooth compression algorithm was proposed to improve the machining efficiency and quality. Finally, the performance of the machining center is tested to verify that it has a high degree of automation, processing efficiency and machining quality, which meets the performance requirements. © 2022 SPIE.

关键词： Machine tools

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Design and experimental study of a novel underwater bionic propulsion mechanism 3

Design and experimental study of a novel underwater bionic p...

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3rd International Conference on Control and Intelligent Robotics, ICCIR 2023

作者： Han, Xiaowu Zhao, Gang Li, Te Xu, Yaohui Xie, Fengran He, Kai Zuo, Qiyang Key Laboratory of Metallurgical Equipment and Control Technology Ministry of Education Wuhan University of Science and Technology China Hubei Key Laboratory of Mechanical Transmission and Manufacturing Engineering Wuhan University of Science and Technology China Shenzhen Institute of Advanced Technology Chinese Academy of Sciences Shenzhen University Town 1068 Xueyuan Avenue Xili Nanshan Shenzhen518055 China Shenzhen Key Laboratory of Precision Engineering 1068 Xueyuan Avenue Shenzhen University Town Xili Nanshan Shenzhen518055 China School of Artificial Intelligence Shenzhen Polytechnic Shenzhen518055 China

ISBN: (纸本)9781510671867

At present, most of bionic robotic fish in BCF mode make use of reciprocating positive and negative rotation of a servo to drive the swing motion of the tail fin. However, the swing frequency of the tail fin of the robotic fish is relatively low and the generated propulsive force is also relatively small due to the influence of the properties of the servo. The other robotic fish which use DC motor or other unidirectional rotation motor to drive the tail fin have to take advantage of complex mechanical structure to realize reciprocating swing motion of the tail fin, even so, the swing amplitude of the tail fin cannot be adjusted directly. This paper presents a novel bionic swing propulsion mechanism which is driven by a stepper motor. The tail fin can swing at a high frequency by controlling the rotate speed in positive rotation of the stepper motor, and correspondingly, the swing amplitude of the tail fin can be adjusted by controlling the stepper motor to reverse rotation. In addition, a steering mechanism is added to this bionic swing propulsion mechanism to realize the steering function for the propulsion mechanism. The presented swing propulsion mechanism can be directly used for a swing mechanism of tail fin of robotic fish, or even can act as a kind of bionic propeller of underwater vehicle to replace the traditional screw propeller. In order to verify the feasibility of this underwater bionic propulsion mechanism, a series of swimming experiment were carried out. © 2023 SPIE.

关键词： Fish

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Effects of nanoceramic particle size and content on the wear resistance of micro-arc oxidation coatings for 2A12 aluminum alloy

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Heliyon 2024年第19期10卷 e38719页

作者： Li, Wen Cheng, Ming Zhang, Xiaochen Wei, Guoke Aviation Key Laboratory of Science and Technology on Advanced Surface Engineering AVIC Manufacturing Technology Institute Beijing 100024 China Science and Technology on Power Beam Processes Laboratory AVIC Manufacturing Technology Institute Beijing 100024 China

The 2A12 aluminum alloy, renowned for its exceptional mechanical properties, encounters significant limitations in applications involving abrasive environments or frequent contact with other surfaces due to its inadequate wear resistance. This shortcoming substantially reduces the service life of components and escalate maintenance costs, highlighting the urgent need for advanced surface modification techniques. This study meticulously investigates the influence of nanoceramic particle size and content on the wear resistance of micro-arc oxidation (MAO) coatings, a surface modification technique renowned for forming dense, adherent ceramic layers on aluminum alloys. The systematic experimentation revealed that the incorporation of 150 nm α-Al₂O₃ nanoparticles into the MAO matrix achieves an optimal dispersion, leading to a substantial enhancement in wear resistance. The sample with a 5 g/L concentration of 150 nm α-Al₂O₃ nanoparticles doping in the MAO electrolyte demonstrated the lowest mass loss, underscoring its enhanced wear resistance. The enhanced microstructure, enriched with hard ceramic phases such as α-Al₂O₃ and mullite, plays a pivotal role in withstanding wear. Moreover, this study identified that an optimal balance of surface roughness and coating thickness is essential for achieving enhanced wear resistance. The findings of this research provide a strategy for the design of wear-resistant coatings tailored for high-performance applications across aerospace, automotive, and general engineering industries. By optimizing the particle size and concentration in MAO coatings, this study paves the way for the development of durable materials capable of thriving in demanding environments, thereby extending the service life and reducing maintenance requirements of components. © 2024 The Authors

关键词： 2A12 aluminum alloy Micro-arc oxidation Nanoceramic particles Surface engineering Wear resistance

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Test of CaF 2 glass sub-surface damage using angle-resolved ellipsometry

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Procedia CIRP 2024年 129卷 157-162页

作者： Tianqi Jia Lihua Peng Dawei Tang Jian Wang Liping Zhou Wuhan 430074 Huazhong University of Science and Technology State Key Laboratory of Digital Manufacturing Equipment and Technology China Huddersfield HD1 3DH University of Huddersfield Centre for Precision Technologies UK

Calcium fluoride (CaF2), as a typical brittle optical material, has been applied in various fields due to its excellent optical properties. However, an existing challenge is how to non-destructively characterize the surface integrity of brittle materials, which may easily suffer from subsurface damage (SSD) during machining processes. This paper explores a novel snapshot surface-integrity test method based on single-exposure back-focal-plane (BFP) imaging of CaF2 within ellipsometric parameter spectra corresponding to an extensive range of incident angles. The relationship between the layer thicknesses of surface roughness, SSD, and ellipsometric spectra was analyzed by establishing a four-layer-subsurface optical model combined with quasi-Brewster angle technology. Through polishing CaF2 under different conditions and combining the measurement results of angle-resolved ellipsometry (ARE), it has been demonstrated that the study based on ARE is a successful non-destructive testing method for surface integrity, which could help to further elucidate the surface evolution mechanism of brittle material polishing processes.

关键词： Subsurface damage test Angle-resolved ellipsometry Quasi-Brewster angle technology Brittle material

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