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Study on Dry Electrical Discharge Assisted Grinding of SiCp/Al Composite

Chinese Journal of Mechanical engineering 2025年第1期38卷 106-118页

作者： Yanjun Lu Yuming Huang Xiaobu Liu Rong Cheng Shunda Zhan Guangdong Provincial Key Laboratory of Micro/Nano Optomechatronics Engineering College of Mechatronics and Control EngineeringShenzhen UniversityShenzhen 518060China School of Intelligent Manufacturing and Equipment Shenzhen Institute of Information TechnologyShenzhen 518172China

SiC-reinforced aluminum matrix(SiCp/Al)composite is widely utilized in the aerospace,automotive,and electronics industries due to the combination of ceramic hardness and metal ***,the significant disparity in properties between SiC particles and the aluminum matrix results in severe tool wear and diminished surface quality during conventional *** study proposes an environmentally friendly and clean dry electrical discharge assisted grinding process as an efficient and low-damage machining method for SiCp/*** experimental platform was set up to study the impact of grinding and discharge process parameters on surface *** study compared the chip formation mechanism and surface quality between dry electrical discharge assisted grinding and conventional grinding,revealing relationships between surface roughness,grinding force,grinding temperature,and related *** results indicate that the proposed grinding method leads to smaller chip sizes,lower grinding forces and temperatures,and an average reduction of 19.2%in surface roughness compared to conventional *** axial,tangential,and normal grinding forces were reduced by roughly 10.5%,37.8%,and 23.0%,*** optimized process parameters were determined to be N=2500 r/min,vf=30 mm/min,a=10μm,E=15 V,f=5000 Hz,dc=80%,resulting in a surface roughness of 0.161μm.

关键词： Dry electrical discharge assisted grinding SiCp/Al composite Surface quality Grinding force Grinding temperature

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Research on sensitivity of measurement points and diagnostic method of combustion chamber health status for marine diesel engine

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Journal of Mechanical Science and technology 2025年第5期39卷 2549-2562页

作者： Hu, Lei Wang, Wentong Yu, Xuekuan Yu, Yonghua Hu, Jia Ma, Bingjie Yang, Jianguo School of Naval Architecture Ocean and Energy Power Engineering Wuhan University of Technology Wuhan430063 China Key Laboratory of Marine Power Engineering and Technology of Ministry of Transport Wuhan University of Technology Wuhan430063 China National Key Laboratory of Marine Engine Science and Technology Shanghai201108 China

The susceptibility of vibration signals to combustion chamber faults of marine diesel engine varies across different measurement points, increasing difficulty of fault diagnosis. The different fault experiments in the combustion chamber are conducted in this paper, vibration data from different positions are collected. Correlation analysis method with information entropy is studies, the correlations of vibration signal characteristics between different faults at the same point and the same fault at different points are analyzed, and the selection of key points with high accuracy for fault diagnosis is optimized. The one dimensional convolutional neural network is used for combustion chamber faults diagnosis based on the data from optimized points. The study shows that the method can optimally select measurement points with high fault feature discrimination and sensitivity, the accuracy rates of the early fault classification and health status recognition of the combustion chamber reach at least 96.67 % and 97.35 % respectively. © The Korean Society of Mechanical Engineers and Springer-Verlag GmbH Germany, part of Springer Nature 2025.

关键词： Convolutional neural networks

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Performance Analysis of a Hexagon Rolling Mechanism with Single Degree of Freedom

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Journal of Mechanisms and Robotics 2025年第8期17卷 081001页

作者： Zhang, Qianqian Li, Yezhuo Yan, Shaoze Yao, Yan-An Department of Mechanical Engineering Tsinghua University Beijing100084 China School of Mechanical Electronic and Control Engineering Key Laboratory of Vehicle Advanced Manufacturing Measuring and Control Technology Beijing Jiaotong University Beijing100044 China

This article presents a comprehensive performance analysis of the step-climbing and passive rolling modes of a hexagon rolling mechanism with single-degree-of-freedom, based on its structural characteristics and the constraints of centroid stability. First, a step-climbing model, incorporating motion parameters and support distance parameters, is established by leveraging the symmetrical posture movement characteristics of the hexagon rolling mechanism. Building on this foundation, the impact of each parameter on the mechanism's step-climbing ability is thoroughly analyzed, and the maximum height achievable during step climbing is also examined. Subsequently, the existence and sufficient conditions for the hexagon rolling mechanism to achieve passive rolling are analyzed using the centroid fluctuation curve and its slope curves. The analysis results indicate that, due to its unique coupling structure design, the hexagon rolling mechanism possesses a passive rolling capability that is not available in conventional planar linkage mechanisms. Finally, the correctness of the theoretical model is validated through both simulation and prototype experiments. Copyright © 2025 by ASME.

关键词： Degrees of freedom (mechanics)

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Advances in the chemical modification of nanocellulose for biodegradable plastics reinforcement

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International Journal of Agricultural and Biological engineering 2025年第1期18卷 10-24页

作者： Shuya Zhang Mingda Che Renliang Huang Mei Cui Wei Qi Rongxin Su State Key Laboratory of Chemical Engineering School of Chemical Engineering and TechnologyTianjin UniversityTianjin 300072China Ningbo Key Laboratory of Green Petrochemical Carbon Emission Reduction Technology and Equipment Zhejiang Institute of Tianjin UniversityNingbo 315201ZhejiangChina Tianjin Key Laboratory for Marine Environmental Research and Service School of Marine Science and TechnologyTianjin UniversityTianjin 300072China Tianjin Sustainable Novel Materials Co.Ltd. Tianjin 300192China

As non-degradable traditional plastics contribute to environmental pollution,biodegradable polymers have been identified as a promising ***,inherent drawbacks such as low toughness,poor tensile strength,and reduced thermal degradation temperatures limit the further development of biodegradable *** has the potential to enhance the properties of biodegradable polymers without compromising their ***,the abundant hydroxyl groups in nanocellulose’s molecular chains result in poor compatibility with hydrophobic polymers,requiring surface modification prior to their *** review first introduces several common biodegradable polymers and three types of nanocellulose,followed by a comprehensive analysis of the recent advancements in the chemical modification methods of nanocellulose over the last five *** methods encompass esterification,oxidation,silylation,and graft *** focus of this discussion is primarily on the modification strategies,enhancement effects,and ***,the degradability and applications of modified nanocellulose composites are ***,the main challenges hindering the development of chemically modified nanocellulose-reinforced biodegradable polymers are *** is hoped that this review will inspire future researchers to develop industrially valuable chemically modified nanocellulose-reinforced biodegradable polymers.

关键词： biodegradable polymers nanocellulose surface modification reinforcement mechanisms degradability application

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An Improved Lightweight Safety Helmet Detection Algorithm for YOLOv8

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Computers, Materials & Continua 2025年第5期83卷 2245-2265页

作者： Lieping Zhang Hao Ma Jiancheng Huang Cui Zhang Xiaolin Gao Key Laboratory of AdvancedManufacturing and Automation Technology EducationDepartment of Guangxi Zhuang Autonomous RegionGuilin University of TechnologyGuilin541004China Guangxi Key Laboratory of Special Engineering Equipment and Control Guilin University of Aerospace TechnologyGuilin541004China Guangxi Tianli Construction Engineering Co. Ltd.Guilin541001China School of Information Engineering Nanning College of TechnologyGuilin541004China

Detecting individuals wearing safety helmets in complex environments faces several *** factors include limited detection accuracy and frequent missed or false ***,existing algorithms often have excessive parameter counts,complex network structures,and high computational *** challenges make it difficult to deploy such models efficiently on resource-constrained devices like embedded *** at this problem,this research proposes an optimized and lightweight solution called FGP-YOLOv8,an improved version of *** YOLOv8 backbone network is replaced with the FasterNet model to reduce parameters and computational demands while local convolution layers are *** modification minimizes computational costs with only a minor impact on accuracy.A new GSTA(GSConv-Triplet Attention)module is introduced to enhance feature fusion and reduce computational *** is achieved using attention weights generated from dimensional interactions within the feature ***,the ParNet-C2f module replaces the original C2f(CSP Bottleneck with 2 Convolutions)module,improving feature extraction for safety helmets of various shapes and *** CIoU(Complete-IoU)is replaced with the WIoU(Wise-IoU)to boost performance further,enhancing detection accuracy and generalization *** results validate the *** proposedmodel reduces the parameter count by 19.9% and the computational load by 18.5%.At the same time,mAP(mean average precision)increases by 2.3%,and precision improves by 1.2%.These results demonstrate the model’s robust performance in detecting safety helmets across diverse environments.

关键词： YOLO safety helmet detection complex environments lightweight WIoU loss function

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Evidence of microstructural evolution linked to non-monotonic distribution of micromechanical properties induced by shot peening

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材料科学技术（英文版） 2025年第4期207卷 238-245页

作者： Guoxin Lu Qiang Wang Bonnie Attard Huhu Su Shijian Zheng Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials Ministry of EducationSchool of Materials Science and EngineeringShandong UniversityJinan250061China Aviation Key Laboratory of Science and Technology on Advanced Corrosion and Protection for Aviation Material AECC Beijing Institute of Aeronautical MaterialsBeijing100095China Department of Metallurgy and Materials Engineering University of MaltaMSD2080Malta Tianjin Key Laboratory of Materials Laminating Fabrication and Interface Control Technology School of Materials Science and EngineeringHebei University of TechnologyTianjin300130China

The residual stress field induced by surface strengthening processes such as mechanical shot peening and other forms of plastic deformation does not generally exhibit a simple"monotonic"distribution *** researchers have analyzed this fact from a mechanical perspective based on Hertz ***,the micro/nano-scale microstructural changes corresponding to the distribution of residual stress fields still appear to be *** this study,we focused on a widely used material in aviation manufacturing,namely nickel-based superalloy GH4169,as our experimental *** subjected GH4169 alloy to me-chanical strengthening treatment using a shot peening intensity of 0.25 mmA,followed by quantitative testing of micromechanical performance indicators such as microhardness and residual *** thor-oughly investigate the relationship between micromechanical properties and microstructure changes,we utilized transmission electron microscopy(TEM)to observe and analyze shot-peened materials at differ-ent *** findings revealed that the most severe microstructural distortion induced by mechanical shot peening in GH4169 alloy was likely to occur within a depth range of 25 to 75 *** observation aligns with the actual phenomenon that the maximum microhardness and maximum residual compres-sive stress did not manifest on the outermost surface of the *** presenting a detailed analysis of deformation defects such as dislocations,stacking faults,and twinning in different depths of mechan-ically strengthened layers,our study contributes to a deeper understanding and practical application of post-processing technologies based on plastic deformation.

关键词： Mechanical shot peening Surface strengthening Residual stress Microstructure

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Robust Output Regulation With Prescribed Performance for Second-Order Non-Polynomial Nonlinear Systems

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IEEE Transactions on Automation Science and engineering 2025年 22卷 14234-14246页

作者： Liu, Wei Luo, Jialei Sun, Weijie South China University of Technology Key Laboratory of Autonomous Systems and Networked Control of Ministry of Education School of Automation Science and Engineering Guangzhou510641 China

This article focuses on the robust output regulation problem with prescribed performance for uncertain second-order nonlinear systems with non-polynomial nonlinearity. According to the existing framework for the robust output regulation problem of such nonlinear systems, we introduce some standard assumptions, and then construct two internal models of nonlinear forms to reproduce the steady-state information. Then, we convert the considered problem into the robust stabilization problem with prescribed performance of an augmented system containing the studied nonlinear system and the internal models. We incorporate a novel error transformation into the existing technique to design a stabilization controller, based on which we synthesize our control law to solve our original problem. Finally, we present two simulation examples to test our results. © 2004-2012 IEEE.

关键词： Nonlinear systems Performance evaluation Regulation Steady-state Transient analysis Polynomials Mathematical models Output feedback Adaptive systems Symmetric matrices

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Robust Orientation Method Based on an Atmospheric Polarization Model for Hazy Weather

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IEEE Internet of Things Journal 2025年第9期12卷 12397-12409页

作者： Yang, Jiangtao Tian, Zhichao Wen, Hao Wang, Zirui Taiyuan University of Science and Technology School of Electronic Information Engineering Shanxi Key Laboratory of Advanced Control and Equipment Intelligence Shanxi Taiyuan030024 China

Accurate and reliable navigation data are key components in the Internet of Things (IoT). High-precision and stable autonomous orientation has attracted considerable attention regarding environments in which the global navigation satellite system signal is unreliable. Bionic polarized light orientation is a method based on the mechanism of insect navigation, and the orientation signal comes from nature, which has broad application prospects. However, there is significant dust or nitrogen oxide particle scattering and sunlight absorption in haze, reducing the polarization degree and abnormal polarization azimuth. This makes heading angle measurements with existing polarized light navigation and positioning methods inaccurate under hazy conditions. A polarization image denoising method based on deep learning can effectively eliminate the influence of haze on heading angles. Noisy polarization images can be decomposed into high- and low-frequency components containing different types of noise. Thus, this study proposes a polarization image denoising method that combines high- and low-frequency image decomposition with a multiscale two-level fusion strategy. This method decomposes the polarization image with noise into a set of low-frequency structural components and a set of high-frequency detailed components by utilizing multiscale Gaussian filters. On this basis, a multiscale two-level fusion strategy based on a complementary feature weighted fusion mechanism is also designed. In the high- and low-frequency merge and reconstruction module, after adding and fusing the high- and low-frequency enhanced features output by LF-UNet and HF-UNet, a residual convolution (Res-Conv) layer and an output convolution layer are used for residual prediction and then fused with the input image to acquire a high-quality polarization image. The proposed method is experimentally verified outdoors using a polarized light/inertial integrated heading measurement system and a vehicle. The e

关键词： Image denoising

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D-FUSION SLAM: A VSLAM SYSTEM OPTIMIZED BY INTEGRATING DEPTH INFORMATION AND RGBD FEATURE POINTS

UPB Scientific Bulletin, Series C: Electrical Engineering an...

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UPB Scientific Bulletin, Series C: Electrical engineering and Computer Science 2025年第1期87卷 121-138页

作者： Zheng, Qingchun Wu, Moudong Zhu, Peihao Yang, Bin Li, Shubo Tianjin Key Laboratory for Advanced Mechatronic System Design and Intelligent Control School of Mechanical Engineering Tianjin University of Technology Tianjin300384 China China

This paper introduces D-Fusion SLAM, an advanced VSLAM system based on ORB-SLAM2. D-Fusion SLAM integrates depth information to enhance feature selection, aiming to improve accuracy and speed in visual SLAM applications. The system mainly comprises two modules: an image grid filtering module based on grayscale information and a feature selection module integrating depth information. These modules effectively eliminate redundant and useless features, ensuring high-quality features for pose estimation. We tested D-Fusion SLAM on the TUM dataset and compared it with ORB-SLAM2. Experimental results demonstrate that D-Fusion SLAM outperforms ORB-SLAM2, significantly enhancing the system's accuracy and robustness. © 2025, Politechnica University of Bucharest. All rights reserved.

关键词： Feature Selection

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Linear active disturbance rejection control of fighter aircraft based on MADDPG algorithm

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International Journal of Systems, control and Communications 2025年第2期16卷 152-172页

作者： Lin, Yetong Ji, Yuehui Song, Yu Liu, Junjie Tianjin Key Laboratory for Control Theory and Applications in Complicated Industry Systems School of Electrical Engineering and Automation Tianjin University of Technology Tianjin300384 China

To address nonlinearity, strong coupling, and disturbances in fighter aircraft attitude control, this paper proposes an intelligent control method based on multi-agent deep deterministic policy gradient (MADDPG) and linear active disturbance rejection control (LADRC). A three-channel LADRC controller estimates and compensates for disturbances, uncertainties, and coupling terms in real time. To overcome the dimensionality curse in multi-parameter optimization, an independent DDPG controller is assigned to each channel, ensuring cooperative control via reward sharing and enhancing dynamic response and disturbance rejection. Additionally, long short-term memory (LSTM) and self-attention mechanisms are integrated into the policy and value networks to improve representation and decision-making. A piecewise combined reward function mitigates sparse rewards. Simulations show that, compared to MADQN-based and traditional LADRC methods, the proposed approach achieves superior control performance and significantly reduces manual parameter tuning efforts. Copyright © 2025 Inderscience Enterprises Ltd.

关键词： Disturbance rejection

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