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Toward Trustworthy Decision-Making for Autonomous Vehicles:A Robust Reinforcement Learning Approach with Safety Guarantees

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engineering 2024年第2期33卷 77-89页

作者： Xiangkun He Wenhui Huang Chen Lv school of mechanical and Aerospace engineering Nanyang Technological UniversitySingapore 639798Singapore

While autonomous vehicles are vital components of intelligent transportation systems,ensuring the trustworthiness of decision-making remains a substantial challenge in realizing autonomous ***,we present a novel robust reinforcement learning approach with safety guarantees to attain trustworthy decision-making for autonomous *** proposed technique ensures decision trustworthiness in terms of policy robustness and collision ***,an adversary model is learned online to simulate the worst-case uncertainty by approximating the optimal adversarial perturbations on the observed states and environmental *** addition,an adversarial robust actor-critic algorithm is developed to enable the agent to learn robust policies against perturbations in observations and ***,we devise a safety mask to guarantee the collision safety of the autonomous driving agent during both the training and testing processes using an interpretable knowledge model known as the Responsibility-Sensitive Safety ***,the proposed approach is evaluated through both simulations and *** results indicate that the autonomous driving agent can make trustworthy decisions and drastically reduce the number of collisions through robust safety policies.

关键词： Autonomous vehicle Decision-making Reinforcement learning Adversarial attack Safety guarantee

Prediction of undeformed chip thickness distribution and surface roughness in ultrasonic vibration grinding of inner hole of bearings

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Journal of Zhejiang university-Science A(Applied Physics & engineering) 2024年第4期25卷 311-323页

作者： Yanqin LI Daohui XIANG Guofu GAO Feng JIAO Bo ZHAO school of mechanical and Power engineering Henan Polytechnic UniversityJiaozuo 454000China

Ultrasonic vibration grinding differs from traditional grinding in terms of its material removal *** randomness of grain-workpiece interaction in ultrasonic vibration grinding can produce variable chips and impact the surface roughness of ***,previous studies used iterative method to calculate the unformed chip thickness(UCT),which has low computational *** this study,a symbolic difference method is proposed to calculate the *** UCT distributions are obtained to describe the stochastic interaction characteristics of ultrasonic grinding ***,the UCT distribution characteristics under different machining parameters are ***,a surface roughness prediction model is established based on the UCT ***,the correctness of the model is verified by *** study provides a quick and accurate method for predicting surface roughness in longitudinal ultrasonic vibration grinding.

关键词： Ultrasonic vibration grinding Undeformed chip thickness(UCT) Distribution characteristics Surface roughness

A Study on Enhancing Chip Detection Efficiency Using the Lightweight Van-YOLOv8 Network

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Computers, Materials & Continua 2024年第4期79卷 531-547页

作者： Meng Huang Honglei Wei Xianyi Zhai school of mechanical engineering and Automation Dalian Polytechnic UniversityDalian116034China

In pursuit of cost-effective manufacturing,enterprises are increasingly adopting the practice of utilizing recycled semiconductor *** ensure consistent chip orientation during packaging,a circular marker on the front side is employed for pin alignment following successful functional ***,recycled chips often exhibit substantial surface wear,and the identification of the relatively small marker proves ***,the complexity of generic target detection algorithms hampers seamless *** these issues,this paper introduces a lightweight YOLOv8s-based network tailored for detecting markings on recycled chips,termed ***,to alleviate the influence of diminutive,low-resolution markings on the precision of deep learning models,we utilize an upscaling approach for enhanced *** technique relies on the Super-Resolution Generative Adversarial Network with Extended Training(SRGANext)network,facilitating the reconstruction of high-fidelity images that align with input ***,we replace the original YOLOv8smodel’s backbone feature extraction network with the lightweight VanillaNetwork(VanillaNet),simplifying the branch structure to reduce network ***,a Hybrid Attention Mechanism(HAM)is implemented to capture essential details from input images,improving feature representation while concurrently expediting model inference *** results demonstrate that the Van-YOLOv8 network outperforms the original YOLOv8s on a recycled chip dataset in various ***,it demonstrates superiority in parameter count,computational intricacy,precision in identifying targets,and speed when compared to certain prevalent algorithms in the current *** proposed approach proves promising for real-time detection of recycled chips in practical factory settings.

关键词： Lightweight neural networks attention mechanisms image super-resolution enhancement feature extraction small object detection

Scuffing failure analysis based on a multiphysics coupling model and experimental verification

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Friction 2024年第6期12卷 1214-1234页

作者： Bugao LYU Xianghui MENG Jiabao YIN Yi CUI Chengen WANG school of mechanical engineering Shanghai Jiao Tong UniversityShanghai 200240China

General reductions in lubricant viscosities and increasing loads in machine components highlight the role of tribofilms in providing surface protection against ***,the relationship between the scuffing process and the growth and removal of tribofilm is not well *** this study,a multiphysics coupling model,which includes hydrodynamic lubrication,asperity contact,thermal effect,tribochemistry reaction,friction,and surface wear,was developed to capture the initiation of surface *** and experiments for a piston ring and cylinder liner contact were conducted following a step-load sequence under different temperature *** results show that high temperature and extreme load could induce the lubricant film collapse,which in turn triggers the breakdown of the tribofilm due to the significantly increased removal *** failures of both lubricant film and tribofilm progress instantaneously in a coupling way,which finally leads to severe scuffing.

关键词： scuffing failure tribofilm boundary lubrication multiphysics coupling effects

Influence of friction-lubrication characteristics varying with rolling speed on instability of chatter and slip in cold tandem rolling process

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Journal of Iron and Steel Research(International) 2024年第4期31卷 894-908页

作者： Yan-li Xin Zhi-ying Gao Bo Tian Qing-dong Zhang school of mechanical engineering University of Science and Technology BeijingBeijing 100083China

In the high-speed cold tandem rolling process of thin plate,chatter or slip instability gives rise to the deterioration of equipment and product *** instability behavior is closely related to interfacial friction-lubrication con-dition which is generally characterized by the friction ***,with higher and higher speed requirements,the commonly used model of friction coefficient is no longer applicable and accurate.A novel approach is suggested to calculate the speed-dependent friction coefficient,in which the viscosity-pressure-temperature effects of the lubricant,surface roughness states of work rolls and rolled piece are comprehensively involved and the mixed flm lubrication theory is ***,the influences of friction coefficient on the instability of slip and chatter are investigated for a five-stand cold tandem rolling *** one side,the critical friction coefficient for each stand is determined by calculating the corresponding slip factor;on the other hand,the friction coefficient varying with rolling speed is combined with the model of theoretical critical rolling speed presented under constant friction coefficient,so that the speed threshold is ***,the stable and unstable regions corresponding to the rear three stands are individually discussed,and the technical strategies are proposed to suppress both slip and chatter frequently occurring in the actual rolling process.

关键词： Cold tandem rolling:Oil film thickness Speed-dependent friction coefficient-Slip:Chatter

Advances in doping strategies for sodium transition metal oxides cathodes:A review

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Frontiers in Energy 2024年第2期18卷 141-159页

作者： Zhijing ZHANG Haoze ZHANG Yaopeng WU Wei YAN Jiujun ZHANG Yun ZHENG Lanting QIAN Department of Chemical engineering Waterloo Institute of NanotechnologyUniversity of WaterlooWaterloo ON N2L 3G1Canada school of mechanical and automotive engineering South China University of TechnologyGuangzhou 510640China Institute of New Energy Materials Science and engineering School of Materials Science and EngineeringFuzhou UniversityFuzhou 350108China

The electrochemistry of cathode materials for sodium-ion batteries differs significantly from lithium-ion batteries and offers distinct ***,the progress of commercializing sodium-ion batteries is currently impeded by the inherent inefficiencies exhibited by these cathode materials,which include insufficient conductivity,slow kinetics,and substantial volume changes throughout the process of intercalation and deintercalation ***,numerous methodologies have been utilized to tackle these challenges,encompassing structural modulation,surface modification,and elemental *** paper aims to highlight fundamental principles and strategies for the development of sodium transition metal oxide ***,it emphasizes the role of various elemental doping techniques in initiating anionic redox reactions,improving cathode stability,and enhancing the operational voltage of these cathodes,aiming to provide readers with novel perspectives on the design of sodium metal oxide cathodes through the doping approach,as well as address the current obstacles that can be overcome/alleviated through these dopant strategies.

关键词： sodium-ion batteries transition metal cathode doping strategy

Nonlinear Characteristic Analysis of Gas-Interconnected Quasi-Zero Stiffness Pneumatic Suspension System:A Theoretical and Experimental Study

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Chinese Journal of mechanical engineering 2024年第3期37卷 338-352页

作者： Xinwei Jiang Xing Xu Tianling Shi Vincent Akolbire Atindana automotive engineering Research Institute Jiangsu UniversityZhenjiang 212013China

Because of significantly changed load and complex and variable driving road conditions of commercial vehicles,pneumatic suspension with lower natural frequencies is widely used in commercial vehicle suspension *** ever,traditional pneumatic suspension system is hardly to respond the greatly changed load of commercial vehicles To address this issue,a new Gas-Interconnected Quasi-Zero Stiffness Pneumatic Suspension(GIQZSPS)is presented in this paper to improve the vibration isolation performance of commercial vehicle suspension systems under frequent load *** new structure adds negative stiffness air chambers on traditional pneumatic suspension to reduce the natural frequency of the *** can adapt to different loads and road conditions by adjusting the solenoid valves between the negative stiffness air ***,a nonlinear mechanical model including the dimensionless stiffness characteristic and interconnected pipeline model is derived for GIQZSPS *** the nonlinear mechanical model of GIQZSPS system,the force transmissibility rate is chosen as the evaluation index to analyze ***,a testing bench simulating 1/4 GIQZSPS system is designed,and the testing analysis of the model validation and isolating performance is carried *** results show that compared to traditional pneumatic suspension,the GIQZSPS designed in the article has a lower natural *** the system can achieve better vibration isolation performance under different load states by switching the solenoid valves between air chambers.

关键词： Pneumatic suspension Quasi-zero stiffness system Gas-interconnected system Nonlinear dynamic modeling

Stability-Considered Lane Keeping Control of Commercial Vehicles Based on Improved APF Algorithm

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Chinese Journal of mechanical engineering 2024年第1期37卷 114-129页

作者： Bin Tang Zhengyi Yang Haobin Jiang Ziyan Lin Zhanxiang Xu Zitian Hu automotive engineering Research Institute Jiangsu UniversityZhenjiang 212013China

Regarding the lane keeping system,path tracking accuracy and lateral stability at high speeds need to be taken into account especially for commercial vehicles due to the characteristics of larger mass,longer wheelbase and higher mass *** improve the performance mentioned above comprehensively,the control strategy based on improved artificial potential field(APF)algorithm is *** the paper,time to lane crossing(TLC)is introduced into the potential field function to enhance the accuracy of path tracking,meanwhile the vehicle dynamics parameters including yaw rate and lateral acceleration are chosen as the repulsive force field *** lane keeping controller based on improved APF algorithm is designed and the stability of the control system is proved based on Lyapunov *** addition,adaptive inertial weight particle swarm optimization algorithm(AIWPSO)is applied to optimize the gain of each potential field *** co-simulation results indicate that the comprehensive evaluation index respecting lane tracking accuracy and lateral stability is reduced ***,the proposed control strategy is verified by the HiL *** provides a beneficial reference for dynamics control of commercial vehicles and enriches the theoretical development and practical application of artificial potential field method in the field of intelligent driving.

关键词： Lane keeping control Commercial vehicles Lateral stability Artificial potential field AIWPSO

Optimized Design of Bio-Inspired Wind Turbine Blades

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Fluid Dynamics & Materials Processing 2024年第7期20卷 1647-1664页

作者： Yuanjun Dai Dong Wang Xiongfei Liu Weimin Wu school of mechanical engineering Shanghai DianJi UniversityShanghai201306China school of Information engineering Yinchuan University of Science and TechnologyYinchuan750000China school of mechanical and Power engineering Chongqing University of Science and TechnologyChongqing401331China school of Aeronautical mechanical and Electrical engineering Chongqing Aerospace PolytechnicChongqing400021China

To enhance the aerodynamic performance of wind turbine blades,this study proposes the adoption of a bionic airfoil inspired by the aerodynamic shape of an *** on the blade element theory,a non-uniform extraction method of blade elements is employed for the optimization design of the considered wind turbine ***,Computational Fluid Dynamics(CFD)is used to determine the aerodynamic performances of the eagle airfoil and a NACA2412 airfoil,thereby demonstrating the superior aerodynamic performance of the ***,a mathematical model for optimizing the design of wind turbine blades is introduced and a comparative analysis is conducted with respect to the aerodynamic performances of blades designed using a uniform extraction *** is found that the blades designed using non-uniform extraction exhibit better aerodynamic performance.

关键词： Airfoil wind turbines blade design CFD