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Dynamic Analysis and Modal Truncation of High-speed Cam Mechanism JIN Guoguang, WEI Zhan, QIN Kaixuan, ZHANG Yangyan Journal of Mechanical Engineering    2015, 51 (13): 227-234.   DOI: 10.3901/JME.2015.13.227 Abstract （3276）      PDF（pc） （1505KB）（154296）       Knowledge map    Save High-speed cam mechanism is widely used in vehicles, textile machinery, printing machinery etc. The research of dynamic analysis is the basis and key point to improve the mechanical properties. Discretization of the flexible elements of cam mechanism is carried out by means of finite-element method. Furthermore, the dynamic model of the rigid-flexible coupled cam mechanism is proposed based on modal synthesis technique and Kane’s equations. The dynamic equation obtained is more general for flexible beam type, and very convenient for solving by computer because it is a modal-coordinates dynamic equation. The system dynamic performance is studied by analyzing the system modal and solving the dynamic equation. The simulation of dynamics model which has different orders is carried on, which can not only ensure accuracy of calculation but also save computational resources. Research results have important guiding significance for determining whether the dynamic analysis of high-speed cam systems in practical application is required, and furthermore, research results can provide strong guide for dynamic modeling and modal characteristics research of similar mechanism. Related Articles | Metrics | Comments（0）

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Current Opportunities in the Field of Mechanisms in China LIU Xinjun, XIE Fugui, WANG Jinsong Journal of Mechanical Engineering    2015, 51 (13): 2-12.   DOI: 10.3901/JME.2015.13.002 Abstract （2230）      PDF（pc） （5623KB）（94580）       Knowledge map    Save For the past two years, robots comeback with a high profile and present huge market prospects; advanced manufacturing equipment especially high-end CNC machine tool is still in urgent demand. However, their development is still not going well due to that basic components and CNC systems rely on imported goods, manufacturing techniques of key functional units are missing, reliability and performance of lead rails and lead screws are not good enough. In particular, swing tool heads and high-performance reducers, which greatly determine the functionality and performance of machine tools and robots, are important barriers for machine tools and robots in China to catch up with the world’s advanced level. Mechanism is a basic discipline of equipment structural design, and mechanism innovation is fundamental to the equipment innovation. Then, mechanism is naturally charged with the responsibility of innovation. Incorporating with the structure, functionality and application of machine tools and robots, the opportunities encountered by mechanism in the current stage of China have been analyzed and discussed. Hopefully, this work can provide references for the effective integration of academic research and industrial demand for advanced manufacturing equipment. Reference | Related Articles | Metrics | Comments（0）

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Semi-analytical FEM Analysis and Experimental Measurement for Propagating Guided Waves Modes in Rail LU Chao, YANG Xuejuan, DAI Xiang, CHANG Junjie Journal of Mechanical Engineering    2015, 51 (6): 79-86.   DOI: 10.3901/JME.2015.06.079 Abstract （3353）      PDF（pc） （2452KB）（92932）       Knowledge map    Save Acoustical guided waves modal analysis in rail is the basis of long distance guided wave inspection and rail vibration and noises control. In particular the various propagating guided waves in the rail are identified in terms of their propagation wavenumber coefficients and their corresponding deformed shapes. The semi-analytical finite element method is used to formulate the governing equation for guided waves propagating in elastic waveguides of arbitrary cross-section on the basis of the virtual work principle, wavenumber dispersion curves and deformed shapes are extracted by solving governing equation, which provide the basis for selecting mode and frequency during application. The propagating guided waves wavenumber dispersion curves and deformed shaped under 0-8 kHz frequency range for CHN60 type free rail are obtained using semi-analytical finite element method, and the characteristics of the eight based guided waves mode in rail are discussed. Instrumented hammer experimental study and modal analysis using sever vibration accelerometers mounted on rail are carried out to verify the vertically vibrating mode and horizontally vibrating mode guided waves wavenumber dispersion coefficient. Modeling and experimental investigations of lateral and vertical excitation in railhead shows that good agreement between numerical calculation and experiment. Related Articles | Metrics | Comments（0）

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Survey on Medical Robotics NI Ziqiang, WANG Tianmiao, LIU Da Journal of Mechanical Engineering    2015, 51 (13): 45-52.   DOI: 10.3901/JME.2015.13.045 Abstract （3010）      PDF（pc） （840KB）（87115）       Knowledge map    Save Robotics in medical have made giant strides in past several decades with its widely use in various aspects. According to it’s function and usage, medical robots are classified into 7 types: neurosurgery robot, orthopedics robot, laparoscopic robot, vascular interventional robot, prosthetics and exoskeleton robot, assistive and rehabilitation robot and capsule robot. The functions, specifications, advantages and disadvantages of present typical commercially available medical robotics are surveyed. The current research foci, key technology and future trends of medical robotics are also discussed. Related Articles | Metrics | Comments（0）

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Research on In-service Detection for Axial Cracks on Drill Pipe Using the Feed-through Alternating Current Field Measurement LI Wei, YUAN Xinan, CHEN Guoming, GE Jiuhao, JIANG Yongsheng, JIA Tingliang Journal of Mechanical Engineering    2015, 51 (12): 8-15.   DOI: 10.3901/JME.2015.12.008 Abstract （1204）      PDF（pc） （2653KB）（50826）       Knowledge map    Save Drill pipe is a critical and vulnerable component in oil & gas industry. A novel feed-through alternating current field measurement (ACFM) is proposed to achieve in-service detection for axial cracks on the surface of drill pipe. The finite element model is built by ANSYS software for analyzing the induced electromagnetic field distribution and disturbance caused by the axial crack on the external surface of drill pipe. Signal features of the crack are extracted through quantitatively analyzing the relationship between the size of crack and disturbance field. On the basis of theory and FEM simulation, the feed-through ACFM system is set up and proved by the axial crack of drill pipe detection experiments. The results show that, the signal features of Bx and Bz from the feed-through ACFM system show the depth and length information of the axial crack respectively on pipe string, and the lift-off effect can meet the demands of in-service detection for drill pipe. Furthermore, the feed-through ACFM system with sensors array can detect all the axial cracks in-service with a single pass scanning. Related Articles | Metrics | Comments（0）

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State-of-art of Compliant Mechanisms and Their Applications YU Jingjun, HAO Guangbo, CHEN Guimin, BI Shusheng Journal of Mechanical Engineering    2015, 51 (13): 53-68.   DOI: 10.3901/JME.2015.13.053 Abstract （2655）      PDF（pc） （745KB）（21535）       Knowledge map    Save Since the concept of compliant mechanisms (CMs) is firstly proposed in late 1980s, it develops rapidly and has become an important branch of modern mechanism community. In the past less than 30 years, dozens of design methodologies and theories for CMs have emerged, which lays a solid foundation on their successful use. With the increasing insight for flexures and CMs, more and more applications of CMs can be found in various fields. After summarizing and comparing the current design methods for flexure-based compliant mechanisms five years ago, the state-of-arts of CMs have been overviewed from the point of application in this paper. Most existing CMs are resorted to three categories, i.e. precision engineering, bionic robotics, and smart structures if considering the difference of their functions and application background. The successful uses, study focuses and even application prospects in each category of CMs are introduced case by case. Afterward, four new types of CMs with great potential applications, i.e. cellular CMs, contact aid CMs, lamina emergent mechanisms, and static balance CMs are illustrated in brief. We hope more scholars all over the world start to study these amazing CMs and industrial personnel pay more attention on the usage of CMs as well after getting the overview of CMs. Related Articles | Metrics | Comments（0）

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μ-SVD Based Denoising Method and Its Application to Gear Fault Diagnosis ZENG Ming, YANG Yu, ZHENG Jinde, CHENG Junsheng Journal of Mechanical Engineering    2015, 51 (3): 95-103.   DOI: 10.3901/JME.2015.03.095 Abstract （1372）      PDF（pc） （500KB）（18950）       Knowledge map    Save In order to extract machinery fault characteristics that are submerged in strong background noise, a general singular value decomposition (SVD) based subspace noise reduction algorithm is applied to signal processing, i.e., μ-SVD based denoising method. It can be proved that the traditional SVD based denoising method is a special case of the μ-SVD based one where μ=0. μ-SVD based denoising method contains a filter factor that plays a role in restraining information contributions of the noise-domain singular values to the denoised signal. μ-SVD based denoising method involves five parameters, including delay time, embedding dimension, noise reduction order, noise power and Lagrange multiplier. The selection methods for these parameters are discussed. In particular, the effects of noise reduction order and Lagrange multiplier on denoising performance are also studied. The experimental results of simulation signal with local fault and vibration signal with early crack fault in gear demonstrate that the μ-SVD based denoising method is superior to the traditional one in denoising performance, and can more effectively extract the gear fault characteristics at the presence of strong background noise. Related Articles | Metrics | Comments（0）

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Interpolation Algorithms Based on Rife-Vincent Window for Discrete Fourier Transforms of Damped Signals DIAO Ruipeng, MENG Qingfeng, FAN Hong Journal of Mechanical Engineering    2015, 51 (4): 1-7.   DOI: 10.3901/JME.2015.04.001 Abstract （1064）      PDF（pc） （457KB）（18445）       Knowledge map    Save The major parameter estimation error source for discrete Fourier transform are spectrum leakage and picket fence effect. A weighted two points vector interpolation algorithm based on Rife-Vincent window for improving the estimation accuracy of parameters for the multi-frequency damped signals is presented, where the signals are weighted by M-order cosine window family before the discrete Fourier transform and the equations with nuknown of frequency deviation and decay factor is established by the ration of two adjacent spectral lines near the real frequency position. The frequencies, amplitudes and phases are calculated by the frequency deviation solved from the above equation. The cosine window family with the characteristic of maximum sidelobe decay can essentially remove the spectral leakage and two point vector interpolation will cope with the problem of the picket fence. To combine the merits of the above two method can effectively increase the accuracy. The simulation and test results show that the proposed algorithm has a higher estimate accuracy and steady estimates. The higher computational efficiency and lower memory demand are suggested especially for poor computing resource situations. It also can be used as an optional method for the features extraction of the multi-frequency damped signals. Related Articles | Metrics | Comments（0）

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Research on Assessment Method of Airbag Cushion System for Airdropping Equipment HONG Huangjie, WANG Hongyan, LI Jianyang, RUI Qiang, ZHANG Fang Journal of Mechanical Engineering    2015, 51 (4): 148-154.   DOI: 10.3901/JME.2015.04.148 Abstract （844）      PDF（pc） （2147KB）（17102）       Knowledge map    Save Based on thermodynamics theory and finite element method, a finite element model of equipment and its airbag cushion system is established and verified experimentally. The simulation results are obtained under the same conditions of the airdrop test and the simulation results agree very well with the experimental results, which indicate the established model is valid for further research. Because nonlinear model of airbags cushion system is very complicated, the calculation takes tens of hours of CPU time. As a result, the large-scale calculation is impossible. In order to overcome this problem, surrogate models are employed instead of the complex finite element model based on extended latin hypercube method and radial basis function. Initial velocity, initial heeling angle, initial pitch angle, lateral velocity and gradient are variables, while maximum acceleration, maximum heeling angle, maximum pitch angle and maximum airbag pressure are responses. Considering the influence of landing condition, Monte Carlo method and surrogate model are used to calculate landing success probability of airdropping equipment under multi-condition. The landing success probability calculated is 95.84%. Acceleration is the primary contributor to cushion performance, while pressure inside airbag is secondary contributor. Related Articles | Metrics | Comments（0）

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Perspectives on Isogeometric Analysis WU Zijun, HUANG Zhengdong, ZUO Bingquan, LIU Qinghua, YIN Xiaoliang Journal of Mechanical Engineering    2015, 51 (5): 114-129.   DOI: 10.3901/JME.2015.05.114 Abstract （1267）      PDF（pc） （916KB）（16705）       Knowledge map    Save Isogeometric analysis (IGA) is a novel numerical method for solving equations of physical fields, which is motivated by improving the integration between numerical simulations of physical phenomena and the computer-aided design tools, and provides a new way to associate product design with analysis and optimization via a common mathematical platform. The method of geometric modeling and its mathematical description are introduced in detail based on the computational framework of IGA. Taking NURBS as an example, the parametric representation in an analysis model and the mesh refinement method are analyzed, and the discretization methods, boundary conditions and quadrature in the parametric domain of IGA are discussed as well by comparing them with those in the standard finite element analysis. Applications of IGA in thermal analysis, fluid-structure interaction, contact problems and structural optimization are summarized and a simple example of 2D problem is provided. Related Articles | Metrics | Comments（0）

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Method for Structural Optimization Design of Wafer Handling Robot Arms LIU Yanjie, WU Mingyue, WANG Gang, CAI Hegao Journal of Mechanical Engineering    2015, 51 (1): 1-9.   DOI: 10.3901/JME.2015.01.001 Abstract （6329）      PDF（pc） （821KB）（16146）       Knowledge map    Save A method for structural optimization design of wafer handling robot is presented. The static deformation of the end effector is employed as the constraint of the method. The nature frequencies of the rigid links flexible joints system are selected as the optimization objectives, and the thicknesses of the arms are determined as the optimization parameters. The dynamic model of the rigid links and flexible joints is established, and the modal analysis is carried out to determine the orders of the modal which will influence the trajectory precision. The masses of the second arm and the third arm are selected as the optimization parameters by the sensitive analysis of the nature frequencies. The deflection model of the arm is established with the variables of the thicknesses of the arm. The relationships between the thicknesses and the deformation of the end effector are analysed, and the structures of the arms are optimized based on the analysis. The comparison between the performance before optimization and the performance after optimization are carried out, and the result shows that the nature frequencies and the frequency of the vertical vibration are significantly enhanced and the deflection of the end effector is obviously reduced. Related Articles | Metrics | Comments（0）

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Three-dimensional Nano Resonant Trigger Probe and Positioning System Based on PVDF Film LI Zhibo, HUANG Qiangxian, SHI Kedi, HAN Bin, YU Huijuan Journal of Mechanical Engineering    2015, 51 (2): 1-6.   DOI: 10.3901/JME.2015.02.001 Abstract （1181）      PDF（pc） （668KB）（14687）       Knowledge map    Save Recently, micro-nano coordinating measuring machine(CMM) has become a research focus in the field of three-dimensional(3D) micro-nano measurement. Due to the difficulty of the development of a 3D nano probe, a novel 3D resonant trigger probe has been proposed. This probe can reach nanometer/sub-nanometer resolution in three-dimensions, and its operation principle is different from the present contact probes and optical non-contact probes. The 3D nano resonant trigger probe is constructed by a piece of piezo-electrical PVDF film, two piezo-actuators, an integrated fiber micro-stem and micro-ball tip. The PVDF film vibrates at its resonant frequency and acts as a sensor. Using the piezoelectric property of PVDF film and the high sensitivity of its resonant parameters to the micro-force, the probe can give 3D trigger signal. The probe contacts the sample in traditional tapping-mode in z direction and friction-mode in both x and y directions. Experimental results show that the trigger resolution of 3D resonant trigger positioning system constructed by the above probe, 3D nano positioning unit, the feedback control module and the signal processing circuit could reach sub-nanometer resolution, which is 0.12 nm in x direction and 0.10 nm in y direction, while 0.12 nm in z direction. The 3D repeatability error is 26 nm, 36 nm and 10 nm respectively. The results demonstrate the validity of the new type of 3D nano resonant trigger probe and positioning system. Related Articles | Metrics | Comments（0）

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Researches on Automated Placement Technologies and Equipment for Carbon Fiber Reinforced Composites：A State-of-the-art Review KE Yinglin, QU Weiwei, LI Jiangxiong, CHENG Liang, KE Zhenzheng, WU Jianbo, ZHU Jianbin, YANG Di, YANG Qian, CAI Zhijia, WANG Qing, ZHU Weidong, DONG Huiyue, XU Qiang, YU Cijun, WANG Qingtao, NI Zuoxi Journal of Mechanical Engineering    2023, 59 (20): 401-435.   DOI: 10.3901/JME.2023.20.401 Abstract （732）      PDF（pc） （2278KB）（11416）       Knowledge map    Save The application proportion of composite materials in the structure of modern aerospace vehicles has become an important indicator to measure progress, and the continuous improvement of the application level of composite materials is an important access to realize the lightweight, functionalization and intelligence of aerospace structures. However, the advanced application of composite materials is a complex system engineering, involving multiple fields such as materials, mechanics, design, manufacturing, control and computer science, and requiring the coordinated development of production-learning-research-application. Starting from the application cases in aviation structure manufacturing, the development direction of automated placement technologies for thermosetting composites are discussed by analyzing the technical demands for two typical aviation structures, large-size hyperbolic panel and specially-shaped rotary inlet. Furthermore, the current research and application status at home and abroad are comprehensively analyzed and summarized from three aspects：process planning technology, automated placement equipment development, and placement process planning software development, and the core technical issues faced in the manufacturing of advanced composite components are discussed. Then, developing the integrated capability of composite design and manufacturing is identified to require in-depth analysis of the complex coupling relationship among design, process and manufacturing factors, while process optimization and manufacturing feedback are achieved through single-factor analysis and multi-factor coordination mechanisms. Finally, the development ideas in the field of automated placement technology and equipment are proposed, aiming to provide directional reference for accelerating the construction of high-performance composite manufacturing capability for China. Reference | Related Articles | Metrics | Comments（0）

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Wave Energy Conversion System Design for Detection Unmanned Underwater Vehicle in Shallow Water DING Wenjun, SONG Baowei, MAO Zhaoyong, ZHAO Xiaozhe Journal of Mechanical Engineering    2015, 51 (2): 141-147.   DOI: 10.3901/JME.2015.02.141 Abstract （1388）      PDF（pc） （1676KB）（10421）       Knowledge map    Save To achieve long operation time for the detection device on the detecting unmanned underwater vehicle (UUV) in shallow water, a wave energy conversion system is proposed. This can harvest wave energy and convert to electrical energy near water surface. The principle structure and the design parameters of the permanent generator are described in detail. The mathematical model of the system is established according to Lagrange Equation. The influence on the power performance is investigated over a range of sea state by solving the simplified equation of motion using the Runge-Kutta method. Research results show that the proposed wave energy conversion system is reasonable and feasible, which can satisfy the energy demand of the detection device under general sea state. And the results also show that the parameters of the amplitude, the period and the coupling motion of roll have a high impact, the impaction of coupling motion of heave can be negligible. The research results will provide a theoretical basis for the engineering test of the wave energy conversion system. Related Articles | Metrics | Comments（0）

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Overview of Fault Diagnosis in New Energy Vehicle Power Battery System SUN Zhenyu, WANG Zhenpo, LIU Peng, ZHANG Zhaosheng, CHEN Yong, QU Changhui Journal of Mechanical Engineering    2021, 57 (14): 87-104.   DOI: 10.3901/JME.2021.14.087 Abstract （2226）      PDF（pc） （2110KB）（10212）       Knowledge map    Save To achieve significant fuel consumption and carbon emission reductions, new energy vehicles have become a transport development trend throughout the world. However, new energy vehicle safety issues are increasingly prominent with the increase of new energy vehicle, which seriously threatens the life and property of drivers, and restricts the development of new energy vehicles industry. According to statistics, 60% of fire accidents in new energy vehicles are caused by power batteries. The development of advanced fault diagnosis technology for power battery system has become a hot spot in the field of safety protection. In order to fill the gap in the latest Chinese review, the faults of power battery system are classified into internal faults and external faults based on the difference of fault location, and the failure mechanisms of over-charge, over-discharge, external short circuit, internal short circuit, sensor fault, connector fault and cooling system fault are described. From the perspectives of internal faults and external faults, the research status and latest progress of three types of fault diagnosis methods are summarized including knowledge-based, model-based and data driven for lithium-ion power batteries. The main problems in the current research and future development on power battery fault diagnosis technology are discussed. In this way, accurate diagnosis and early prevention of power battery system faults can be realized, the life and property safety of drivers can be guaranteed, and the safety and the further development of the new energy vehicle can be promoted. Reference | Related Articles | Metrics | Comments（0）

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Investigation on Transient Vibro-impacts of Vehicle Driveline Based on Clearance and Friction Nonlinearity Yang Liang, Xia Yuanfeng, Pang Jian, Chu Zhigang Journal of Mechanical Engineering    2021, 57 (10): 50-64.   DOI: 10.3901/JME.2021.10.050 Abstract （2992）      PDF（pc） （2243KB）（9839）       Knowledge map    Save Due to gear clearances of automotive driveline, transient vibro-impacts between gear teeth easily cause serious noise and vibration problem during fast engagement clutch, which decrease the vehicle sound quality. To analyze the transient vibro-impacts of driveline system excited by fast engagement of the clutch, a 9 degree-of-freedom lumped parameter dynamical model with piecewise linear clearance elements and nonlinear friction element for a rear-wheel-drive vehicle driveline system is established based on nonlinear theory of clearance and friction. The transient vibro-impact phenomena of the vehicle driveline excited by fast engagement of the clutch are numerically simulated. The plane phase reveals the phenomenon of multiple impacts and rebounds of the gear teeth in each transient impact, and shows the relationship between the relative contact deformation of the gear teeth and the relative angular velocity. Compared to axle clearance element, the transmission clearance element produces the largest transient impact force and elastic potential energy. During speed synchronization of the flywheel and clutch, the friction torque and Stick-Slip phenomenon between flywheel and clutch plate with different normal force are analyzed. Compared to the widely used friction model based on Karnoop friction theory, the numerical friction model established in this paper can better simulate the driveline vibro-impact caused by speed synchronization and the friction torque between flywheel and clutch plate during clutch engagement. The numerical results are verified by the vehicle tests. Reference | Related Articles | Metrics | Comments（0）

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Structural Optimization and Kinematic Analysis of Deformable Wheel-claw Configured Unmanned Platform LIU Jianfeng, MENG Qingkai, SHU Yongjie, KE Zhifang, LIU Cheng, WEI Wei Journal of Mechanical Engineering    2025, 61 (19): 91-100.   DOI: 10.3901/JME.2025.19.091 Abstract （205）      PDF（pc） （628KB）（9720）       Knowledge map    Save To address the challenges of limited mobility and obstacle-crossing capability for land-air hybrid unmanned platforms in complex building environments, a high-mobility deformable wheel-claw unmanned platform with a large expansion ratio, capable of switching between wheel and claw states, is proposed. A structural parameter optimization model is established to minimize both the deformation trigger torque and the average pressure angle of the deformable wheels. The sequential quadratic programming (SQP) method is applied to solve this constrained optimization problem. Additionally, a kinematic model of the entire platform is developed based on periodic motion analysis of a single deformable wheel, and the theoretical model is validated through multibody dynamics simulations and motion capture experiments. The results show that, compared to the initial structure, the optimized trigger torque is reduced by 20%, and the average pressure angle is decreased by 38.5%, with only a 6.25% error between the theoretical and simulated trigger torque values. The displacement and velocity curves of the optimized platform closely align with the simulation and experimental trends, providing a theoretical foundation for further dynamic modeling and trajectory optimization of high-mobility unmanned platforms. Reference | Related Articles | Metrics | Comments（0）

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Abrasive Waterjet Machining — State of the Art and Future Perspectives WANG Jun, JING Yanyan, DU Xinhao, ZHENG Lijuan, WANG Chengyong, CHEN Ping Journal of Mechanical Engineering    2025, 61 (9): 46-77.   DOI: 10.3901/JME.2025.09.046 Abstract （573）      PDF（pc） （1287KB）（9088）       Knowledge map    Save Owing to its various distinct advantages, the abrasive waterjet (AWJ) machining technology has been increasingly used in industry. It is gaining particular favour in the machining of thermal sensitive and advanced materials where it has demonstrated as one of the most effective technologies to machine difficult-to-machine materials. Since the advent of the AWJ machining technology, a lot of research efforts have been undertaken to understand the science associated with AWJ machining, which has enabled the technology to be developed as a widely used one. To facilitate future research, this study reviews, analyzes and discusses the investigations that have been undertaken in relation to AWJ machining, covering the formation principle, flow field characteristics and impact characteristics of high-pressure waterjet and AWJ, the fluid dynamics and energy transfer on the jet impact zone, the microscopic materials removal mechanism and macroscopic kerf formation mechanism under AWJ impacts, as well as the technologies and processes that have been developed in the last decades. It provides good support to future research both theoretically and technologically. Finally, how the AWJ technology may develop and the possible research directions in the near future are proposed. Reference | Related Articles | Metrics | Comments（0）

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Establishing a New Paradigm of Embodied Intelligence: A Review of the Current Status and Development Trends in Humanoid Robot Technology TAO Yong, WAN Jiahao, WANG Tianmiao, XIONG Youjun, WANG Baicun, ZHANG Wenbo, DENG Changyi, TAO Yu, YANG Geng, WEI Hongxing Journal of Mechanical Engineering    2025, 61 (15): 121-147.   DOI: 10.3901/JME.2025.15.121 Abstract （1603）      PDF（pc） （922KB）（8723）       Knowledge map    Save The technology of humanoid robots is currently evolving rapidly, becoming a new focal point for global technological innovation and industrial upgrading. As an important representative of embodied intelligence, humanoid robots possess vast development potential and application prospects. Based on the multidisciplinary intersections, complex systems, and high levels of integration inherent in humanoid robot technology, this review synthesizes the latest research achievements and industry developments in this field, focusing on the current technological status and development trends of humanoid robots. First, the definition and developmental history of humanoid robots are introduced, describing the current status of development in both foreign and domestic contexts from the perspectives of technological level, industrial landscape, and policy support. A comparison and summary of the typical technological development characteristics and product features between domestic and international advancements are provided. Key core technologies are analyzed in detail, including critical components, environmental perception and scene understanding, gait control and dexterous manipulation, embodied intelligence and large models, human-robot collaboration and interaction, as well as operating systems and toolchains. The implementation pathways and current research progress of these technologies are discussed. Furthermore, typical applications of humanoid robots in specialized service environments, intelligent manufacturing, and household and social services are presented, exploring their expansion potential in emerging application areas. The main challenges faced by humanoid robot development are analyzed, focusing on technological bottlenecks and application difficulties. Finally, based on the development status of technologies and applications, an outlook on the trends in embodied intelligence represented by humanoid robots is provided, particularly in areas such as multimodal vertical large models, high-performance simulation training platforms, and safety and ethics. This review aims to summarize and grasp the dynamics of cutting-edge technological developments in humanoid robots domestically and internationally, while offering insights and references for those engaged in the research and development of humanoid robot technologies and products, thus contributing to the advancement and industrialization of humanoid robot technology in China. Reference | Related Articles | Metrics | Comments（0）

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Review of Machine Learning Based Remaining Useful Life Prediction Methods for Equipment PEI Hong, HU Changhua, SI Xiaosheng, ZHANG Jianxun, PANG Zhenan, ZHANG Peng Journal of Mechanical Engineering    2019, 55 (8): 1-13.   DOI: 10.3901/JME.2019.08.001 Abstract （5000）      PDF（pc） （1101KB）（8719）       Knowledge map    Save With the development of science and technology as well as the advancement of production technology, contemporary equipment is increasingly developing towards large-scale, complex, automated and intelligent direction. In order to ensure the safety and reliability of equipment, the remaining useful life (RUL) prediction technology has received widespread attention and been widely used. Traditional statistical data-driven methods are obviously influenced by the choice of models. Machine learning has powerful data processing ability, and does not need exact physical models and prior knowledge of experts. Therefore, machine learning has a broad application prospect in the field of RUL prediction. In view of this, the RUL prediction methods based on machine learning are analyzed and expounded in detail. According to the depth of machine learning model structure, it is divided into shallow machine learning methods and deep learning methods. At the same time, the development branches and research status of each method are sorted out, and the corresponding advantages and disadvantages are summarized. Finally, the future research directions of RUL prediction methods based on machine learning are discussed. Reference | Related Articles | Metrics | Comments（0）

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Research on Short Fatigue Crack Initiation and Propagation of Metallic Materials:A Review WANG Shuancheng, YANG Bing, LIAO Zhen, XIAO Shoune, KANG Guozheng, YANG Guangwu, ZHU Tao Journal of Mechanical Engineering    2023, 59 (16): 32-53.   DOI: 10.3901/JME.2023.16.032 Abstract （731）      PDF（pc） （952KB）（8035）       Knowledge map    Save The short fatigue cracks of metal materials are systematically sorted out in terms of their definition, classification, test methods, initiation mechanism, and typical growth rate models, as well as the problems facing the current research on short crack behavior, are summarized and prospected. The results show that the microstructure of materials plays an important role in the initiation and propagation of short cracks. When the crack tip reaches the grain boundary, the growth rate of cracks decelerates due to the influence of grain orientation and grain boundary resistance, and the short crack propagation path appears to be locally deflected after the crack tip breaks through the grain boundary constraint. In terms of the short cracks propagation behavior description, the driving force of short crack propagation is related to the load level, residual stress, surface treatment and local wear condition, and so on. During propagation, the crack tip materials yield in a small area and produce a local plastic zone. At the same time, the plastic wake is gradually formed, which results in plastic-induced closure and a decrease in the crack propagation threshold value. Besides,the interaction between crystal dislocations and dislocation stacking can hinder the dislocation development. The machine learning algorithm, as an advanced technological tool, has been applied in the characterization of short crack growth behavior, which has contributed to the improvement of prediction accuracy. With further research on the behavior of short cracks in metal materials, we can focus on real-time monitoring of short crack initiation and propagation, control of test influencing factors, discrete data analysis,and engineering applications of the growth rate model in the future. The establishment of a unified characterization model for long and short crack growth rate as well as real-time monitoring and safety assessment techniques will be explored. In addition, more effective and accurate safety assessment and remaining life management of critical metal structures can be realized by combining advanced machine learning algorithms. Reference | Related Articles | Metrics | Comments（0）

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Review of Thermal Runaway and Safety Management for Lithium-ion Traction Batteries in Electric Vehicles ZHU Xiaoqing, WANG Zhenpo, WANG Hsin, WANG Cong Journal of Mechanical Engineering    2020, 56 (14): 91-118.   DOI: 10.3901/JME.2020.14.091 Abstract （1293）      PDF（pc） （7129KB）（7484）       Knowledge map    Save Lithium-ion battery is considered to be the most promising type of traction battery of electric vehicles (EVs) for its high energy density, long cycle life and no memory effect. With the continuous improvement of energy density of lithium-ion batteries and the reduction of manufacturing costs, the safety accidents characterized by thermal runaway have occurred frequently, which seriously threatens the safety of passengers' lives and property. Therefore, the issue of lithium-ion battery thermal runaway has become a research focus in the field of EVs. Meanwhile, the development of related fields also needs the guidance of such review articles. From a safety point of view, a comprehensive overview of current state of thermal runaway within lithium-ion batteries used in EVs is summarized, as well as the latest research results. Moreover, the trigger and failure mechanisms of thermal runaway are clarified, and the methods to improve the safety of lithium-ion power battery system are summarized comprehensively, with the aim of promoting the development of safety management methods and strategies for advanced lithium-ion battery systems and improving the safety of traction battery systems. The gap of the lack of Chinese review papers is filled in this field. Reference | Related Articles | Metrics | Comments（0）

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Recent Advances and Tendency of Optical Fiber Sensing Technology for Equipment Manufacturing and Operating States Monitoring in Extreme Environments LI Tianliang, GUO Jinxiu, WU Dongjian, TAN Yuegang, ZHOU Zude Journal of Mechanical Engineering    2022, 58 (8): 27-53.   DOI: 10.3901/JME.2022.08.027 Abstract （842）      PDF（pc） （1914KB）（6104）       Knowledge map    Save The safe operation of large-scale manufacturing equipment is related to the development of the national economy and national defense construction. The use of advanced sensing technology is of great significance to the performance evaluation of manufacturing equipment and the monitoring of its operating conditions under extreme environments such as ultra-high/low temperature, ultra-high pressure, intense radiation, strong magnetic field, etc. Optical fiber sensor has become an important tool for equipment manufacturing and operating condition monitoring in extreme environments due to its intrinsic advantages such as small size, resistance to high temperature, corrosion and electromagnetic interference, explosion-proof, passive sensing, and easy realization of multi-point distributed measurement. Equipment manufacturing and operating condition monitoring technology based on the extreme parameter optical fiber sensing under extreme environments has been investigated. And the design, fabrication, calibration, error compensation and application of extreme parameter optical fiber sensors have been summarized. The design principle of the extreme parameter optical fiber sensor's energy converter and the modulation mechanism of the optical fiber signal are introduced. The manufacturing method, packaging process, calibration and error compensation methods of the optical fiber sensor are elaborated and analyzed. The research achievements on the extreme parameter optical fiber sensor for equipment manufacturing and operating condition monitoring have been summarized. The tendency of the extreme parameter optical fiber sensing technology is discussed and outlooked. Reference | Related Articles | Metrics | Comments（0）

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Research on the State-of-art, Connotation and Key Implementation Technology of Assembly Process Planning with Digital Twin GUO Feiyan, LIU Jianhua, ZOU Fang, ZHAI Yunong, WANG Zhongqi, LI Shaozhuo Journal of Mechanical Engineering    2019, 55 (17): 110-132.   DOI: 10.3901/JME.2019.17.110 Abstract （1688）      PDF（pc） （1315KB）（5961）       Knowledge map    Save Based on the entire digital coordination transfer process in manufacturing process, with the strategy of ‘fusion of virtuality and reality, control the reality with virtuality’, the optimization-feedback-improvement loop mechanism of assembly process that driven by digital twin model is studied. Firstly, the essence and technical composition of (1) the quantitative partition/solution/evaluation of assembly unit, (2) the construction of digital twin model, and (3) assembly precision controlling with a closed-loop are analyzed, and the research status and existing problems are summarized. Then considering the detailed constraints of design in virtual field and assembly in physical field, three key technology are proposed, i.e. (1) assembly process planning and evaluation with the thought of DFA, (2) dynamic construction and analysis of twinning process model considering physical topological relation, (3) optimization-feedback-improvement ring mechanism construction orienting for the actual assembly field. Then the specific solutions and possible innovation directions are given. With the above analysis, the connotation of manufacturing technology based on virtual model can be expanded. Finally, the closed-loop optimization decision of production activity and the change of product development mode are expected to be realized in product development and production, and the assembly accuracy/consistency and assembly efficiency can be improved. Reference | Related Articles | Metrics | Comments（0）

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Status Analysis and Prevention-treatment Technology Study of Abnormal Wear of Pantograph Catenary System in Urban Rail Transit ZOU Dong, ZHONG Shuncong, GENG Yan, CHENG Yao, MO Zhigang, XU Kejia, SONG Bing, CHENG Bin, ZHANG Shiyu, WANG Zhicheng, HUA Lujie, ZHANG Yanan Journal of Mechanical Engineering    2023, 59 (10): 152-178.   DOI: 10.3901/JME.2023.10.152 Abstract （382）      PDF（pc） （1570KB）（5755）       Knowledge map    Save Aiming at the frequent abnormal wear phenomenon of pantograph-catenary systems in domestic urban rail transit in recent years, the anomaly of pantograph-catenary contact behaviour from nearly 10 subway lines are sorted out from the perspectives of structural characteristics, temporal and spatial attributes of fault phenomena, and treatment measures. The main research results regarding the influence of contact force, current, arc, and other factors on the wear of pantograph and catenary system are analysed; The researches on the wear mechanism of pantograph and catenary system are discussed; A wear model of the pantograph-catenary system proposed by foreign research teams is introduced. Based on the current status analysis of engineering and scientific research, the root cause analysis method of the abnormal wear of pantograph and catenary system is formulated from the wear model; From the perspectives of the ground test, line test, and simulation analysis, data processing technology, etc., the methods available for verifying and validating the cause of abnormal wear are sorted out, together with introducing the method of segmenting operating data between rigid conductor overlaps and sections. Aiming at the hot topics of abnormal wear, the quantitative evaluation of system performance affected by wear groove on pantograph strip and rigid conductor stagger arrangement is realized by using simulation technology. Referring to the standards analysis of pantograph and catenary system, the application and maintenance measures to inhibit abnormal wear are introduced. Finally, a framework dealing with the abnormal wear of pantograph-catenary contact pairs is proposed, which includes four stages:abnormal wear definition and evaluation, root cause analysis, causes verification and validation, and maintaining control. Based on the status analysis results and the proposed framework, the future exploration content of scientific and engineering problems has been prospected. The results of the study would provide technical and management references for the relevant units of urban rail transit to deal with the abnormal wear of pantograph and catenary systems. Reference | Related Articles | Metrics | Comments（0）

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Cognitive Empowerment for Human-robot Collaboration: Research Progress and Challenges KOU Yiqun, YANG Ye, LIU Jie, HU Youmin, LI Lin, YU Baichuan, XU Jiahe, HU Zhongxu, SHI Tielin Journal of Mechanical Engineering    2025, 61 (3): 1-22.   DOI: 10.3901/JME.2025.03.001 Abstract （1360）      PDF（pc） （612KB）（5663）       Knowledge map    Save In the transition from Industry 4.0 to Industry 5.0, a human-centered approach has gradually emerged as a focal point in the field of smart manufacturing. Current human-machine collaboration not only emphasizes technological advancements and efficiency improvements but also stresses the integration of human higher-order cognitive thinking with machine computational capabilities to achieve cognitive empowerment. Based on this premise, this study reviews existing research on cognitive empowerment in human-machine collaboration, focusing on key areas such as interactive perception, task planning and execution, and skill learning. The challenges of multimodal information integration, task reasoning, dynamic decision-making, and skill knowledge representation are highlighted. Furthermore, methods are proposed to support human-machine cognitive using knowledge graph construction technologies, as well as to optimize tasks and facilitate dynamic decision-making in complex environments through the application of knowledge graph reasoning techniques. Building upon an analysis of the limitations in current research on cognitive empowerment in human-machine collaboration, this study also forecasts the future directions for deep cognitive collaboration within intelligent manufacturing environments. Reference | Related Articles | Metrics | Comments（0）

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Review on Grinding Technology of Nickel-based Superalloys Used for Aero-engine DING Wenfeng, MIAO Qing, LI Benkai, XU Jiuhua Journal of Mechanical Engineering    2019, 55 (1): 189-215.   DOI: 10.3901/JME.2019.01.189 Abstract （1799）      PDF（pc） （131608KB）（5621）       Knowledge map    Save Grinding plays the critical role in manufacturing the aero-engine components composed of nickel-based superalloys. In order to further improve the material removal rate and workpiece quality, a large number of researches on grinding technology of nickel-based superalloys are conducted in terms of the fundamental theory and process expending. In this review article, the basic principle and development process of grinding are firstly introduced briefly. Then, the technologies are reviewed detailed concerning the material removal mechanism, the grinding characteristics, and the novel application type of grinding for nickel-based superalloys. Finally, the development trends during grinding of nickel-based superalloys are proposed as well as the difficulties in grinding of such materials. Reference | Related Articles | Metrics | Comments（0）

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Fundamentals and Prospects of Additive Friction Stir Deposition：Opportunities and Challenges SHEN Zhikang, LI Dongxiao, SUN Zhonggang, MA Liangchao, LIU Xiaochao, TIAN Yanhong, GUO Wei, HOU Wentao, PIAO Zhongyu, YANG Xinqi, LI Wenya Journal of Mechanical Engineering    2025, 61 (2): 56-85.   DOI: 10.3901/JME.2025.02.056 Abstract （1578）      PDF（pc） （1718KB）（5571）       Knowledge map    Save Integrative design and integrated manufacturing of major equipment’s’ large critical structure such as aeronautics, astronautics and weapons provide guarantees of lightweight manufacturing and service performance. As a transformative technology can achieve innovative structure, additive manufacturing has received extensive attention and being applied, nevertheless, additive manufacturing of lightweight and high-strength metals such as high strength aluminium alloy and magnesium alloy faces many challenges. Additive friction stir deposition provides a new thought and method for such kind metals, since its process involves strong plasticity and non-melting, which further facilitates the progress of solid-state additive manufacturing and equipment. Dominant advantages of additive friction stir deposition have aroused worldwide attention and investigation; However, this technology’s basic theory and deposited materials’ microstructure evolution and performance need to be clarified. Research progress in additive friction stir deposition was systematically summarized, domestic and foreign research achievements such as heat production mechanism, material flow behavior, design of printing tool, processing parameters, microstructure evolution and performance of additive friction stir deposition were comprehensively reviewed. Finally, future opportunities and development trends of additive friction stir deposition were pointed out. Reference | Related Articles | Metrics | Comments（0）

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Research Progress on Composite Protection of Advanced Equipment Surfaces Using Magnetron Sputtering Technology ZHAO Licun, WANG Zhiyuan, LIU Yang, JIANG Wei, LIU Jinna Journal of Mechanical Engineering    2025, 61 (10): 36-65.   DOI: 10.3901/JME.2025.10.036 Abstract （251）      PDF（pc） （2199KB）（5508）       Knowledge map    Save With the development of science and technology, the issue of surface protection for advanced equipment has become increasingly prominent, especially the research on surface protection technology for high-precision and high-performance components, which is one of the key scientific problems that has long troubled many researchers. Nowadays, many technological advancements rely on creating new composite materials with enhanced performance. Among them, magnetron sputtering technology, due to its strong adaptability to material surfaces and diverse element selection, provides a new control dimension for the preparation of surface protection films for various advanced equipment. Therefore, to further summarize the protection requirements of high-precision and advanced components inside advanced equipment and to address the challenges of surface protection of equipment, this study reviews the latest progress in magnetron sputtering thin film deposition technology. On the one hand, it reviews the variation mechanism and formation mechanism of the magnetron sputtering thin film deposition process, clarifies the influence of target sputtering on the performance of substrate materials, and further analyzes the reliability of thin film deposition in the time and space dimensions. On the other hand, it elaborates on the application characteristics and formation behavior of various surface protection films for equipment. Finally, in light of the technological attributes of magnetron sputtering coating, a thorough analysis of the flux features during the magnetron sputtering film deposition process is conducted, and the factors influencing the film deposition state, such as microstructure and surface properties, are explored. This paper summarizes the application mechanism of advanced equipment surface magnetron sputtering coating technology. Starting from the perspectives of the microstructure, mechanical properties, and service performance of magnetron sputtering coatings, and in combination with typical applications of magnetron sputtering coating technology, the development trends of magnetron sputtering coating technology are reviewed. The advantages and existing problems of its application prospects are summarized, and an assessment and outlook on the future advanced film systems of magnetron sputtering coating technology are provided. Reference | Related Articles | Metrics | Comments（0）

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XJTU-SY Rolling Element Bearing Accelerated Life Test Datasets: A Tutorial LEI Yaguo, HAN Tianyu, WANG Biao, LI Naipeng, YAN Tao, YANG Jun Journal of Mechanical Engineering    2019, 55 (16): 1-6.   DOI: 10.3901/JME.2019.16.001 Abstract （4845）      PDF（pc） （577KB）（5294）       Knowledge map    Save Prognostics and health management (PHM) is crucial for ensuring the safe operation of machinery, improving the productivity and increasing economic benefits. High-quality life-cycle data, as the basic resource in the field of PHM, are able to carry the key information which reflects the complete degradation processes of machinery. However, due to the high costs in data acquisition and insufficient development in storage and transmission technology, typical life-cycle data is extremely scarce, which limits the theoretical research and engineering application of PHM for machinery. In order to solve this dilemma, accelerated life tests of rolling element bearings are carried out by Prof. Yaguo Lei's research group from School of Mechanical Engineering, Xi'an Jiaotong University (XJTU) and the Changxing Sumyoung Technology Co., Ltd. (SY), Zhejiang. These tests lasted for two years and the acquired datasets, i.e., XJTU-SY bearing datasets, have been publicly released for all PHM researchers. The XJTU-SY bearing datasets contain run-to-failure vibration signals of 15 rolling element bearings under three different operating conditions. These datasets have high sampling frequency, large amount of data, abundant failure types and detailed recording information. Accordingly, these datasets not only provide fresh "data blood" for PHM and promote the research of fault diagnosis and remaining useful life prediction, but also are able to help to improve intelligent maintenance decision making in industry. Reference | Related Articles | Metrics | Comments（0）

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Overview of the Application of Big Data Analysis Technology in New Energy Vehicle Industry: Based on Operating Big Data of New Energy Vehicle SHE Chengqi, ZHANG Zhaosheng, LIU Peng, SUN Fengchun Journal of Mechanical Engineering    2019, 55 (20): 3-16.   DOI: 10.3901/JME.2019.20.003 Abstract （2979）      PDF（pc） （241KB）（5247）       Knowledge map    Save New energy vehicle(NEV) has been widely used around the world in response to the fossil energy crisis and environmental pollution problems. NEV will generate massive real-world data during its daily operating which is contributed by high electrification and intelligent networking. Applying these multi-source heterogeneous data for a security warning and technical analysis will play a key role in promoting the development of NEV industry in China. The current situation of data-driven analysis technology in the NEV field is reviewed. Firstly, the basic theory of big data analysis techniques are introduced and the development of big data technology is depicted. The structure and function of the National Monitoring and Management Platform for New Energy Vehicles are introduced, and the particular process of big data analysis on NEV is emphasized. The previous data-driven research and methods in power battery, NEV daily operation and charging behavior are proposed for discussion respectively. Some representative research results and applications are displayed at the same time. Finally, the issues and prospects of the data-driven method on NEV application field are summarized and forecasted. Reference | Related Articles | Metrics | Comments（0）

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Research Progress of Underwater Vehicle-manipulator Systems: Configuration, Modeling and Control CHANG Zongyu, ZHANG Yang, ZHENG Fangyuan, ZHENG Zhongqiang, WANG Jiliang Journal of Mechanical Engineering    2020, 56 (19): 53-69.   DOI: 10.3901/JME.2020.19.053 Abstract （1376）      PDF（pc） （716KB）（5238）       Knowledge map    Save Underwater vehicle-manipulator systems (UVMS) can fulfill underwater sampling, grabbing, operation and other tasks in addition to observation. It is widely used in marine scientific investigations, marine engineering and other fields. The state of the art of UVMS is reviewed. Different configurations of vehicles and manipulator in UVMS are introduced, and the kinematics, dynamics and hydrodynamics modeling method of UVMS are summarized. Then the teleoperation control of human-machine interaction is analyzed. In the autonomous control of UVMS, motion planning, position and trajectory tracking, independent and coordinated control, motion compensation control, position/force hybrid control, visual servo control and other issues are classified and summarized. Finally, the conclusion is given and the future trend of UVMS is discussed, it can provide a reference for relevant researchers. Reference | Related Articles | Metrics | Comments（0）

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Review of Hydraulic Driven Key Technologies for Legged Robots YU Bin, LI Huashun, HUANG Zhipeng, HE Xiaolong, BA Kaixian, SHI Yapeng, KONG Xiangdong Journal of Mechanical Engineering    2023, 59 (19): 81-110.   DOI: 10.3901/JME.2023.19.081 Abstract （872）      PDF（pc） （2329KB）（5148）       Knowledge map    Save Legged robots are based on footed creatures such as mammals, reptiles or insects that have evolved over billions of years in nature, and they have both limbs motion flexibility and uneven terrain adaptability that are comparable to those of legged animals. When combined with hydraulic driven that has the advantages of high power-to-weight ratio and fast response, its motion performance and load-carrying capacity can be greatly improved. This paper firstly introduces the background and basic principles of hydraulic driven of legged robots, analyzes the important role of hydraulic driven in the design and control of legged robots, and lists various forms of hydraulic legged robots that have been publicly reported both domestically and internationally. Secondly, recent research contents and achievements on key technologies in hydraulic driven units, hydraulic power units, and hydraulic control methods for legged robots from both domestic and international research institutions have been elaborated. Finally, based the deep integration with bionics, the future development trend of hydraulic legged robots is proposed, including the integrated bionic design of the leg’s “muscles and bones”, the compact bionic layout of the trunk “internal organs”, and the multi-level bionic integration of the control “nerves”. Reference | Related Articles | Metrics | Comments（0）

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Geometric Feature Evolution-driven Topology Design for the Supporting-free Multicell Structure WU Zijun, XIAO Renbin Journal of Mechanical Engineering    2025, 61 (17): 300-313.   DOI: 10.3901/JME.2025.17.300 Abstract （826）      PDF（pc） （818KB）（5073）       Knowledge map    Save Multicellular structures are a class of cross-scale structures characterized by complex pore features and specific mechanical properties. The intricate topological relationships inherent in the geometrical features of multicellular structures within the design space introduce significant challenges to their formation in the fabrication space. In this paper, in order to break through the self-supporting characteristic design of multi-cellular structures, a multi-cellular structure design method based on the evolution of geometric features is proposed. Starting from the geometric features, the superposition and combination mode of the rod unit is investigated, and the mapping relationship between the spatial position of the rod unit, the single-cell stiffness matrix, and the density of the single cell is analysed, and the two-dimensional and three-dimensional single-cell models driven by the geometric features of the rod unit are established; When employed in conjunction with the topological optimization method, the sensitivity of the multicellular structure is deduced, and the optimization model of the multicellular structure with single-cell matching is constructed. The distribution range of the forming angles of the shared rod units between single cells, as well as the exclusive rod units within a single cell, is analysed in conjunction with the spatial position of the rod units in the cell. The search algorithm for matching the forming angles of the rod units is designed to establish the manufacturing voxel with self-supporting characteristics and realize the self-supporting design of multi-cellular structures. This paper provides a comprehensive illustration of the multi-cellular structure manufacturing voxel construction process through the optimization example of a 2D cantilever beam and a 3D bracket. It also verifies the validity of the proposed method by using the model slicing software of the additive manufacturing equipment. This provides a new theoretical basis and methodological approach for the self-supporting design of multi-cellular structures. Reference | Related Articles | Metrics | Comments（0）

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Review on Motion Control of Autonomous Vehicles XIONG Lu, YANG Xing, ZHUO Guirong, LENG Bo, ZHANG Renxie Journal of Mechanical Engineering    2020, 56 (10): 127-143.   DOI: 10.3901/JME.2020.10.127 Abstract （2795）      PDF（pc） （8545KB）（5020）       Knowledge map    Save The motion control problem of autonomous vehicles is reviewed. From the perspective of model, algorithm, and control structure, the domestic and foreign research progress is reviewed at three levels of longitudinal motion control, path following and trajectory tracking control, and the development prospect of motion control technology for autonomous vehicles is proposed. The current motion control research mainly focuses on normal conditions. In order to realize the potential of autonomous vehicles in handling critical scenarios that human drivers find challenging or lack the ability to navigate, it is necessary to extend the research to extreme working conditions. However, the properties of non-linearity and multi-dimensional coupled dynamics are significantly enhanced in extreme working conditions. The requirements of system modeling and adaptability and robustness of motion control algorithm are further increased. At the same time, in order to deal with the multi-objective coordination in complex scenarios, the integration of motion planning and control considering environmental uncertainty needs to be studied in depth. Adding actuators can increase the lateral response speed and control margin, but the research of control allocation of redundant and heterogeneous actuators is still to be broken through. The realization of motion control depends on road adhesion coefficient, sideslip angle, etc. Therefore, it is urgent to solve the problem of key state and parameter estimation under multi-source sensor information fusion. In addition, the application of machine learning to the field of vehicle motion control is also an important development direction. Reference | Related Articles | Metrics | Comments（0）

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A Review on Knowledge Graph and Its Application Prospects to Intelligent Manufacturing ZHANG Donghao, LIU Zhenyu, JIA Weiqiang, LIU Hui, TAN Jianrong Journal of Mechanical Engineering    2021, 57 (5): 90-113.   DOI: 10.3901/JME.2021.05.090 Abstract （2179）      PDF（pc） （119732KB）（4924）       Knowledge map    Save Data and knowledge are the basis for the deep integration of new-generation information technology and intelligent manufacturing. However, the storage of data and knowledge in the processes of product design, manufacturing, assembly and service is mostly based on relational database, which brings data redundancy and inefficiency of searching and reasoning. Recently, knowledge graph technology, based on the idea of semantic network, has developed rapidly. It can achieve the description of real-world things and their relationships, which provides a mean for the correlation representation of data and knowledge, and a solution of the relevance searching and reasoning problem in the area of intelligent manufacturing. Therefore, it plays an increasingly important role in the realization of intelligent manufacturing. In order to provide the theoretical support for the application of knowledge graph, a review about the research status of knowledge graph is provided. At the same time, three major applications of knowledge graph in the area of intelligent manufacturing are explored, including a total of 15 small application prospects. Among them, the differences compared with traditional methods, the knowledge graph technology to be introduced and the key technologies to be breakthrough are detailed. It is hoped that it can provide inspiration for researchers to further carry out study on the knowledge graph in the area of intelligent manufacturing, and provide reference for mechanical companies on the application of knowledge graph. Finally, a case about the lathe failure analysis is used to verify the superiority of the knowledge graph in the area of intelligent manufacturing. Reference | Related Articles | Metrics | Comments（0）

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Opportunities and Challenges of Machinery Intelligent Fault Diagnosis in Big Data Era LEI Yaguo, JIA Feng, KONG Detong, LIN Jing, XING Saibo Journal of Mechanical Engineering    2018, 54 (5): 94-104.   DOI: 10.3901/JME.2018.05.094 Abstract （3823）      PDF（pc） （359KB）（4733）       Knowledge map    Save Faults are a potential killer of large-scale mechanical equipment, such as wind power equipment, aircraft engines and high-end CNC machine. And fault diagnosis plays an irreplaceable role in ensuring the health operation of such equipment. Since the amount of the equipment diagnosed is great and the number of the sensors for the equipment is large, massive data are acquired by the high sampling frequency after the long-time operation of equipment. Such massive data promote fault diagnosis to enter the era of big data. And machinery intelligent fault diagnosis is a promising tool to deal with mechanical big data. In the big data era, new opportunities have been brought to intelligent fault diagnosis. For instance, data-centric academic thinking will become mainstream, it makes fault diagnosis in the system level possible, and a comprehensive analysis of faults becomes a trend. Meanwhile, new challenges have also been brought:the data are big but fragmentary, the fault feature extraction relies on much prior knowledge and diagnostics expertise, and the generalization ability of the shallow diagnosis model is weak. The characteristics of big data in intelligent fault diagnosis are discussed, and the inland and overseas research advances are reviewed from the three steps of intelligent fault diagnosis. The existing key problems of the current research in the era of big data are pointed out, and the approaches and research directions to these problems are discussed in the end. Reference | Related Articles | Metrics | Comments（0）

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Review on Thermal Error Compensation for Feed Axes of CNC Machine Tools LIU Kuo, HAN Wei, WANG Yongqing, LIU Haibo, SONG Lei Journal of Mechanical Engineering    2021, 57 (3): 156-173.   DOI: 10.3901/JME.2021.03.156 Abstract （1137）      PDF（pc） （1839KB）（4644）       Knowledge map    Save The thermal deformation of the machine tool under the combined action of internal and external heat sources seriously affects the accuracy stability of the machine tool and the machining accuracy of components. How to suppress the thermal error of the machine tool is an important research field. The research progress of machine tool thermal error avoidance method and thermal error compensation method are introduced. The cause of the error of the linear feed axis is analyzed, and the thermal deformation process and mechanism of the ball screw with or without preload are explained. The optimization method of temperature measurement point location is introduced, as well as data-driven and physics-based thermal error modeling concepts, methods and characteristics. This paper introduces the thermal error test method of the rotary feed axis, and gives its modeling and compensation effects. Finally, the prospect of the research on the thermal error compensation technology of the feed axis is presented. Reference | Related Articles | Metrics | Comments（0）

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Study on the Formation Mechanism of Phase Transformation and the Influencing Factors of Cutting Layer of the Typical Titanium Alloy HE Genghuang, WU Mingyang, LI Lingxiang, ZOU Lingli, CHENG Cheng Journal of Mechanical Engineering    2018, 54 (17): 133-141.   DOI: 10.3901/JME.2018.17.133 Abstract （224385）      PDF（pc） （554KB）（4575）       Knowledge map    Save In the view of denaturation mechanism and its influence factors of machined surface of titanium alloy, firstly, the action mechanism of cutting edge on the cutting area during cutting process is analyzed. The energy method is used to establish the model of structure parameters, three factors of cutting and cutting energy consumption. The model is solved combined with Matlab. The influence of feed rate f on the cutting energy consumption W of titanium alloy is the biggest, cutting speed vc is the second, and the influence of cutting depth ap is the least. In order to verify the validity of the model, two kinds of different type of cemented carbide index-able inserts are used to conduct the contrast experiments of titanium alloy TC1, TC4, TA5 and alloy steel 30CrMnSiA under the conditions of normal air cooling and argon cooling. Meanwhile, the denaturation mechanism of machined surface of titanium alloy is defined as well as the regularity of the development. The research results can offer data support for the high quality processing of titanium alloy. Reference | Related Articles | Metrics | Comments（0）

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A Deep Learning-based Method for Machinery Health Monitoring with Big Data LEI Yaguo, JIA Feng, ZHOU Xin, LIN Jing Journal of Mechanical Engineering    2015, 51 (21): 49-56.   DOI: 10.3901/JME.2015.21.049 Abstract （3029）      PDF（pc） （1232KB）（4566）       Knowledge map    Save Mechanical equipment in modern industries becomes more automatic, precise and efficient. To fully inspect its health conditions, condition monitoring systems are used to collect real-time data from the equipment, and massive data are acquired after the long-time operation, which promotes machinery health monitoring to enter the age of big data. Mechanical big data has the properties of large-volume, diversity and high-velocity. Effectively mining characteristics from such data and accurately identifying the machinery health conditions with advanced theories become new issues in machinery health monitoring. To harness the properties of mechanical big data and the advantages of deep learning theory, a health monitoring and fault diagnosis method for machinery is proposed. In the proposed method, deep neural networks with deep architectures are established to adaptively mine available fault characteristics and automatically identify machinery health conditions. Correspondingly, the proposed method overcomes two deficiencies of the traditional intelligent diagnosis methods: (1) the features are manually extracted relying on much prior knowledge about signal processing techniques and diagnostic expertise; (2) the used models have shallow architectures, limiting their capability in fault diagnosis issues. The proposed method is validated using datasets of multi-stage gear transmission systems, which contain massive data involving different health conditions under various operating conditions. The results show that the proposed method is able to not only adaptively mine available fault characteristics from the data, but also obtain higher identification accuracy than the existing methods. Reference | Related Articles | Metrics | Comments（0）