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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
    Abstract224210)      PDF(pc) (554KB)(4504)       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.
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    Impact Damage Behavior of the Cemented Carbide Insert in the Heavy Cutting Process
    LIU Xianli;LIU Ming;HE Genghuang;YAN Fugang;CHENG Yaonan;LIU Li
       2014, 50 (23): 175-185.   DOI: 10.3901/JME.2014.23.175
    Abstract149831)      PDF(pc) (8028KB)(733)       Save
    Impact fracture process of cemented carbide turning tool is analyzed by using mechanics impact theory and the critical condition is also determined when the impact fracture happened. Finite element simulation is used to analyze and research production mechanism and damage form of impact fracture of cemented carbide turning tool, and through impact experiment the impact fracture rules of cemented carbide turning tool is revealed. The fatigue behavior of cemented carbide turning tool is researched, and through finite element simulation, production mechanism of fatigue fracture of cemented carbide under dynamic load is put forward, and the load condition of fatigue fracture of cemented carbide is given. Through intermittent cutting experiment, the essential reason why cemented carbide produced fatigue behavior is analyzed. All above will provide theory support and reference to prevent cemented carbide tool from failure too early.
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    Generation Mechanism of Saw-tooth Chip in Turning of GH4169 with PCBN Tool
    WU Mingyang ZHAO XU JI Wei CHENG Yaonan LIU Li LIU Xianli
    Journal of Mechanical Engineering    2016, 52 (3): 179-186.   DOI: 10.3901/JME.2016.03.179
    Abstract109347)      PDF(pc) (2273KB)(833)       Save
    Superalloys are applied in the aerospace industry, and it is one of classical difficult-to-cut materials, which cause the exacerbation of cutting tool wear. Polycrystalline cubic boron nitride (PCBN) is super-hard cutting tool material, which has a big potentiality in machining superalloys. However, there is no chip breaker on PCBN tool, so that it is difficult to break chip. Therefore, it is very important to research the relationship between the chip generations and both cutting parameters and tool wear for application of PCBN tools. The experiment was done to make sure the relationships cutting force, chip macro- sharp and micro-sharp with the cutting parameter and tool wear. The results demonstrate that the best chip macro sharp can be obtained when v=97 m/min, ap=0.1 mm and f=0.14 mm/r. Also the position of adiabatic shear band and the sequence between two saw teeth of chip based on the result of the test. Then the model of generation of saw-tooth chip is presented: in the process of cutting of GH4169 with PCBN tool, adiabatic shear band is generated when cutting tool is at a point, and then the saw tooth of chip is formed at a next point, after which the next adiabatic shear band can be generated.
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    Research on the Stability of the Machining Process Based on the Dynamic Cutting Force Coefficient
    YUE Caixu, GAO Haining, LIU Xianli
    Journal of Mechanical Engineering    2017, 53 (17): 193-201.   DOI: 10.3901/JME.2017.17.193
    Abstract109086)      PDF(pc) (2324KB)(553)       Save
    The cutting force coefficient changes with the cutting parameters during cutting process. If the cutting force coefficient is assumed to be constant during the cutting force simulation and the stability boundary drawing process, which makes the prediction error larger. In view of the above-mentioned problems, 0Cr13 stainless steel which is the processing material of the impact bucket, is taken as the research object. On the basis of the milling force model, the dynamic cutting force coefficient model with the cutting parameters is obtained by orthogonal test, average milling force method and partial least squares method. The main factors that affect the cutting force coefficient Kt, Kr and Ka are the feed rate, the radial width and the feed rate. Based on the dynamic cutting force coefficient, the cutting force and stability of the milling process are studied. Cutting force simulation and stability boundary, which are obtained by using constant cutting force coefficient and dynamic cutting force coefficient, compared with cutting test, the simulation results show that the dynamic cutting force coefficients is more close to the actual processing results, to provide theoretical support for the optimization of Pelton turbine bucket plunge milling process.
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    Adhering Failure of the Tool-chip in the Process of Extremely Heavy Cutting
    CHENG Yaonan;LIU Xianli;LI Zhenjia;LIU Li;WANG Haiting
       2012, 48 (19): 169-176.  
    Abstract103030)      PDF(pc) (5404KB)(243)       Save
    Based on the cutting experiments of the tube section material that is the 2.25Cr-1Mo-0.25V steel, the study on the adhering failure problem of the tool-chip in the process of the extremely heavy cutting is done, so to provide the theoretical basis for avoiding the cutter adhering failure in the actual machining process. The fluctuation characteristics of the variable load in the extremely heavy turning process is analyzed, and then the influence of the fluctuant temperature and mechanical load on the strength of the tool surface is studied based on the simulation analysis and experiments analysis, so to have adhering failure analysis of the tool-chip. The comprehensive theoretical analysis is done, and the critical adhering condition of the tools-chip under the condition of the extremely heavy cutting is established, and the verification analysis on it is done combined with the experimental test data. The preventive measures are provided from the aspects of the technical means and optimization of the process parameters. The research results show that the coupling impact of the fluctuant heat and mechanical load is the main factor that leads to the adhering of the tool-chip generating in the cutting area, and the adhering degree is connected with the size of stress between the tool and work-piece material contact area.
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    Design and Force Control of an Underactuated Robotic Hand for Fruit and Vegetable Picking
    JIN Bo;LIN Longxian
    Chinese Journal of Mechanical Engineering    2014, 50 (19): 1-8.  
    Abstract12330)      PDF(pc) (627KB)(3406)       Save
    To achieve non-destructive fruit and vegetable picking, an end-actuator with a simpler and more versatile structure is designed based on underactuated principle. The underactuated mechanism refers to machine that has fewer drivers compared with the number of degrees of freedom. The robotic hand designed by adopting the underactuated principle is simpler and more reliable. Due to simple structure and better adaptability to shape of objects, the robotic hand can fold the object completely with its fingers. Non-destructive harvesting is achieved by using a closed-loop force-feedback control algorithm which controls the maximum contact forces. Based on this design idea, a three-finger gripper which is driven by only one motor is designed. Through theoretical analysis, mechanism design and modeling, and structural optimization, the final model size is determined and physical production is completed. A control circuit combined with force-feedback control is designed for grasping experiments. The experimental results show that the robotic hand can achieve the desired grasping function, maximum contact force control and has such features as simple and reliable control, stable grasping and non-damaging.
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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
    Abstract6165)      PDF(pc) (821KB)(15913)       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.
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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
    Abstract4445)      PDF(pc) (1101KB)(6920)       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.
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    High-speed Point-to-point Trajectory Planning of a 2-DOF Cable Driven Parallel Manipulator
    ZHANG Wenjia, SHANG Weiwei
    Journal of Mechanical Engineering    2016, 52 (3): 1-8.   DOI: 10.3901/JME.2016.03.001
    Abstract4224)      PDF(pc) (387KB)(2242)       Save
    Suitable trajectory planning methods can improve the smoothness, rapidity and efficiency of motion control of robot. Polynomial and trigonometric formulation are often adopted to realize smooth trajectory planning for cable-driven parallel manipulator, while the two approaches are complex and have weak rapidity. A new combined planning method with S-trapezoid curve is proposed for the point-to-point motion of planar 2-DOF cable-driven parallel manipulator, and the unilateral constraints on cable tensions are computed according to the dynamic model. Considering the specific point-to-point trajectory includes a list of target points that must be reached in sequence, thus it can be divided into the initial segment, the middle segment and the final segment. And then the combined planning method with S-trapezoid curve is applied to plan the velocity curve of the three segments. The acceleration is zero at the initial and final point, while it’s nonzero at the middle points. The dynamic trajectory planning can be realized with this state. The proposed planning method is implemented on a 2-DOF cable-driven parallel manipulator, and the simulation results indicate that the unilateral constraints on cable tensions could be satisfied and the acceleration curve is simple first-order curve, thus high-speed point-to-point motion could be realized.
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    Grasping Performance Analysis of a Biped-pole-climbing Robot
    JIANG Li, GUAN Yisheng, ZHOU Xuefeng, YANG Tieniu, SU Manjia WU Hongmin
    Journal of Mechanical Engineering    2016, 52 (3): 34-40.   DOI: 10.3901/JME.2016.03.034
    Abstract4055)      PDF(pc) (791KB)(1926)       Save

    Biped climbing robots have become an important class of climbing robots, where the reliability of pole-grasping with the end grippers is a basic and critical requirement for safe climbing, and the analysis of grasping reliability is a key issue. A biped pole-climbing robot, the Climbot developed is first introduced. The problem of force-closure of grasping with the robot climbing on a round pole is presented and proved. The dynamic loads generated onto the base gripper when the robot climbs in different climbing gaits are analyzed, and the balance models are proposed, respectively, in 2D and 3D cases. Based on these models, the effect of geometric parameters of the gripper on grasping performance is analyzed. The correctness of the models and effectiveness of the corresponding analysis are verified with several grasping experiments. The results are helpful and valuable to gripper design for biped climbing robots and guarantee of grasp reliability.

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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
    Abstract3859)      PDF(pc) (577KB)(3989)       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.
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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
    Abstract3320)      PDF(pc) (359KB)(4179)       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.
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    Multi-body Dynamic Modeling and Mobility Simulation Analysis of Deep Ocean Tracked Miner
    ZHANG Tao, DAI Yu, LIU Shaojun, CHEN Jun, HUANG Zhonghua
    Journal of Mechanical Engineering    2015, 51 (6): 173-180.   DOI: 10.3901/JME.2015.06.173
    Abstract3257)      PDF(pc) (1046KB)(1040)       Save
    Deep seafloor extremely soft cohesive sediment is completely different from land surface soils, which need high requirements for structure design and mobility performance of the seafloor operated machine. According to the physical and mechanical properties of the seafloor sediment, laboratory simulated sediment is prepared. Based on the theory of terramechanics, mechanics experiments on the simulated tracks and simulated sediment interactions are performed. The normal pressure-sinkage and horizontal shear stress-shear displacement mathematical relationships are obtained. According to the detailed structure design parameters of the deep seafloor tracked miner, its multi-body dynamic model is built by the dynamic modeling and simulation code RecurDyn/Track. Application of the mechanics relationships of the seafloor sediment obtained from experiments, user-written subroutines are compiled with C language. Based on the secondary development for RecurDyn/Track, the development of the deep seafloor sediment mechanics model in the RecurDyn/Track is realized. Various dynamic simulations of the tracked miner on the seafloor special sediment are carried out. The mobility performance of the miner are analyzed and evaluated, which lay the foundations for the structure design optimization, mobility performance evaluation and moving control of the practical deep seafloor tracked miner.
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    Multi-UAV Finite-time Ring Formation Control Considering Internal Collision Avoidance
    LIU Yunping, JIANG Zhangsheng, ZHANG Tingting, ZHAO Zhongyuan, DENG Zhiliang
    Journal of Mechanical Engineering    2022, 58 (1): 61-68.   DOI: 10.3901/JME.2022.01.061
    Abstract3248)      PDF(pc) (2644KB)(1326)       Save
    Aiming at the problem that multi-UAV system is prone to collision when using finite-time ring formation algorithm to perform ring formation tasks, this paper proposes a multi-UAV finite-time ring formation control algorithm based on improved artificial potential field method. A set of auxiliary potential fields perpendicular to the direction of obstacle movement are introduced, which avoids the internal collision of multi-UAV in the process of rapid formation, and solves the problem that traditional artificial potential field method is easy to fall into local optimal solution. In order to verify the effectiveness of the proposed algorithm, computer simulation experiments are carried out under the same parameters such as the initial position of the UAV, the influence range of the potential field and the surrounding radius. The results show that the proposed algorithm can effectively avoid the collision of multiple UAVs in the ring formation process. In order to further verify the practicability of the algorithm, this paper uses three"X"rotor UAVs with axial distance of 450 mm to carry out physical experiments. The experimental results show that the proposed algorithm has good collision avoidance effect when completing the ring formation of multiple UAVs in limited time.
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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
    Abstract3193)      PDF(pc) (2452KB)(92357)       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.
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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
    Abstract2832)      PDF(pc) (1505KB)(153498)       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.
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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
    Abstract2826)      PDF(pc) (2243KB)(9696)       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.
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    Soft Robotics:Structure, Actuation, Sensing and Control
    WANG Tianmiao, HAO Yufei, YANG Xingbang, WEN Li
    Journal of Mechanical Engineering    2017, 53 (13): 1-13.   DOI: 10.3901/JME.2017.13.001
    Abstract2761)      PDF(pc) (9902KB)(2616)       Save

    Soft robots primarily consist of soft materials which can generate continuous deformation. Soft robots are considered to be safer, more adaptable and compliant than the rigid robots. These advantages lead them to have potential applications in the human-robot interaction, grasping complex and fragile objects, and navigate through narrow space for operation tasks. In the review paper, the soft robots have been divided into three categories: the cable-driven and traditional pneumatic soft robots, the hyperelastic material soft robots, and the smart material soft robots. While from the scientific perspective, the principal challenges of the soft robotics are summarized from the following three aspects: the structure and locomotion, the actuation and fabrication, as well as the sensing and control. The potential applications of the soft robots in areas including manipulation, medical and wearable devices were also reviewed. In the end, the variable stiffness, the integration of actuation sensing and control of soft robots are proposed as the promising potential research directions.

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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
    Abstract2717)      PDF(pc) (840KB)(86917)       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.
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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
    Abstract2716)      PDF(pc) (1232KB)(4037)       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.

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    Driverless Walking Method of Electric Construction Machinery Based on Environment Recognition
    LIN Tianliang, YAO Yu, XU Wenjie, FU Shengjie, REN Haoling, CHEN Qihuai
    Journal of Mechanical Engineering    2021, 57 (10): 42-49.   DOI: 10.3901/JME.2021.10.042
    Abstract2714)      PDF(pc) (996KB)(1829)       Save
    Driverless technology is the technology that the vehicle is completely controlled by the driverless system to complete the driving task under any environment and road conditions. The operating environment of construction machinery is harsh, and some tasks are highly repetitive; driverless technology of construction machinery can effectively reduce the operation risk of drivers, save labor costs and improve operation efficiency. To realize the driverless electric construction machinery, according to the characteristics of construction machinery, an end-to-end decision system based on monocular camera is adopted. Considering the operation scenarios particularity, a semantic segmentation network is proposed that can fuse the spatial features acquired by the camera in real time, shorten the image processing time, and reduce the system memory occupation. Through testing in the Udacity, it is found that the system can smoothly complete the driving simulation task. To validate the system, an electric crawler excavator is chosen as the system’s experimental platform. The driverless experiments is carried out on an unstructured road. It can safely complete straight-line driving and turning tasks, and it has good control characteristics when returning to the center at a small angle, lays the foundation for the multi-camera construction machinery complex working condition recognition and decision system in addition.
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    Simulation Analysis and Experimental Research on the Movements of Biomimetic Fin
    LIU Fangfang;YANG Canjun;SU Qi;WANG Donghai;ZHANG Yizhong
       2010, 46 (19): 24-29.  
    Abstract2620)      PDF(pc) (2747KB)(657)       Save
    Researchers Pay more and more attention to the biomimetic underwater propulsive technologies, especially to the research on the robotic fish. To improve the performances of the propulsion system based on long flexible undulating fin, a method of combination of caudal fin and long flexible fin is proposed. The propulsive model of long flexible undulating fin and the propulsive model of composite fin are introduced. Comparison and analysis of the results obtained by using a two-dimensional computational fluid dynamics method for rigid caudal fin oscillating model and for long flexible undulating model are emphasized. Experiments which use a simplified particle image velocity method are done for better understanding the fluid mechanism and validating the simulation results. It provides the foundation for further research on the performance of this propulsive system.
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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
    Abstract2492)      PDF(pc) (8545KB)(4633)       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.
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    Research on Product Function Expansion Driven by Text Mining and Patent Data Collaboration
    LIN Wenguang, LIU Xiaodong, XIAO Renbin
    Journal of Mechanical Engineering    2024, 60 (13): 56-70.   DOI: 10.3901/JME.2024.13.056
    Abstract2469)      PDF(pc) (940KB)(1701)       Save
    Function expansion is an important way to achieve innovative product design, and data-drivenis also the key supporting technology for product function expansion. In this context, a product function expansion method driven by text mining and patent data collaboration is proposed and expected to provide a quantitative research method for changing and upgrading existing products. Firstly, the function-structure mapping information of the target product are analyzed, then a partial hypergraph model based on existing network models is proposed to calculate the weight of product's components. Secondly, four extracting product functional and structural knowledge, text data of us patent is retrieved and obtained, then part of speech tagging (POS tagging) and dependency parsing (DP) are used to construct mining rules to extract subject-action-object (SAO) in sentences. Thirdly, patent text is used as the corpus and BERT(Bidirectional encoder representations from transformers) model is utilized to train word vectors as a tool for finding similar structures and functions, then four function expansion strategies combined with collaborative recommendationalgorithms are proposed as follows: other function expansion, similarity function expansion, similar component’s functions expansion, and similar components’ functions expansion based on the target product components; finally, according to the requirements of enterprise, the case of showerhead is applied to verifies thefeasibility and effectiveness of the method.
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    The Research of Geometric Error Modeling of Robotic Machining: I Spatial Motion Chain and Error Transmission
    LI Wenlong, XIE He, YIN Zhouping, DING Han
    Journal of Mechanical Engineering    2021, 57 (7): 154-168.   DOI: 10.3901/JME.2021.07.154
    Abstract2421)      PDF(pc) (7066KB)(2844)       Save
    It is one of the frontier research directions of intelligent manufacturing to use robots as manufacturing equipment executor integrating intelligent vision sensors to realize small margin grinding/milling/cutting/drilling for large and complex parts. At present, the main problem confronting in application is that the machining error is hard to reduce. The study systematically investigates the geometric error modeling and accuracy control of visually-guided robotic machining, where the machining error reduction is regarded as the main objective and the robot/visual sensor/workpiece/tool are regarded as the main targets. The first I part introduces the research status of geometric error modeling and parameter identification, studies the spatial motion chain and metric index definition of robotic machining, and derives the static error (originating from workpiece/tool pose error) transmission model as well as dynamic error (originating from joint kinematic error and joint weak stiffness) transmission model. The second II part builds the objective function and calculation method of accurate identification for hand-eye/workpiece/tool pose parameters, and proposes a general pose optimization model of robotic machining (grinding/milling/cutting/drilling) for overall error control, where the joint kinematic error and weak stiffness deformation are both considered.
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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
    Abstract2403)      PDF(pc) (241KB)(4488)       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.
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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
    Abstract2344)      PDF(pc) (745KB)(20969)       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.
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    Review and Prospect of Micro-nano Vibration Energy Harvesters
    QI Youchao, ZHAO Junqing, ZHANG Chi
    Journal of Mechanical Engineering    2020, 56 (13): 1-15.   DOI: 10.3901/JME.2020.13.001
    Abstract2336)      PDF(pc) (246984KB)(2942)       Save
    Harvesting vibration energy, which is widely distributed in the ambient environment, such as human motions, machine vibration, breeze blowing, water ripple and sound vibration, is of great significance for self-powering of electronics. The working mechanisms and current research progress of micro-nano vibration energy harvesters based on electromagnetic, piezoelectric, triboelectric are elaborated. The characteristics and existing challenges are summarized. The development prospect of the micro-nano vibration energy harvesters is finally expected.
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    The Current Research Status and Development Strategy on Biomimetic Robot
    WANG Guobiao, CHEN Diansheng, CHEN Kewei, ZHANG Ziqiang
    Journal of Mechanical Engineering    2015, 51 (13): 27-44.   DOI: 10.3901/JME.2015.13.027
    Abstract2297)      PDF(pc) (8055KB)(3595)       Save
    Bionic robots are good performance mechanical and electrical systems which imitate biological structures and motion characteristics of organisms according to the principles of bionics. They have shown their potential use in the dangerous conditions to human beings, such as anti-terrorism, space exploration and rescue. The bionic robots can be divided into three types according to their work conditions, such as the land bionic robots, the air bionic robots, and the underwater bionic robots. The developments of the bionic robots have experienced three stages, such as original exploration, imitation of the biological prototypes’ appearances and motions, mechanical and electrical systems with partial biological properties. The research status at home and abroad of these three types robots is discussed. And several problems of the researches are found after analysis, such as the lack of the biological motion mechanism researches, the traditional construction, material, driving and controlling mode, and the low efficiency of the power, leading to the difference between robots and creatures. These problems make the bionic robots similar in shape to the creatures but very different in essence. So the bionic robots now days are absence of effective applications. The development trend is pointed out that the bionic robots are developing towards lifelike system, including moving toward the rigid-flexible mechanism, integration of the bionics construction, material and driver, neuron fine control, and the efficient power transformation.
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    Coupling Vibration Analysis for Planetary Gear System Considering Flexible Structure
    WEI Jing, ZHANG Aiqiang, QIN Datong, SHU Ruizhi
    Journal of Mechanical Engineering    2017, 53 (1): 1-12.   DOI: 10.3901/JME.2017.01.001
    Abstract2283)      PDF(pc) (3009KB)(1956)       Save
    Aimed at the problems of lower calculation accuracy of lumped mass method and large-scale computing, difficult post processing of finite element model, a novel coupling vibration analysis method for multistage planetary gear system is presented. The various components in planetary gear system are divided into three shaft models, which are simple shaft unit, planet carrier shaft unit and ring gear shaft unit, according to the structure characteristics of planetary gear system. Different types coupling dynamics model are established for planetary gear system. The results indicate that, the dynamic meshing force deviations obtained by shafting element method are almost same as that by the lumped mass method under the circumstance of lower rotation speed. But the dynamic meshing force and the resonance frequencies are both slightly lower with the increasing of speed. For a same input speed, the dynamic meshing force deviation is increasing with the thickness of ring gear, but the change tendency of the quantity is gradually decreasing. In all flexible structures, flexible shaft has a largest influence and planet carrier has a minimal impact to the vibration of the system. The gear meshing frequency in multi-stage planetary gear system are coupled with each other and become the excitation frequency of the system, and the mesh frequency of high speed stage is main excitation frequency of system. The vibration energy of the system is not only transmitted along the power flow direction but also reverse the direction of power flow transmission.

     

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    Smooth Interpolation of Short Lines in Five-axis CNC Machining
    ZHAO Jianhua, ZHU Bei, LIU Fang, TAN Yundong, FAN Liuqun, GU Xianjie, HUANG Wei
    Journal of Mechanical Engineering    2016, 52 (12): 1-8.   DOI: 10.3901/JME.2016.12.001
    Abstract2274)      PDF(pc) (475KB)(867)       Save
    In the programming of five-axis machining, computer aided manufacturing system manufacture usually uses lines instead of curves while surface machining. A large number of micro G01 straight line segments are used to machine surface, sharp creases will appear on surface of workpieces with large radius of curvature, which results in bad surface machining quality of workpieces. In order to improve the surface quality of workpieces machined by five-axis CNC machining system, a micro-line smooth interpolation algorithm for five-axis CNC machining is presented. In view of the dimensional difference of cutter axis vectors, our algorithm identifies discontinuous and continuous micro-line blocks of cutter axis vectors machining regions through the length of linearity axis, the angular variation of rotation axis and the intersection angle of linearity axis between adjacent command points. For the discontinuous micro-line blocks of machining regions, direct interpolation is conducted to guarantee the processing precision based on original lines and the rotation axis. For the continuous micro-line blocks of machining regions, get node parameters using five dimensions variables, least square method is used to correct command points in an allowed error range; Second-order tangent vectors of corrected command points are calculated by using four continuous corrected command points, cubic spline curves with continuity of second order are obtained according to corrected command points, node parameters and second-order tangent vectors; Real-time interpolation calculation is conducted on the second order smooth curves, machine tool is controlled to five-axis machining. Experimental results demonstrate that fitted path by smooth interpolation of micro lines in five-axis CNC machining is more close to the original surface model, the surface quality of smoothing pieces is better than the non-smoothing, our algorithm can improve the free curved surface quality of five-axis.
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    Overview of the Artificial Muscle Actuators
    XING Zhiguang, LIN Jun, ZHAO Jianwen
    Journal of Mechanical Engineering    2021, 57 (9): 1-11.   DOI: 10.3901/JME.2021.09.001
    Abstract2266)      PDF(pc) (164819KB)(3806)       Save
    Artificial muscle usually refers to a flexible material or device that can perform movements such as extension, expansion, bending, and twisting under external physical or chemical stimulation and do work to external object. The artificial muscle can greatly improve the robot's flexibility and adaptability, and human-machine interaction. The development of artificial muscles has a history of more than sixty years, and the methods to stimulate them are also various, such as by electricity, by heat, by internal pressure, etc. This research attempts to give a review of artifical muscles in driving principle, performances, applications and development trends, with a view to provide references and comparisons for roboticists and other researchers who are interesting in it.
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    Review of Biomimetic Mechanism, Actuation, Modeling and Control in Soft Manipulators
    YAN Jihong, SHI Peipei, ZHANG Xinbin, ZHAO Jie
    Journal of Mechanical Engineering    2018, 54 (15): 1-14.   DOI: 10.3901/JME.2018.15.001
    Abstract2218)      PDF(pc) (721KB)(2808)       Save
    Soft manipulators are new type of machine mainly made of soft materials. They possess the characteristics of high flexibility, good adaptability to complex environment and safely human-machine interactivity. New soft material and fabrication, the variable stiffening, the flexible sensor are proposed as the key technology and the promising potential research directions of soft manipulators. The research involves a combination of material science, bionics, mechanics and sensor technology. And it provides theoretical and technical guidance for application of soft materials and bionic research. The soft manipulators have been intensively studied for their wide application prospects in the fields of industrial production, minimally invasive surgery, rescue, Nursing Gerontology and so on. The review of existing soft manipulators in terms of bionic principle, actuation, stiffening methods, modeling and control is presented. The bionic mechanism from octopus arms and elephant trunks is introduced. Soft manipulators are summarized as FEA, TDA, PAM, SMA, EAP and hybrid mode by their actuating mechanisms. The methods of stiffening are summarized as antagonistic, jamming and phase change. The common modeling methods and control strategies are also introduced. The difficulties, current issues and possible solutions are discussed. The lack of repeatability, precision, lower output force, modeling and control method can be summarized as limiting factors for their applications. The key technology and future development include the preparation and molding technology, rigid flexible combination/variable stiffness robot, flexible sensor technology and so on.
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    Dynamic Performance Analysis of Jack-up Platform’s Jacking System with Staggering Tooth
    XU Changhang;LÜTao;CHEN Guoming;YIN Shumeng
       2014, 50 (19): 66-72.  
    Abstract2209)      PDF(pc) (1010KB)(544)       Save
    Rack and pinion jacking system is an important load transmission and bearing device for jack-up platform. Contact stress generated by the meshing between rack and pinion, together with vibration caused by the stiffness excitation, are two important factors that affect the transmission performance and service life of the jacking system, so it has great engineering significance to improve its dynamic performance by optimized structural design and simulation analysis. Through setting appropriate phase differences between the pinions, the staggering tooth meshing of pinion is realized and the bearing performance and dynamic characteristics of the mechanism are improved effectively. In terms of staggered tooth meshing optimization scheme, the finite-element analysis for staggered tooth meshing process and normal meshing process of rack and pinion are done, and the improvements of staggered tooth meshing optimization to the transmission mechanism strength and time-varying stiffness are verified. The modal characteristics, stationarity and synchronicity of the rack and pinion system during meshing process and the uniformity of pinions’ load distribution are also compared. The results show that the contact stress and bending stress of the rack and pinion pinions with staggering tooth are smaller, and gears’ stiffness step value is significantly reduced. At the same time, the rack and pinion pinions with staggering tooth have good performances in the dynamic stationarity and synchronicity and the loads distribution. Pinion’ staggering tooth meshing can improve the bearing capacity and motion performance effectively, which is important for optimization design of jack-up’s jacking system.
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    Deep Reinforcement Learning-based Integrated Control of Hybrid Electric Vehicles Driven by High Definition Map in Cloud Control System
    TANG Xiaolin, CHEN Jiaxin, GAO Bolin, YANG Kai, HU Xiaosong, LI Keqiang
    Journal of Mechanical Engineering    2022, 58 (24): 163-177.   DOI: 10.3901/JME.2022.24.163
    Abstract2086)      PDF(pc) (1390KB)(1018)       Save
    In the context of the development of intelligence, connectivity, and new energy, the automotive industry combines computer, information communication, artificial intelligence(AI) to achieve integrated development. Based on the new generation of information and communication technology——cloud control system(CCS) of intelligent and connected vehicles(ICVs), the cloud-level automatic driving of new energy vehicles is realized driven by connected data, which provides innovative planning and control ideas for vehicle driving and power systems. Firstly, based on the resource platform of CCS, the latitude, longitude, altitude, and weather of the target road are obtained, and a high definition(HD) path model including slope, curvature, and steering angle is established. Secondly, a deep reinforcement learning(DRL)-based integrated control method for hybrid electric vehicle(HEV) drive by the HD model is proposed. By adopting two DRL algorithms, the speed and steering of the vehicle and the engine and transmission in the powertrain are controlled, and the synchronous learning of four control strategies is realized. Finally, processor-in-the-loop(PIL) tests are performed by using the high-performance edge computing device NVIDIA Jetson AGX Xavier. The results show that under a variable space including 14 states and 4 actions, the DRL -based integrated control strategy realizes the precise control of the speed and steering of the vehicle layer under the high-speed driving cycle of 172 km, and achieves a fuel consumption of 5.53L/100km. Meanwhile, it only consumes 104.14s in the PIL test, which verifies the optimization and real-time performance of the learning-based multi-objective integrated control strategy.
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    Remaining Useful Life Estimation of Mechanical Systems Based on the Data-driven Method and Bayesian Theory
    ZHAO Shenkun, JIANG Chao, LONG Xiangyun
    Journal of Mechanical Engineering    2018, 54 (12): 115-124.   DOI: 10.3901/JME.2018.12.115
    Abstract2076)      PDF(pc) (319KB)(1101)       Save
    A novel remaining useful life(RUL) estimation method is proposed based on the data-driven method and Bayesian theory for the remaining useful life estimation of complex mechanical systems. Firstly, the condition monitoring data of same or similar systems are fused to form the Health Index indicating the degradation degree of systems and the state model by the data-driven method. Then, a Bayesian model of the state model parameters is built on Bayesian theory. With the on-line condition monitoring data of system to be estimated and the Bayesian model, the model parameters are updated by Markov Chain Monte Carlo (MCMC) and the RUL of system is estimated. At last, a turbofan engine case is used to show the effectiveness of the present method.
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    Research Status and Development Trend of Intelligent Emergency Rescue Equipment
    DONG Bingyan, ZHANG Ziqiang, XU Lanjun, ZHU Zihu, YANG Qi, ZHAO Jing, LI Dewu, CHEN Shujun
    Journal of Mechanical Engineering    2020, 56 (11): 1-25.   DOI: 10.3901/JME.2020.11.001
    Abstract2060)      PDF(pc) (41350KB)(2418)       Save
    In the disaster scenes, such as earthquake and fire, the urgency of the rescue mission highlights the urgent need for intelligent emergency rescue equipment. The use of intelligent emergency rescue equipment can greatly improve the combat effectiveness of the rescue team, and deal with various disasters quickly and efficiently, especially the sudden and serious disasters. It can reduce the casualties and property losses, which is of great significance for its research. According to the working environment and use, intelligent emergency rescue equipment can be divided into air, land, underwater and common rescue equipment. On the basis of summarizing the research status of intelligent emergency rescue equipment and key technologies, it is found that there are still some problems in the current research, such as lack of efficient mechanism design method, poor reliability of equipment, low intelligence, low maturity of communication technology and poor man-machine friendliness, which lead to the low application of intelligent emergency rescue equipment in large-scale disaster field. Intelligent emergency rescue equipment will develop in the direction of advanced structure design, reliable motion performance, high intelligence, fast and accurate communication and good human-computer interaction.
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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
    Abstract1994)      PDF(pc) (5623KB)(94381)       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.
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    Review of Soft-bodied Manipulator
    ZHANG Jinhua, WANG Tao, HONG Jun, WANG Yu
    Journal of Mechanical Engineering    2017, 53 (13): 19-28.   DOI: 10.3901/JME.2017.13.019
    Abstract1976)      PDF(pc) (3786KB)(2719)       Save

    Soft-bodied manipulators are new type of mechanical devices mainly made of soft materials, which possess the characteristics of high flexibility, good adaptation in complex environment and safe human-machine interaction because of the flexibility and passive adaptability of soft materials. The soft-bodied manipulators have been intensively studied and shown great potential applications. The review of existing soft-bodied manipulators in terms of applications, actuation methods, materials and fabrication, modeling and control is presented. The current issues and possible solutions are also discussed. Soft-bodied manipulators are an important branch of soft robotics, which involves a combination of material science, mechanics, chemistry, mechanical design and manufacture, electronic and control science and biology. The study of soft-bodied manipulators will greatly enrich people’s understanding of the complex and rich characteristics of soft materials, and will provide theoretical and technical guidance for integrating soft materials into design of products.

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    State-of-art of Metamaterials with Negative Poisson's Ratio
    YU Jingjun, XIE Yan, PEI Xu
    Journal of Mechanical Engineering    2018, 54 (13): 1-14.   DOI: 10.3901/JME.2018.13.001
    Abstract1965)      PDF(pc) (751KB)(1694)       Save
    Since the concept of metamaterials is firstly proposed in the early 21st century, it has gradually developed into an important branch of new material technology. In recent years, dozens of metamaterials with diverse functions have emerged in endlessly in various fields. A comprehensive overview of metamaterials involved in acoustics, optics, thermology, mechanics and electromagnetics is stated. Focusing on metamaterials with negative Poisson's ratio, a research progress about the design of negative Poisson's ratio unit cells (including re-entrant structure, rotating polygons, chiral structure, etc.) is systematically reviewed in the perspective of their deformation mechanism. The thermal and acoustic metamaterials based on negative Poisson's ratio unit cells are detailed investigated from functional principles to basic properties. Prospects to the upcoming challenges and development trends of negative Poisson's ratio metamaterials are made.
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