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Yaw Rate Calculation and Vehicle Stability Control Considering Tire Nonlinearity MIN Delei, TONG Ruting, WEI Yintao China Mechanical Engineering    2023, 34 (21): 2521-2530.   DOI: 10.3969/j.issn.1004-132X.2023.21.001 Abstract （595）      PDF（pc） （7794KB）（948）       Knowledge map    Save Based on the nonlinear tire model， an accurate yaw rate calculation method was proposed to calculate the accurate yaw rate and applied to vehicle stability control. Tire nonlinearity was characterized by the brush model. The equivalent stability factor was obtained by perturbation analysis， and the accurate analytical solution of the yaw rate was obtained. The analysis of the existence of analytical solutions indicates that tire nonlinearity may impact vehicle stability. Real vehicle tests and control simulations based on vehicle models show that considering tire nonlinearity may effectively improve the calculation accuracy of the steady-state yaw rate as the target parameter， and improve the effect of vehicle stability control.  Reference | Related Articles | Metrics | Comments（0）

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Research Progresses of Superhydrophobic Surface Processing Technology and Abrasion Resistance HUANG Yun, HUANG Jianchao, XIAO Guijian, LIU Shuai, LIN Ouchuan, LIU Zhenyang China Mechanical Engineering    2024, 35 (01): 2-26.   DOI: 10.3969/j.issn.1004-132X.2024.01.001 Abstract （915）      PDF（pc） （50387KB）（826）       Knowledge map    Save The abrasion resistance of currently prepared superhydrophobic surfaces is generally poor, which limite the applications in various fields. Studied results found that micro-nano structure and low surface energy were the key factors to achieve superhydrophobic properties. Firstly, based on the mechanism of superhydrophobic surface, the superhydrophobic surface texture was summarized, aiming to solve the wear-prone challenge of micro-nano structures by optimizing the surface texture. Secondly, the superhydrophobic surface processing technology was summarized, and measures to reduce surface energy were analyzed in terms of cost and efficiency which might provide ideas for expanding the superhydrophobic surface processing system. Then, the means of analyzing the abrasion resistance of superhydrophobic surfaces were concluded in detail and the methods of improving the abrasion resistance of superhydrophobic surfaces were described. Finally, the future development prospects of abrasion resistant superhydrophobic surfaces was prospected, with a view to promote the large-scale applications of superhydrophobic surfaces in engineering. Reference | Related Articles | Metrics | Comments（0）

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A Topology Optimized Design Method for High-performance Structures with Fluid-thermal-mechanics Coupling LI Rongqi, YAN Tao, HE Zhicheng, MI Dong, JIANG Chao, ZHENG Jing China Mechanical Engineering    2024, 35 (03): 487-497.   DOI: 10.3969/j.issn.1004-132X.2024.03.011 Abstract （840）      PDF（pc） （5000KB）（745）       Knowledge map    Save The rapid advancement of topology optimization and additive manufacturing technology provided efficient methods for designing and manufacturing high-performance complex equipment. However, current topology optimization techniques for high-performance structures only considered the design of thermal-mechanics coupling or fluid-thermal coupling, and were mostly limited to simple structures. The design under the combined effects of fluid-thermal-mechanics fields was not considered, which restricted the enhancement of structural performance. This paper tackled the challenge of designing high-performance complex structures under multi-physics fields, encompassing fluid-thermal-mechanics interactions. A topology optimization method was proposed to enhance the ability to withstand temperature of intricate structures. Firstly, the governing equations of flow field, temperature field and structural displacement field were introduced to provide a unified description of the fluid-solid materials within the computational domain. Secondly, the topology optimization model was formulated with fluid-thermal-mechanics coupling. The objective function was set to minimize the average temperature, while flow energy dissipation and structural compliance served as constraint functions. Sensitivity analysis of design variables was carried out by using a combination of the variational method and Lagrangian function. Finally, the established topology optimization model was applied to the structural design of a turbine, resulting in a structure suitable for additive manufacturing with excellent heat dissipation performance and well-balanced flow channel distribution. Reference | Related Articles | Metrics | Comments（0）

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Green Scheduling Optimization Method of Special Vehicle Body-in-White Prototype Shops Considering Equipment Preventive Maintenance LI Xixing, ZHOU Wenlong, TANG Hongtao, WU Rui, China Mechanical Engineering    2023, 34 (15): 1832-1847.   DOI: 10.3969/j.issn.1004-132X.2023.15.008 Abstract （435）      PDF（pc） （9794KB）（720）       Knowledge map    Save A typical multi-objective flexible job-shop green scheduling model was established， and the makespan， total energy consumption of equipment and total smoke emission were taken into consideration. And an improved artificial bee colony algorithm was designed to solve this model. Firstly， according to the characteristics of periodic power attenuation of laser equipment， a preventive maintenance strategy that could distinguish laser equipment from ordinary mechanical equipment was proposed to reduce the makespan and the frequency of equipment failure. Then， a mutation method was designed based on equipment allocation and power selection， which could improve the local search ability of the algorithm. A selection method was introduced based on crowded distance in the follow bee search stage for population regeneration to obtain high-quality individuals. Finally， the comparison experiments were carried out based on the expanded common benchmark. Meanwhile， the effectiveness and feasibility of the model and algorithm were verified through the production case of a special vehicle body-in-white prototype workshop in an automotive equipment manufacturing enterprise.  Reference | Related Articles | Metrics | Comments（0）

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Patent Data Driven Product Innovation Design Based on SAO LIN Wenguang, LIU Xiaodong, XIAO Renbin China Mechanical Engineering    2023, 34 (15): 1765-1777.   DOI: 10.3969/j.issn.1004-132X.2023.15.001 Abstract （592）      PDF（pc） （5241KB）（703）       Knowledge map    Save The patent data-driven product innovation design method was proposed based on SAO using big data mining technology. Firstly， semantic dependency parsing was used to mine the SAO structure and interaction relationships among product components from patent text databases. Subsequently， a complex network knowledge model was constructed for product systems， and the constraint coefficients of components in the complex network were calculated by using structural hole theory to identify the innovative target components. Then， the semantic similarity coefficients of components were calculated using Word2Vec， and the functional similarity coefficients were calculated using SAO similarity algorithm. And the recommendation algorithm and combination matrix were integrated to achieve structural innovation， functional innovation， and functional optimization. Finally， a typical bathroom shower product was taken as an example to demonstrate the method in detail， which fully verifies the effectiveness and progressiveness of the method.  Reference | Related Articles | Metrics | Comments（0）

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Study on Influences of Ni Content, Nitriding Hardening Depth, and Shot Peening on Bending Fatigue Performance of 42CrMo Gears WU Zhongrui, CHEN Difa, WU Jizhan, YANG Yudian, LIU Huaiju China Mechanical Engineering    2024, 35 (03): 394-404.   DOI: 10.3969/j.issn.1004-132X.2024.03.002 Abstract （413）      PDF（pc） （9652KB）（700）       Knowledge map    Save  Single tooth bending fatigue tests were conducted on 42CrMo gears with different combinations of Ni content, nitriding hardening depth, and shot peening. The effectiveness of different process combinations on improving the bending fatigue limit of gears was investigated, providing process guidance for gear fatigue resistance manufacturing. Additionally, the contribution of surface hardness, nitriding hardening depth, surface residual stress, and Ni content to the bending fatigue limit of gears with different process combinations was analyzed using the random forest algorithm. A multiple regression model considering surface hardness, nitriding hardening depth, surface residual stress, and Ni content was established to predict the bending fatigue limit of gears. Comparing the predicted values with experimental values, the maximum error is controlled within 7.80%, providing a theoretical basis for the rapid and low-cost assessment of gear bending fatigue limit in engineering applications. Reference | Related Articles | Metrics | Comments（0）

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A Bionic Bouncing Robot Design and Made Inspired by Locusts WANG Kaidi, CHEN Suifan, TANG Wei, QIN Kecheng, LI Qipeng, YANG Zhan, LIU Yang, ZOU Jun China Mechanical Engineering    2023, 34 (24): 2946-2951.   DOI: 10.3969/j.issn.1004-132X.2023.24.006 Abstract （711）      PDF（pc） （3896KB）（593）       Knowledge map    Save  In order to improve the mobility of small robots and increase the diversity of movement gait, a jumping robot imitating locust bouncing was designed based on the body structure and movement mechanism of locusts, and the main body was made by 3D printing. And for reproducing the locusts bouncing mechanism, a torsion spring was installed at the joints of the robot body to simulate the locusts SLP(semilunar energy storage) mechanism. When the robot met an obstacle, the torsion spring released the stored elastic potential energy and generated a ground reaction force, which realized the robots bouncing and thus crossed the obstacle. The robot might imitate the locusts jumping actions, and simulate the locusts flexibility to a certain extent. It was experimentally verified that the robot has good jumping performance, with a jumping distance of up to 100 cm and a jumping height of up to 120 cm which is about 15 times of the own length. Reference | Related Articles | Metrics | Comments（0）

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Flexible Skin-shaped Optical Fiber Reconstruction Method for Allomorphic Aircrafts WANG Yuanfeng, ZHU Lianqing, HE Yanlin, ZHOU Kangpeng, China Mechanical Engineering    2023, 34 (15): 1873-1880.   DOI: 10.3969/j.issn.1004-132X.2023.15.012 Abstract （452）      PDF（pc） （5104KB）（532）       Knowledge map    Save  Large-scale deformation monitoring of allomorphic aircrafts in the flight processes was a research difficulty and hot spot in the aerospace field， and the existing methods were difficult to achieve high-precision three-dimensional deformation monitoring during the flight of the aircrafts. Aiming at this problem， a flexible skin-shaped fiber reconstruction method for a variant aircraft was proposed based on optical fiber sensing to achieve deformation monitoring during flight of the aircrafts. Based on the principle of fiber grating strain sensing， the relationship between fiber strain and curvature was derived， the conversion matrix between the local coordinate system and the global coordinate system of optical fiber sensing was established， the conversion of fiber measurement point coordinates to the global coordinate system was realized， and the three-dimensional deformation reconstruction algorithm was studied based on curve fitting according to the spatial curve fitting method. At the same time， in order to reduce the measurement errors of the fiber optic sensors， the calibration tests of the fiber optic sensors were carried out to obtain the strain sensitivity of the sensors. In order to verify the effectiveness of the proposed method， the three-dimensional deformation reconstruction of flexible skin samples under different curvatures was tested experimentally. Experimental results show that the average error of the shape reconstruction method is as 3.5% and the minimum error is less than 2.1% in the deformation ranges of 0～15.38 m-1 curvature of flexible skin samples. The proposed method has a good application prospect in aerospace and other fields.  Reference | Related Articles | Metrics | Comments（0）

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Study on Force Model and Surface Integrity of Cylindrical Grinding 18CrNiMo7-6 Steels WANG Dong, CHEN Lei, ZHANG Zhipeng China Mechanical Engineering    2024, 35 (03): 381-393.   DOI: 10.3969/j.issn.1004-132X.2024.03.001 Abstract （424）      PDF（pc） （8185KB）（506）       Knowledge map    Save  In order to accurately and effectively control the influences of grinding parameters on grinding force and surface integrity, a three-stage grinding force theoretical model was established based on the plastic deformation, indentation theory and shear strain effect between abrasive particles and materials by analytical method. The brown corundum grinding wheels were selected for grinding experiments to explore the effects of grinding parameters on grinding force and the effects of grinding parameters and grinding force on surface integrity. The optimal processing parameters for cylindrical grinding were obtained through orthogonal experiments of cylindrical transverse grinding. The results show that the average prediction errors of normal and tangential grinding forces in the cylindrical grinding force model are 5.56% and 7.08%, respectively. The radial feed speed of the grinding wheel has the greatest impact on grinding force, followed by grinding width, and the influences of workpiece speed and grinding wheel particle size are relatively small. The radial feed speed and grinding width of the grinding wheel have a significant impact on residual stress, and the particle size of the grinding wheel has the greatest impact on surface roughness. As the grinding force increases, the surface roughness value continuously increases, and the residual stress firstly decreases and then increases. The maximum residual stress value along the depth direction firstly increases and then decreases. Within the parameters taken in the experiments, the distribution range of residual stress is basically 20~40 μm. The optimal combination of processing parameters is a radial feed speed of 0.15 mm/min for the grinding wheel, a workpiece speed of 120 r/min, a grinding width of 10 mm, and a grinding wheel particle size of 80. Reference | Related Articles | Metrics | Comments（0）

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Cross-domain Fault Diagnosis of Bearings Based on Discriminant Feature Extraction and Dual-domain Alignment DONG Shaojiang, ZHOU Cunfang, CHEN Lili, XU Xiangyang China Mechanical Engineering    2023, 34 (15): 1856-1863.   DOI: 10.3969/j.issn.1004-132X.2023.15.010 Abstract （486）      PDF（pc） （4455KB）（504）       Knowledge map    Save  A deep transfer learning method was proposed to address the challenge of inconsistent feature distributions and difficulties in removing noise components in vibration data collected under different operating conditions for rolling bearings. The method utilized a combination of discriminative feature extraction and dual-domain alignment. Firstly， the labeled vibration signals and unlabeled vibration signals were segmented into fixed-length data sets using a data segmentation method. To mitigate the interference of noise signals in practical operating conditions， a channel attention mechanism known as SENet was employed. Additionally， a discriminative loss term was incorporated to assist the feature extractor in extracting features that exhibit discriminative properties. To handle the issue of inconsistent data feature distributions， the MMD was utilized to align the global domain distributions between the source and target domains. Furthermore， conditional adversarial learning techniques were employed to align the sub-domain distributions， resulting in dual-domain alignment. Experimental validation was conducted on two publicly available rolling bearing fault datasets collected under different operating conditions. The results show that the proposed method achieves an average recognition accuracy of over 98%. Comparative analyses with different diagnostic methods further demonstrate the effectiveness and superiority of the proposed method.  Reference | Related Articles | Metrics | Comments（0）

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Inverse Kinematics Solution of Robots Based on IQPSO Algorithm CHEN Zhuofan, ZHOU Kun, QIN Feifei, WANG Binrui China Mechanical Engineering    2024, 35 (02): 293-304.   DOI: 10.3969/j.issn.1004-132X.2024.02.014 Abstract （489）      PDF（pc） （9273KB）（487）       Knowledge map    Save Aiming at the problems of singular pose, non-unique solution and low solution precision in the inverse kinematics solution processes of general robots, an improved quantum particle swarm optimization algorithm was proposed. Firstly, the robot kinematics model was established by using the D-H parameter method, and the minimum pose errors at the end of the manipulators were the main optimization goal, and the constraints of the minimum joint angle changes before and after the movement and the smooth and continuous stroke were added, and the objective function was designed. Secondly, an IQPSO algorithm was designed by using the Levy flight strategy to improve the particle update method, nonlinear dynamic adjust the shrinkage and expansion factors, and using the variable weight method to calculate the optimal average position. Then, the simulation and comparison experiments of three algorithms（IQPSO,APSO,QPSO） were carried out by simulating two different solutions of single point pose and continuous trajectory. The results show that the IQPSO algorithm has the advantages of fast convergence speed and high solution accuracy; finally, the IQPSO algorithm was used in the body of the robot arm for physical verification. The results show that the trajectory composed of interpolation points obtained by the IQPSO algorithm is continuous and smooth, which further proves the stability and feasibility of the algorithm in practical motion control. Reference | Related Articles | Metrics | Comments（0）

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Identification of Position-independent Geometric Errors for Rotary Axes of Five-axis Table-tilting Machine Tools LIANG Xiaobing, LU Yaoan, WANG Chengyong, China Mechanical Engineering    2023, 34 (21): 2585-2591.   DOI: 10.3969/j.issn.1004-132X.2023.21.007 Abstract （475）      PDF（pc） （5263KB）（482）       Knowledge map    Save  PIGEs of rotary axes were the important factors that affected the machining accuracy of five-axis machine tools. Taking AC type five-axis table-tilting machine tools as an example， an identification method of PIGEs of rotary axes was proposed based on the differential evolution algorithm. Firstly， a mathematical model of PIGEs and length change of ball bar was established. The initial PIGEs may be identified by existing methods. Then， an optimization objective function was defined， and the PIGEs of the rotary axes were optimized as a whole by a differential evolution algorithm to improve the identification accuracy of the rotary axes PIGEs. The experimental and simulation results show that the proposed method may effectively improve the identification accuracy of the PIGEs of the rotary axes.  Reference | Related Articles | Metrics | Comments（0）

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Design and Analysis of a Novel Weak-coupling Parallel Hip Exoskeleton with Large Angle of Rotation XU Jilong, LIU Fucai, NIU Yunzhan China Mechanical Engineering    2023, 34 (21): 2540-2547.   DOI: 10.3969/j.issn.1004-132X.2023.21.003 Abstract （427）      PDF（pc） （7047KB）（467）       Knowledge map    Save A novel bio-syncretic hip exoskeleton with large-angle and weak-coupling characteristics was proposed to solve the problems such as small workspace， difficult forward kinematics modeling， and complex control of parallel hip exoskeletons. The detailed structures of two-stage prismatic joint were designed， and the expression for calculating the slope of the groove was obtained. The man-machine complexs forward and inverse position solutions were derived by closing-vector-circle method. The inverse Jacobian matrix was obtained by taking the derivative of the inverse position solution equation. Performance analysis shows that the man-machine complex has the advantages such as large range motion， no internal singularities， good force transfer performance， and easy control. Reference | Related Articles | Metrics | Comments（0）

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Research on Dynamic Modeling and Solving Method of Integrated Transmission System under Time-varying Conditions ZHANG Dingge, WANG Liyong, LI Le, ZHANG Jinle China Mechanical Engineering    2023, 34 (22): 2665-2673.   DOI: 10.3969/j.issn.1004-132X.2023.22.003 Abstract （410）      PDF（pc） （3130KB）（467）       Knowledge map    Save In order to meet the demands of real time monitoring of load characteristics and the demands of health management of the special vehicle integrated transmission system under actual complex conditions， by using the matrix analysis method and numerical solution method of planetary transmission mechanisms， and taking the real vehicle sensor data as the model input， a dynamic model of integrated transmission system was established to rapidly and continuously solve the transmission output speed and torque under time-varying conditions. The kinematic matrix， differential equation and torque balance equation of the planetary transmission mechanisms were constructed. The fast continuous solution method of the dynamic model under time-varying conditions and the method for solving road load under the conditions of missing road load information were proposed. The calculated transmission output speed and torque were compared with the bench test results under the three typical conditions of launching， shifting and acceleration. The results show that the dynamic model may realize the dynamic simulation calculation of the output characteristic of the integrated transmission under the conditions of missing road load information. It provides support for real-time monitoring， dynamic control and intelligent operation and maintenance of special vehicle integrated transmission systems.  Reference | Related Articles | Metrics | Comments（0）

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Research Status and Development Trends of Large Wind Turbine Main Shaft Sliding Bearings ZHU Caichao1, ZHANG Ronghua1, SONG Chaoshen1, TAN Jianjun1, YANG Liang2 China Mechanical Engineering    2024, 35 (10): 1711-1721.   DOI: 10.3969/j.issn.1004-132X.2024.10.001 Abstract （874）      PDF（pc） （4422KB）（459）       Knowledge map    Save The pace of large wind turbine units was accelerating, and the reliability of core components was increasingly important for wind turbine operations. Sliding bearings had the advantages of high load capacity, long life, easy maintenance, scalability and small size, and they had advantages and great potential for the reliable replacement of wind turbine main bearings key components produced at home. The problems of main shaft rolling bearings in high-power wind turbines and the advantages of using sliding bearings on the main shaft were analyzed herein. The technical methods and application status of wind turbine main shaft sliding bearing design, materials, lubrication, and experimental verification were present in detail, and the existing problems of high-power wind turbine main shaft sliding bearings and future development trends were summarized. It is expected to provide reference for the digital design and industrial development of high-power wind turbine main bearings. Reference | Related Articles | Metrics | Comments（0）

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Analysis and Test on Dynamic Transmission Errors of RV Reducers under Load Conditions XU Lixin, XIA Chen, YANG Bo China Mechanical Engineering    2023, 34 (18): 2143-2152.   DOI: 10.3969/j.issn.1004-132X.2023.18.001 Abstract （571）      PDF（pc） （8485KB）（455）       Knowledge map    Save  For the current RV reducer transmission accuracy factory calibration value was detected under no-load conditions, it was difficult to reflect the real accuracy performance under torque loading conditions, in order to effectively reveal the dynamic transmission error characteristics of the RV reducers under the action of the load, a theoretical dynamic model of contact multi-body system of standard RV reducer with two crankshafts was proposed, which took the multi-error factors of geometry and position of key transmission parts into consideration. In order to effectively reveal the dynamic transmission error characteristics of RV reducers under load, during modeling, firstly, the parametric model of the whole reducer was designed and completed for the RV reducer transmission structure characteristics. Secondly, a detailed dynamic contact analysis method was proposed considering involute gear drive of the first stage, cycloidal-pin drive of the second stage, and multiple sets of turning-arm bearings and support bearings. Thus, the dynamic transmission error characteristics of reducer under torque load were discussed taking RV20E as the object. The results show that with the increase of load torque, the transmission error amplitudes of reducer are increasing, but the amplitude growth rate is decreasing. Compared with no-load conditions, the increase of theoretical transmission errors of the reducers under rated torque is as 73.1%, and the increase of experimental transmission errors under rated torque is as 58.9%. Reference | Related Articles | Metrics | Comments（0）

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Product Architectures Evolution and Their Open Design Strategies CHENG Xianfu, ZHANG Zhihong, WANG Chenghui, PAN Yifei China Mechanical Engineering    2024, 35 (01): 109-124.   DOI: 10.3969/j.issn.1004-132X.2024.01.011 Abstract （344）      PDF（pc） （2035KB）（449）       Knowledge map    Save Product architecture represented the arrangements and combinations of physical components. It might promote innovation of product diversity, component sharing, and meet customers personalized needs. Open design might support customers to participate in product development, and open product architecture provided platform strategy for personalized product development. To further study the theory and applications of product architecture, the concept and effect of product architecture were introduced, as well as the characteristics, association and difference between single product architecture, product family architecture and open product architecture were expounded. The evolution processes of product architecture and their internal motivation were analyzed from the aspects of architecture topology, architecture development strategy, architecture organization and management. The concept, connotation, function and mechanism of product architecture were reviewed. The dependence of customers personalized needs, product architecture and enterprises open innovation strategy were discussed, and then open design strategies of product architecture were explored. Reference | Related Articles | Metrics | Comments（0）

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SOC Estimation of Lithium-ion Batterys Based on Second-order Approximation Extended Kalman Filter DUAN Linchao, ZHANG Xugang, ZHANG Hua, SONG Huawei, AO Xiuyi China Mechanical Engineering    2023, 34 (15): 1797-1804.   DOI: 10.3969/j.issn.1004-132X.2023.15.004 Abstract （560）      PDF（pc） （4607KB）（436）       Knowledge map    Save To improve the accuracy of battery SOC estimation， a higher order EKF algorithm was used to estimate SOC. Firstly， the first-order Thevenin equivalent circuit model（ECM） of lithium-ion battery was established， and the function relationship between open circuit voltage（OCV） and SOC was expressed by spline function. In order to more accurately identify the ECM parameters， a new kind of with VFFRLS algorithm was proposed for on-line identification of model parameters. Since the accuracy of the VFFRLS solution depended on the setting of the initial values of the algorithm， the improved particle swarm optimization algorithm was used to obtain the initial parameters of ECM， which helped to obtain more accurate initial values of VFFRLS. Finally， the second-order EKF was employed to estimate the SOC of the batterys to improve the estimation accuracy. Two different datasets were used to demonstrate the universality of second-order EKF estimation SOC. The experimental results indicate that the mean absolute error（MAE） of second-order EKF is within 1% when estimating SOC under different working conditions， which proves the effectiveness of the proposed method.  Reference | Related Articles | Metrics | Comments（0）

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Modeling and Experimental Research of Ground Workpiece Surface Topography after Grinding with Structured Grinding Wheels YI Jun, YI Tao, CHEN Bing, DENG Hui, ZHOU Wei, China Mechanical Engineering    2023, 34 (22): 2711-2720.   DOI: 10.3969/j.issn.1004-132X.2023.22.008 Abstract （447）      PDF（pc） （9016KB）（428）       Knowledge map    Save  The rough surface modeling method was employed to establish the surface topography model of a straight groove structured grinding wheel, considering the influences of structural characteristic parameters on the continuity of the grinding wheel surface through actual measurements. Based on the kinematics relationship between the grinding wheel and workpiece, as well as the trajectory equation of cutting edge, a prediction model for workpiece surface topography after grinding was formulated. Grinding experiments were conducted using both electroplating CBN and brazing CBN straight groove structured grinding wheels. The results show that relative errors between predicted Ra values and experimental ones are below 10%, while relative errors between predicted Rz values and experimental ones are below 12%, thereby validating the accuracy of the prediction model. Furthermore, the influences of various structural parameters on the surface topography of the workpiece were investigated. When the groove width of the grinding wheel remaines constant, an increase in the intermittent ratio of the grinding wheel resultes in an elevation of workpiece surface roughness. Conversely, when the intermittent ratio is held constant, variations in groove width have a minimal effect on workpiece surface roughness. Additionally, it is observed that roughness of the grinding wheel itself is a significant factor determining ground workpiece surface roughness. Among the three characteristic parameters of the grinding wheel surface topography investigated herein, it is observed that the skewness of the grinding wheel surface height exerts the most significant influence on the ground workpiece surface roughness. Reference | Related Articles | Metrics | Comments（0）

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Research Advances in Chatter of Metal Cutting Systems Involving Time Delays REN Yongsheng, YAO Donghui, ZHANG Jinfeng China Mechanical Engineering    2023, 34 (21): 2548-2567,2576.   DOI: 10.3969/j.issn.1004-132X.2023.21.004 Abstract （424）      PDF（pc） （9923KB）（413）       Knowledge map    Save Metal cutting processes typically had distinct characteristics of delayed system.  Chatter phenomenon was a highly complex phenomenon which widely occured in various metal cutting processes.  Chatter prediction in cutting processes was the premise of chatter suppression.  The theoretical method for chatter prediction， in-process recognition techniques for chatter prediction， and influencing factors for metal cutting dynamics were reviewed.  Applications of machine tool structure materials were introduced.  Some problems and research directions in future were proposed.  Reference | Related Articles | Metrics | Comments（0）

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Influences of Horizontal Forced Vibration Finishing on Surface Integrity Parameters of TC4 Titanium Alloys HAN Rui, LI Xiuhong, WANG Jiaming, LI Wenhui, CHENG Siyuan, YANG Shengqiang, China Mechanical Engineering    2023, 34 (17): 2037-2047.   DOI: 10.3969/j.issn.1004-132X.2023.17.003 Abstract （402）      PDF（pc） （7498KB）（411）       Knowledge map    Save  To explore the influences of horizontal forced vibration finishing on the surface integrity of TC4 titanium alloy specimens， a single factor experiment was designed to analyze the effects of main processing parameters on surface roughness， microhardness， surface residual stress and contact angle， a better combination of processing parameters was obtained. The changes of the surface morphology， microstructure and surface lattice of the specimens were analyzed before and after processing under the optimal parameters. The results show that particle diameter is the main factor affecting surface roughness， microhardness and surface residual stress. As the particle diameter becomes larger， the roughness reduction rate increases first and then decreases， and the microhardness and surface residual compressive stress become larger. With the increasing of amplitude and frequency， the decreasing rate of surface roughness， microhardness and surface residual compressive stress increase. The maximum decreasing rate of surface roughness Ra， Rq， Rz， Rt and RSm may reach 65.0%， 62.2%， 45.2%， 42.0% and 73.7% respectively. Microhardness may be increased from 320.8HV0.1 to 363.9HV0.1. The residual compressive stress may be changed from -420.38 MPa to -621.25 MPa. The surface peaks are removed. A dense layer is formed on the surface， and the grain structure is refined. The diffraction peak is shifted and the greater residual compressive stresses are introduced.  Reference | Related Articles | Metrics | Comments（0）

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Design Techniques of Soft Robot Arms Based on Mechanics Metamaterials CHENG Jibin, DAI Ning, GUO Pei, XIONG Jiyuan, YE Shiwei, CHENG Xiaosheng China Mechanical Engineering    2023, 34 (16): 1900-1906.   DOI: 10.3969/j.issn.1004-132X.2023.16.002 Abstract （487）      PDF（pc） （7243KB）（410）       Knowledge map    Save Based on mechanics metamaterials, the soft robot arm might realize multiple bending motions through the deployment design of mechanics metamaterials. In order to investigate the deformation characteristics of this kind of soft robot arms, based on the analysis of the structure of the soft robot arms and the driving principle, a mathematical model of voxels deformation was established through the piecewise constant curvature hypothesis. At the same time, according to the bending characteristics of soft robot arm units, single-section and multi-section soft robot arm deformation prediction model were proposed. Finally, the effectiveness of the deformation prediction model was verified by the physical experiments, and the bending of more than ±90° was completed， the environment around the end was explored, which might be applied to the inspection of complex and narrow spaces. Reference | Related Articles | Metrics | Comments（0）

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Design of 3K Planetary Gear Reducers with No Backlash WANG Weijun, YANG Guilin, DU Qinghao, CHEN Qingying, China Mechanical Engineering    2024, 35 (01): 36-44,55.   DOI: 10.3969/j.issn.1004-132X.2024.01.003 Abstract （677）      PDF（pc） （10399KB）（382）       Knowledge map    Save Due to the presence of clearances in the gearing of 3K planetary gear reducers， transmission clearances were introduced into the transmission chain， resulting in a decrease in transmission accuracy and causing impacts during driving direction changes. By utilizing the characteristics that the carrier did not participate in torque transmission in 3K planetary gear transmission， a flexible planetary carrier was innovatively proposed to eliminate clearances of 3K planetary gear reducers， and the effectiveness of the proposed clearance elimination mechanisms was verified through simulation analysis. Gear matching and efficiency optimization were performed to achieve high forward and backward driving efficiency. Through the development of a prototype and testing of transmission accuracy， hysteresis characteristics， sinusoidal response error， transmission efficiency， and reverse starting torque， the effectiveness of the proposed flexible planetary carrier in eliminating clearances， transmission accuracy improvement， transmission efficiency and reverse transmission performance promoting was verified.  Reference | Related Articles | Metrics | Comments（0）

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Machining Performance and Material Removal Mechanism of High-speed Milling of CFRP with Variable Angle under Minimal Quantity Lubrication ZHANG Lifeng, ZHANG Xiaoguang China Mechanical Engineering    2023, 34 (21): 2622-2628.   DOI: 10.3969/j.issn.1004-132X.2023.21.012 Abstract （406）      PDF（pc） （9036KB）（379）       Knowledge map    Save  High-speed cutting performance of CFRP was investigated by a specially designed regular dodecagonal cutting trajectory method. Factors such as cooling and lubrication conditions， fiber cutting angles， cutting speed， and down/up milling were analyzed for their influence mechanism on the cutting performance of CFRP. Material removal mechanism under typical fiber cutting angles was analyzed. The results indicate that when PCD milling cutter mills unidirectional CFRP with a constant 30° angular difference， both of normal cutting force（Fn）and tangential cutting force（Ft） follows a specific pattern. Compared to down milling， Fn reduces 25% at least and Ft reduces 40% at least in up milling， while the surface roughness Sa reduces 10% to 35%. Compared to dry cutting， nanofluid for minimal quantity lubrication machining Ft reduces 20% approximately， and cutting temperature decreases around 40%. Reference | Related Articles | Metrics | Comments（0）

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Research on Flexible Job-shop Scheduling Problems Considering Optimization of Worker Number Allocation#br# LIANG Xianglin, SONG Yuchuan, LEI Qi, SUN Aihong China Mechanical Engineering    2023, 34 (17): 2065-2076.   DOI: 10.3969/j.issn.1004-132X.2023.17.006 Abstract （484）      PDF（pc） （4704KB）（377）       Knowledge map    Save Under the background of the shortage of workers and the increasing of workers costs， it was very important to complete the manufacturing tasks with a reasonable allocation scheme of the number of workers.  Previous studies of flexible job-shop scheduling considering worker constraints assumed that the number of workers was given.  In order to optimize the number allocation of workers with different technical levels and flexible job-shop scheduling in an integrated way， considering the penalty cost， worker base cost and performance cost， a mixed integer programming model was established to minimize the total cost， and an improved TLBO algorithm was proposed to solve the problems.  In the algorithm， an activity scheduling decoding method was designed based on the three-layer coding of worker number allocation， operation sequencing and machine selection.  A hybrid heuristic initialization method was used for initialization. An effective neighborhood structure was designed for the problem features.  The tests of several groups of examples were verified that the proposed algorithm may determine the actual number of workers with different technical levels and obtain the excellent scheduling scheme， and is superior to the comparison algorithms in performance.  Reference | Related Articles | Metrics | Comments（0）

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Compound Rules and Reinforcement Learning Based Scheduling Method for Mixed Model Assembly Lines GUO Jutao, LYU Youlong, DAI Zheng, ZHANG Jie, GUO Yu China Mechanical Engineering    2023, 34 (21): 2600-2606,2614.   DOI: 10.3969/j.issn.1004-132X.2023.21.009 Abstract （385）      PDF（pc） （3348KB）（363）       Knowledge map    Save  A scheduling method was proposed based on compound rules and reinforcement learning for balancing and sequencing problems of mixed model assembly lines. A balancing rule set and a sequencing rule set were designed with the consideration of mathematical model, and a proximal policy optimization(PPO) algorithm featured with Actor-Critic training procedure and preferential experience learning mechanism was employed to regulate weighted parameters of these rules, in order to generate reasonable balancing and sequencing solutions. In comparative experiments, the proposed scheduling method demonstrates the effectiveness over other methods including PPO algorithm with single rule, compound rules, and a genetic algorithm. Reference | Related Articles | Metrics | Comments（0）

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Research on Energy Transfer Model and Optimisation of Operating Parameters of Vibratory Rollers HUI Jizhuang, LUO Wei, ZHANG Zeyu, ZHANG Jun, WANG Jie China Mechanical Engineering    2024, 35 (03): 541-547.   DOI: 10.3969/j.issn.1004-132X.2024.03.016 Abstract （313）      PDF（pc） （1996KB）（358）       Knowledge map    Save  In order to improve the compaction quality of vibratory rollers, the energy transfer model of vibratory rollers and the optimisation of operating parameters were studied. Firstly, the system vibration dynamics model of “wheel-compacted material” was established based on the U-K equation, and the energy transfer model of vibratory roller was proposed in combination with energy conservation.Then, the vibration frequency and compaction speed were taken as the optimal working parameters to construct the optimisation model of road compaction quality.Finally, the feasibility and effectiveness of the proposed method were proved through case verification. The results show that: the ratio between the working frequency and the intrinsic frequency of the compacted material is kept within the range of 2～2 to avoid the effect of resonance.The initial stage of low-speed rolling, and after the material properties were stabilised, the rolling speed may be increased to ensure efficient compaction, which results in the vibration frequency in the range of 21.8～27 Hz and the compaction speed in the range of 2.36～2.91 km/s, to achieve the optimal compaction effectiveness. The proposed energy transfer model and operation parameter optimisation model lay a foundation for guaranteeing the compaction quality of vibratory rollers and provide a reference for improving the compaction quality and efficiency of vibratory rollers. Reference | Related Articles | Metrics | Comments（0）

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An Adaptive Robust Unscented Kalman Filter Localization Algorithm Based on Dynamic Residual XU Wan, CHENG Zhao, XIA Ruidong, CHEN Hancheng China Mechanical Engineering    2023, 34 (21): 2607-2614.   DOI: 10.3969/j.issn.1004-132X.2023.21.010 Abstract （495）      PDF（pc） （5703KB）（355）       Knowledge map    Save  Aiming at the problems that the standard unscented Kalman filter（UKF） localization algorithm could not meet the high-precision localization requirements of mobile robots when moved on uneven ground， an ARUKF localization algorithm was proposed based on robust estimation theory. The ARUKF adaptively adjusted the predicted value of UKF according to the dynamic residual， reduced the influences of external interference on the predicted values of the systems， improved the accuracy and robustness of the system， speeded up the operation by reducing the computational complexity of the sampling processes， and improved the real-time performance of the system. The simulation and field test results show that the ARUKF algorithm may converge faster for the disturbance generated by uneven ground， and have better accuracy， robustness， and real-time performance， compared with the UKF algorithm and the improved UKF algorithm based on Sage-Husa. The average distance error is less than 2 mm， and the average angle error is less than 0.016 rad， which may meet more stringent requirements of the construction site.  Reference | Related Articles | Metrics | Comments（0）

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Research on Multi-objective Golden Eagle Optimizer for No-tardiness Job Shop Scheduling Problems with Overtime Consideration SHI Shuangyuan, XIONG Hegen China Mechanical Engineering    2023, 34 (17): 2077-2088.   DOI: 10.3969/j.issn.1004-132X.2023.17.007 Abstract （441）      PDF（pc） （5011KB）（352）       Knowledge map    Save Delivery on time was one of the important goals of the production operations in make-to-order industries. When the production load of the manufacturing system was heavy， overtime work was the most commonly used effective measure to ensure the delivery time. In order to realize the no-tardiness delivery of order tasks and the optimal use of overtime hours， a multi-objective no-tardiness job shop scheduling problem considering overtime was proposed， and a mathematical model with the objective of minimizing the total overtime hours and the makespan was established. To solve the problem effectively， a multi-objective golden eagle optimizer was proposed. In the algorithm， a coding method was designed to map the continuous solution space to the discrete solution space of the problem， a two-stage decoding scheme was proposed， an elitist no-dominated sorting selection operator was integrated， and an adaptive offspring individual generation strategy was introduced. The effectiveness and superiority of the proposed algorithm were verified by comparison experiments on 23 modified job shop scheduling problem benchmarks as experimental objects.  Reference | Related Articles | Metrics | Comments（0）

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Design and Processing Research of Dynamic Pressure Assisted Non-Newtonian Fluid Polishing Tools ZHANG Qicong, JIANG Chen, YE Hui, SHEN Lingxin, JIAO Mengdie China Mechanical Engineering    2023, 34 (23): 2805-2811，2823.   DOI: 10.3969/j.issn.1004-132X.2023.23.004 Abstract （331）      PDF（pc） （8987KB）（342）       Knowledge map    Save To overcome the problems of low and uneven material removal rate when polishing with NNFL, the design and processing research of dynamic pressure assisted non-Newtonian fluid polishing tools(DNNFTs) were carried out. The DNNFT was designed by adding the pressure-controllable center-int to form a dynamic pressure film. The mechanics properties of the filling material Silly-putty were analyzed, numerical simulation of NNFL fixed point polishing was carried out. The influences of liquid supply pressure on the dynamic pressure field, total pressure field and velocity field of liquid film in the processing area of DNNFT were analyzed based on FLUENT. The material removal function models were constructed based on Preston material removal principle. The polishing process experiments were carried out on 304 stainless steel workpieces. It is concluded that the material removal rate and uniformity may be effectively improved by adding the pressure-controllable center-int. The smallest value of surface roughness(Ra=19 nm) and the best material removal rate(2.431 mg/min) are obtained when the liquid pressure is as 0.8 MPa, the rotational speed is as 1200 r/min and the feed rate is as 6 mm/s. The results prove that DNNFT effectively improves the quality and efficiency of polishing, and improves the uniformity of material removal. Reference | Related Articles | Metrics | Comments（0）

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Comprehensive Performance Optimization of High Pressure Threaded Plug-in Relief Valves CHEN Junxiang, KONG Xiangdong, XU Kelong, AI Chao, China Mechanical Engineering    2023, 34 (24): 2909-2919,2926.   DOI: 10.3969/j.issn.1004-132X.2023.24.002 Abstract （441）      PDF（pc） （4914KB）（341）       Knowledge map    Save In views of the coupling of structural parameters affecting different performance of high-pressure threaded plug-in relief valves, it was difficult to optimize the comprehensive performance, a multi-objective particle swarm optimization algorithm was proposed to optimize the comprehensive performance. Based on the structural characteristics of high-pressure threaded plug-in relief valves, the mathematical models of opening and closing characteristics, pressure regulation deviation and stability were established. Based on the first-order sensitivity analysis of the influences of structural parameters on the dynamic response, according to the mapping relationship between structure and performance, with the opening rate, pressure regulation deviation, stability and dynamic response performance improvement as the optimization objectives and coupling structure parameters as variables, a comprehensive performance optimization model was established, and the optimal solution of coupling structural parameters was obtained in the form of Pareto set by particle swarm optimization algorithm. The experimental results show that after optimization, the pressure oscillation of the high pressure threaded plug-in relief valves is reduced by 22.7%, the opening rate is increased by 1.5%, the pressure flow gradient is reduced by 14.58%, the pressure overreach in front of the valves is reduced by 14.1%, the response time is shortened by 9.52%. Reference | Related Articles | Metrics | Comments（0）

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Effects of Tool Wear on Milling Surface Integrity and Fatigue Properties of Allvac 718Plus Superalloy GOU Ruijie, ZHANG Xiaofeng, ZHANG Hongbin, YAO Jun, LI Xun China Mechanical Engineering    2023, 34 (24): 2920-2926.   DOI: 10.3969/j.issn.1004-132X.2023.24.003 Abstract （376）      PDF（pc） （4539KB）（341）       Knowledge map    Save Based on the premise of Allvac 718Plus superalloy milling tool wear law, the influence rules of tool wear on the indicators of fine milled surface integrity were studied，and combined with specific fatigue performance tests of specimens, the influence rules and mechanism of tool wear on the fatigue performance of specimens were analyzed. It is obtained that the control range of flank face tool wear under the parameters of Allvac 718Plus fine milling is less than 0.15 mm, and the main influencing factors on fatigue performance of the specimens are also obtained. The relevant research results provide a reference for controlling the surface integrity and tool wear of Allvac 718Plus specimens in fine machining. Reference | Related Articles | Metrics | Comments（0）

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An Evaluation Method for Tooth Surface Load Capacity of Polymer Gears Based on Nominal Gear Equivalent Load HU Xinlei, LIU Huaiju, WEI Peitang, LU Zehua, LIAO Changjun, ZHU Jiazhan China Mechanical Engineering    2023, 34 (24): 2927-2935.   DOI: 10.3969/j.issn.1004-132X.2023.24.004 Abstract （399）      PDF（pc） （6709KB）（341）       Knowledge map    Save The current evaluation methods for the tooth surface load capacity of polymer gears still rely on the methods for metal gears, which did not comprehensively consider the influences of material type, lubrication condition and stress of the polymer gears. This would lead to significant reliance on engineering experience for material selection, strength design and loading capacity evaluation in practical engineering applications. Therefore, a polymer gear tooth surface load capacity evaluation method was proposed based on the nominal gear equivalent load. Over 169 sets of data and more than 6000 hours of durability tests on polymer gears were obtained, considering different lubrication conditions, gear materials, and machining methods. The results show that oil lubrication may significantly improve the tooth surface load capacity of plastic gears, and the tooth surface load capacity of PEEK(polyether ether ketone) gears is more than 30% higher than that of POM(polyoxymethylene) and PA66(polyamide) gears under oil lubrication, which provides an evaluation method and basic data support for active design and transmission power applications of polymer gears. Reference | Related Articles | Metrics | Comments（0）

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Research on Distributed and Multi-flexible Assembly Job-shop Scheduling Problems WEI Guangyan, YE Chunming China Mechanical Engineering    2023, 34 (20): 2442-2455.   DOI: 10.3969/j.issn.1004-132X.2023.20.007 Abstract （628）      PDF（pc） （4457KB）（333）       Knowledge map    Save Aiming at distributed flexible assembly job-shop environments, the machine selection flexibility, worker scheduling flexibility, and process sequence flexibility in scheduling were comprehensively considered, and a model of DMFAJSP was constructed taking minimizing the makespan and minimizing the total energy consumption as optimization objectives. To solve the DMFAJSP model, MDMA was proposed using estimation of distribution algorithm as the global search component and the neighborhood search operators as the local search component. Finally, comparative experiments were conducted between the proposed algorithm and other algorithms, and the results show that the MDMA has significant advantages in solving DMFAJSP model. Reference | Related Articles | Metrics | Comments（0）

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Numerical Simulation of Residual Stress and Welding Deformation for High Strength Steel Q960E Butt-welded Joints LUO Wenze, CHENG Huimei, LIU Hongyan, WANG Yifeng, YE Yanhong, DENG Dean China Mechanical Engineering    2023, 34 (17): 2095-2105,2141.   DOI: 10.3969/j.issn.1004-132X.2023.17.009 Abstract （476）      PDF（pc） （10205KB）（328）       Knowledge map    Save  A multi-pass butt-welded joint of low alloy high strength steel Q960E was prepared by equal strength matching wire and mixed gas shielded welding method. Microstructure， hardness distribution， welding temperature cycles， welding deformation and welding residual stress were observed and measured by experiments. With the consideration of the microstructure characteristics of Q960E， a thermal-elastic-plastic finite element method which considered the coupling behaviors among multiple physical fields of “thermal-microstructure-stress” was developed based on SYSWELD software platform. The material model focused on solid-state phase transformation in the heat-affected zones（HAZs）. The JMAK equation was employed to describe the austenitization processes during the heating stages， while the K-M equation was utilized to simulate the martensitic transformation processes in the cooling stages. At the same time， the transformation-induced plasticity in the cooling processes was considered based on the Leblond model. The comparison between the numerical simulation results and the experimental measurements shows that both the residual stress distribution and the welding deformation obtained by the finite element model are in a good agreement with the measured data， and the numerical simulation results also show that the solid-state phase transformation has a significant effect on the distribution and magnitude of welding residual stress in the HAZ of Q960E steel butt-welded joints.  Reference | Related Articles | Metrics | Comments（0）

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Levitation Force Characteristics and Parameter Optimization of Permanent Magnet Tracks ZHANG Mingliang, YANG Dawei, LI Mingyuan, YANG Xinmeng, LIU Liru, ZHANG Lianpeng China Mechanical Engineering    2023, 34 (19): 2370-2380.   DOI: 10.3969/j.issn.1004-132X.2023.19.012 Abstract （367）      PDF（pc） （6125KB）（322）       Knowledge map    Save  Facing on the high temperature superconducting flux pinned maglev trains， a method of optimizing permanent magnet tracks was proposed by Taguchi orthogonal method. The influences of Halbach double peak permanent magnet tracks size on magnetic field was studied by finite element method， and the influencing factors were optimized in order to obtain the comprehensive magnetic field performance. A method of equivalent treatment of high-temperature superconductors(abbreviation for equivalent treatment method) was proposed based on frozen image mode， and the correctness of the equivalent treatment method was verified by experimental data. The results show that the influences of the height of the permanent magnet tracks on the average magnetic flux intensity and the average magnetic flux intensity per unit mass are far greater than that of the sectional width， and the pure iron thickness is a non-significant factor. Based on the equivalent treatment method， it is found that the suspension forces increase as the suspension gaps decrease. The suspension forces provided by the optimized permanent magnet railway are of 1.5 times that provided by the experimental permanent magnet tracks， the suspension stiffness increases rapidly as the number of rows of high temperature superconductors increase.  Reference | Related Articles | Metrics | Comments（0）

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Design of Lane Keeping Assist Systems Based on Improved Preview Control Model LIANG Yongbin, FU Guang, LIN Zhigui, HE Zhicheng, ZHANG Jialuo, CHEN Tao China Mechanical Engineering    2024, 35 (03): 548-558.   DOI: 10.3969/j.issn.1004-132X.2024.03.017 Abstract （349）      PDF（pc） （8767KB）（321）       Knowledge map    Save To address the issues of low robustness, consistency in vehicle manufacturing, and severe road surface interference in LKA system of torque control, a LKA system was designed based on angle control by using neural network technology, Autofix algorithm, and preview feedback control theory, through expected trajectory decision-making and following PID control algorithm. A hardware-in-the-loop simulation test platform was built to verify the effectiveness and accuracy of the design of the angle based lane protection systems through virtual simulation based on Carsim/Veristand/ MATLAB. Based on GB/T 39323—2020, CN-CAP—2021, Euro-NCAP—2022 and the testing requirements of the car retention systems based on real-road commissioning and user concern scenarios, the simulation and comparison with real-road scenarios show that the angle-controlled LKA system has better lane keeping capability, stability, adaptability and robustness than that of the torque-controlled LKA system in the same usage scenarios. Reference | Related Articles | Metrics | Comments（0）

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Simulation and Investigation on a Synthetic Jet Piezoelectric Fan with Multiple Jet Holes WANG Jiantao, GAO Mingze, ZHU Jian, WANG Qizhi, LI Hao China Mechanical Engineering    2023, 34 (16): 1929-1935.   DOI: 10.3969/j.issn.1004-132X.2023.16.006 Abstract （470）      PDF（pc） （5736KB）（319）       Knowledge map    Save In order to improve the gas driving ability of piezoelectric gas drivers, a piezoelectric fan with multiple jet holes was proposed, which used piezoelectric transducer to excite gas particle oscillation and to form the gas jet. Working characteristics were studied on the aspects of simulation and investigation. The gas driving law of piezoelectric fans with different density of jet holes was obtained through FLUENT simulation analysis. Multiple jet holes may improve the energy utilization efficiency of piezoelectric transducer, and further improve the gas driving performance of piezoelectric fans. Experimental results on the prototypes show that the piezoelectric fan with single jet hole which is set in the center has better gas driving performance; the energy utilization efficiency of piezoelectric transducer may be improved by using multiple jet holes, and there is an optimal jet hole density; when the driving voltage Vpp is 90 V, the gas velocity of piezoelectric fan with 89 jet holes reaches 4.7 m/s. Reference | Related Articles | Metrics | Comments（0）

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Research on Compliant Legs of Bionic Hexapod Robots WANG Wei, WEI Lang, LIU Fusheng, WANG Guoshun China Mechanical Engineering    2023, 34 (17): 2089-2094.   DOI: 10.3969/j.issn.1004-132X.2023.17.008 Abstract （502）      PDF（pc） （6492KB）（318）       Knowledge map    Save In order to explore the specific influences of the curved legs with compliance on the motion performance of the bionic hexapod robots， firstly， the PRB model was used to describe the deformation features of the curved legs， and the mathematical expression of the stiffness was given.  Then， based on the stiffness model， a virtual prototype was built in the Webots simulation environment， and the changes in velocity and energy consumption rate of the bionic hexapod robots were analyzed by setting different stiffnesses of the curved legs.  Finally， the curved legs with different stiffness were fabricated and verified in the physical prototype.  The results show that the compliance of the curved legs may be more accurately described by the PRB model， which improves the velocity of the bionic hexapod robots and reduces the energy consumption.  Reference | Related Articles | Metrics | Comments（0）

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A Structural Reliability Calculation Method Based on Adaptive Kriging Ensemble Model GAO Jin, CUI Haibing, FAN Tao, LI Ang, DU Zunfeng China Mechanical Engineering    2024, 35 (01): 83-92.   DOI: 10.3969/j.issn.1004-132X.2024.01.008 Abstract （483）      PDF（pc） （4853KB）（317）       Knowledge map    Save  The reliability analysis results of complex structures based on the Kriging model were highly dependent on the fitting accuracy of the Kriging model. In the constructing processes of the Kriging model, the selection of different correlation and regression functions affected the accuracy of the model. In order to solve the impacts of model uncertainty on the reliability analysis results, while considering computational efficiency and accuracy, based on the Kriging model and Monte Carlo simulation(MCS) method, a structural reliability calculation method combining adaptive ensemble strategy and active learning function was proposed. Considering the modeling uncertainty of Kriging models, combined with multiple Kriging models, this methed constructed an active learning function that comprehensively considered sample point contribution and sample point distance. The ensemble Kriging model was iteratively updated through the active learning function until the convergence conditions were satisfied. Finally the structural reliability analysis was carried out by the constructed ensemble Kriging model and MCS method. The validity of the proposed method was verified by numerical and engineering examples, and the results show that the proposed method is more robust than other major methods, and the computational efficiency is higher while ensuring the computational accuracy. Reference | Related Articles | Metrics | Comments（0）