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    25 May 2026, Volume 37 Issue 5
    A Probabilistic Fatigue Life Prediction Method for Wind Turbine Towers Based on a Physics-informed Neural Network
    XIE Bingbing, ZHAO Feng, GUO Xinxing, QIAO Li, CHENG Sichuang, LIU Xiaohui, ZHANG Tongzhou, HU Weifei
    2026, 37(5):  1017-1025.  DOI: 10.3969/j.issn.1004-132X.2026.05.001
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    To address the limitations that the traditional fatigue design for wind turbine towers using deterministic S-N curves might not accurately quantify fatigue life dispersion, a probabilistic fatigue life prediction method was proposed based on physics-informed neural networks. By embedding the physical prior knowledge such as fatigue life dispersion, monotonicity and nonlinearity into the neural networks, a probabilistic prediction model capable of accurately quantifying uncertainty was constructed. Compared with traditional methods, the proposed method reduces the normalized root mean square error(NRMSE) by up to 31.58%. A 16 MW wind turbine simulation model was established in accordance with IEC standards, and tower load data were obtained by using Bladed software. Combined with wind-speed distribution, rain flow counting and the Miner rule, the probabilistic fatigue life prediction of the towers was achieved. The results show that the proposed method effectively characterizes the probabilistic features of fatigue damages, and the tower lifetime varies significantly with reliability requirements (shortening from 83.3 years at 50% probability to 18.2 years at 99.9% probability), which provides a reliable basis for probabilistic fatigue design and safety assessment of wind turbine towers.

    Dynamic Evolution Correlation Quantitative Analysis Method of Complex Product Design Specification Decomposition
    ZHANG Haizhu, CHEN Xiang, GU Sunquan, LI Rong, ZHU Xuechao, MA Kai
    2026, 37(5):  1026-1036.  DOI: 10.3969/j.issn.1004-132X.2026.05.002
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    Aiming at the problems that the complex interaction relationship in the evolution processes of the complex product design specification often caused the module design parameters to be overestimated or underestimated, which led to repeated iteration of design, a method was proposed for quantitatively analyzing the interaction relationship in the dynamic evolution processes of the design specifications. Firstly, based on the design structure matrix, combined with regression analysis and grey entropy correlation degree calculation method, the calculation model of design specification coupling correlation strength was constructed, and the multiple coupling relationship of design specification decomposition was quantitatively analyzed. Then, the theory of community ecology was introduced, and based on Lotka-Volterra model, a quantitative analysis method of dynamic evolution correlation of design specification decomposition was proposed to characterize the interaction relationship in the processes of design specification decomposition. By further integrating the quantitative analysis results of coupling correlation and evolution correlation of design specification decomposition, the quantitative analysis of dynamic evolution correlation relationship of complex product design specification decomposition was realized. Finally, taking the axle load and braking capacity specification decomposition of a high-speed train bogie as an example, the feasibility and effectiveness of the method were verified.

    Design and Applications of Disc Cutter Changing Robots for Shield Machines
    JIANG Lijie, YANG Hang, HAN Dong, SUN Yanming, WANG Yixin, WU Qiankun, JIA Lianhui
    2026, 37(5):  1037-1044.  DOI: 10.3969/j.issn.1004-132X.2026.05.003
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    To address the problems of high labor intensity, high operational risk, and low operational efficiency in manual disc cutter changing during shield tunneling machine construction, a changing operation plan using robot instead of humans was proposed. A new type of tool system suitable for robot operation and a high-power density redundant degree of freedom robot mechanisms were designed.The D-H parameter method was used for kinematic modeling, the robot pose calculation was achieved. The rapidly-exploring random tree(RRT) algorithm was used for robot tool change path planning, the obstacle avoidance path calculation was achieved during the motion processes. Based on the B-spline curves, the robot joint motion trajectory calculation was achieved. A simulation analysis platform was built for robot tool changing, and the effectiveness of the proposed solution was verified. Finally, a tool changing robot test bench was built, and a tool changing robot control system was constructed based on the operation layer, control layer, and execution layer. The feasibility of the tool changing robot system design scheme was verified through parameter calibration, laboratory and engineering testing.

    Radiation Shielding Structure Multi-objective Optimization of Imagine Sensors Based on Monte-Carlo Variance Reduction Method
    FU Haocheng, WU Shaowei, JIANG Chao
    2026, 37(5):  1045-1053.  DOI: 10.3969/j.issn.1004-132X.2026.05.004
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    The radiation simulation method and shielding structure multi-objective optimization design method were proposed based on MC variance reduction for the radiation shielding problems of image sensors in nuclear radiation environments. According to the principles of coupled neutron and photon transport, a multi radiation source composite shielding model was constructed for image sensors, and a shielding simulation method of characteristic interpolation weight window MC variance reduction was proposed for the thick-shielding micro-detection structure characteristics, effectively improving the computational efficiency and accuracy of the shielding simulation. By combining the genetic algorithms with parameterized geometric modeling of radiation shielding structures, a multi-objective optimization design method for image sensors was constructed to obtain the optimal solution under volume, mass, and dose rate parameters and obtain a non-dominated solution combination of Pareto front. Numerical experiments verified the effectiveness of the imagine sensor radiation shielding structure optimization design method.

    Study on Topology Design and Crashworthiness of Novel Anti-impact Units for Hydraulic Supports
    ZENG Qingliang, LI Zhaoji, QI Guoqing, LIU Peng, WAN Lirong
    2026, 37(5):  1054-1062.  DOI: 10.3969/j.issn.1004-132X.2026.05.005
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    In order to improve the anti-impact of hydraulic supports, based on the characteristics of non-dimensional parameters governing the crashworthiness of thin-walled structures proposed by authors, a new type of anti-impact unit, namely the window multi-celled structures(WMCS), was designed by adopting bi-tubular and mixed multi-celled structures. The crashworthiness of anti-impact units with different cross-sectional shapes was systematically investigated by using a combination of experimental tests, simulation analysis and theoretical prediction. The results show that the inner and outer contours of the bi-tubular structures and the number of cells affect the deformation modes of the anti-impact units. As the increase of wall thickness, the energy absorption and initial peak crushing forces of the anti-impact units increase, among which the initial peak crushing forces are highly sensitive. Differently, the specific energy absorption and crushing forces efficiency increase first and then decrease. According to the optimal intersection among deformation modes, force-displacement curves and crashworthiness, the WMCS-C1 with a wall thickness of 5 mm was selected as the anti-impact unit.

    Model-driven Early Functional Design and Verification of Small and Modular Natural Circulation Lead-based Fast Reactors
    WU Xuanyu, FENG Yixiong, CHEN Zhao, YUAN Weiquan, DUAN Chengjie, HONG Longzhuang, ZHANG Zhifeng, TAN Jianrong
    2026, 37(5):  1063-1071.  DOI: 10.3969/j.issn.1004-132X.2026.05.006
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    The traditional document-based nuclear power equipment development pattern had problems such as discrete and poorly correlated design information, ambiguous design intentions that were difficult to trace, and a lack of intuitiveness and immersion in the design argumentation processes. Taking the small and modular natural circulation lead-based fast reactor(NCLFR) as the research object and taking the assembly and disassembly processes as an example, the MBSE method was combined with the virtual prototype technology, and three aspects of requirement analysis, functional design, and functional verification were discussed. Based on the independently developed MBSE modeling platform M-Reactor in the China Nuclear Power Technology Research Institute Co., Ltd., the requirement analysis and functional design of the assembly and disassembly processes were carried out. On the basis of the early 3D modeling of the NCLFR, the consistent mapping and model linkage between the system logic model and the functional virtual prototype were achieved, verifying the completeness, correctness, and traceability of the assembly and disassembly processes, providing designers with a more immersive design experience and a visual design verification method. In this way, the results may provide a reference for the applications of the MBSE method in the systematic design of nuclear power equipment.

    Simulation Modeling of Single-pulse Electrical Discharge Bubble Behaviors
    WANG Jin, QIAO Chunkai, JIA Zhixin, HE Hu
    2026, 37(5):  1072-1081.  DOI: 10.3969/j.issn.1004-132X.2026.05.007
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    Based on the underwater explosion theory and the ideal gas equation of state, considering the energy loss caused by the wall resistance when the fluid flows in the machining gaps, and combining the maximum expansion volume and the steady-state volume of the bubbles observed in the experiments, a calculation method was determined for the initial temperature, pressure and volume of the bubbles generated by a single-pulse EDM within the inter-electrode gaps. A simulation model for single-pulse discharge bubble behaviors was further developed by using the volume of fluid(VOF) method. The results of the single-pulse discharge bubble observation experiments show that the simulation results are in good agreement with the experimental ones.Using this model, the influences of peak current and pulse duration on bubble evolution behaviors were analyzed. Finally, based on the experimental data obtained from high-speed camera observations, the calculation formulas for the maximum expansion volume, expansion time and steady-state volume of the bubbles were derived under different peak currents and pulse durations. Moreover, the simulation calculation of the single-pulse discharge bubble behaviors may be carried out without observing the experiments.

    Development Status and Key Technologies in Subsea Pipeline Inspection ROVs
    JIN Yongping, SHI Zimu, WAN Buyan, LIU Deshun
    2026, 37(5):  1082-1094.  DOI: 10.3969/j.issn.1004-132X.2026.05.008
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    Defects such as corrosion and cracks were easily generated in subsea pipelines under the long-term influences of the marine environment. Limitations such as low safety, insufficient efficiency, and high cost existed in traditional detection methods, therefore, ROVs equipped with professional detection equipment were gradually adopted as the mainstream detection scheme. The classification, performance, and system composition of ROVs were first comprehensively analyzed. Then, based on the actual requirements of subsea pipeline inspection and combined with the research status of ROV-based inspection technology, the existing technical characteristics of subsea pipeline inspection ROVs were analyzed. Subsequently, the key technologies of ROV-based subsea pipeline inspection were further discussed. The technical principles of optical inspection technology, acoustic inspection technology, electromagnetic inspection technology, and radiographic inspection technology were elaborated, and the characteristics and applicable scenarios of each inspection technology were summarized. Finally, the future development of subsea pipeline inspection ROVs was prospected.

    Design and Multi-gait Implementation of Layered Actuators Based on Fiber-Pneumatic Coupled Variable-stiffness Snake Robots
    MU Junqi, WEI Yiyang, HOU Xuping, ZONG Xiaofeng
    2026, 37(5):  1095-1104.  DOI: 10.3969/j.issn.1004-132X.2026.05.009
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    To address the issues of wheeled snake robots, such as easy toppling and poor adaptability in complex terrains, a pneumatic snake robot with multiple gaits was proposed based on the principle of fiber interference variable stiffness. The robot used a triple-layer structure pneumatic actuator to dynamically adjust stiffness via air pressure. The modular design integrated components such as air pumps, electromagnetic valves, and unidirectional wheels. The experimental results show that the bending angle of the actuator is positively correlated with the air pressure. The design of dual-cavity combined with fiber reinforcement significantly enhances the load-bearing capacity. By coordinating the steering and load-bearing actuators, the robot may perform serpentine linear motion, C-shaped turns, and accordion-like motion, even crossing obstacles a third of the height. The modular structure reduces maintenance costs and supports rapid functional expansion. These findings offer an efficient actuation solution for wheeled soft snake robots, and support applications in complex scenarios such as rescue and pipe inspection.

    Deep Learning Method of Flow Time History for Optimizing Position of Vortex Flowmeter Probes
    ZHAN Qingliang, CAO Zihan, WANG Zhiyong, BAI Chunjin, LIU Xin
    2026, 37(5):  1105-1110.  DOI: 10.3969/j.issn.1004-132X.2026.05.010
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    A vortex flowmeter used the time-varying features of the wake flow around a blunt body to measure flow field. A reasonable probe position might obtain a more robust flow signal, which improved signal processing and measurement accuracy. Based on the deep learning of flow time history data, a probe positioning optimization method was proposed to address the probe location issue in vortex flowmeters. The method was illustrated by using the flow around a triangular prism vortex generator. Feature dimensionality reduction was performed on the flow time history dataset and a comprehensive analysis of the time-varying flow features at the numerous measurement points within the wake was realized. Then, clustering analysis was applied to the low-dimensional representation codes to identify spatial distributions with similar time-varying characteristics. Finally, by analyzing the flow characteristics of different categories, the significant regions of measured variable signals were obtained as the reasonable layout regions for the measuring points of the vortex flowmeters. The results show that the proposed method may provide a finer measurement point layout scheme than that of the traditional methods. And the reasonable sizes of the probes may be obtained according to the sizes of the characteristic areas, providing a new method for the design of vortex flowmeters.

    Analysis for Influences of Joints on Dynamic Characteristics of Precision Machine Tools
    WANG Bingxu, GAO Tong, WAN Min, JIAO Longfei, YU Fei, ZHANG Weihong
    2026, 37(5):  1111-1121.  DOI: 10.3969/j.issn.1004-132X.2026.05.011
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    To investigate the influence mechanism and effects of joints on the dynamic characteristics of an entire machine tool, an accurate equivalent dynamic analysis model for joints was constructed by using ANSYS simulation software based on a multi-objective genetic optimization method. Subsequently, an accurate dynamic model of the entire machine tool was established, and the modal testing of the entire machine tool was completed. The testing results show that the errors between the calculated natural frequencies of the first six modes from the entire machine tool and the experimental data are less than 5%, verifying the effectiveness and accuracy of the analysis model. Based on this dynamic model, a comparative analysis was conducted to examine the relationships among movable joints, screw joints, foundation joints, and the dynamic characteristics of the machine tools. The analysis results indicate that movable joints have the greatest influence on the 4th, 5th and 6th order natural frequencies of the entire machine tools, followed by foundation joints, with screw joints having the least influences. Additionally, foundation joints are identified as the primary factors affecting the whole-body modal shapes of the machine tools, while screw joints and movable joints have relatively minor effects on the modal shapes.

    Load Analysis and Driver Selection of Electric Cylinder Lifting Servo Mechanisms
    WAN Ziping, ZOU Zhijun, TANG Lewei, FAN Dapeng, ZHANG Kaikai
    2026, 37(5):  1122-1131.  DOI: 10.3969/j.issn.1004-132X.2026.05.012
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    To tackle the challenges of drive component selection in electric cylinder lifting servo mechanisms with nonlinear dynamics characteristics, an efficient selection method of drive components was proposed based on peak parameter matching. The analytical formulae for the mechanism's inertial torque, Coriolis torque, unbalanced torque, frictional torque, and environmental loads were obtained via Lagrange dynamics, explicitly revealing the computational complexity involved. Then, leveraging peak external loads and mechanism arm lengths, along with the system's nonlinear characteristics, an efficient selection approach was formulated. Finally, the application constraints were established based on the load-to-drive mass ratio, when the mechanism's load-to-drive ratio exceeded the critical value, the method might be applied. Simulation results demonstrate that based on the time and spatial complexity,the computational efficiency of the efficient selection method is 1629 times that of the conventional method under a sampling step of 0.01 rad. Experimental results confirm that the electric cylinder lifting servo mechanism's load-to-drive ratio is as 15.37, which is greater than the critical value of 11.68, achieving 1 rad/s² acceleration under sinusoidal instructions and 0.785 rad/s velocity under step instructions.

    Prediction of Micro-milling Forces Considering Flank Wear with Cutting Edge Radius
    GAO Shuaishuai, DUAN Xianyin, ZHANG Yu, ZHU Kunpeng
    2026, 37(5):  1132-1140.  DOI: 10.3969/j.issn.1004-132X.2026.05.013
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    To accurately predict cutting forces in the micro-milling processes, a micro-milling force mechanism model was proposed that comprehensively considering the cutting edge radius, tool flank wear and tool runout. A precise analytical relationship between flank wear of micro-milling tools and the cutting edge radius was established and the trochoidal trajectory of the cutting edge was accurately analyzed under tool runout. An analytical model was constructed for instantaneous undeformed chip thickness and entry-exit angles, along with a tool-workpiece contact area and cutting force coefficient model that accounted for flank wear. Consequently, a generalized micro-milling force model was developed, incorporating critical factors such as cutting edge radius, flank wear and tool runout. The effectiveness of the proposed model was validated through micro-milling experiments and statistical analysis of cutting force results. When flank wear is considered, the average prediction errors of forces in three directions are reduced by 35%, 27% and 58%, respectively. Furthermore, the case studies were conducted to investigate the effects of flank wear on cutting force coefficients, mean force error and root mean square error, demonstrating the necessity of considering flank wear in micro-milling force modeling.

    An Enhancement Method for Induction Heating Efficiency Based on Ferrite Magnetic Circuit Optimization
    LI Yunlong, ZHANG Dahai, LU Fangzhou, LI Yanjie, XU Peifei, FEI Qingguo
    2026, 37(5):  1141-1149.  DOI: 10.3969/j.issn.1004-132X.2026.05.014
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    To meet the strict requirements of ground thermal experiments for advanced composite material performance testing, an efficient optimization scheme was proposed for a graphite induction heating system of non-conductive materials. The overall structure of the graphite induction heating furnace and two ferrite structures were designed, and the COMSOL simulation model was established covering the coupling of electromagnetic field, temperature field and thermal radiation multiphysics fields. The results show that under the working conditions of 20 kW input power and 20 kHz frequency of the coil, the number of coil turns is positively correlated with the temperature rise of the graphite, but the thermal radiation effect decreases nonlinearly with the increasing of the number of turns. After comprehensive evaluation, it is determined that the four-turn coil is the optimal parameter. The enhancement of the heating effectiveness by ferrite materials is the combined results of the overall structure's ability to gather the magnetic field and the power drop problem caused by the gathered magnetic field. The cylindrical structure is overall superior to the spiral structure, and the heating performance is the best at a coil-to-cylinder spacing of 4 mm. The high magnetic permeability ferrite cylindrical structure may significantly improve the heating performance of the induction heating furnace, providing a feasible strategy for high-demand ground thermal experiments.

    Simulation of Braking and Heat Dissipation Performance for a Novel Comb-type Magnetorheological Brake
    CAO Zhiqiang, LIU Xiaomin, CHEN Liang, ZENG Shunyan, ZHOU Shaoting
    2026, 37(5):  1150-1159.  DOI: 10.3969/j.issn.1004-132X.2026.05.015
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    In order to solve the problems of existing magnetorheological brakes with large size, small braking torque and poor heat dissipation performance,based on the contradiction analysis method and conflict matrix of TRIZ, a novel comb-type magnetorheological brake applied to electric vehicles was designed, and the braking torque and temperature field simulation mathematical model were established. The various performance indicators of the brake were verified through simulation and experimental study. The results show that the magnetic field of comb-type magnetorheological brake is concentrated in the comb-type brake disk part, and the maximum braking torque increases gradually with the increasing of input current, the saturation current is as 3.6 A, the braking torque is as 334 N·m, and the torque/volume ratio is as 65.215 kN/m2. The heat of the brake is mainly generated in the comb-type brake disk part, which gradually spreads from the brake disk to the casing and the shaft body with the passage of time. The paper verifies that the novel comb-type magnetorheological brake has better heat dissipation performance when achieving continuous braking.

    Integrated Kinematics Modeling and Parametric Calibration of Large Gantry Fiber Placement Machines
    KE Zhenzheng, WU Jianbo, ZHANG Tianyu, WANG Kai, CHENG Liang
    2026, 37(5):  1160-1169.  DOI: 10.3969/j.issn.1004-132X.2026.05.016
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    Automation equipment was typically a strongly coupled, nonlinear, and flexible complex mechanical system, which made it challenging to establish an accurate kinematics model. A kinematics modeling method was proposed that integrated geometric deviations and gravity deformations for a large gantry automatic fiber placement machine. A theoretical kinematics model was developed based on multi-body system theory, the geometric deviations were analyzed in model coordinate conversion, and the gravity deformation-sensitive parts of the gantry fiber placement machines were studied. The gravity deformation matrix was obtained through mechanics abstraction and parameter extraction. The geometric deviations and gravity deformations were incorporated into the theoretical kinematics model to establish a comprehensive kinematics model of the gantry fiber placement machines. Parametric calibration was achieved through objective function establishment, measurement point selection, and parameter identification. Experimental results demonstrate that the proposed method may significantly improve the precision of the kinematics model, the position errors of the gantry fiber placement machines are reduced by over 74%.

    Energy-saving Control Method for Aerial Work Platforms Based on Variable Speed and Variable Displacement Electro-hydraulic System under Different Working Conditions
    LIU Yuchao, XI Yi, DAI Juchuan, SUN Yifan, ZHANG Yuxiao
    2026, 37(5):  1170-1182.  DOI: 10.3969/j.issn.1004-132X.2026.05.017
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    To address the issues of significant throttling losses at the main valves of the load-sensing system in electric aerial work platforms, a collaborative energy-saving control method for pumps and valves was proposed based on variable speed and variable displacement electro-hydraulic system under different operating conditions. This method combined electro-hydraulic system optimization with a new energy-saving control strategy to reduce throttling losses in the main valve assembly. In terms of electro-hydraulic system optimization, a dual-variable electro-hydraulic system with variable speed-variable displacement was designed, an electro-hydraulic proportional pump was adopted to replace the load-sensing pump, and the pressure compensating valve in the original load-sensing system was removed. In terms of control strategy, under single-action operating conditions, an underflow control strategy was adopted to further reduce throttling losses at the main valves. Under composite action conditions, based on the load mathematical model, a valve port pressure difference feedforward compensation algorithm was proposed, which achieved precise flow distribution for each action while ensuring the system operates at minimum throttling loss. Simulation and experimental results show that compared to the original load-sensing system, the proposed new system and energy-saving control method reduce throttling losses by 59%~85% under single-action conditions and by 10.7% under composite-action conditions, while keeping the flow coupling error in composite actions within 5%.

    Digital Twin Based Vibration Performance Monitoring Method for Gear Transmission Systems
    ZHANG Runcheng, LIU Jiezhou, WANG Yiwei, LIU Geng, TONG Ruiting
    2026, 37(5):  1183-1192.  DOI: 10.3969/j.issn.1004-132X.2026.05.018
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    In order to monitor the vibration states of the gear transmission systems during operation, a digital twin-based method was proposed for monitoring the vibration performances of the gear transmission systems. Considering the physical model, the digital twin model and the interaction between the two models, a digital twin framework of the gear transmission systems was developed. A mechanism model of the gear transmission systems was presented based on the generalized finite element method, and the simulation data produced were used to construct a surrogate model which was constructed using the simulation data generated by this mechanism model, so as to replace the original computationally expensive mechanism model. The model parameters were selected by the Sobol sensitivity analysis method, and a genetic algorithm was used to update the model in combination with the experimental data. The updated model was then used to monitor the vibration performances, thus completing the construction of the digital twin model. The proposed method was applied to monitor the vibration performances of a herringbone gear transmission system. The results show that the digital twin model may reflect the vibration performances of the gear transmission systems accurately during operation. Under different rotational speeds, the maximum relative error among the simulation and experimental results at each measurement point is as 15.21%, which verifies the effectiveness of the proposed method.

    Mechanism Design and Experimental Validation of a Novel Rigid-Flexible Hybrid Continuum Robot with a Tension-Torsion Synergistic Actuation
    DONG Jiaxiang, ZHAO Xuezhi, HU Xiping, LIU Quanquan
    2026, 37(5):  1193-1198.  DOI: 10.3969/j.issn.1004-132X.2026.05.019
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    Combining a dual-segment flexible body and a single-segment rigid body, a novel rigid-flexible hybrid continuum robot mechanism was designed by utilizing the tension-torsion synergistic actuation of flexible shafts, which realized 6 tension-torsion power inputs from the flexible shafts and a 7-degree-of-freedom motion output. The bending configurations of the flexible segments were controlled by the pulling motion of the flexible shafts, while the motions of the terminal rigid joint were controlled through their twisting motion. An experimental platform was built to experimentally validate the physical performance of the prototype. Experimental results show that the mechanism demonstrates flexible multi-DOF bending capability and a good load-carrying capacity. In repeatability experiments, the maximum standard deviations for the single and dual-segment continuum robot account for 1.62% and 7.66% of the manipulator's length, respectively, which verifies that the robot mechanism design possesses good positioning stability and reliability.

    Physics-guided Neural Network Model for Predicting Rolling Forces in Aluminum Strip Cold Rolling
    ZHANG Ji, YUAN Haibo, WANG Zhixuan, ZHU Sihua, BAI Zhenhua
    2026, 37(5):  1199-1209.  DOI: 10.3969/j.issn.1004-132X.2026.05.020
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    Accurate prediction of rolling forces in aluminum strip cold rolling was essential for process optimization and ensuring product quality. Traditional physical models often struggled to accurately capture the complex interactions among various factors, while purely data-driven models typically lacked physical constraints and exhibited limited generalization ability. In order to develop a rolling force prediction model for aluminum strip cold rolling that combined both physical interpretability and high prediction accuracy, taking 5182 aluminum strip as the research object, a yield strength model was fitted. After preprocessing a large volume of real production data, the traditional Hill rolling force model was optimized by using the PSO-Nelder-Mead algorithm, which significantly improved the predictive capability. Then, a PGNN model was proposed. This model was based on a convolutional neural network, integrating a physical constraint term derived from the optimized mathematical model into the loss function,which enabled the model to follow the physical laws while simultaneously being data-driven. Bayesian optimization was employed to optimize the model's hyperparameters. Finally, the established model was verified by using actual production data. The results show that the PGNN model exhibits excellent prediction performance on the validation set. The prediction accuracy is significantly higher than that of the mathematical models both before and after optimization, and shows strong generalization ability. Furthermore, the iterative analysis of the loss function further confirms the effectiveness of the physical constraints.

    Underwater Target 3D Reconstruction Method Based on AUV Equipped with Monocular-Line Laser
    YANG Yongjun, YANG Renyou, LI Yufeng, QIN Hao
    2026, 37(5):  1210-1217.  DOI: 10.3969/j.issn.1004-132X.2026.05.021
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    The underwater targets were scanned and 3D reconstructed based on the autonomous underwater vehicle(AUV) platform equipped with a monocular camera and a line laser sensor. Aiming at the difficulty of extracting stripe coordinates in underwater laser images, an adaptive method was proposed for extracting laser stripe coordinates in the HSV space, and the 3D spatial coordinates of the target point were calculated by combining the laser triangulation model and the camera inverse projection matrix. Further, the AUV pose information was utilized to stitch multiple frames of point clouds, achieving the reconstruction of the complete 3D structure of the target object. By constructing the described algorithm framework described, AUV experiments were conducted to verify the feasibility of the method and the effectiveness of point cloud reconstruction under the pool environment.

    Prescribed Performance Visual Servo Control Strategy for Mobile Robots Integrating Preview Mechanism
    CAO Yiran, GAO Lei, WU Mengli, WANG Xuhao, PENG Cong, GUO Zhiyong, LIANG Yao
    2026, 37(5):  1218-1225.  DOI: 10.3969/j.issn.1004-132X.2026.05.022
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    In the automated transportation of large aerospace structures, image-based mobile robot tracking of variable-curvature trajectories faced image visibility constraints and steering angular velocity limits. An image-based visual servo control strategy was proposed with a preview mechanism and prescribed performance control. By employing an error transformation function, constrained normalized plane errors were converted into unconstrained errors, and a prescribed performance function was introduced to ensure error convergence within predefined bounds, and maintain the feature point visibility. Meanwhile, combined with a curvature-driven adaptive preview distance model,a “dual-region” feature extraction scheme was developed to anticipate and correct state feedback, effectively suppressing angular velocity spikes. The proposed method was verified through MATLAB/Simulink simulation and physical experiments, the results show that the proposed method effectively constrains errors within prescribed limits, and the integration of the preview mechanism significantly improves the tracking accuracy and motion smoothness of the mobile robots.

    A Method of Multi-type Job Identification Based on Improved Faster-RCNN
    MEI Qizhen, SUN Xuan
    2026, 37(5):  1226-1235.  DOI: 10.3969/j.issn.1004-132X.2026.05.023
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    To solve the problems of missing workpiece detection and low accuracy of workpiece detection in traditional machine vision algorithm, an improved Faster-RCNN multi-type job identification method was proposed. Firstly, at the backbone network level, the original VGG16 was discarded, the Res2Net101 was adopted to strengthen the efficiency of network feature extraction. Secondly, in the feature fusion module, the SCConv was deeply embedded into the FPN, and then a new SCFPN architecture was constructed, and the architecture was organically integrated with Res2Net101 to realize the full extraction and refinement of multi-scale feature information. Finally, in the post-processing link, Soft-NMS algorithm was used to replace the traditional non maximum suppression(NMS) algorithm, effectively avoiding the false deletion of high coincidence candidate box, significantly improving the adaptability of the model in the workpiece occlusion scene, and greatly reducing the probability of missing detection. The results show that the proposed improved Faster-RCNN model significantly improves the performances compared with that of the original algorithm, the average precision reaches 93.2% and recall rate is as 91.8%. It may detect and identify all kinds of workpieces in complex environment.

    Investigation on Impacts of CR450 EMU under Operation of Open Line Intersection on Aerodynamic Characteristics of Trackside Equipment
    ZHOU Zijian, ZHOU Zhenbin, HUANG Zundi, KONG Weikai, YANG Xiaofeng
    2026, 37(5):  1236-1244.  DOI: 10.3969/j.issn.1004-132X.2026.05.024
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    To investigate the impacts of increasing the speed of high-speed trains to 450 km/h on the aerodynamic safety performances of trackside signaling equipment, the sliding mesh technology was employed to analyze the aerodynamic performance affected trackside three-aspect signal lights, switch machines, and terminal boxes under complex conditions, as well as the flow field evolution when high-speed trains pass by these trackside equipment. The results show that under the open line and crossing operation conditions, as train speed increases, the positive peak, negative peak, and peak-to-peak values of pressure on trackside equipment all increase. Moreover, the peak-to-peak pressure values on trackside equipment are proportional to the square of the train speed. Trackside equipment experiences two pressure fluctuations as the train's head and tail pass by, with the head car's pressure wave having a greater impact than that of the tail car. The lateral force has the most significant impact on the safety of each device, with signal lights and switch machines being more affected than that of terminal boxes.

    Research on Effects of Medium-low Speed Maglev Operation Speed and Levitation Module Length on Stability of Vehicle Crossing Turnouts
    ZHUANG Xubin, YAN Jiahai, LIU Yu, ZHANG Min, MA Weihua
    2026, 37(5):  1245-1253.  DOI: 10.3969/j.issn.1004-132X.2026.05.025
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    In order to investigate the influences of the suspension module length on the vehicle dynamics performance, and to explore the module length that met the requirements of dynamics stability and vehicle economy, through the multi-body dynamics software SIMPACK, a four suspension frame mid-mounted magnetic levitation vehicle dynamics model was established, and the dynamics responses of the vehicle passing through the turnouts were analyzed under different suspension module lengths. The results show that: the length of the suspension module and the speeds of the turnouts jointly affect the stability of the vehicles passing the turnouts. The fluctuation of the suspension gap may not exceed 4 mm as a technical indicator, in order to ensure that the vehicle may safely and stably pass the turnouts, when the suspension module length is as 2.8~3.2 m, the vehicle lateral speed may not exceed 35 km/h. When the length of the suspension module is increased to 3.6 m, the maximum speed of the vehicle passing the turnouts is decreased to 25 km/h. When the length of the suspension module is reduced to 2.4 m, although the manufacturing cost may be reduced to a certain extent, the vertical force area between the electromagnet and the vehicle body may also reduce accordingly, which leads to the fluctuation of the electromagnet suspension gap increasing, and then restricts the vehicle's speed of the turnouts, preventing the vehicles from exceeding 30 km/h. Through the in-depth study of the relationship between the levitation module length and the lateral overrun speed, the threshold value of the levitation module length is obtained, which provides a reference for the design of the levitation module length of the low and medium-speed maglev vchicles.

    Finite Element Simulation and Tests of Non-plate Nut Lap Joints for Load-bearing
    WANG Shoucai, GUO Yan, GUO Dongni, LI Hui
    2026, 37(5):  1254-1261.  DOI: 10.3969/j.issn.1004-132X.2026.05.026
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    A damage initiation and evolution criterion was adopted based on the equivalent plastic strain and stress triaxiality, taking the TC4 titanium alloy bolts commonly used in aviation for example, the finite element model was established for a typical lap joint of non-plate nut. The stress details, plastic deformation and failure mode of the lap joints were analyzed, and the tensile-shear static tests and tensile fatigue life tests of the lap joints were carried out. The testing results show that the finite element simulation model is in good agreement with the test load curve, and the deviation of the failure load from the testing result is less than 5%. There is a gap between the inner wall of the nut and the outer circle of the bolts, and the lap joint contacts with the inner wall of the nut after deformation to form a support reaction forces during the processes of static tensile-shear loads. And there is an angle of about 83° between the final section and the axis of the bolts. Compared with the self-locking nut of the same specification, the tensile-shear failure load of the lap joints is reduced by 5%~7%, but the fatigue life is increased by 19%~182%. Different from the static tensile-shear test, the failure form of the fatigue life tests is the fracture of the connecting interlayer.

    Investigation on Injury Protection Effectiveness of Active Seatback Reset Safety Strategy for Reclined Occupants
    WANG Yanxin, ZHAO Hongqian, LIU Chong, SU Jingjun, CUI Shihai, HE Lijuan, LYU Wenle, LI Haiyan
    2026, 37(5):  1262-1269.  DOI: 10.3969/j.issn.1004-132X.2026.05.027
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    To explore the effects of an active seatback reset safety strategy on the motion response, injury risk and potential hazards of reclined occupants, a comparative analysis was conducted to assess the differences in occupant motion response and injury risk without the safety strategy and those with the safety strategy implemented at different reset rates. The results show that the safety strategy has an impact on the motion response, injury risk and injury mechanism of the head-neck, chest-abdomen and lumbar-pelvic regions of reclined occupants. The safety strategy significantly improves lumbar-pelvic motion response and mitigates the risk of submarining and lumbar injuries. When the reset rate is as 2.585 rad/s, substantially reduces the overall injury risk of reclined occupants is reduced. However, when the reset rate is higher or lower than 2.585 rad/s, the injury risks of neck and abdomen is increased.