最新刊期
卷 ， 期 3 ， 2024
- 摘要：The automatic configuration (inauguration) of train communication networks (TCN) is emphasized as a distinguishing feature of train control and management systems (TCMS). This process establishes the composition and sequence of nodes, identifies the master node, and determines node orientations relative to the master node within TCNs, laying a foundation for train control and management. In scenarios of TCMSs based on wireless communication, the absence of physical wire/cable connections between nodes in the wireless train backbone (WLTB) network renders automatic inauguration in traditional ways impractical. Consequently, manual setting of parameters remains the prevailing configuration practices in engineering applications. Furthermore, the automatic configuration is demanded in a dynamic manner for virtual coupling (VC) systems, where multiple trains are virtually coupled into platoons through WLTB. The configuration mode by manual parameter setting is not viable, since following trains run in an automatic operation mode. This paper analyzed the TCN and WLTB inauguration as well as VC platoon coupling/uncoupling, and delved into the nature and root causes of obstacles encountered in the initialization and dynamic configuration of train platoons based on wireless communication. The findings inspired the introduction of an expanded network system that merges TCMSs and signaling systems to provide an automatic configuration solution. This solution included automatic configuration methods, layered functions, and system architecture for communication network-based train control (CBTC) systems, focusing on automatic train operation aspects. Additionally, the paper also explored CBTC-related domains for potential future research endeavors.关键词：train control and management system (TCMS);wireless train backbone (WLTB);inauguration;virtual coupling;com-munication network-based train control (CBTC)
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发布时间：2024-08-01
General
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Design and verification of levitation system for superconducting electrodynamic suspension test line
摘要：Superconducting electrodynamic suspension is a maglev transportation system for high-speed and ultra-high-speed operation. After the design of the coil structure and electromagnetic parameters of the superconducting electrodynamic suspension system is finalized, the change patterns of the levitation force and guiding force cannot be adjusted by the onboard controller. Therefore, the size of the coil is very important. From an engineering perspective, the feasible design method for the electrodynamic suspension system was expounded and analyzed in this study. Firstly, based on the dynamic circuit equation and virtual work principle, the peak value of the average levitation force under a certain parameter condition was calculated. And the structure parameters of the levitation coil were obtained by conducting a process and cost analysis. Then, the relationship between the size of the "8" shaped coil and the superconducting magnetic poles was calculated, and the vertical offset when the vehicle weight was equal to the average levitation force was obtained, which was the steady-state working balance position of the levitation system. In addition, the influence pattern of the "8" shaped coil size on the peak value of average levitation force was determined: the half coil height exhibited an extremely large point for the peak value of the average levitation force, and the winding width and coil thickness were monotonic increasing on the function of the peak value of the average levitation force respectively, if other variables remain unchanged. Finally, the levitation system test was carried out on the superconducting electrodynamic suspension test line of CRRC Changchun Railway Vehicles Co., Ltd.. The test results show that the difference between the measured vertical average height of the vehicle and the calculated balance position is 0.56 mm, which have checked the accuracy and effectiveness of the design method for the levitation system.关键词：electrodynamic suspension;levitation system;design method;test line- 58
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发布时间：2024-08-01 - 摘要：Track irregularities are the main excitation source of vibration of straddle monorail vehicles. It is of great significance to study the vibration source of straddle monorail vehicles for vehicle and track beam maintenance. A dynamics model of straddle monorail vehicles was established based on SIMPACK multi-body dynamics software. Continuous wavelet transform was carried out on the time-domain signals of frame acceleration and irregularity signals, and time-frequency analysis was carried out with the continuous wavelet transform coefficient serving as the index to determine the frequency band where the energy of vehicle vibration and irregularity signals was mainly concentrated. Cross wavelet transform and wavelet coherence method were used to study the wavelet correlation of acceleration signals in time domain under multiple working conditions, and the average wavelet coherence value was used to evaluate the contribution of track beam irregularities to lateral and vertical vibration of vehicles. The results show that as for the guide surface irregularity, the transverse mean wavelet coherence peak values are 0.93, 0.71 and 0.66 at 0.5 Hz, 2 Hz and 14 Hz respectively, and the vertical mean wavelet coherence values fluctuate around 0.3. As for the stable surface irregularity, at 6 Hz, the transverse mean wavelet coherence peak value is 0.44, and the vertical mean wavelet coherence value fluctuates around 0.3. As for the running surface irregularity, at 6 Hz, the transverse mean wavelet coherence peak value is 0.53, and the vertical mean wavelet coherence value is stable at 0.98. As for the irregularity caused by overall track beam deformation, the transverse mean wavelet coherence peak value at 14 Hz is 0.41, and the vertical mean wavelet coherence peak value at 2 Hz is 0.47.关键词：straddle monorail;track irregularity;dynamics;cross wavelet;wavelet coherence
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发布时间：2024-08-01 - 摘要：It is critical in the implementation of structural health monitoring for rolling stock to acquire load characteristics of vital interfaces such as air suspensions, auxiliary components, axle box springs, and rubber joints during the service life. This paper explored an estimation method for loads on bogie frames. Based on an initially established vehicle system dynamics model, lateral and vertical dynamics models were derived, incorporating localized refinements specific to rocker type axle boxes. Based on these models, Kalman filtering was applied for inversion estimation of system state quantities through the system state equation. The study results, which considered excitations from track irregularities, show a correlation surpassing 0.8 between the estimated and simulated values for vertical loads on the bogie frame, while a correlation exceeding 0.6 for lateral loads. These findings indicate consistent change trends in the time-frequency domain between the estimated and simulated values. Moreover, as the vehicle speed increases, the accuracy of the inversion results based on Kalman filtering progressively improve in correlation with the simulated values. Based on the above outcomes, conclusions can be drawn that the proposed load estimation method is sufficiently accurate and stable in the inversion calculations for loads on the critical interfaces of bogie frames. This method can serve as a data foundation for subsequent damage monitoring and evaluation, remaining life calculations, and optimizing the structural design for key bogie components.关键词：rolling stock;bogie frame;vibration acceleration;Kalman filtering;load inversion
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发布时间：2024-08-01 - 摘要：Polygonal wear of wheels has a significant influence on the fatigue life of components in the wheel and rail system, as well as on the ride comfort and operational safety of trains. This paper investigates the vibration responses of locomotive axle boxes to the excitation of wheel polygons. To this end, a rigid-flexible coupling dynamics model was developed by combining multi-body dynamics software and finite element analysis software to simulate the locomotive-track system. This model incorporated the flexibility of bogie frames, wheelsets, sleepers, and rails. The measured vibration acceleration results of locomotive axle box were used to verify this model. This study further examined the effects of ideal harmonics and measured irregular wheel polygons in typical cases on vibration responses of locomotives. The findings show that the amplitude of axle box vibration accelerations increase significantly as the wheel polygon passing frequency approaches the resonant frequency of the wheel-rail system in the P2 mode or the wheelset frequency in its natural mode. The magnitude of axle box vibration accelerations exhibit a positive correlation with the depth of the polygon waveforms, rather than a linear correlation with the order of the wheel polygons. Furthermore, under the excitation of measured irregular wheel polygons, the dominant order of the wheel polygons is identified as the primary influencing factor on the axle box vibration accelerations.关键词：locomotive;wheel polygon;rigid-flexible coupling;vibration response
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发布时间：2024-08-01 - 摘要：During the operation of high-speed trains, the loads on the gearbox are very complex, and cracks often occur in the boxbody. To ensure the service safety of the gearbox body, a dynamic model of high-speed trains with a gear transmission system was established based on SIMPACK. Comparative analysis of the vibration response of the gearbox rigid body at speeds of 200 km/h, 250 km/h, 300 km/h and 350 km/h was conducted, considering only track excitation and both gears internal excitation and track excitation. In addition, a rigid-flexible coupling dynamic model of a high-speed train considering a flexible gearbox body was established to analyze its impact on the vibration calculation results of the gearbox body. The results indicate that the internal excitation of the gearbox has a little impact on the lateral vibration acceleration of the gearbox body, but at the rotational frequency of the driving gear and the engagement frequency of the gears, the vertical vibration acceleration of the gearbox body will exhibit a peak value, which significantly increases its root mean square value, with an average increment of 4.8 m/s2. At a speed of 200 km/h, the resonance is caused by the similarity between the rotational frequency of the driving gear and the modal frequency of the gearbox pitching, resulting in a very significant increase in the root mean square value of the vertical vibration acceleration of the gearbox body. Therefore, when analyzing the vibration of the gearbox body, the internal excitation of the gearbox cannot be ignored. The flexibility of the gearbox body has a little impact on the lateral vibration acceleration of the gearbox body when considering the internal excitation, but it will reduce the root mean square value of the vertical vibration acceleration to some extent. The average reduction after the speed reaches 300 km/h is large, reaching 2.72 m/s2.关键词：high-speed train;gear transmission system;gearbox;vibration response;resonance
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发布时间：2024-08-01 - 摘要：This paper addresses the challenges associated with quickly computing far-field radiated noise originating from the bogie zone of high-speed trains. Initially, an assumption was given that countless dipole sound sources are distributed on the train surface, reflecting the predominant nature of dipole sound sources in the aerodynamic noise of high-speed trains. This assumption led to the establishment of an identification method, which was then used to identify sound sources in the bogie zone, with the support of Computational Fluid Dynamics (CFD). Through this identification process, the main dipole aerodynamic sources were found to be located near the walls of 11 components within the bogie zone, including cow catchers and front wheels. Subsequently, computational methods were established to determine the sound source intensity and far-field noise respectively for these components. The simulation results at three different speeds were utilized to establish a relational expression of the far-field sound pressure level of each component concerning frequencies, train speeds, characteristic sizes, and propagation distances through fitting. The far-field radiated noise from the 11 components was aggregated to create an empirical formula for calculating far-field noise from the bogie zone. These findings demonstrate the satisfactory accuracy of the fitted formula in quickly computing the far-field aerodynamic noise of the bogie zone, based on models of varying scales for high-speed trains. This methodology also offers a reference for establishing computational methods for aerodynamic noise radiation of other types of vehicles.关键词：high-speed train;bogie;dipole sound source;numerical simulation;wind tunnel experiment
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发布时间：2024-08-01 - 摘要：In order to investigate pressure variations on both the tunnel wall and train body surface when 140 km/h medium-low-speed maglev trains intersect in two-track tunnels, numerical calculations were performed, focusing on the effects of different parameters of the train/tunnel on the aerodynamic performance of the tunnel wall and train body surface. Moreover, a comparison was conducted across different train consist lengths and various tunnel clearance areas to assess their effects on internal train pressures. The results indicated an inversely proportional relationship between the peak value of pressure variations at measuring points on the tunnel wall and the 1.379th power of the tunnel clearance area, as well as between the peak value of pressure variations at measuring points on the train body surface and the 1.231st power of the tunnel clearance area during the intersection of 4-car maglev trains in the middle section of two-track tunnels. Additionally, under an airtightness index of 0.5 s, the pressure variations over 3 s at measuring points inside 8-car trains resulting from the intersection in tunnels with a tunnel clearance area of 66.2 m2 increased by 102.2%, compared with the 4-car scenarios. Under an airtightness index of 8 s, this figure decreased to 50.4%. The study findings of this paper provide a reference basis for the construction of tunnels to accommodate the operation of medium-low-speed maglev trains.关键词：maglev train;aerodynamic characteristics;two-track tunnel;aerodynamics;numerical calculation
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发布时间：2024-08-01 - 摘要：Torsional vibration represents a crucial aspect of vibration in power transmission systems, especially for rail engineering vehicles featuring long power transmission pathways. In this study, a multi-rigid-body torsional vibration model was created for the power transmission system of a hydraulic rail engineering vehicle. The analysis focused on the free and forced torsional vibration characteristics of the system. A comparison was conducted on the vibration responses of crankshafts with or without a torsional damper. Further study delved into the influence of elastic coupling parameters on the system's torsional vibration responses. The results highlight the single-node elastic coupling mode as the torsional mode with the lowest frequency. In the single-node torsional vibration mode, couplings with a torsional stiffness less than 0.005 7 MN∙m/rad are determined to effectively avoid resonance points from disturbance torques across all harmonics within the operational speed range. Torsional angular displacements at the crankshaft front end and torsional stress levels exhibit an increase with rising engine speeds. The introduction of a torsional damper lead to a significant reduction in the torsional vibration responses of the crankshaft. At idle speed (600 r/min), controlling the relative damping coefficient of couplings between 0.5 and 2.0 significantly reduces the output torque inequality, while at high speeds (1 800 r/min), a lower damping coefficient is conducive to mitigating this inequality. In order to adapt to both idle and high-speed conditions, it is recommended to keep the relative damping coefficient of couplings as minimal as possible, such as 0.5.关键词：hydraulic;rail engineering vehicle;power transmission system;torsional vibration
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发布时间：2024-08-01 - 摘要：Utilizing the multi-body dynamics software Simpack, a dynamics model was established for an articulated hot metal ladle car. The axle load distributions across different articulated positions were obtained from both theoretical calculations and simulations. Based on a comparative analysis the curve passing performance of the hot metal ladle car at different articulated positions, the optimal articulation position was determined, taking into account the axle load distributions, and the nonlinear critical speed of the hot metal ladle car at this optimal articulation position was verified. Further exploration was conducted to investigate the influence of line parameters, such as track irregularities and curve radii, as well as operating speeds on the operational safety of the car on small-radius curves. The results indicate that the optimal articulation position can be attained when the longitudinal distance from the center of the bolster spring to the first position wheelset's center is half of that to the articulation point at the rear arm of the middle axle box, ensuring a balanced load distribution among the car axles and the optimal curve passing performance. The nonlinear critical speed of the hot metal ladle car is identified to be 40 km/h, which meets the operational requirements with a safety margin. Moreover, track irregularities exert a significant influence on the operational safety performance indexes of the car on small radius curves, followed by curve radii. In contrast, the influence of curve superelevation is found less significant. Meanwhile, operating speeds are chosen to ensure operational safety under different track irregularity and curve radius conditions.关键词：hot metal ladle car;dynamic performance;articulated three-axle bogie;axle load balance;curve passing safety;operating parameter
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发布时间：2024-08-01 - 摘要：To enhance the curve negotiation performance of high-temperature superconducting (HTS) maglev trains equipped with a rigid levitation frame, this paper proposes a semi-decoupled levitation frame structure with specific degrees of freedom in both pitching and yawing. Initially, a dynamic theoretical model for HTS maglev trains was established, utilizing linear characteristics derived by simplifying the levitation and guidance forces stemming from HTS. This theoretical model was confirmed rational following the validation through dynamic response simulations conducted using UM software under periodic excitations. Subsequently, UM software was further utilized to assess the horizontal curve-passing performance of HTS maglev trains. Furthermore, comparisons were made regarding the impacts of different vertical and lateral torsional rigidities of levitation frames, along with varying air spring vertical rigidities on Dewar lateral and vertical displacements. The simulation results indicate improved adaptability in the proposed semi-decoupled levitation frame with specific pitching and rolling degrees of freedom on curved and twisted track configurations. By reducing the adverse effects of the framework on the levitation system and maximizing the pinning effect characteristics of HTS, this approach demonstrates effective in enhancing the trains' curve-passing performance. Additionally, an appropriate air spring rigidity is also found a contributor to effectively suppressing Dewar vibration, thus further ensuring the operational quality of trains. This paper conclusively proposes a levitation system solution that aligns with the safety requirements of train operation, displaying a strong potential to improve the curve-passing performance of HTS trains.关键词：high-temperature superconducting (HTS) maglev;levitation frame;Horizontal curve;UM simulation
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发布时间：2024-08-01 - 摘要：Conducting secondary development on CAE software for post-processing stands as an efficacious approach to evaluate fatigue strength in welded frames of railway vehicles. This paper presents a fatigue strength evaluation program for welded frames, employing ABAQUS as the platform and utilizing Python language along with the ABAQUS/GUI toolkit. This program is devised to rapidly extract data from result files, process them, establish local coordinate systems of base metal and welds, and generate comprehensive material utilizations at evaluation points in the local coordinate systems based on the DVS 1612 standard, and write them into result files, enabling rapid analysis and visualization of fatigue strength in welded frames. The proposed approach offers an efficient and feasible way for evaluating fatigue strength in welded frames. This study provides valuable insights for extending the applications of ABAQUS secondary development for post-processing in other domains.关键词：ABAQUS secondary development;python;frame;fatigue strength;DVS 1612 standard;visualization
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发布时间：2024-08-01
Railway Rolling Stock
- 摘要：In response to the longitudinal impulse issue caused by wheel slip under low-adhesion contact conditions, this paper established a vertical-longitudinal coupled dynamics model for a 20,000-ton heavy-haul train in a '1+1' formation. A comparative analysis was conducted to examine the impact of different wheel/rail contact states on the longitudinal impulse of the 20,000-ton train under electric braking conditions. The impact of wheel slip position and electric braking force loads on the longitudinal impulse was calculated separately. The results indicate that under electric braking operation, wheel slip was detected for the train under wet, oily and icy contact conditions when the train applies 100% electric braking force. In contrast, under 25%~75% electric braking conditions, wheel slip was only detected when the train under icy contact conditions. Wheel slip led to fluctuations in the coupler forces, particularly when wheel slip occurred in the middle locomotive, causing significant fluctuations in the coupler forces at the front, middle, and rear of the middle locomotive and increasing the coupler force at the front of the middle locomotive, thereby seriously affecting the smooth operation of the train. As the braking force decreased, the impact of wheel slip on the maximum coupler force reduced significantly under low-adhesion contact conditions.关键词：heavy-haul train;wheel/rail adhesion;longitudinal impulse;re-adhesion anti-slip control
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发布时间：2024-08-01 - 摘要：Bench experiments play a crucial role in studying the eddy-current braking characteristics. The longitudinal end effect significantly influences experimental results, when the number of magnetic poles used in these experiments is below the design level. Therefore, studying the generating mechanism of this effect and correction methods become imperative. This study introduced experimental schemes with varying magnetic pole counts to verify the influence of the end effect on braking force and dynamic attractive force. The study employed 2-D finite element electromagnetic simulations to extract the distribution patterns of the magnetic field, eddy current density, and Lorentz force, elucidating the generating mechanism of the end effect. By calculating the braking force of individual magnetic pole at different speeds, the study inferred the contribution of the end magnetic pole to the braking force, deriving the correction formulation of end effect. The study results show that a minor influence of the end effect on the dynamic attractive force, while a significant impact on the braking force, necessitating correction solely for the braking force. The braking force of the leading pole is identified nearly equal to that of the intermediate pole, while that of the trailing pole is lower and its contribution is approximately linearly related to speed. By correcting the braking force experimental data using a trailing pole contribution function, a notable reduction in the relative error between the correction results and the braking force derived from 3-D finite element simulations is observed. The research findings serve as a reference for the design of eddy-current braking experiments and the processing of experimental data. This enhancement contributes to a better comprehending of accurate eddy-current braking characteristics, thereby offering guidance in product research and development.关键词：eddy-current braking;permanent magnetic eddy-current braking;end effect;electromagnetic braking;electromagnetic simulation;high-speed train
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发布时间：2024-08-01 - 摘要：This paper introduced in detail the theoretical basis, control effects, and limitations associated with existing power correction control methods for plateau diesel locomotives in different application scenarios, and proposed an adaptive power control strategy, considering the power correction requirements of diesel locomotives operating at high altitudes as the design input. Through a thorough examination of operating characteristics of diesels and complex operating conditions at high altitudes, an algorithmic model was established to capture the relationships between diesel power outputs and parameters such as altitude, ambient temperatures, supercharger exhaust temperatures, and supercharger speeds. Subsequently, a full-scenario adaptive diesel power correction control algorithm was designed, taking into account the fluctuating features in post-intercooling temperature differences between the leading and other locomotives while operating under coupled conditions in tunnels. Furthermore, the validity of the proposed algorithm was verified through field experiments, where the power outputs of the diesels were maximized while ensuring their operational reliability.关键词：plateau diesel locomotive;power correction;supercharger exhaust temperature method;coupled multiple locomotives;adaptive control
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发布时间：2024-08-01 - 摘要：The traction system of urban rail transit vehicles is recognized as one of the main electromagnetic interference sources significantly impacting the electromagnetic compatibility of trains, primarily attributed to the implementation of pulse width modulation control, which involves high voltage, high current, and pulse interference characteristics. This study analyzed the main electromagnetic emission loops of the traction inverter system, taking into account both the vehicle system design and the flow path of electromagnetic interference current. By establishing a simplified calculation model for high-frequency interference currents, this study explored the method for designing filtering parameters aimed at reducing electromagnetic emissions from the traction system. Moreover, a comparative simulation was conducted to evaluate the suppression effects of various filtering schemes. Finally, the effectiveness of the proposed optimization method was verified by external radiation emission tests using trains.关键词：urban rail transit vehicles;traction system;electromagnetic interference;filtering design;vehicle radiation
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发布时间：2024-08-01
Electric Traction and Control
- 摘要：The classical Iterative Closest Point (ICP) registration algorithm is commonly applied to rail profile wear detection systems. However, during the operation of track inspection vehicles, the profile data collected by the rail profile wear detection system based on linear structured light is often disrupted by noise from various outliers, leading to significant geometric variations in the rail profile calculation results. Given the dynamic detection accuracy requirements for rail profile wear using track inspection vehicles of ±0.5 mm for lateral wear and ±1.0 mm for vertical wear in practical applications, it is crucial that the design of wear detection algorithms do not compromise the detection accuracy due to outlier-induced noise in the profile data. To address this, this paper presented an improved two-stage rail profile wear detection algorithm. In the first stage, this algorithm enabled rapid initial registration based on feature point pairs extracted from the rail profile, providing an improved initial pose for the two point clouds. The second stage utilized an enhanced robust ICP algorithm for precise registration, followed by calculating geometric parameters related to rail profile wear. A laboratory experimental platform was set up to evaluate the developed rail profile wear detection system. This setup simulated typical disruptions from outliers in the measured data of rail web and rail base segments, in comparison with the measurements obtained using a manual contact-type wear tester for benchmarking. Moreover, the accuracy errors and effectiveness of wear detection were analyzed by comparing the classical ICP algorithm and articles with the proposed improved algorithm. Furthermore, a comparative evaluation was conducted to examine the detection speed of the algorithms, and the accuracy in repeatability measurements using the improved algorithm was verified. Finally, validation was conducted on a metro line using a track inspection vehicle, and the results highlighted the enhanced accuracy and speed of rail profile wear detection based on the improved algorithm in scenarios with disruptions from outliers, demonstrating the practical engineering value of the proposed algorithm.关键词：rail profile;profile registration;rail wear;feature points;robust ICP algorithm
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发布时间：2024-08-01 - 摘要：Safety incidents caused by pedestrians illegally intruding onto railway tracks occur frequently in rail transit scenes, significantly affecting the safe operation of trains. Utilizing single sensor data for pedestrian detection often leads to low recall rates of detection results and lack of category or orientation information in the results, which cannot meet practical field requirements. To address these issues, this paper proposed a pedestrian detection method based on the fusion of 3D point clouds and images in rail transit scenes. This method first employed a deep learning model trained on a constructed dataset of pedestrian data in rail transit scenes to detect pedestrians separately in 3D point clouds and images. Subsequently, based on the principle of spatial position consistency of the targets in 3D point clouds and images, the rotation and translation matrix between the LiDAR and camera was solved. Finally, the 3D point cloud object detection results were projected onto the image coordinate system. To solve the issues of misalignment between multiple adjacent targets and the one-to-many relationship between detection results, the intersection over union ratio and center point distance between the two detection results were calculated as fusion constraints, enabling more accurate pedestrian detection. Experimental results using data acquired from the field demonstrate that, compared to detection results from separate data of 3D point clouds and images, while maintaining timeliness, this method improves the recall rate by 4.5% and 5.5%, respectively, effectively reducing the risk of safety accidents caused by missed pedestrian detections, meeting the demand for pedestrian detection during actual train operations.关键词：3D point clouds;image detection;deep learning;multi-sensor fusion;object detection
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发布时间：2024-08-01 - 摘要：As an effective means to diagnose the insulation status of on-board cable terminals, partial discharge detection faces strong interference in the actual operating environment of trains. To address this issue, this paper proposed a strategy for separating partial discharge pulses of on-board cable terminals based on waveform parameter analysis and fuzzy C-means clustering. A partial discharge test platform was built in the laboratory, and high-frequency current transducers (HFCT) were used to acquire partial discharge signals and the typical pulse interference signals from cable terminals. By performing envelope analysis on individual pulses, three parameters of the pulses were extracted as the feature vectors. Subsequently, fuzzy C-means clustering was employed to separate the partial discharge signals from the pulse interference signals. The experimental results demonstrate that the proposed method can effectively separate partial discharge signals from pulse interference signals, reducing the impact of pulse interference on partial discharge detection, and is of some significance in improving the accuracy of assessing the insulation status of the on-board cable terminals through partial discharge means.关键词：EMU;cable terminal;partial discharge;pulse interference;fuzzy C-means clustering
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发布时间：2024-08-01 - 摘要：The increasing demand for transportation by the public has directly promoted the opening and expansion of train services and routes, which has also led to increasing pressure on the daily inspection work for trains. As an important part of ensuring train braking safety, the tightness detection of air braking pipeline is indispensable in daily train inspection. To meet practical needs and address deficiencies in the current capabilities of intelligent inspection robots, this paper introduced a dual-arm robot platform. Based on the principle of turbulence generated by small leakage holes and the subsequent generation of ultrasonic waves, a "one board, two ends" structural design was adopted to design and develop an ultrasonic detection device for air leakage. The design focused on the structure and hardware configuration of the device from the aspects of signal acquisition, signal amplification and filtering preprocessing capabilities. In addition, an algorithm for air leakage detection was designed based on FFT and the Parseval's theorem. By simulating the air leakage conditions of small holes with different diameters (0.125 mm, 0.200 mm and 0.400 mm) under different conditions, the experimental prototype was verified to be able to receive and correctly judge air leakage signals within a range of 50° cone angle and 600 mm distance in a 0.3 s acquisition time.关键词：daily train inspection;dual-arm robot;air leakage;ultrasonic detection;urban rail transit
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发布时间：2024-08-01
Intelligent Technology
- 摘要：To achieve energy conservation, emission reduction, and low-carbon development in electrified railways, and address the issues of negative sequence and electrical phase separation, this paper proposes a control method for co-phase power supply system of hydrogen containing power generation and energy storage device. Firstly the topology and basic principle of the system was analyzed; then, a collaborative control strategy for the system was proposed, on this basis, energy management strategies under different operating conditions were further analyzed, and the control method for co-phase compensation, hydrogen power generation, and energy storage devices were derived; and finally case analysis was carried out, the feasibility and effectiveness of the proposed method were verified by building a system simulation model from two aspects: power quality compensation effect and typical working condition, and the economical efficiency of connecting hydrogen storage devices was studied according to the system operation analysis result based on the measured data. The results show that the proposed method can effectively control the operation of hydrogen power generation and energy storage devices, optimize the energy consumption structure and regenerative braking energy utilization efficiency of electrified railways, and effectively solve the problems of negative sequence and electrical phase separation, thus creating certain economic benefits.关键词：co-phase power supply;collaborative control;energy storage technology;hydrogen power generation
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发布时间：2024-08-01 - 摘要：Overlaps serve vital components of the overhead contact system (OCS) on high-speed railways, and their dynamic behaviors directly affect the current-collecting performance of the pantograph-catenary systems in the high-speed operational conditions of trains. Instances of dropper breakage and other failures have been prevalent in overlap sections along high-speed railways, directly threatening the operational stability of the pantograph-catenary systems. Studying the dynamic behaviors of overlap sections under the influence of dropper failures holds important significance in guaranteeing the current-collecting performance of the pantograph-catenary systems. This study focused on the overlap sections within the catenary system of a high-speed railway. Based on a three-dimensional overlap model created using the finite element method, a pantograph-catenary coupling model incorporating the overlap sections was established. This model was utilized to analyze the influence of various operating speeds on the pantograph-catenary coupling contact force, and to delve into the dynamic behaviors of the overlap sections under the influence of dropper failures. The results from simulation calculations indicate the efficacy of the established model in accurately representing the dynamic behaviors. Dropper failures at the overlaps significantly degrade the current-collecting performance and the dynamic behaviors of neighboring droppers, elevating the risk of dropper breakage. Therefore, assessing the condition of droppers at overlaps is necessitated during the OCS patrol inspections.关键词：overlap;current-collecting performance;pantograph-catenary system;dropper failure;dropper breakage;simulation;high-speed railway
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发布时间：2024-08-01
Railway Electrification
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