IEEJ Transactions on Industry Applications
Online ISSN : 1348-8163
Print ISSN : 0913-6339
ISSN-L : 0913-6339
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Displaying 1-26 of 26 articles from this issue
Special Issue on “J-RAIL 2022”
Special Issue Paper
  • Hiroki Mukojima, Nozomi Nagamine
    2024 Volume 144 Issue 3 Pages 60-69
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    Railways are laid out with facilities scattered along the tracks. Therefore, human resources are required to check the status of such facilities. We have been developing a system that supports the maintenance of facilities along railway lines using video footage captured from the front of the train. In this paper, we propose a novel method to generate a more natural top-view image by changing the composition method. Although it is difficult to generate a top-view image of the entire running range of a train by generating a panoramic image, we confirm that our method can successfully generate a top-view image of the entire train run.

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  • Ryo Kageyama, Nozomi Nagamine
    2024 Volume 144 Issue 3 Pages 70-78
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    We present the development of a train forward surveillance method using a camera and sensors. In train forward surveillance methods for railroads, it is crucial to establish a sensor technology capable of reliably detecting distant obstacles hundreds of meters away. Therefore, we developed a detection method by sensor fusion between 4K camera and 3D LiDAR. Using a combination of a camera and nine LiDARs, we confirm that the proposed method can detect a person located 400m away with a detection rate of 94% and a car located 600m away with a detection rate of 100%. Moreover, based on the trend that detection performance improves as the number of LiDARs increases, we estimated the conditions required to reliably detect a person 500m away.

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  • Riho Maeda, Nozomi Nagamine, Wataru Goda, Yosuke Tsubokawa, So Kato
    2024 Volume 144 Issue 3 Pages 79-86
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    In railway track maintenance, the inspection of wooden sleepers is crucial for the safety of train operations. However, the inspection of wooden sleepers is basically performed through manual visual inspection by workers, which is time-consuming and labor-intensive. Therefore, we developed a wooden sleeper inspection system that uses images of the front of a train obtained by a camcorder. The proposed system uses deep learning to judge the deterioration of the images and ranks the degree of deterioration. This paper outlines the developed system, evaluates its judgment accuracy, and compares the results with judgments made by multiple train maintenance engineers. Accordingly, the accuracy of the proposed method in accurately judging the degree of deterioration reached 86.3% to 94.1% when compared with the experts' results, indicating that the developed deterioration judgment model has comparable performance to that of the train maintenance engineers in terms of judgment accuracy and distribution of answers.

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  • Tomoyuki Ogawa, Toshihide Yokouchi, Yoko Takeuchi, Tatsuhito Saito
    2024 Volume 144 Issue 3 Pages 87-93
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    In this study, we have developed a driver advisory system using a speed estimation technique developed for freight railways aiming to ensure energy-saving and punctuality. The driver advisory system focuses cruising driving operation for a freight railway by maintaining the planned time of passage station. The driver advisory system proposes a recommended driving operation for each passage station.

    First, we discuss an energy saving driving method called cruising driving for freight railways considering the running resistance and motor efficiency. As a result of an energy calculation, we found that is necessary to use constant-speed and saw-toothed driving operations properly depending on speed and load characteristics, including hauling mass and gradient of running line. Then, we have developed a driving operation assignment method using the speed estimation, which switches between constant-speed and saw-toothed driving operations depending on speed and load characteristics. Finally, we present a trial result focusing on energy consumption. We confirm the energy-saving effect comparing the energy consumption with or without the developed driver advisory system.

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  • Yosuke Yamazaki, Takahiro Fujimoto, Yoshiyuki Shimokawa, Hideki Minami ...
    2024 Volume 144 Issue 3 Pages 94-101
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    Despite ensuring the integrity of bogie frames for railway vehicles via nondestructive inspections during periodic maintenance, the possibility of fatigue cracks occurring at locations other than the predetermined inspection points cannot be dismissed. Therefore, fatigue cracks can be prevented more efficiently by assessing the overall degree of fatigue damage to the entire bogie frame and determining the results via nondestructive inspections. In this study, dynamic stresses in the bogie frame during running were estimated via finite element dynamic analysis by using the axle box acceleration as input, and the fatigue damage degree and life were calculated from the waveform of the estimated stresses. Furthermore, we developed a bogie frame fatigue prediction system based on a high- speed and high-precision stress calculation method. The developed system visualized the overall relative life.

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  • Shota Miyoshi, Wataru Ohnishi, Takafumi Koseki
    2024 Volume 144 Issue 3 Pages 102-111
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    Generating and modifying speed profiles for running trains is a crucial and evolving aspect of automatic train operation, aiming to achieve high-precision positioning during train stopping motions, traditionally managed through smart manual control. This study focuses on developing a feedforward control for train operation that ensures ride comfort by explicitly limiting the maximum jerk in the speed profile and enables rapid calculation with position-dependent and time-varying restriction parameters. This study proposes a feedforward control design method that creates a braking trajectory with minimum running time and satisfying position-dependent and ride comfort constraints. The method optimizes the stopping trajectory, that is a key factor in maintaining ride comfort and positional accuracy, through bang-bang jerk control. In the numerical train driving simulations, the speed profile complied with the ride comfort limit for acceleration and jerk, as well as the position-dependent speed and acceleration limits. The proposed method not only guarantees safety and comfort in the braking trajectory by explicitly limiting speed, acceleration, and jerk but also facilitates rapid recalibration of speed profiles on trains for adaptive response.

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Paper
  • Shota Miyoshi, Wataru Ohnishi, Takafumi Koseki, Motoki Sato
    2024 Volume 144 Issue 3 Pages 112-121
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    Precise variable output voltage control of boost converters has wide possibility of industrial applications. However, it is challenging owing to the nonlinear and nonminimum phase characteristic of the boost converter. In a previous study, the authors have proposed a nonlinear noncausal feedforward control method for precise control, and the experimental varidation was shown for a small load. This study verifies the validity of the proposed nonlinear noncausal feedforward control with current and voltage feedback control with a 10kW load, which is 500 times greater than the conceptual validation of the previous paper. The result confirms the effectiveness and validity of the proposed control method on a practical boost converter system.

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  • Masahiro Hori, Masanori Sawahata, Takafumi Hara, Minori Nagata
    2024 Volume 144 Issue 3 Pages 122-129
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    Electrification is progressing across different fields such as automobiles and construction machinery. Motors for electric systems are required to be compact and achieve high power density. In this study, we developed a small motor with rotation speed of 22000r/min by reducing stress concentration. Each pole has three magnets in the circumferential direction, and the magnets are arranged in a U-shape. The magnet insert slots are comprised of expanded flux barriers on the inner diameter side and a guide-less structure. The magnet slots reduce stress concentration. Additionally, the rotor has two dents on the outer diameter surface and expanded flux barriers on the outer diameter side. The dents have different shapes between the N and S poles. The structures reduce the torque ripple.

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  • Naoto Nakamura
    2024 Volume 144 Issue 3 Pages 130-139
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    The dual three-phase PMSM exhibits a current control destabilization phenomenon due to the magnetic coupling between each three-phase winding of the system; in particular, this problem is more difficult to solve in the case of the characteristics of each three-phase winding are different. This paper proposes a new current control method for dual three-phase PMSM with different winding characteristics. Proposed method achieves stabilization of the current control system of dual three-phase PMSM with close-coupling and is realized applying simple additional processing to independent PI controller of each system. This simple structure avoids increase computation load at the motor parameters changing. This paper verifies the performances of proposed method through the experimental result of current control of test motor.

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  • Hiroyasu Iwabuki, Shigeo Morimoto, Akihiko Iwata
    2024 Volume 144 Issue 3 Pages 140-148
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
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    In this study, we considered a stray-capacitance charge recovery circuit to reduce the switching loss of a high-voltage high-frequency inverter. The recovery circuit causes the reactor and stray capacitance to resonate to reduce the stray-capacitance charging voltage. This loss can be reduced by switching the MOSFET of the inverter when the voltage drops. In this paper, we first study the stray capacitance of the gate transformer, which is the cause of the loss increase. We then explain the circuit configuration and operation of the circuit that recovers this stray-capacitance charge. Next, the simulation results of the circuit operation are presented. Finally, according to the results from a prototype test, we show that it is possible to reduce the loss of the inverter main circuit and double the repetition frequency with respect to the conventional approach.

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  • Tomoya Shiono, Tomoyuki Tamura, Akira Nakano, Nobuo Satoh
    2024 Volume 144 Issue 3 Pages 149-155
    Published: March 01, 2024
    Released on J-STAGE: March 01, 2024
    JOURNAL RESTRICTED ACCESS

    We present a novel class-E switching method, and the design and fabrication of a class-Φ2n DC-DC converter based on such a method. To demonstrate the effectiveness of the proposed circuit, we compare the switching voltage waveforms of a class-Φ2 converter and a class-Φ2,4 converter, both constructed and validated for operation at 2.2MHz. The results confirm a 13.6% reduction in peak switching voltage for the class-Φ2,4 converter with respect to the class-Φ2 one, thereby proving the suitability of the former. Moreover, at 2.2MHz, the output power of the class-Φ2,4 converter is 37.8W, achieving a power conversion efficiency of 83.6%. A comparative assessment against a hard-switching circuit based on frequency spectrum analysis demonstrates the effectiveness of soft-switching operation in the proposed circuit.

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