JOURNAL OF THE JAPAN SOCIETY FOR AERONAUTICAL AND SPACE SCIENCES
Online ISSN : 2432-3691
Print ISSN : 1344-6460
ISSN-L : 1344-6460
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Paper
  • Yoshikazu Miyazawa, Eri Itoh
    2020 Volume 68 Issue 6 Pages 213-222
    Published: 2020
    Released: December 05, 2020
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    The performance of incoming air traffic flow control to Tokyo International Airport is studied using surveillance data for future automatic arrival management system development. A probabilistic model that simulates the queueing mechanism of air traffic flow control is built from the time data of all flights that cross the boundaries of appropriately assumed traffic control area. The probabilistic model presents the nature of daily changes in air traffic flow control. Monte Carlo simulations using the model predict variations in flight time delay due to various conditions, such as spacing accuracy and incoming traffic density fluctuation. This paper quantitatively evaluates the importance of spacing accuracy to reduce delay time due to increasing air traffic volume. It demonstrates the effectiveness of a practical method of controlling spacing more appropriately to comply with the minimum spacing regulation of the wake turbulence category depending on the weight of aircraft.

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  • Masayuki Sato
    2020 Volume 68 Issue 6 Pages 223-231
    Published: 2020
    Released: December 05, 2020
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    This paper addresses the design problem of Fault-Tolerant Control (FTC) for airplane longitudinal motions against possible elevator efficiency reduction. The supposed FTC is composed of a feedforward gain and the conventional airplane control system, i.e. Stability/Control Augmentation System (S/CAS). The FTC is required to maintain good tracking performance with respect to pitch angle control under time-invariant plant modeling errors as well as time-varying possible elevator faults. The design problem is then formulated as structured robust H controller design for parameter-dependent systems, i.e. single structured H controller design for parameter-varying plant models. It is hard to obtain the globally optimal controllers for the problem due to the structural constraint for the controllers and the parameter-varying plant models. We thus adopt two-step design, viz., we first design a single common structured H controller for finitely many plant models using non-smooth optimization technique, which has been implemented to Matlab® as hinfstruct, under the supposition that the elevator faults are time-invariant, and we then check the control performance of the designed FTC for the parameter-varying closed-loop system via Linear Matrix Inequality (LMI) condition. The control performance is examined via linear simulations as well as hardware-in-the-loop simulations.

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  • Masato Okamoto, Akira Shirakawa
    2020 Volume 68 Issue 6 Pages 232-240
    Published: 2020
    Released: December 05, 2020
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    The aerodynamic characteristics of the thick stream-lined airfoil were studied by conducting the wind tunnel tests at Reynolds number ranging between 3×103 and 7×104. The Reynolds number based on the wing chord of insect wings is less than 1×104 and that of bird wings is more than 1×104. The aerodynamic characteristics of airfoils are strongly affected by the leading-edge thinness. The thin leading-edge which was obtained by attaching the thin flat plate at the rounded leading-edge was effective at lower Reynolds numbers. However the stream-lined airfoil with rounded leading-edge performed well at higher Reynolds numbers. The course of this phenomenon was the laminar separation bubble generated on the upper surface of the wing. The Reynolds number effects on the leading-edge profiles for the thick stream-lined airfoils were cleared in this paper.

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