Kenji Minesugi

Japan Aerospace Exploration Agency, Chōfu, Tokyo, Japan

Are you Kenji Minesugi?

Claim your profile

Publications (52)37.93 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: The three telescopes on Hinode, a highly sophisticated solar observational satellite, must be able to simultaneously observe the same point on the sun in order to ascertain data on the physical mechanisms for activity and heating in the solar atmosphere. To fulfill this mission requirement, the telescopes must remain co-aligned to within 2.0 arcsec under the temperature fluctuations the satellite experiences while orbiting the earth. Hinode consists of two modules and a connecting structure. Most of the structural elements are made of CFRP in order to suppress thermal deformations. In particular, the laminate configuration of the CFRP in the module holding the telescopes was carefully designed in terms of not only its stiffness and strength but also its coefficient of thermal expansion and thermal conductivity. A thermal deformation analysis was performed to estimate the co-alignment drift on-orbit and a thermal deformation test was conducted to verify the estimation. The results showed that the structural design would sufficiently suppress the drift on-orbit. Measurements on-orbit were conducted using the image of the sun, and the measured drift was in good agreement with the estimation.
    No preview · Article · Mar 2013 · Transactions of the Japan Society for Aeronautical and Space Sciences
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper exhibits a novel invention: "digital self-powered autonomous" vibration-suppressor using a digital micro-processor. The invented unit is a completely self-powered vibration-suppression system that does not require any external power-supply at all. Nevertheless, this digital, self-directive, and self-powered approach enables the system to be programmable and thus versatile in control scheme implementation. The digital-autonomous suppressor is much more advanced and progressive than previously proposed analog-autonomous ones that are clumsy and awkward. This digital system can be implemented in multiple-input multiple-output systems to suppress even complicated structural vibration, such as multi-modal vibration. To our best knowledge, our invention is the first one in the world, and quite useful for various applications to energy-saving or energy-shortage systems, such as large space structures, artificial satellites, and isolated lunar bases, which all are vulnerable to long night-time. Copyright © 2011 by the American Institute of Aeronautics and Astronautics, Inc.
    No preview · Conference Paper · Apr 2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: We conduct comprehensive investigation of a semiactive vibration suppression method using piezoelectric transducers attached to structures. In our system, piezoelectric transducers are connected to an electric circuit composed of the diodes, an inductance, and a selective switch. Our method (SSDI) makes better use of counterelectromotive force to suppress the vibration, instead of simple dissipation of vibration energy. We use an actual artificial satellite to verify their high performance compared to conventional semi-active methods. As a consequence, we demonstrate that our semi-active switching method can suppress the vibration of the real artificial satellite to as much as 50% amplitude reduction. In our experiment, we reveal that the suppression performance depends on how multiple piezoelectric transducers are connected, namely, their series or parallel connection. We draw two major conclusions from theoretical analysis and experiment, for constructing effective semi-active controller using piezoelectric transducers. This paper clearly proves that the performance of the method is the connection (series or parallel) of multiple piezoelectric transducers and the their resistances dependent on frequency.
    No preview · Article · Jan 2011
  • Hiroshi Okubo · Naoyuki Watanabe · Kenji Minesugi · Junjiro Onoda
    [Show abstract] [Hide abstract]
    ABSTRACT: Passive damping augmentation is one of attractive methods for vibration suppression to various kinds of structures because it is definitely stable and generally simple. Using viscous adhesive indicated a remarkable effect to the vibration suppression in the practical application to a satellite. In this paper, mathematical model of thin viscous adhesive layer using non-linear elements has been proposed. In this model, the characteristics of elements are correlated with non-linear internal phenomena of polymer. The simulation results using this proposal model are good agreement with experimental ones.
    No preview · Article · Jan 2011
  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper describes a problem that we encountered in our noise attenuation project and our solution for it. We intend to attenuate low-frequency noise that transmits through aircraft fuselage panels. Our method of noise attenuation is implemented with a piezoelectric semi-active system having a selective switch instead of an active energy-supply system. The semi-active controller is based on the predicted sound pressure distribution obtained from acoustic emission analysis. Experiments and numerical simulations demonstrate that the semi-active method attenuates acoustic levels of not only the simple monochromatic noise but also of broadband noise. We reveal that tuning the electrical parameters in the circuit is the key to effective noise attenuation, to overcome the acoustic excitation problem due to sharp switching actions, as well as to control chattering problems. The results obtained from this investigation provide meaningful insights into designing noise attenuation systems for comfortable aircraft cabin environments.
    No preview · Article · Jul 2010 · Smart Materials and Structures
  • [Show abstract] [Hide abstract]
    ABSTRACT: Acoustic management is essential for establishing a reliable and cost-competitive rocket system. A solid propellant motor during its lift-off imposes high levels of pressure and vibration on the fairing of the rocket, sometimes leading to crucial damage of the payload. One approach to resolve this problem is to decrease the sound sources caused by high-speed plume of the rocket booster. Japan Aerospace Exploration Agency (JAXA), aiming at the advanced solid rocket, started computational prediction that helps design a launch-pad with less acoustic impact. For validating the computation codes and modeling the acoustic characteristics, the experimental acoustic data of solid rocket motors have long been desired. Fortunately, we had opportunities of the ground firing tests with several motors. In this presentation, the acoustic measurement including the sensors, the set-up, and the data reduction carried out in these tests will be discussed.
    No preview · Article · Mar 2010 · The Journal of the Acoustical Society of America
  • Shigeru Shimose · Kenji Minesugi · Junjiro Onoda
    [Show abstract] [Hide abstract]
    ABSTRACT: We conducted various investigation of energy recycling semi-active vibration suppression method by using piezoelectric transducers attached to structures. In this method, piezoelectric transducers are connected to a shunt circuit with diodes and an inductance, and it makes better use of counter electromotive force to suppress the vibration. We had proposed some new ideas in order to upgrade this method. And we verified their high performances compared to conventional semi-active method by many experiments. In results of experiment that practically apply this method to an actual satellite structural model using lots of the piezoelectric transducer, it was found that vibration suppression performance depend on how piezoelectric transducers were connected each other. It is because their connection affects a resonance frequency and a total resistance of the shunt circuit. The performance of the method related to the connection of the piezoelectric transducers and their resistances dependent on frequency are described using experimental results in this paper.
    No preview · Article · Mar 2010 · Proceedings of SPIE - The International Society for Optical Engineering
  • S. Shimose · K. Minesugi · K. Makihara · J. Onoda
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper demonstrates, from viewpoint of electrical connection, comprehensive investigation of a semi-active vibration suppression method using piezoelectric actuators attached to structures. In our system, piezoelectric actuators are connected to an electric circuit composed of diodes, an inductance, and a selective switch. Our method (LR-Switching) makes better use of counter electromotive force to suppress the vibration, instead of simple dissipation of vibration energy. We use an actual artificial satellite to verify their high damping performance compared to conventional semi-active methods. As a consequence, we demonstrate that our semi-active switching method can suppress the vibration of the real artificial satellite to as much as 50% amplitude reduction. In our experiment, we reveal that the suppression performance depends on how multiple piezoelectric transducers are connected, namely, their series or parallel connection. We draw two major conclusions from theoretical analyses and experiment, for contracting effective semi-active controller using piezoelectric actuators. In this paper clearly proves that the performance of the method is the connection of multiple piezoelectric actuators and the their resistances dependent of frequency. Copyright ©2010 by the International Astronautical Federation. All rights reserved.
    No preview · Article · Jan 2010
  • K. Makihara · S. Takeuchi · S. Shimose · J. Onoda · K. Minesugi
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper demonstrates an innovative invention: "digital self-powered autonomous" vibration-suppressor using a digital micro-processor. Our invented unit is a completely self-powered vibration-suppression unit that does not require any external power-supply at all. Nevertheless, this digital, self-directive, and self-powered approach enables the vibration suppressor to be programmable and thus versatile in control scheme. The digital-autonomous suppressor is much more advanced and progressive than clumsy analog-autonomous ones. This digital system can be implemented in MIMO (multiple-input multiple-output) systems to suppress even complicated structural vibration. To our best knowledge, this invention is the first one in the world, and quite useful for various applications to energy-saving or energy-shortage systems, such as large space structures, artificial satellites, and isolated lunar bases, which all are subject to long night-time. Copyrihgt©2010 by the International Astronautical Federation. All rights reserved.
    No preview · Article · Jan 2010
  • [Show abstract] [Hide abstract]
    ABSTRACT: Acoustic measurements are executed in two series of static-firing tests of a solid rocket motor. The obtained data are quantitatively compared with calculation results of an empirical prediction method, NASA SP-8072 and CFD. According to the results, the NASA SP-8072 overestimates the sound pressure levels at the 20° and 35° points from the jet axis in the far field, although the SPLs at other measured points are reasonably predicted. On the other hand, the CFD calculation can clearly explain the generation and propagation mechanism of the acoustic wave and reasonably predict the SPLs at all the measured points. From the results, it is confirmed that the prediction accuracy of the CFD calculation is within 5 [dB] in overall sound pressure level, which is within the experimental uncertainty involved in the measured data, and the CFD is effective for the prediction of both the near and the far field acoustics generated from the rocket motors. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc.
    No preview · Conference Paper · May 2009
  • [Show abstract] [Hide abstract]
    ABSTRACT: BepiColombo is a ESA-JAXA joint mission to Mercury with the aim to understand the process of planetary formation and evolution in the hottest part of the proto-planetary nebula as well as to understand similarities and differences between the magnetospheres of Mercury and Earth. The baseline mission consists of two spacecraft, i.e. the Mercury Planetary Orbiter (MPO) and the Mercury Magnetospheric Orbiter (MMO). The two orbiters will be launched in 2013 in one Soyuz-Fregat 2B. JAXA is responsible for the development and operation of MMO, while ESA is responsible for the development and operation of MPO as well as the launch, transport, and the insertion of two spacecraft into their dedicated orbits. JAXA has made preliminary design of the MMO spacecraft system including the interface with the cruising composite system in collaboration with ESA) with selected payload. MMO is designed as a spin-stabilized spacecraft to be placed in a 400 km x 12000 km polar orbit. The spacecraft accommodates instruments mostly dedicated to the study of the plasma environment near and around Mercury. Selection of the PI responsible instruments was finished on 2004. EM design of MMO is almost finished. Subsystem level PDR was finished and system level PDR is planned to be held in March, 2008. 4th BepiColombo science working team (SWT) meeting, which discusses science related matters, was held on September 2007. In this paper, we will report the latest information of MMO project status.
    No preview · Article · Jan 2008
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: To understand the physical mechanisms for activity and heating in the solar atmosphere, the magnetic coupling from the photosphere to the corona is an important piece of information from the Hinode observations, and therefore precise positional alignment is required among the data acquired by different telescopes. The Hinode spacecraft and its onboard telescopes were developed to allow us to investigate magnetic coupling with co-alignment accuracy better than 1 arcsec. Using the Mercury transit observed on 8 November 2006 and co-alignment measurements regularly performed on a weekly basis, we have determined the information necessary for precise image co-alignment and have confirmed that co-alignment better than 1 arcsec can be realized between Solar Optical Telescope (SOT) and X-Ray Telescope (XRT) with our baseline co-alignment method. This paper presents results from the calibration for precise co-alignment of CCD images from SOT and XRT.
    Full-text · Article · Oct 2007 · Publications- Astronomical Society of Japan
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The X-ray Telescope (XRT) aboard the Hinode satellite is a grazing incidence X-ray imager equipped with a 2048×2048 CCD. The XRT has 1 arcsec pixels with a wide field of view of 34×34 arcmin. It is sensitive to plasmas with a wide temperature range from < 1 to 30 MK, allowing us to obtain TRACE-like low-temperature images as well as Yohkoh/SXT-like high-temperature images. The spacecraft Mission Data Processor (MDP) controls the XRT through sequence tables with versatile autonomous functions such as exposure control, region-of-interest tracking, flare detection, and flare location identification. Data are compressed either with DPCM or JPEG, depending on the purpose. This results in higher cadence and/or wider field of view for a given telemetry bandwidth. With a focus adjust mechanism, a higher resolution of Gaussian focus may be available on-axis. This paper follows the first instrument paper for the XRT (Golub et al., Solar Phys. 243, 63, 2007) and discusses the design and measured performance of the X-ray CCD camera for the XRT and its control system with the MDP.
    Full-text · Article · Jun 2007 · Solar Physics
  • Kanjuro Makihara · Junjiro Onoda · Kenji Minesugi
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper discusses a self-sensing vibration suppression method that measures only the value of the piezoelectric voltage. The method separates the electrical status into two cases concerning electrical current and characterizes each of these to establish a self-sensing system using extended system equations and a Kalman filter. Our self-sensing system can avoid estimation blackout during closed-circuit status and lessen harmful influences from residual modes. Experiments revealed that the self-sensing system suppressed vibrations in cooperation with state-switching and synchronized-switching controls. We confirmed that the self-sensing method is robust against model errors in a vibration suppression experiment in which there are model errors caused by an intentional frequency shift.
    No preview · Article · Feb 2007 · Smart Materials and Structures
  • Kanjuro Makihara · Junjiro Onoda · Kenji Minesugi
    [Show abstract] [Hide abstract]
    ABSTRACT: We enhanced the bang-bang vibration control by using an electrical resonance mechanism. The bang-bang method is used in many engineering applications because of its simplified hardware configuration in which a constant-voltage supplier is shared by multiple actuators. However, its control performance is restricted, because the supplied voltage is constant and the sharp modulation of the control input induces chattering, which wastes a significant amount of energy. Our approach to overcome these problems was to combine the bang-bang method with tuned electrical resonance. Based on an elaborate analysis of phase relations between mechanical and electrical vibrations, three switching logics were devised for the hybrid method. Experiments on a 10-bay truss structure demonstrated that our hybrid method not only enhanced vibration suppression of the bang-bang method, but also prevented control chattering. Copyright © 2006 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.
    No preview · Article · Feb 2007 · AIAA Journal
  • Kanjuro Makihara · Junjiro Onoda · Kenji Minesugi
    [Show abstract] [Hide abstract]
    ABSTRACT: This paper presents an extensive investigation on the LR-switching method (also called the energy-recycling semi-active method). Compared with the energy-dissipative R-switching method, the LR-switching method has been shown to have significantly better vibration suppression performance. However certain essential issues affecting a system employing the LR-switching method remained to, be dealt with. In particular we had to clarify its vibration suppression mechanism from the viewpoint of mechanical and electrical energy exchange. Second, the robustness of the method against model errors and control time delays had to be verified. The experiments and numerical simulations that we conducted on a 10-bay truss structure demonstrate that the LR-switching method outperforms other suppression methods under sinusoidal and random excitations, which are more common in real systems and more difficult to deal with than transient vibrations. This paper provides fundamental insights on the LR-switching method and gives the method a guarantee for actual applications.
    No preview · Article · Feb 2007 · Journal of Vibration and Acoustics
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The Hinode satellite (formerly Solar-B) of the Japan Aerospace Exploration Agency’s Institute of Space and Astronautical Science (ISAS/JAXA) was successfully launched in September 2006. As the successor to the Yohkoh mission, it aims to understand how magnetic energy gets transferred from the photosphere to the upper atmosphere and results in explosive energy releases. Hinode is an observatory style mission, with all the instruments being designed and built to work together to address the science aims. There are three instruments onboard: the Solar Optical Telescope (SOT), the EUV Imaging Spectrometer (EIS), and the X-Ray Telescope (XRT). This paper provides an overview of the mission, detailing the satellite, the scientific payload, and operations. It will conclude with discussions on how the international science community can participate in the analysis of the mission data.
    Full-text · Article · Jan 2007 · Solar Physics
  • K. Makihara · J. Onoda · K. Minesugi
    [Show abstract] [Hide abstract]
    ABSTRACT: We developed the novel control logic for a shock damper using particledispersion Electro-Rheological (ER) fluid. This is a high-powered means of shock attenuation for satellite instruments that are subjected to lift-off shock or pyrodevice ignition shock. The proposed method attenuates the shock so that the instrument's acceleration does not exceed the critical value, even when the shock is too large to be accepted. In contrast to the conventional linear shock controls, the proposed shock control does not attempt to attenuate a small shock in order to prepare for attenuating a coming large shock.
    No preview · Article · Jan 2007
  • Kanjuro Makihara · Junjiro Onoda · Kenji Minesugi
    [Show abstract] [Hide abstract]
    ABSTRACT: This novel control logic for a shock absorber using particle-dispersion Electro-Rheological (ER) fluid is a powerful means of shock attenuation for satellite instruments that are subjected to lift-off shock or pyrodevice ignition shock. Satellite instruments may be damaged when the acceleration generated by the input shock exceeds their critical acceleration value. The proposed method attenuates the shock so that the instrument's acceleration does not exceed the critical value, even when the shock is too large to be accepted. In contrast to conventional linear shock controls, the proposed shock control does not attempt to attenuate a small shock in order to prepare for attenuating a coming large shock. This innovative nonlinear control enables the absorber to effectively attenuate a powerful shock. Numerical simulations show that the new shock absorber system attenuates shocks better than a passive system or a conventional linear control system.
    No preview · Article · Jan 2007 · Transactions of the Japan Society for Aeronautical and Space Sciences
  • Kanjuro Makihara · Junjiro Onoda · Kenji Minesugi
    [Show abstract] [Hide abstract]
    ABSTRACT: A novel self-sensing method using piezoelectric actuators for semi-active vibration suppression is proposed and investigated. By using extended system equations, this self-sensing method can be implemented with a Kalman filter instead of the conventional bridge circuit technique. The method separates electrical status into two cases concerning electrical current, and characterizes each of these to establish the self-sensing system. This method is applicable to multiple-degree-of-freedom structures with multiple piezoelectric actuators. A numerical vibration suppression simulation demonstrated that the self-sensing method works well on a truss structure and has significant robustness against parameter variations. Experimental results also demonstrated that the self-sensing method suppresses not only single-mode vibration but also multiple-mode vibration.
    No preview · Article · Jul 2006 · AIAA Journal