研究者詳細 - 平木　講儒

論文 - 平木　講儒

分割表示78 件中 1 - 20 件目／全件表示 >>

Attitude Determination and Control System Design for a 3U CubeSat to Monitor Forward Light Scattering over Earth Horizon 査読有り

Mehmet Esit, Kudakweshe Jeje , Ratatamanun Subsinchai , Rodrigo Cordova , Minh Anh Pham , Necmi Cihan Orger , Victor Schulz , Koju Hiraki , Mengu Cho

74 th International Astronautical Congress 2023年10月

Global Trajectory Optimization for Solar-Sail Propelled Mercury Rendezvous and Impact Missions 査読有り

Amirul Fiqri Abdullah, Bernd Dachwald, Renuganth Varatharajoo , Yew-Chung Chak, Koju Hiraki and Letícia Barros

6th International Symposium on Space Sailing 2023年06月

Comparative Study on Trajectory Optimization for Solar Sail Mercury Mission

Mehmet ESIT, Leticia BARROS, Koju HIRAKI

34th International Symposium on Space Technology and Science 2023年06月

Evaluation of Folding-Pattern Designs for Large-Scale Square Solar Sail

Leticia SANTOS LULA BARROS, Koju HIRAKI, Hiroki MIYAGAWA, Mehmet ESIT, Yew-chung CHAK ,Renuganth VARATHARAJOO, Amirul FIQRI ABDULLAH, Bernd DACHWALD

34th International Symposium on Space Technology and Science 2023年06月

Digital streak imaging of compressible flows 査読有り

V. Sridhar, K. Hiraki, S.L. Gai, H. Kleine

Optics and Lasers in Engineering ( Elsevier ) 160 2023年01月

Rotational Motions of Axisymmetric Blunt Body in Different Degrees of Freedom

K. Hiraki, Y. Kuronuma, M. Sakai, H. Kliene

Proceedings of 33rd International Symposium on Space Technology and Science 2022年03月

Electromagnetic Stabilization System Algorithm During Energy Restriction Mode for the Near-Symmetric Satellite 査読有り国際誌

P. Zheliabov, E. Lapkhanov, D. Faizullin, A. Kulabukhov, K. Hiraki

International Review of Aerospace Engineering 15 ( 1 ) 62 - 70 2022年02月

The Experimental Study of Ultra Fine Bubbles in Coolant on Surface Grinding 査読有り

K. Hiraki, M. Sakai, S. Tamaki, T. Watanabe, R. Takada, K. Ushijima

Proceedings of International Conference on Leading Edge Manufacturing in 21st century : LEM21 2021年11月

Effect of Solidity on Efficiency for High-Advance-Ratio Propeller 査読有り

K. Hiraki, H. Kai

Proceedings of 2021 Asia-Pacific International Symposium on Aerospace Technology 2021年11月

Damping Experiments of a Blunt Body with Rough Surfaces 査読有り

K. Hiraki, M. Sakai, H. Kleine

Proceedings of 2021 Asia-Pacific International Symposium on Aerospace Technology 2021年11月

Kite-Flying in High Altitude

HIRAKI Koju, TAKEI Ryosuke, MURAHASHI Reo

The Proceedings of the International Conference on Motion and Vibration Control ( 一般社団法人日本機械学会 ) 2020 ( 0 ) 10109 2020年01月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

<p>In order to investigate the feasibility of high-altitude flight of a kite, the static force balance on a mooring cable and a kite is considered. The kite is treated as a single-point mass and the mooring cable is divided to multiple fragments with mass. First, the kite-flying experiment is carried out to validate the analytical technique. The kite flies at a height of 94m and the measured tensile force is about 12N. Next, the flight at height of 5km is investigated analytically. Normally available polyethylene line can withstand the required load and the flight is shown possible. Moreover, it is shown that the 7km flight is also possible by using ultra-high-strength polyethylene fiber. For a higher-height flight it is not possible in the analyses made here.</p>

DOI： 10.1299/jsmeintmovic.2020.15.10109

CiNii Article

CiNii Research

その他リンク： https://ci.nii.ac.jp/naid/130008057334

Dynamic Motions of Re-Entry Bodies Induced by Rough Surface 査読有り

Koju Hiraki, Akihiro Aoki, Dmytro Faizullin, Harald Kleine

Proceedings of 32nd International Symposium of Space Technology and Science & 9th Nano-Satellite Symposium 2019年06月

Estimating sun vector based on limited in-orbit data 査読有り

Faizullin D., Hiraki K., Cho M.

International Review of Aerospace Engineering 12 ( 2 ) 101 - 108 2019年01月

記述言語：英語掲載種別：研究論文（学術雑誌）

This paper introduces an attitude and orbit determination system, in particular a sun vector determination algorithm, for HORYU-IV nano-satellite by Kyushu Institute of Technology (Kyutech). Usually, nano-satellites cannot use sensors with high specs because of limited budget and onboard space. In order to achieve the required accuracy of attitude determination, estimation algorithms combining different sources of attitude information should be used. One of the HORYU-IV missions has required sun vector information. In order to detect the sun angle, six sun sensors, which have originally been designed and developed by the authors, and five solar panels have been used. However, due to the narrow field of view and to the saturation property of these sensors, the duration of sun detection is quite limited. At a non-detection period, a gyro sensor is used in order to propagate the attitude. However, the sensor has the bias error in its measured value. Hence, the Extended Kalman Filter has been used in order to estimate the sun vector and the bias error of gyro sensors. A simulation result shows that the algorithm can estimate the sun vector in 1deg accuracy.

DOI： 10.15866/irease.v12i2.16189

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85070450565&origin=inward

Simultaneous time-resolved density-sensitive visualization of high-speed flows 査読有り

Kleine H., Hiraki K., Nonaka S.

Proceedings of SPIE - The International Society for Optical Engineering 11051 2019年01月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

By using two high-speed cameras and a slightly extended visualization setup (typically based on a Toepler system) one can generate two simultaneous time-resolved records of the same flow, where these records can be obtained with different visualization methods, different spatial and different temporal resolutions. This allows one to generate visualizations that can complement each other in various ways and thus yield a considerably increased amount of information on the observed flow.

DOI： 10.1117/12.2523565

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85061807597&origin=inward

Improvement of Efficiency of Darrieus Turbine by Pitch Variation 査読有り

Koju Hiraki, Katsuhiro Henzan, Koju Hifumi

Proceedings of the Thirteenth ISOPE Pacific-Asia Offshore Mechanics Symposium 2018年10月

Improvement of Self-Starting of Darrieus Turbine by Pitch Variation 査読有り

Koju Hiraki, Katsuhiro Henzan

Proceedings of the 4th Asian Wave and Tidal Energy Conferece 2018年09月

Flow Induced Motions observed in Blunt Body with Free Rotational Apparatus in Three Degrees of Freedom 査読有り

K.Hiraki, S.Otomo, A. Aoki, K. Tanaka, H. Kleine

AIAA Aviation Forum 2018年06月

Flow induced motions observed in blunt body with free rotational apparatus in three degrees of freedom 査読有り

Hiraki K., Otomo S., Tanaka K., Faizullin D., Kleine H.

2018 Fluid Dynamics Conference 2018年01月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

For an investigation of the dynamic stability of a blunt body in a wind tunnel, a free rotational apparatus in three degrees of freedom (3-DOF) is developed. This 3-DOF apparatus allows a model to rotate simultaneously about the pitch, yaw and roll axes. With this apparatus dynamic tests are carried out for a blunt in flows of various Mach numbers. In flows below Mach 0.6 the model exhibits oscillations in pitch with an amplitude of more than five degrees. Especially in the flow of Mach 0.3, it shows this oscillation not only in pitch but also in yaw. It should be noted that the model also rotates along its longitudinal axis. In the flow of Mach 0.9 no obvious oscillation is observed. In order to visualize the flow which induces such oscillations and the rotation, a combined technique of schlieren and tufts is applied. From the comparison of the flow visualization images at Mach 0.3 and 0.6, an obvious difference is found in the flow reattachment on the back surface of the model. The results by the differential-pressure measurement supports that the flow reattachment on the back surface of the model happens asymmetrically, and it generates a rolling moment.

DOI： 10.2514/6.2018-3235

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85051282082&origin=inward

Improvement in efficiency of Darrieus turbine by pitch variation 査読有り

Hiraki K., Henzan K., Hifumi K.

13th ISOPE Pacific/Asia Offshore Mechanics Symposium, PACOMS 2018 315 - 318 2018年01月

担当区分：筆頭著者記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

In order to improve the performance of Darrieus turbine, the pitch angles of the blades are varied and tested in a low-speed wind tunnel. First, the pitch angles of the blades are varied with an interval of 15 degrees, to evaluate the possibility of the improvement. The tested tip-speed ratio is ranged from 0.5 to 2.8, which covers the peak of the power, and the generated torque is measured by a torque meter. However, none of the blades exceed the performance of zero-pitched blade. Then, the pitch angles of the blades are varied but with an interval of 2 degrees. As a result, it is found that the blades with pitch angle of 4 and 6 degrees give the highest torque, especially in a tip-speed ratio over 1. By changing the pitch angle of the blade from 0 to 6 degrees, the peak value of the power coefficients is improved by more than 30 percent.

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85059435746&origin=inward

Development of Dragonfly-Like Flapping Robot 査読有り

Kizu T., Inoue M., Yoshino K., Hiraki K.

Proceedings - 4th International Conference on Applied Computing and Information Technology, 3rd International Conference on Computational Science/Intelligence and Applied Informatics, 1st International Conference on Big Data, Cloud Computing, Data Science and Engineering, ACIT-CSII-BCD 2016 87 - 92 2017年05月

記述言語：英語掲載種別：研究論文（国際会議プロシーディングス）

In this study, we aimed to develop a dragonfly-like flapping robot with four wings and achieve advanced flight such as hovering and sudden turn. We developed a two-wings-flapping-robot that links the flapping motion moving the wing up and down and feathering motion twisting the wing and perform at the same time. Next, we investigated the performance of the developed robot whether it's possible to control it. In the end, in order to control the vertical of the aircraft we modeled the robot and simulated.

DOI： 10.1109/ACIT-CSII-BCD.2016.028

Scopus

その他リンク： https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=85020203957&origin=inward

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