| 1. |
Yuki Takao, Osamu Mori, Jun Matsumoto, Toshihiro Chujo, Shota Kikuchi, Yoko Kebukawa, Motoo Ito, Tatsuaki Okada, Jun Aoki, Kazuhiko Yamada, Takahiro Sawada, Shigeo Kawasaki, Shuya Kashioka, Yusuke Oki, Takanao Saiki, Jun’ichiro Kawaguchi, Sample return system of OKEANOS—The solar power sail for Jupiter Trojan exploration, Acta Astronautica, 10.1016/j.actaastro.2023.08.044, 213, 121-137, 2023.12. |
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Yuki Takao, One-Winged Momentum-Biased Solar Sail: A New Methodology for Propellantless Attitude Control, Journal of Guidance, Control, and Dynamics, 10.2514/1.g007289, 46, 7, 1331-1347, 2023.07, This paper proposes a new methodology for solar-sail attitude control that uses only momentum wheels. Different from conventional solar sails packaged in a central hub, the sailcraft is deployed in the direction of one side of the storage. In this single-wing configuration, the offset between the center of mass (c.m.) and center of pressure (c.p.) is large and lies in the sail plane. When specular reflection is dominant, solar-radiation-pressure (SRP) force vector points in the out-of-plane direction, thus causing an in-plane SRP torque orthogonal to the c.m./c.p. offset vector. Therefore, by placing a bias momentum in the c.m./c.p. direction, the sailcraft keeps rotating in the same plane while maintaining its orientation relative to the sun. Analysis reveals that the attitude motion of the one-winged momentum-biased solar sail is basically unstable, but the system can be stabilized in a neutral manner through minor control of the bias momentum. Furthermore, adding another control moment in the out-of-plane direction enables asymptotic stability. Control in the remaining in-plane direction makes it possible to avoid wheel saturation. Numerical simulations demonstrate that both attitude maintenance and maneuver can be performed and that the controller is robust to parameter errors.. |
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Yuki Takao, Analytical Model for Transverse Vibrations of Spinning Membranes, Journal of Spacecraft and Rockets, 10.2514/1.a35367, 60, 2, 481-498, 2023.03. |
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Yuki Takao, Osamu Mori, Masanori Matsushita, Nobukatsu Okuizumi, Yasutaka Satou, Junichiro Kawaguchi, Active Shape Control of Membrane Structures Using Spin-Synchronous Vibrations, Journal of Spacecraft and Rockets, 10.2514/1.a35084, 59, 1, 295-311, 2022.01, A novel approach for shape control of membrane structures is presented to realize their use in three-dimensional and variable configurations. The shape control is accomplished by exciting a spinning membrane. The membrane forms a shape consisting of several vibration modes, depending on the input frequency, and the wave surface stands still when its frequency is synchronized with the spin rate; that is, the wave propagation and the spin cancel each other, resulting in a static wave surface in the inertial frame. This idea enables control of continuous membrane structures with large deformation using fewer actuators than conventional methods. This paper describes the general theory of the static wave-based shape control. The mathematical model of membrane vibration, the classification of control input, and the control system for exciting a static wave are summarized. The proposed method is demonstrated through a ground experiment. A 1 m large polyimide film is rotated and vibrated in a vacuum chamber, and the output shape is measured using a real-time depth sensor. It is shown that the observed shapes agree with numerical simulation results. An additional simulation that models the Japanese solar sail Interplanetary Kite-craft Accelerated by Radiation Of the Sun (IKAROS) demonstrates that the proposed method also works with a practically large-scale membrane in the space environment.. |
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Yuki Takao, Toshihiro Chujo, Delta-V Earth-Gravity-Assist Trajectories with Hybrid Solar Electric–Photonic Propulsion, Journal of Guidance, Control, and Dynamics, 10.2514/1.g006136, 45, 1, 162-170, 2022.01. |
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Yuki Takao, Osamu Mori, Masanori Matsushita, Ahmed Kiyoshi Sugihara, Solar electric propulsion by a solar power sail for small spacecraft missions to the outer solar system, Acta Astronautica, 10.1016/j.actaastro.2021.01.020, 181, 362-376, 2021.04. |
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Yuki Takao, Osamu Mori, Jun’ichiro Kawaguchi, Analysis and design of a spacecraft docking system using a deployable boom, Acta Astronautica, 10.1016/j.actaastro.2020.10.031, 179, 172-185, 2021.02, Automated spacecraft docking is a technology that has long been pursued. Deep space explorers and small spacecraft can carry fewer resources for docking, such as navigation sensors or latching structures, than can their larger near-Earth counterparts. The concept of the probe-cone docking mechanism is an effective solution to this problem. In this approach, a probe attached to the chaser satellite is guided automatically to the connection part of the target satellite by a conical structure. It is important to have a shock attenuation mechanism at the docking interface to prevent the chaser from being bounced away from the target. In the present paper, an automated docking mechanism that uses a flexible and deployable boom as the probe is proposed, and results of an analysis of the multi-body system dynamics are presented. Although analytical investigations into docking dynamics have been reported, the dynamics depend on many interdependent design parameters, the interaction of which is yet to be investigated. The present work involved a numerical analysis of the effect of each design parameter on the satellite behavior. An energy-based index that can predict the success or failure of docking was also developed in this study. In addition, a design scheme for the parameters is presented based on the results of the analysis in which the optimal combination of the design parameters is determined by searching the solution space.. |
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Yuki Takao, Osamu Mori, Jun’ichiro Kawaguchi, Self-excited oscillation of spinning solar sails utilizing solar radiation pressure, Astrodynamics, 10.1007/s42064-018-0047-4, 4, 3, 177-192, 2020.09, © 2019, Tsinghua University Press. The present paper proposes a control method to excite spinning solar sail membranes for three-dimensional use. Using optical property switching, the input is given as the change in magnitude of the solar radiation pressure. The resonance point of this system varies with the vibration state due to its nonlinearity and the change in equilibrium state. To deal with this, a state feedback control law that automatically tracks the resonance point is developed in the present study. The proposed method enables decentralized control of the actuators on the sail, each of which determines the control input independently using only the information of vibration state. The proposed method is validated using numerical simulations. The results show that the nonlinear system behaves differently from the linear system, and the vibration grows using the decentralized control regardless of resonance point variation.. |
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Yuki Takao, Yuya Mimasu, Yuichi Tsuda, Simultaneous estimation of spacecraft position and asteroid diameter during final approach of Hayabusa2 to Ryugu, Astrodynamics, 10.1007/s42064-020-0078-5, 4, 2, 163-175, 2020.06, © 2020, Tsinghua University Press. This paper presents the optical navigation results of the asteroid explorer Hayabusa2 during the final rendezvous approach phase with the asteroid Ryugu. The orbit determination of Hayabusa2 during the cruising phase uses a triangulation-based method that estimates the probe and asteroid orbits using the directions from which they are observed. Conversely, the asteroid size is available as optical information just prior to arrival. The size information allows us to estimate the relative distance between the probe and the asteroid with high accuracy, that is strongly related to the success or failure of the rendezvous. In this study, the relative distance and asteroid size in real space are simultaneously estimated in real time by focusing on the rate of change of the asteroid size observed in sequential images. The real-time estimation results coincided with those of precise analyses performed after arrival.. |
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Yuki Takao, Osamu Mori, Jun’ichiro Kawaguchi, Optimal Interplanetary Trajectories for Spinning Solar Sails Under Sail-Shape Control, Journal of Guidance, Control, and Dynamics, 10.2514/1.g003776, 42, 11, 2541-2549, 2019.11. |
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Yuki Takao, Toshihiro Chujo, Osamu Mori, Jun’ichiro Kawaguchi, Active Shape Control of Spinning Membrane Space Structures and Its Application to Solar Sailing, Transactions of the Japan Society for Aeronautical and Space Sciences, 10.2322/tjsass.61.119, 61, 3, 119-131, 2018.03. |
