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Mitani S.,Japan Aerospace Exploration Agency | Mitani S.,Aerospace Research and Development Directo | Yamakawa H.,Kyoto University | Yamakawa H.,Research Institute for Sustainable Humanosphere
Journal of Guidance, Control, and Dynamics | Year: 2014

A rendezvous problem under thrust magnitude and direction constraints is considered. A constraint-satisficing scheme has been newly proposed by introducing two barrier functions. The constraint-satisficing set smoothly establishes an intersection between the unconstrained satisficing set and the input constraint set as the perturbation parameters of two barrier functions tend toward zero. For a simple nonlinear controller, a controller generated by projecting a constraint-free linearized optimal controller onto the input constraint is proposed and its stability is investigated. Some numerical simulations treating nonlinear relative orbit systems show that various control sets, which guide the orbit to the origin, can be generated, whereas the convergence property of the closed-loop system is analyzed by the proposed parameter design with the assistance of a graphical plot. Copyright © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Source

Nakamiya M.,Kyoto University | Nakamiya M.,Research Institute for Sustainable Humanosphere | Kawakatsu Y.,Japan Aerospace Exploration Agency
Journal of Guidance, Control, and Dynamics | Year: 2014

The transfer trajectories from the moon to a Halo orbit was studied. Assuming the usage of the stable manifold for the transfer, the connectivity of the stable manifold with the orbit of the moon was investigated. As a consequence, there were four connecting points even if the size of the Halo orbit is small. It allows sending spacecraft into the small Halo orbit using the stable manifold and to increase the opportunity of launch via the moon. Moreover, it was found that the relative velocity of the stable manifold at the connecting point with respect to the moon and the time of flight from the moon to the Halo orbit decrease with the decreasing size of the Halo orbit. Source

Bando M.,Kyoto University | Bando M.,Research Institute for Sustainable Humanosphere | Ichikawa A.,Kyoto University
Journal of Guidance, Control, and Dynamics | Year: 2010

A new formulation of formation flying in an elliptic orbit with restricted control interval is discussed. The main performance index is the L1 norm of the control input generated by an employed feedback control, which is proportional to the fuel consumption. The null controllability with vanishing energy (NCVE) property enables to design feedback controllers through the linear quadratic regulator (LQR) theory, which generate control inputs with arbitrarily small L2 norms by imposing a large penalty on control. The L1 norm of the control input decreases monotonically as the penalty on control increases, and suboptimal controllers are designed. The velocity of the satellite near the apogee is smaller, a relatively small velocity change is required for orbit control and it is assumed that t = 0 is the perigee passage time of the leader, and restrict the control input to the interval. Source

Tsujii S.,Kyoto University | Bando M.,Kyoto University | Yamakawa H.,Kyoto University | Yamakawa H.,Research Institute for Sustainable Humanosphere
Journal of Guidance, Control, and Dynamics | Year: 2013

The motion of a charged satellite subjected to the Earth's magnetic field is considered. The Lorentz force, which acts on a charged particle when it is moving through a magnetic field, provides a new concept of propellantless electromagnetic propulsion. A dynamic model of a charged satellite, including the effect of the Lorentz force in the vicinity of a circular or an elliptic orbit, is derived and its application to formation flying is considered. Based on Hill-Clohessy-Wiltshire equations and Tschauner-Hempel equations, analytical approximations for the relative motion in Earth orbit are obtained. The analysis based on the linearized equations shows the controllability of the system by stepwise charge control. The sequential quadratic programming method is applied to solve the orbital transfer problem of the original nonlinear equations in which the analytical solutions cannot be obtained.Astrategy to reduce the charge amount using sequential quadratic programming is also developed. Copyright © 2012 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Source

Sato M.,Japan National Institute for Fusion Science | Fukushima J.,Nagoya University | Kashimura K.,Research Institute for Sustainable Humanosphere | Tanaka M.,Chubu University
Proceedings of SPIE - The International Society for Optical Engineering | Year: 2011

The monochromatic and single phase electromagnetic fields generate ordered motions in the electrons and ions in the solid and liquid materials. The coherent motion stored kinetic energy. If the kinetic energy is large enough to destroy the crystal structures, the phase deformations happens at much under temperatures expected in the thermally equilibrium state. If it could couple to the optical light generated by thermal motions of the material, it would excite stimulated Brillouin emissions. The stimulated emission supply the energy under the thermally non-equilibrium state. © 2011 SPIE. Source

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