<p>In this paper, the completion conditions for a latch mechanism with a kinematic coupling, which consists of three v-groove/sphere pairs (Maxwell type), are approximately derived as a relationship between the slope angle of v-grooves and friction coefficient. The kinematic coupling is an economical and suitable method for attaining high repeatability in fixtures. Therefore, the kinematic coupling is used in various types of deployable space structures, such as the James Webb Space Telescope and the extensible optical bench of ASTRO-H (Hitomi). In previous studies, numerical simulations were carried out to determine the amount of additional force that should be applied to complete the latch from the incomplete state. However, it is difficult to use such numerical solutions as general design criteria. In this paper, approximated completion conditions are described using analytic functions. As a result, the derived completion conditions are intuitively clear and usable as design guidelines. The most severe condition, where two v-groove/sphere pairs are latched and only one pair remains unlatched, is clarified. It is shown that there are an optimum slope angle and upper limit of the friction coefficient for latch completion. Finally, the most severe completion condition is verified through experiments.</p>

© The Author(s) 2017. This study involved designing and developing a smart structural system for pointing control of large-scale trusses. The system consisted of a pointing control mechanism, an internal displacement-sensor, and a controller. The significant points of the system included the following: (1) artificial thermal expansions of truss members were utilized as linear actuators, (2) elastic hinges were employed instead of ball joints, and (3) the internal displacement-sensor that did not require external jigs and possessed high measuring accuracy was applied. The study involved conducting a feasibility study and an experimental demonstration. The results indicated that the pointing control mechanism produced a sufficient tilt angle to satisfy typical requirements of recent scientific satellites. Furthermore, the findings confirmed that the hysteresis of the pointing control mechanism could be kept sufficiently small due to the absence of sliding parts. The difference between the finite element analysis and the measured value corresponded to 2:9% for a 3:6m long truss. Additionally, the results suggested that the proposed smart structural system for pointing exhibited high control accuracy and tracking performance for a periodic motion. The root mean square error value for a circular trajectory with a radius of 500µm for a period of 15 min corresponded to 4:6% for the 3:6m long truss.

<p>This paper proposes a new strategy for improving deployment repeatability in deployable structures using kinematic couplings. In this strategy, the order of the pressing and the pressing load applied to the coupling are controlled to meet the necessary conditions. The basic theory for latch completion conditions is derived based on our previous study, which revealed the mating completion conditions of kinematic couplings. An experimental model that consists of two circular plates and three parts of two-degrees of restraint (2-DOR) (balls with grooves) with pressing load mechanisms using tension springs is developed. The shape repeatability in the experimental model is evaluated by measuring the relative displacements of two plates in each installation while changing the pressing order and load applied. The effects pressing order and load applied on shape repeatability are evaluated through these experiments, and the effectiveness of the strategy for pressing load adjustment is demonstrated.</p>

© 2018 The balloon-borne very long baseline interferometry (VLBI) experiment is a technical feasibility study for performing radio interferometry in the stratosphere. The flight model has been developed. A balloon-borne VLBI station will be launched to establish interferometric fringes with ground-based VLBI stations distributed over the Japanese islands at an observing frequency of approximately 20 GHz as the first step. This paper describes the system design and development of a series of observing instruments and bus systems. In addition to the advantages of avoiding the atmospheric effects of absorption and fluctuation in high frequency radio observation, the mobility of a station can improve the sampling coverage (“uv-coverage”) by increasing the number of baselines by the number of ground-based counterparts for each observation day. This benefit cannot be obtained with conventional arrays that solely comprise ground-based stations. The balloon-borne VLBI can contribute to a future progress of research fields such as black holes by direct imaging.

© 2018 The Authors. The Canadian Astro-H Metrology System (CAMS) on the Hitomi x-ray satellite is a laser alignment system that measures the lateral displacement (X/Y) of the extensible optical bench (EOB) along the optical axis of the hard x-ray telescopes (HXTs). The CAMS consists of two identical units that together can be used to discern translation and rotation of the deployable element along the axis. This paper presents the results of in-flight usage of the CAMS during deployment of the EOB and during two observations (Crab and G21.5-0.9) with the HXTs. The CAMS was extremely important during the deployment operation by providing real-time positioning information of the EOB with micrometer-scale resolution. We show how the CAMS improves data quality coming from the hard x-ray imagers. Moreover, we demonstrate that a metrology system is even more important as the angular resolution of the telescope increases. Such a metrology system will be an indispensable tool for future high-resolution x-ray imaging missions.

© The Authors. The Hitomi (ASTRO-H) mission is the sixth Japanese x-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft x-rays to gamma rays. After a successful launch on February 17, 2016, the spacecraft lost its function on March 26, 2016, but the commissioning phase for about a month provided valuable information on the onboard instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.

<p>In the development of the recent scientific satellites, requirements of increases in size and improvements in shape accuracy of observation instruments have become more stringent. In order to satisfy those requirements, our research group has examined a pointing control mechanism utilizing artificial thermal expansion as a linear actuator. Our previous research indicated that the pointing control mechanism could satisfy a design requirement of the next generation scientific satellites under a certain orbital environment. It is desirable to conduct performance evaluation under various orbital environments to design a flight model. In order to do that, a detailed thermal mathematical model needs to be built. In this paper, estimated parameters in a thermal mathematical model were estimated by correlating numerical simulation with experiments obtained by thermal vacuum experiments. As a result, the temperature errors between the numerical simulation and the experiments were minimized when the thermal conductance of elastic hinges of the pointing control mechanism was lower than expected. This implies that the estimation of the thermal conductance of the elastic hinge needs to be carefully done.</p>

<p>The validation of deformation caused by the thermal expansion of structures is an important issue for the success of a mission that requires the large-scale and precise positioning of instruments. Therefore, an accurate alignment monitor system was installed in the X-ray astronomy satellite Hitomi to correct observation data. We compared the analysis results of a finite element model with the flight telemetry data of the alignment monitor installed on Hitomi to validate the finite element model. As a result, it was shown that the finite element analysis was able to reproduce the global and slow trends of thermal deformation on orbit. However, the analysis could not reproduce the rapid changes in thermal deformation. To realize more precise and large structures in the future, we need to identify these rapid changes and correctly improve the FE model of thermal deformation through ground tests prior to launch.</p>

<p>An Extensible Optical Bench (EOB) for a X-ray satellite (ASTRO-H) had a length of 6.4m in extended configuration. Although the same type of extensible mast was used in Space Radio Telescope (Halca) in 1997, the tip mass was quite different in the case of ASTRO-H. Due to the tip mass of 150 kg, the natural frequency of EOB was less than 1Hz in the extended configuration. ASTRO-H was launched on Feb. 17, 2016, and the EOB was extended on Feb. 28, 2016, successfully. However, because the vibration of EOB occurred during the extension, the extension operation was carried out over four passes intermittently. When the amplitude of induced vibration excessed the predefined threshold, we stopped the extension, then stayed until the vibration was damped. In this paper, the induced vibration during extension and its mechanism are reported. Through simulations, it is confirmed that one of the major causes of the vibration is a periodic change of gap between mast and canister at the root of EOB.</p>

© The Authors 2018. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. The soft x-ray spectrometer (SXS) onboard ASTRO-H (named Hitomi after launch) is a microcalorimeter-type spectrometer, installed in a dewar to be cooled at 50 mK. The energy resolution of the SXS engineering model suffered from microvibration from cryocoolers mounted on the dewar. This is mitigated for the flight model (FM) by introducing vibration isolation systems between the cryocoolers and the dewar. The detector performance of the FM was verified before launch of the spacecraft in both ambient condition and thermal-vacuum condition, showing no detectable degradation in energy resolution. The in-orbit detector spectral performance and cryocooler cooling performance were also consistent with that on ground, indicating that the cryocoolers were not damaged by launch environment. The design and performance of the vibration isolation system along with the mechanism of how the microvibration could degrade the cryogenic detector is shown. Lessons learned from the development to mitigate unexpected issues are also described.

Inherently nonlinear vibration isolation systems offer compelling analytical performance advantages over their linear alternates. Verification testing followed by post-test correlation is essential to convincing otherwise conservative project management teams to adopt these technologies for their mission. This paper details a comprehensive test verification program developed and executed for a novel vibration isolation system developed for the Soft X-ray Spectrometer (SXS) onboard ASTRO-H (named Hitomi after launch). More specifically, the dual-stage / thermally conductive / nonlinear vibration isolation system developed for on-orbit amelioration of cryocooler-induced mechanical vibration, needed to undergo ground testing to demonstrate both on-orbit performance and launch induced response level rejection to protect sensitive payload temperature control components. The system, referred to as the VIS, realizes both small signal transmissibility at high frequency and small acceleration and displacement against vibration during launch and ground testing.

A prototype for a space-borne smart reconfigurable reflector, whose reflector surface can be changed intentionally using surface adjustment actuators, has been developed, and its performance was evaluated through experiments. The smart reconfigurable reflector was designed as a sub-reflector of a space antenna for observations in the extremely high-frequency band (frequency range: 30 -300 GHz) and is used for correcting the path length errors in the antenna system caused by surface deformations of the main reflector. It consists of a solid surface, supporting members, and surface adjustment actuators. The surface adjustment actuators are a key part of the smart reconfigurable reflector, and each consists of a piezoelectric stack actuator and a displacement magnifying mechanism. Functional tests were performed in order to investigate the performance of the actuator. The results indicate that the actuator has a stroke of more than 0.9 mm with an accuracy of 0.01 mm and a force of more than 90 N. The control accuracy was much better than the required surface accuracy for an extremely high-frequency antenna system. The effectiveness of the developed reflector system was demonstrated through numerical simulations and shape modification experiments. In order to clarify the effectiveness of the developed smart reconfigurable reflector, the performance of the antenna system, equipped with the smart reconfigurable reflector, was evaluated. The experimental results confirmed the performance expected from the numerical simulation and indicated that the antenna could be adequately controlled as expected.

<p>New artificial Lagrange points for spacecraft with a tethered anchor are presented in this paper. The positions of conventional artificial Lagrange points generated by solar radiation pressure are restricted depending on the sail lightness number. Using a tethered anchor, that restriction can be relaxed. Around the L2 point, the new artificial Lagrange points for spacecraft with a tethered anchor are derived based on the circular restricted three-body problem. The dependence of the position of the new artificial Lagrange point on the parameters such as mass ratio and tether's length is investigated for spacecraft with a tethered anchor. The trajectories of spacecraft with and without tethered anchors are calculated numerically. Results show that the tethered anchor can halve the offset of artificial Lagrange points. The effect of tethered anchor on the shift of artificial Lagrange point increases if a tether is long and the mass ratio m_anc /m_sc is large.</p>

© 2016 SPIE. The Hitomi (ASTRO-H) mission is the sixth Japanese X-ray astronomy satellite developed by a large international collaboration, including Japan, USA, Canada, and Europe. The mission aimed to provide the highest energy resolution ever achieved at E > 2 keV, using a microcalorimeter instrument, and to cover a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. After a successful launch on 2016 February 17, the spacecraft lost its function on 2016 March 26, but the commissioning phase for about a month provided valuable information on the on-board instruments and the spacecraft system, including astrophysical results obtained from first light observations. The paper describes the Hitomi (ASTRO-H) mission, its capabilities, the initial operation, and the instruments/spacecraft performances confirmed during the commissioning operations for about a month.

We designed and developed a novel smart structural system for pointing control of large-scale support structures, such as trusses. The system consists of a pointing control mechanism, an internal displacement-sensor and a controller. Remarkable points of our system are (1) artificial thermal expansion of truss members is utilized as linear actuators, (2) elastic hinges are applied instead of boll joints, and (3) the internal displacement sensor which does not need external jigs and has high measuring accuracy is applied. In this paper, we conducted the feasibility study and the experimental demonstration. As a result of the feasibility study, the proposed pointing control mechanism can produce several hundred arcseconds of the rotational displacements within three minutes, therefore it has potential for using in practical operations. As a result of the experimental demonstration, we confirmed that the hysteresis of the pointing control mechanism can be kept sufficiently small due to the absence of the sliding parts, and has high control accuracy and followability (the error RMS value for a circle of the radius of 500 in is 3.6 %).

The pointing performance of a truss structure on orbit that is used for a large space telescope is discussed. To achieve advanced science missions, large and precise support structures such as truss structures are needed. However, the preciseness of the structure might be lost due to various disturbances on orbit. Therefore, to realize ultra-large and precise support structures, active shape control of the structures is needed. To control the shape, we use artificial thermal expansion caused by heaters instead of mechanical actuators. Control systems without mechanical mechanisms have high reliability, which is very attractive for use on orbit. However, there are some constraints regarding the usage of heaters. The control input is restricted to positive inputs because heaters can give off heat but cannot dissipate heat actively, and there will be upper limits on the heat input. To improve the control performance under such constraints, we apply model predictive control as a feedforward control method with preview information. In this article, we mainly show the effectiveness of model predictive control compared with proportional-integral control, which is one of the typical feedback control methods. We developed a structural mathematical model and a thermal mathematical model in order to evaluate the performance of the control system. It is confirmed through numerical simulations that the total error is reduced by model predictive control compared with proportional-integral control.

This study investigates the strength and long-term durability of a spin-axis extensible rigid antenna element, made of tri-axial woven carbon fiber-reinforced polymer (CFRP), for a spinning spacecraft. Due to a slight deviation between the spin axis and antenna-extended axis with the spin, the antenna is subjected to centrifugal body force; the centrifugal force enhances the antenna deflection. A relationship between centrifugal force and antenna deflection is derived from beam theory. As the apparent material modulus decreases with time, the deflection increases simultaneously. The time dependence of mechanical properties of the tri-axial woven CFRP is hence examined by a creep test. The time-dependent failure criterion of the antenna is then examined using a flexural durability test. Based on the beam theory and experimental results, we examine the long-term reliability of applying the tri-axial woven CFRP to extensible rigid antenna for the spinning spacecraft, especially for SCOPE mission; it is verified that the current design tolerance for the mission assures certain durability for long-term usage.

Pointing performance of the truss structure on orbit which is used for large space telescope is discussed. To achieve advanced science missions, large and precise support structures such as truss structures are needed. However, the preciseness of the structure might be lost due to various disturbances on orbit. Therefore, to realize ultra large and precise support structures, active shape control of the structures is needed. To control the shape, we use artificial thermal expansion caused by heaters instead for mechanical actuators. Control systems without mechanism have high reliability, which is very attractive to use on orbit. However, there are some constraints in the usage of heaters. To improve the control performance under such constraints, we apply "Model based Predictive Control (MPC)" as feedforward control method with preview information. In this paper, we mainly show the effectiveness of MPC compared PI control, which is one of the typical feedback control methods. We constructed structural mathematical model and thermal mathematical model in order to show performance of control system. It is confirmed that total error is decreased by MPC compared with the case of PI control through 'numerical simulations.

© 2014 SPIE. The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions developed by the Institute of Space and Astronautical Science (ISAS), with a planned launch in 2015. The ASTRO-H mission is equipped with a suite of sensitive instruments with the highest energy resolution ever achieved at E > 3 keV and a wide energy range spanning four decades in energy from soft X-rays to gamma-rays. The simultaneous broad band pass, coupled with the high spectral resolution of ΔE ≤ 7 eV of the micro-calorimeter, will enable a wide variety of important science themes to be pursued. ASTRO-H is expected to provide breakthrough results in scientific areas as diverse as the large-scale structure of the Universe and its evolution, the behavior of matter in the gravitational strong field regime, the physical conditions in sites of cosmic-ray acceleration, and the distribution of dark matter in galaxy clusters at different redshifts.

Multi-cellular inflatable structures are ultralight and robust against membrane damage such as pinholes caused by space debris. Due to their robustness, inflatable structures supported by inner gases can be applied as space structures. In the present study, shape control for a simple multi-cellular inflatable panel was achieved via a novel diaphragm mechanism. When the bending actuator in a center membrane bends, the inner pressures of sub-cells become different, and the diaphragm mechanism bends as a whole. Because a sliding component is not included, this deformable system is a reliable mechanism. In addition, the proposed mechanism has higher rigidity than that of a bending actuator used alone. In the present paper, we investigate the feasibility of a novel diaphragm mechanism and its characteristics using experimental and numerical results. © 2013 Higher Education Press and Springer-Verlag Berlin Heidelberg.

Large space structures require limitations in weight and assembly effort in order to be realistically constructed and operated. Components for transmitting tensile and compressive loads are the most fundamental, wires and membranes being ones that are most efficient for tensile load transmission, whereas the development of lightweight component for compressive load transmission is still expected. New concept of compression carrying component is proposed, based on the simple principle of momentum conservation. This new concept utilizes the momentum of medium that reciprocates between the load transmitting points. Various media for this new component are examined from the points of utility, handling and load carrying capacity. Proposed innovative component may be readily realized by adopting photon or ion particles, if the required level of load is small. (C) 2010 Elsevier Ltd. All rights reserved.

© 2010 SPIE. The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the high-energy universe by performing high-resolution, high-throughput spectroscopy with moderate angular resolution. ASTRO-H covers very wide energy range from 0.3 keV to 600 keV. ASTRO-H allows a combination of wide band X-ray spectroscopy (5-80 keV) provided by multilayer coating, focusing hard X-ray mirrors and hard X-ray imaging detectors, and high energy-resolution soft X-ray spectroscopy (0.3-12 keV) provided by thin-foil X-ray optics and a micro-calorimeter array. The mission will also carry an X-ray CCD camera as a focal plane detector for a soft X-ray telescope (0.4-12 keV) and a non-focusing soft gamma-ray detector (40-600 keV). The micro-calorimeter system is developed by an international collaboration led by ISAS/JAXA and NASA. The simultaneous broad bandpass, coupled with high spectral resolution of ΔE ~7 eV provided by the micro-calorimeter will enable a wide variety of important science themes to be pursued.

In this research, we focus our discussion on the discontinuous dynastic behavior transition of a walking robot. For the transition, bifurcation of potential function is utilized. We demonstrate the behavior transition of the walking robot between biped and quadruped locomotion as an adaptation to the environment depending on the gradient of a slope. The behavior transition is carried out by using bifurcation of parameters used for control. We also show the effectiveness of hysteresis in the transition. (C) 2008 Elsevier B.V. All rights reserved.

A small satellite named Hokkaido Satellite &ldquo;TAIKI&rdquo; has been designed by NPO Frontier Incubation center for space applications and intellectual activities in Hokkaido. The missions of TAIKI are an agricultural remote sensing using a hyper-spectral sensor and a hi-vision video image filming. As the first step of the Hokkaido satellite project, a space experiment using a 2.7kg nano-satellite was executed. To demonstrate the performance of the bus system of the small satellite, a cube-sat &ldquo;HIT-SAT&rdquo; was developed as a scale model of the Hokkaido Satellite. This paper describes the development and results of launch and operation. The HIT-SAT is 2.7 kg in weight and 12cm cubed sizes. The bus system of the satellite consists of five subsystems; power generation system, structure system, data handling system, communication system and attitude control system. The HIT-SAT was launched successfully on Sep. 23, 2006 (JST) as a sub-payload of M-V-7 rocket. The CW telemetry has been received around the world by many radio amateurs.

The parameter dependency of large space structures on the coupling among attitude motion, structural vibration, and orbital motion has been investigated, particularly for structure's such as tethered satellite systems. Tethered satellites are noticed for their possible applications. From space solar power systems to deorbit system, the applications of tethered satellites spread out over various fields. In this paper, we investigate planar motion of a satellite model, which consists of two tip particles and a massless spring. For such a space structure, the characteristics of the planar motion are shown to be determined by the mass ratio of tip particles, the natural frequency ratio of axial vibration to orbital motion, and the axial length ratio of the spring to the orbital radius. Among these three parameters, the natural frequency ratio has the greatest influence on the coupling phenomenon. Furthermore, the parameter range over which the coupling phenomenon occurs is specified.

A planar space structure suspended by multi-tethers is one candidate for large and lightweight structures. For such flexible structures, coupling phenomena between structural deformation and attitude motion must be considered. In the present paper, the dynamic characteristics of a planar structure suspended by multi-tethers are investigated. Simulation results reveal that the coupling occurs for low tether stiffness. In addition, it is shown that the coupling can also occur if a number of the tethers become slack. Thermal deformation of the planar structure is one cause of tether slack. Thermal deformation and the induced attitude motion are also investigated. It is shown that roll and yaw motions become unstable due to thermal deformation. Finally, we modify the condition of the connection between sub-panels in order to reduce the overall thermal deformation, and it is confirmed that large deformation can be inhibited by the modification. (c) 2006 Elsevier Ltd. All rights reserved.

Tethered solar power satellite (Tethered-SPS) consisting of a large panel with a capability of power generation/transmission and a bus system which are connected by multi-wires is proposed as an innovative solar power satellite (SPS). The power generation/transmission panel is composed of a huge number of perfectly equivalent power modules. The electric power generated by the solar cells at the surface of each module is converted to the microwave power in the same module. Since the modules are controlled by the bus system using wireless LAN, no wired signal/power interfaces are required between the modules. The attitude in which the microwave transmission antenna is directed to the ground is maintained by the gravity gradient force. The tethered panel is composed of individual tethered subpanels which are loosely connected to each other. This configuration enables an evolutional construction in which the function of the SPS grows as the construction proceeds. A scale model of the tethered subpanel can be used for the first step demonstration experiment of the SPS in the near future. (c) 2006 Elsevier Ltd. All rights reserved.

ハイパースペクトル画像は，従来のマルチスペクトル画像と比較して，高周波数分解能であることから，対象物の分光スペクトル分布をより詳細に取得できる．そのため，従来よりも精ちな画像分類が可能と期待される．一方で，データ量が増大することから計算コストが膨大となるといった課題点も指摘されている．そこで，本論文では，従来の特徴抽出・選択を行うクラスタリング手法の一つであるGLDB（Generalized-Local Discriminant Bases）アルゴリズムを改良することにより，高速性を維持し，かつ高精度な画像分類を実現する三つのクラスタリング手法の有効性の検証を行った．実データを用いて実験を行った結果，本論文で用いた画像に関しては，特徴抽出処理により得られた平均特徴数は従来手法よりも減少し，処理時間の短縮，分類精度の向上が実現できた．最後に，三つの改良手法の特徴を比較し，各手法の用途に関する考察を行った．

This research is concerned with shape and attitude control of nonholonomic space robot. An integrator backstepping method with neural network is applied to the kinematics control of 2-dimensional free-flying space robot to expand it into dynamics control. The stability of control method is guaranteed by Lyapunov theory, even if there are some unstructured dynamics and/or unmodeled bounded disturbance. Therefore the controller does not have to know about the strict dynamical parameters of the robot. The effectiveness of proposed controller is confirmed through numerical simulations.

Passive walking is generated by the dynamic interaction of gravity and ground on slope and the walking doesn&#039;t need active control or energy input. Moreover, it is known that chaotic behavior appears when the slope angle exceeds a certain value. In this research, we make use of this chaos dynamics of passive walking, and attempt not only on slope but also on a level ground and uphill by OGY method. In the simulation, the walking in such environment is succeeded. Moreover, we evaluate the OGY method through experiments of an actual robot. At last, we success walking with the control in real ...

In city traffic flow, vehicles driven by human interact with each other with velocity fluctuations. We simulate the such city traffic and analyze it. It should be important to research the relation between traffic signals and drivers' strategies. Then, we. prepare two CML(coupled map lattice) models to treat complex traffic system with varying their characteristics, and research the effects of traffic signals. Each model has different strategies to avoid collision between vehicles. The one is the "Mixture Model" strategy which changes vehicles' running dynamics when their gaps have gotten narrow, and the other is the "Tracking Model" strategy which decelerate vehicles' goal velocities to follow previous one when their gaps have gotten narrow. We compare these CML models on a oneway traffic lane under the aperiodic boundary condition. "The transition point, of the jam" which separates between "free flow phase" and "congestion phase" is observed. In free flow phase, major differences are not confirmed between these models. But, when it gets congested, each model takes on dissimilar complex features stem from difference of strategies. Additionally, we research effect of signal control parameters in free flow phase. We observed that whole performance is improved as cycle length is getting shorter, at that time offset can't be very effective. When cycle length is long, whole performance is not very lower if offset is proper.

A Space Solar Power System (SSPS) has been proposed at the Institute for Unmanned Space Experiment Free Flyer and ISAS/JAXA. The objective of this paper is to evaluate the attitude stability of the SSPS under construction. At first, we investigate &quot;line construction&quot;, where the modules are arranged in the shape of line. Through approximate estimation, it is shown that the roll and yaw angular frequencies of attitude motion are twice and once of the orbital angular velocity in the first step of construction, respectively. Furthermore, through dynamical analysis, roll and yaw angles tend to divergence in first step. To avoid such a divergence, we consider another construction way, &quot;construction with similarity&quot;, where satellite is constructed keeping similar configuration. From the analysis, it is shown that divergences in the roll and yaw angles can be avoided in the construction with similarity. However, the resorting torques around the pitch and yaw axes are weak in the first step when the SSPS is constructed with similarity. In particular, maximum amplitude around the yaw axis becomes about 29 degrees. Therefore, for both construction ways, active attitude control is desired in first step of the constructions.

The purpose of this study is to measure muscle fatigue from EMG through non-invasive way. The measurements of muscle fatigue have been required in various fields. The linear analysis method such as Fast Fourier Transformation (FFT) has been used as th[e common way to analyze EMG. However, there would be some types of muscle fatigue which cannot be detected by the linear analysis but could be detected by nonlinear analysis because of nonlinearity of biological signals. In this study, we analyzed EMG recorded from 17 subjects to evaluate the ability of nonlinear analysis. As a result, more ki...

This study focuses on emergence of biped robot locomotion based on the concept called&amp;lsquo;Global Entrainment.&amp;rsquo;Originally, this concept was proposed as a principle of human locomotion emergence; locomotion is self-organized as limit cycles of the coupled dynamical systems, which consist of the neurons, body and environment. In this paper, the author designs the neural system using computer simulations of the biped robot at first. With the designed neural system, the simulated robot steps with oscillatory motion in the lateral plane, and then starts to walk. It is also investigated that the realized locomotion has adaptability to changes of the robot and environment models. The last experiment shows that the real robot is able to walk in the same way as the simulations.

A solar power system, in which a large flat panel with a capability of power generation and transmission is suspended by multi-wires, is proposed as an innovative Solar Power Satellite (SPS). This SPS concept is highly robust and potentially low cost, with special features in the integration, construction, attitude control, heat management, and evolutional development strategy. The power generation and transmission panel is composed of a huge number of perfectly equivalent modular panels, that is essential for low-cost mass production. The electric power generated by the solar cells at the surface of each module is converted to the microwave power in the same module. There are no wired signal/power interfaces between the modules. All modules are controlled by a wireless LAN system. The wireless interface between the modules leads to easy deployment and integration. Since the solar light is not concentrated in this configuration, quite different from the recent SPS concepts equipped with condensing lens or mirrors, the temperature of the module is kept within an operational range for the commercial electrical parts without any active heat rejection. The attitude in which the microwave transmission antenna is directed to the ground is automatically maintained by the gravity gradient force of the suspension system. The tethered panel is composed of individual tethered subpanels which are loosely connected to each other. This configuration enables an evolutional construction in which the function of the SPS grows as the construction proceeds. A scale model of the tethered sub-panel can be used for the first step demonstration experiment of the SPS in the near future. The demonstration experiment can verify the power transmission from the orbit to the ground, which is the most important subject at this stage of the SPS research. This concept of the SPS has disadvantages that the power to the ground varies with the local time and the working ratio is 64 % on the average as compared with the sun-pointing type SPS, but they are well compensated by the advantages in the electrical, mechanical, thermal and integration aspects.

Modularized structures are promising as present and future structures from the viewpoints of their high fault tolerance and easy extensible nature. Averaging interactive cooperation in the decentralized control of modularized structures is studied. The averaging interaction is defined as an interaction, which averages some physical properties of each module such as deformation, shape and stress. The most remarkable point of this study is that analogy of the heat conduction is used to realize the averaging interaction. The interaction based on a heat conduction equation enables us to grasp the physical sense of control parameters intuitively. Furthermore, the stable characteristics of heat conduction imply control stability. As case studies, two subjects are discussed: position control of the end-effector of a variable geometry truss, and deployment control of a modularized structure. Some numerical results are shown to illustrate the capability of the proposed control method.

An autonomous distributed control has been presented as novel control methods for complex or large systems. In this paper, it is applied to the position control of variable geometry trusses, which have high redundancy. It is shown that the fault-tolerance of the system is easily realized through this control method. Additional behavior for obstacle avoidance is also accomplished easily. Furthermore, the area of avoidable obstacles can be extended through the cooperation of each agent. Compared with a conventional control method using inverse kinematics, the proposed method is shown to be more effective from the viewpoint of calculation time.

Deployment behavior of modularized structures is numerically analyzed from the viewpoint of synchronism. Elastic panels with single and double accordion folding patterns are examined as examples of modularized structures. Through computer simulations, it is shown that asynchronous deployments are caused by inertia forces. To improve the synchronism of the deployment, an autonomous distributed control method is introduced. Because the control method uses only local information, some advantages are expected; parallel processing, flexible extensibility and fault-tolerance. The control rule is derived by the analogy of heat conduction. Stable characteristic of heat conduction implies stability of the control method. Furthermore physical sense of control parameters can be understood intuitively because the control method is based on real physical phenomenon. It is confirmed that the autonomous distributed control can improve the synchronism of the deployment.

In the neurophysiology it has been clarified that some rhythm generators called the Central Pattern Generator (CPG) exists in animal locomotion. The CPG is able to generate various walking patterns without any previous plan and environment model. Using the CPG one can simplify the complicated walking system. In this paper, the CPG model for quadruped static walk is proposed and applied to the quadruped robot, TITAN-VIII. Moreover, we consider the irregular terrain as a walking environment with the sensor to recognize the softness of ground. By using the neural reflex control, it is shown that the robot can autonomously walk the soft terrain.

Deployment behavior of modularized space structures is analyzed from the viewpoint of dynamic and simultaneous deployment. Actuators, which are attached to each substructure individually, realize the decentralized and simultaneous deployment. Elastic panels with double-accordion folding pattern are examined as an example of modularized structures. Corresponding analytical model is derived from the hybrid variational principle. At first, the deployment behavior of one module is simulated numerically to analyze the deployment characteristics of the double-accordion folding. The influences of panels' shape and flexural rigidity on the deployment characteristics are clarified. Furthermore, the deployment behavior of multi modules is simulated numerically to analyze the synchronism of the deployment. It is shown that high flexural rigidity of elastic panels improves the synchronism of the deployment, and the strain energy of each module depends on constraints of the module. The synchronism of the deployment and the distribution of the strain energy are then considered qualitatively for general dynamic and simultaneous deployment.

第35回宇宙構造・材料シンポジウム（2019年12月2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県著者人数: 14名資料番号: SA6000146022レポート番号: B-02

Balloon Symposium 2019 (November 7-8, 2019. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency(JAXA)(ISAS)), Sagamihara, Kanagawa Japan

大気球シンポジウム 2019年度（2019年11月7-8日. 宇宙航空研究開発機構宇宙科学研究所(JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 21名資料番号: SA6000140030レポート番号: isas19-sbs-030

<p>For future advanced missions, large and highly accurate space structures are required. A prior shape adjustment of the structure before launch is not sufficient to achieve such accurate space structures. For example, thermal deformation on orbit cannot be eliminated by the preliminary adjustment of the structure. Therefore, the shape control of the structure is a promising technique for highly accurate space structures. For the shape control, the shape error should be measured on-orbit. In this study, a measurement system for the displacement of a slender space structure has been developed as an alignment monitor. The characteristics of this measurement system are long working distance and simple configuration. The measurement system consists of a laser, retro-reflector and positioning sensing device. The performance on the ground was already demonstrated through the satellite ground test. As a first step to on-orbit experiment, the demonstration experiment on the balloon is planned. In this paper, the system configuration and development progress are reported.</p>

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000137027レポート番号: B05

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000137039レポート番号: B17

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000137041レポート番号: B19

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000137042レポート番号: B20

第34回宇宙構造・材料シンポジウム（2018年12月4日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県著者人数: 15名資料番号: SA6000137008レポート番号: A08

大気球シンポジウム 平成30年度（2018年11月1-2日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)）, 相模原市, 神奈川県著者人数: 27名資料番号: SA6000128002レポート番号: isas18-sbs-002

Balloon Symposium 2018 (November 1-2, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

Balloon Symposium 2018 (November 1-2, 2018. Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency (JAXA)(ISAS)), Sagamihara, Kanagawa Japan

This paper develops an athermalization method to cancel the mismatch of the coefficient of thermal expansion (CTE) that exists in active control mechanisms, through analysis, prototyping, and tests. Essentially, the CTE mismatch between piezoceramics and the other structures made of super invar is cancelled by combing with another metallic part. In addition, this paper clarifies the mechanism of thermal deformation caused by inner structure of a piezoelectric stack actuator. It shows in both finite-element analysis and tests that the CTE mismatch cancellation is affected by the dimension tolerance of the inner structure, but successfully adjustable by the proposed methods. Moreover, the high thermal sensitivity of the actuator is exploited to propose another type of smart actuator, which uses active thermal deformation. This alternative approach is also evaluated through analysis, prototyping, and tests.

The ASTRO-H mission was designed and developed through an international collaboration of JAXA, NASA, ESA, and the CSA. It was successfully launched on February 17, 2016, and then named Hitomi. During the in-orbit verification phase, the on-board observational instruments functioned as expected. The intricate coolant and refrigeration systems for soft X-ray spectrometer (SXS, a quantum micro-calorimeter) and soft X-ray imager (SXI, an X-ray CCD) also functioned as expected. However, on March 26, 2016, operations were prematurely terminated by a series of abnormal events and mishaps triggered by the attitude control system. These errors led to a fatal event: the loss of the solar panels on the Hitomi mission. The X-ray Astronomy Recovery Mission (or, XARM) is proposed to regain the key scientific advances anticipated by the international collaboration behind Hitomi. XARM will recover this science in the shortest time possible by focusing on one of the main science goals of Hitomi, "Resolving astrophysical problems by precise high-resolution X-ray spectroscopy".(1) This decision was reached after evaluating the performance of the instruments aboard Hitomi and the mission's initial scientific results, and considering the landscape of planned international X-ray astrophysics missions in 2020's and 2030's.Hitomi opened the door to high-resolution spectroscopy in the X-ray universe. It revealed a number of discrepancies between new observational results and prior theoretical predictions. Yet, the resolution pioneered by Hitomi is also the key to answering these and other fundamental questions. The high spectral resolution realized by XARM will not offer mere refinements; rather, it will enable qualitative leaps in astrophysics and plasma physics. XARM has therefore been given a broad scientific charge: "Revealing material circulation and energy transfer in cosmic plasmas and elucidating evolution of cosmic structures and objects". To fulfill this charge, four categories of science objectives that were defined for Hitomi will also be pursued by XARM; these include (1) Structure formation of the Universe and evolution of clusters of galaxies; (2) Circulation history of baryonic matters in the Universe; (3) Transport and circulation of energy in the Universe; (4) New science with unprecedented high resolution X-ray spectroscopy. In order to achieve these scientific objectives, XARM will carry a 6 x 6 pixelized X-ray micro-calorimeter on the focal plane of an X-ray mirror assembly, and an aligned X-ray CCD camera covering the same energy band and a wider field of view. This paper introduces the science objectives, mission concept, and observing plan of XARM.

<p>In this paper, large space structures such as solar power satellite systems are investigated from the view point of construction. For large space structures, it is necessary to satisfy different requirements depending on the phases. During launch, the strength against the launch load and small storage size are required to the structure. Although the load conditions are greatly relaxed after launch, maintenance of large area is required on orbit. In order to satisfy the different requirements for each phase, deployment mechanisms and assembly techniques in space have been studied. In this paper, functional requirements for the construction of large space structures are investigated. After the hardware designs of an assembly mechanism, its fundamental characteristics are shown.</p>

&lt;p&gt;人工衛星を用いたミッションの高度化に伴い，衛星搭載用のアンテナや望遠鏡といった衛星搭載機器も，より高精度であることが求められている．そのような高精度な機器の実現に向け，軌道上での変形を計測し，アクチュエータにより補正することで高い精度を得る形状可変構造システムが，多くの機関で研究・開発されている．著者らも積層型圧電素子と変位拡大機構を組み合わせたアクチュエータを用いてアンテナ反射鏡面の形状調整を行う形状可変鏡（スマート形状可変鏡）の研究・開発に取り組んでおり，製作したアクチュエータの性能評価や，実際のアンテナシステムに組み込んだ状態での形状可変鏡の有効性確認試験を実施している．本稿では，そのようなスマート形状可変鏡に関して，研究内容を紹介する．&lt;/p&gt;

Copyright © (2017) by International Astronautical Federation. All rights reserved. A mechanism for the high-precision positioning of reflector segments by using kinematic couplings has been developed for balloon-borne radio telescopes, and the effectiveness of the mechanism is demonstrated through experiments. A high-precision reflector for radio telescopes is under development, and it is intended to be used for the observation of radio waves of up to 300 GHz. The reflector consists of six segments, a back structure, and a high-precision positioning mechanism. The high-precision positioning mechanism utilizes kinematic couplings, and the segments are positioned and fixed precisely to the back structure by the kinematic couplings. The positioning of the segments on the back structure is one of the largest sources of error in reflector systems. Therefore, kinematic couplings are important components of a reflector system for achieving a high surface accuracy. Three combinations of a ball and a V-groove are employed in the positioning mechanism. Load-applying mechanisms are used to apply and control pressing loads between the segment and back structure. In order to demonstrate the effectiveness of the mechanism, the positioning repeatability between a segment and a back structure was investigated through experiments. In these experiments, the reflector segment was attached to and detached from the back structure, and the relative positions of the reflector with respect to the back structure were measured using a photogrammetry system during the process of attachment. The cycle of attachment, measurement, and detachment was repeated five times, and the positioning repeatability was evaluated. A positioning accuracy of approximately 20 um RMS was achieved using the developed reflector system. The results demonstrate the effectiveness of the positioning mechanism, which incorporates kinematic couplings for the high-precision positioning of a reflector for a balloon-borne radio telescope.

第32回宇宙構造・材料シンポジウム（2016年12月9日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000087012レポート番号: A11

第32回宇宙構造・材料シンポジウム（2016年12月9日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000087016レポート番号: A15

© 2016, American Institute of Aeronautics and Astronautics Inc, AIAA. All rights reserved. The present paper reports the results of shape-control experiments using the smart secondary reflector prototype for satellite-borne radio-astronomy. The shape of the secondary reflector is modified by six special piezoelectric actuators with displacement magnification mechanisms. The experiments successfully demonstrated that the reception power of the antenna system has been improved by the shape control.

<p>ASTRO-H (hitomi) was an X-ray astronomy satellite in Japan which was launched on 17 Feb. 2016. To meet its science goals, four kinds of instruments and six detectors were equipped on the satellite. The focal length of two soft X-ray telescopes was 5.6 m, and that of two hard X-ray telescopes is 12m. One of the most difficult challenges for the satellite structure was to meet the alignment requirements for instruments and detectors. Through the ground tests and observation results on orbit, it was confirmed that the performance of alignment meet the requirements. In this paper, the results of on-orbit alignment performance of the instruments and obtained techniques to control the alignment are reported.</p>

第31回宇宙構造・材料シンポジウム（2015年12月8日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000047027レポート番号: B13

To realize structure systems of future high-precision space observation satellites, smart structure systems which measure and correct their configuration or/and suppress their vibration on obit have been studied. Among sensors and actuators to be used in the smart structure systems, piezoelectric materials are expected to be a good candidate since they have less mechanical parts and high compatibility for space environment. When a shape of a smart space structure is controlled by the piezoelectric actuators attached to its structural element, electric voltage must be continued to be applied to retain a desired shape. To save the amount of electricity usage, a new control method was proposed and its feasibility was examined in the previous papers [Ikeda and Takahashi, Proc. SPIE 8689; Ikeda et al., Trans. JSASS 12 ists29]. In the method the hysteretic behavior of piezoelectric actuators was utilized effectively. The results showed that displacement of a smart beam with a piezoelectric ceramic actuator bonded remained without any voltage applied to the actuators after a pulsed voltage was applied. However, the displacement of the beam overshot a final position. In this paper this overshoot is suppressed. To this end another type of piezoelectric actuator showing almost no hysteretic behavior is bonded on the beam opposing the actuator showing the hysteretic behavior. Result shows that the overshoot can be suppressed by applying a feedback plus feedforward control to the additional actuator while the pulsed voltage is applied to the actuator showing hysteretic behavior.

© 2015, American Institute of Aeronautics and Astronautics Inc. All rights Reserved. ASTRO-H is a next-generation X-ray observatory satellite planned for launch in fiscal 2015. Because ASTRO-H is a large structure and requires precise and accurate pointing, an understanding of on-orbit thermal deformation behavior is particularly important to the success of the ASTRO-H mission. In the conventional technique for predicting thermal deformation, testing is performed in a thermal vacuum chamber so asto simulate the temperature distribution on orbit. However, when using this conventional technique it is difficult to observe the detailed characteristics of the tested structures due to the limits of the applied temperature distribution cases. To overcome this problem, we propose a new evaluation technique for ASTRO-H. In our technique, on-orbit prediction of thermal deformation is performed thorough numerical simulation using a finite element (FE) model. The validation and correlation of the FE model are carried out by comparing results with thermal deformation test data collected in advance. This technique is especially suitable for satellites that are exposed to various thermal conditions on orbit. Using this technique, we confirmed all of the requirements for on-orbit pointing accuracy and precision in ASTRO-H.

Recently, structural requirements for observation accuracy of satellites&#039; instruments become increasingly high. This research proposes a new pointing control system which uses Stewart platform with elastic hinge. As a linear actuator, artificial thermal expansion of rod is utilized. This system is highly reliable and enables precise control with 6 DOF. We designed the shape control system whose size is about 300mm on each side. By finite element analysis, it is shown that the shape control system can generate translational motion which is over 100μm in the horizontal direction and 20μm in the vertical direction without rotation. Finally, it is confirmed that relative error between analysis and experimental values is within 15% or less when the displacement is more than 100μm from experiments.

This paper discusses the configuration of design of smart space reflector system for realization of future high-accuracy antenna in space. This study aims at establishing of design methods for a smart secondary reflector to correspond to deformation mode which caused on the primary reflector surface in space. Authors have investigated effects that perturbation of Kinematic Coupling (KC), which restricted the primary reflector and a back structure, affecting to the primary reflector surface by using finite-element method (FEM). Furthermore, the number of piezoelectric actuators of the back of secondary reflector surface is varied to compare deformation modes of secondary reflector surface with that of primary reflector. Through correlations of deformation of the primary reflector and configuration of the smart secondary reflector, new knowledge of antenna system while considering two reflectors at the same time is obtained.

© 2015, American Institute of Aeronautics and Astronautics Inc. All rights reserved. This study clarifies the effect of thermal deformation in the reconfigurable space reflector system, through a series of experiments in a thermostatic chamber using a prototype of reconfigurable space reflectors. This study then discusses possible countermeasures against precision degradation of such system due to the thermal deformation, exploiting a finite- element model that is tuned to the experimental results. Though reconfigurable reflector systems inherently have the mismatch in the coefficients of thermal expansion among their structural members, the effect of the mismatch may be minimized by a proper combination of several materials. The prototype used in this study is designed as a preliminary model of a secondary mirror for future radio astronomy satellites.

The present paper reports the results of shape-control experiments using the smart secondary reflector prototype for satellite-borne radio-astronomy. The shape of the secondary reflector is modified by six special piezoelectric actuators with displacement magnification mechanisms. The experiments successfully demonstrated that the reception power of the antenna system has been improved by the shape control.

第30回宇宙構造・材料シンポジウム（2014年12月1日. 宇宙航空研究開発機構宇宙科学研究所 (JAXA)(ISAS)), 相模原市, 神奈川県資料番号: SA6000043001レポート番号: A01

An efficient estimation method for thermal properties is presented, where elements of thermal conductive matrix are considered as estimation parameters. Linear heat balance equations in vector-matrix form are rearranged as least square equations of estimation parameters, where the coefficient matrix and the right-hand side vector are composed of temperature data and derivative of temperature data. Transient thermal test data in steady-state thermal tests are effectively used to construct these equations. A simple numerical example is presented to validate the effectiveness of the presented method.

Pointing performance of the truss structure on orbit which is used for large space telescope is discussed. To achieve advanced science missions, large and precise support structures such as truss structures are needed. However, the preciseness of the structure might be lost due to various disturbances on orbit. Therefore, to realize ultra large and precise support structures, active shape control of the structures is needed. To control the shape, we use artificial thermal expansion caused by heaters instead for mechanical actuators. Control systems without mechanism have high reliability, which is very attractive to use on orbit. However, there are some constraints in the usage of heaters. To improve the control performance under such constraints, we apply "Model based Predictive Control (MPC)" as feedforward control method with preview information. In this paper, we mainly show the effectiveness of MPC compared PI control, which is one of the typical feedback control methods. We constructed structural mathematical model and thermal mathematical model in order to show performance of control system. It is confirmed that total error is decreased by MPC compared with the case of PI control through 'numerical simulations.

The Soft Gamma-ray Detector (SGD) is a Si/CdTe Compton telescope surrounded by a thick BGO active shield and is scheduled to be onboard the ASTRO-H satellite when it is launched in 2015. The SGD covers the energy range from 40 to 600 keV with high sensitivity, which allows us to study nonthermal phenomena in the universe. The SGD uses a Compton camera with the narrow field-of-view (FOV) concept to reduce the non-Xray background (NXB) and improve the sensitivity. Since the SGD is essentially a nonimaging instrument, it also has to cope with the cosmic X-ray background (CXB) within the FOV. The SGD adopts passive shields called "fine collimators" (FCs) to restrict the FOV to &lt;= 0.6 degrees for low-energy photons (&lt;= 100 keV), which reduces contamination from CXB to less than what is expected due to NXB. Although the FC concept was already adopted by the Hard X-ray Detector onboard Suzaku, FCs for the SGD are about four times larger in size and are technically more difficult to operate. We developed FCs for the SGD and confirmed that the prototypes function as required by subjecting them to an X-ray test and environmental tests, such as vibration tests. We also developed an autocollimator system, which uses visible light to determine the transmittance and the optical axis, and calibrated it against data from the X-ray test. The acceptance tests of flight models started in December 2013: five out of six FCs were deemed acceptable, and one more unit is currently being produced. The activation properties were studied based on a proton-beam test and the results were used to estimate the in-orbit NXB.

To keep a shape of a smart structure with piezoelectric actuators bonded on it, electric voltage must be applied continuously. To reduce the amount of electricity usage, a new control method was proposed and its feasibility was examined in the previous studies [Proc. of SPIE 8689 86890C, Proc. of 29th ISTS 2013-c-40]. In this method hysteretic behavior of piezoelectric actuators in strain-electric field relationship was utilized effectively, which behavior is that some amount of strain remains even at zero voltage once a large voltage is applied. The results showed that displacement of a smart beam with a piezoelectric ceramic actuator bonded remained without applying voltage to the actuators after applying a pulsed voltage. However, the displacement overshot a final position while applying the pulsed voltage. That is generally undesirable. In this paper a suppression method of this overshoot was proposed. To this end another piezoelectric actuator was bonded on the beam opposing the original actuator. The original actuator was a soft type while a hard type piezoelectric actuator was used as the opposing actuator. With help from the two types of actuators, the overshoot could be suppressed while applying the pulsed voltage by controlling the voltage for the opposing actuator adequately, and a desired displacement could be obtained at zero voltage after the pulse.

This paper experimentally evaluates the shape-control performance of the prototype of smart reconfigurable reflectors, and proposes an updated design that will ameliorate the problems identified in the experiments. The prototype is a preliminary model of a secondary mirror for future radio astronomy satellites. The prototype can control the shape of a 300mm-diameter CFRP mirror, using six piezoelectric actuators integrated with displacement-magnification mechanisms.

An efficient scheme for steady-state thermal temperature prediction in vacuum tests is presented. First, heat balance equations of spacecraft thermal mathematical models are analytically solved without nonlinear radiation terms. Then, perturbation solutions with radiation terms are deduced. Observation equations based on both linear and nonlinear solutions are presented, which are applied for the least square estimations of steady-state thermal temperature prediction with transient temperature data. A simple experimental result shows the effectiveness of presented scheme.

For future space sciences, there is an increase of the demand of large and precise space structures such as JWST, ASTRO-H and so on. To realize such ultra-large and highly precise space structures, the conventional design concept and development process should be changed drastically. Not only novel materials with high shape stability, but also smart structures which can change their characteristics are promising candidates. In this paper, advanced techniques of structures and materials including smart space structures are summarized.

Smart space structure systems which measure and correct their shape on orbit have been studied as a future high-precision space structure systems. Piezoelectric ceramics are often used as an actuator in the system. To correct and retain the shape of the structure, electric voltage must be applied continuously. To reduce the amount of electricity usage, a new control method was proposed, where a fact that strain remains after a pulsed voltage input due to the hysteresis in strain-electrcic curve of the piezoelectric actuators was utilized effectively. In this paper, feasibility of the proposed method was verified for a piezoelectric ceramic plate and a beam on which the piezoelectric ceramic plate was bonded. The result showed that the strain of the piezoelectric ceramic plate and the tip displacement of the beam remained after the pulse. Although the beam vibrated after the pulse, the vibration was suppressed by applying a feedback control or controlling the shape of the applied pulse input.

宇宙構造物の高精度化のために軌道上で圧電セラミックスアクチュエータを用いてその形状を補正する研究が行われている,軌道上では昼夜の温度差が大きく,熱歪で構造物の精度が低下しないように複合材で製作される場合がある.しかしながら,圧電セラミックスは熱変形するので,その変形が,構造物の精度を低下させたり,制御限界程度になる可能性もある.そこで,熱歪をキャンセルするような圧電セラミックスアクチュエータを提案し,その剛性や圧電特性を評価した.

To meet advanced science missions, large and precise support structures such as truss structures are needed. Temperature and shapes change depending on solar radiation. As a result, the structure lost its preciseness. In this research, pointing accuracy of the truss structure on orbit is discussed. To control the shape, artificial thermal expansion caused by heater is used instead for mechanical actuators. Control systems without mechanism have high reliability because heater has no sliding parts. To maintain pointing accuracy on orbit, preview control method in this paper is expected to be more useful than feedback control methods.

A Conceptual design of "Space Colony" for long-term residence is reported in this paper. As constraint conditions, micro gravity and high vacuum are considered in the structural design. Although such conditions are constraint, they have possibilities to be utilized for further innovative human life style which can not be realized on the ground. Especially, the environmental condition of micro gravity may have great impact to the life style from the viewpoint of mobility and immobility. In this paper, we propose some conceptual designs of the space colony utilizing micro gravity and discuss its characteristics.

A novel measurement apparatus with extremely high accuracy called Laser Displacement-meter with Long-working-distance (LDL) was developed to measure micro-meter-scale deformation of large space structures in the ground test. The combination of a laser source and a position sensitive detector makes it possible to measure accurately with long working distance. It is confirmed that LDL has the performance with 7 μm error at 6.1m working distance through the thermal deformation test of X-ray telescope satellite: ASTRO-H. Because LDL is compact and portable one, it can be applicable for measurement of other large objects such as buildings, bridges, and so on.

Highly precise structural analysis of tension-stabilized space reflectors using geometrically nonlinear finite-element (FE) model usually requires accurate knowledge of the design parameters. However, internal forces in the deformed configuration or temporal change of stiffness parameters are usually unable to be measured; thus, accurate numerical modeling of a tension-stabilized structure is difficult. The present paper describes a methodology to construct a high-fidelity FE model of high-precision gossamer structures by applying a conventional method of FE model updating to a geometrically nonlinear FE analysis. Using the FE model updating methodology, an accurate FE model can be constructed through the estimation of unmeasured parameters. In this study, a simple tension-stabilized beam structure is analyzed for demonstration of the concept. © 2012 AIAA.

The joint JAXA/NASA ASTRO-H mission is the sixth in a series of highly successful X-ray missions initiated by the Institute of Space and Astronautical Science (ISAS). ASTRO-H will investigate the physics of the highenergy universe via a suite of four instruments, covering a very wide energy range, from 0.3 keV to 600 keV. These instruments include a high-resolution, high-Throughput spectrometer sensitive over 0.3-12 keV with high spectral resolution of ?E 5 7 eV, enabled by a micro-calorimeter array located in the focal plane of thin-foil X-ray optics; hard X-ray imaging spectrometers covering 5-80 keV, located in the focal plane of multilayer-coated, focusing hard X-ray mirrors; a wide-field imaging spectrometer sensitive over 0.4-12 keV, with an X-ray CCD camera in the focal plane of a soft X-ray telescope; and a non-focusing Compton-camera type soft gamma-ray detector, sensitive in the 40-600 keV band. The simultaneous broad bandpass, coupled with high spectral resolution, will enable the pursuit of a wide variety of important science themes. © 2012 SPIE.

To meet advanced science missions, large and precise support structures such as truss structures are needed. In this paper, pointing control of a truss structure is discussed. To control the truss structure, thermal expansion of truss members is utilized instead of mechanical actuators. Heaters are equipped to truss members so that the thermal expansion of the members is controlled by heaters. PI control is applied to an experimental model which is box truss with 1.9m height. Through experiments, it is shown that the truss structure can be controlled with good accuracy, for example, within ...

A large space reflector consisting of radial ribs and hoop cables is considered to satisfy rigorous design requirement of a high shape precision as well as lightweight. Due to difficulty of verification of such a large and high-precision space structure by on-ground testing, a simulation-based verification is required. As the first step of establishment of the simulation-based verification, this research investigates the computational accuracy of several nonlinear finite element codes in comparison of numerical solution based on Elastica for the simplified beam model that allows large deformation. Then, sensitivities of deformation with respect to Young&#039;s modulus and applied load are investigated.

An effective method for sensitivity analysis of uncertain parameters in space reflectors is presented. In the method, the sensitivities of uncertain parameters with respect to structural modes are explicitly derived by utilizing the singular value decomposition of sensitivity matrix, which can predict which modes are excited due to the variation patterns of uncertain parameters. A simple numerical example, the model of which is a radial rib and hoop cable antennas that consists of 60 radial ribs, are provided to verify the effectiveness of the presented method.

In SCOPE mission, flexible extendable rod antennas are equipped along the spin axis of satellite. For the extendable function, STEM (Stowable Tubular Extendable Member) is used as the rod antenna. The apparent natural frequency of the STEM changes depending on the spin-rate. Furthermore, bending and torsion of the STEM are coupled because the STEM has open section. The dynamic characteristics of the STEM are clarified through analysis and tests. Especially, the coupled vibration of bending and torsion, and the effect of spin motion on apparent natural frequency of the STEM are investigated. As a result, it was shown that the effect of spin motion can be quantitatively predicted by simple analytical model. In addition, it was found that the characteristics of the vibration are strongly affected by the boundary condition of the STEM.

Requirement for shape stability of space structures such as barrel for space telescope tends to become more precisely. In addition to it, large size over 10 meters is sometimes required for such support structure to meet advanced science missions. To realize large and precise support structures, comprehensive techniques including prediction, measurement and stabilization techniques on orbit are needed. In this paper, we introduce some fundamental techniques to keep the precise shape for a slender box truss as a representative support structure. The structural deformation on orbit is induced by thermal distribution, disturbance (RW/MW/SAD etc.) and so on. At first, we analyzed temperature distribution and thermal distortion of the truss structure to predict the thermal deformation. The accuracy of analysis results is evaluated through experiments with a five-bay truss structure. Then, system identification is carried out to identify the stiffness of the structure because such identification of the stiffness becomes important for the precise prediction of thermal deformation in the case of indeterminate structure. As a first step, the stiffness matrix is identified by using particle swarm optimization method from the experimental data of natural frequency. By using the identified stiffness matrix, the natural frequency can be estimated within 1% error. At last, we attempt the shape control of truss structure by using artificial thermal expansion. It is experimentally shown that deformation of truss structure could be controlled with good accuracy, for example, within 30μm error for 1.9m height truss. Copyright ©2010 by the International Astronautical Federation. All rights reserved.

Space Inflatable Membrane structures Pioneering Long-term Experiments (SIMPLE) unit is one of ISS Japanese Experimental Module (JEM) Kibo&#039;s exposed facility payloads scheduled to be launched in 2012. Manufacturing and function testing phase of the engineering model (EM) has been completed and the proto-flight model (PFM) is now underway. The SIMPLE mission consists of three experimental verifications using Inflatable Extension Mast (IEM), Inflatable Space Terrarium (IST) and Inflatable Material Experimental Panel (IMP). The combination of the experiments is aimed to demonstrate the usefulne...

In the past decades, extensive researches about space structures have taken place in Japan from conceptual studies to practical mission studies. The recent holy grail of space structures is to establish the ultra-light, large and stable space structure with high precision and high packaging efficiency that is &quot;Gossamer&quot; space structure. This paper presents the summary of Japanese recent activities for the past several years for space structures research, and they are classified into five major divisions in this survey paper; concept, design, application, analysis, and experiment/test. On the whole, membrane and cable mesh structures have been studied intensively. Copyright © 2009 by the American Institute of Aeronautics and Astronautics, Inc.

Tethered-Solar Power Satellite (Tethered-SPS) consists of power generation/transmission panels suspended by tether wires. The most important feature of the Tethered-SPS is that it is constructed by perfectly equivalent power generation/transmission units. Each unit panel, 100 m × 95 m, is suspended by four 5 km-tether wires deployed from a bus unit. The weight and output power of the unit SPS are 42.5 MT and 2.1 MW, respectively. The engineering studies have been conducted to design the power generation/ transmission panel and to show how to deploy the panel. In addition to the engineering research, two major environmental issues, the effect of hyper-velocity impact of the debris or meteoroids and the interaction of the solar cell array with the ambient plasma, have been studied. The engineering studies have shown that the power generation/transmission panel is technically feasible using the near-term technologies. The environmental studies have shown preliminary guidelines to design the power generation/transmission panel.

&quot;HIT-SAT&quot; is a small satellite to demonstrate performance of the bus systems of &quot;Hokkaido Satellite&quot;. The main purpose of the attitude control system of &quot;HIT-SAT&quot; is to get basis data for the attitude control and determination system of &quot;Hokkaido Satellite&quot;. &quot;HIT-SAT&quot; was launched on Sep. 23, 2006 by M-V-7. Attitude control system of &quot;HIT-SAT&quot; could get magnetometer data and gyro data on orbit. This paper describes the attitude determination from magnetometer data obtained on orbit.

HIT-SAT has been designed and developed in order to examine functions of the bus system. It was successfully launched by M-V rocket #7 on 23rd September 2006. The volume and weight of HIT-SAT are about 12[cm^3] and 2.7[kg], respectively. HIT-SAT has a flame-panel structure that consists of 6 panels, 4 columns and 2 shelves made of the aluminum alloy that has a high conductivity. The passive thermal control is adopted. Thermal analysis was conducted using Thermal Desktop/SINDA/FLUINT before launch. However, the result of thermal analysis is quite different from on-orbit thermal data of HIT-S...

A CubeSat size class &quot;HIT-SAT&quot; is a micro satellite that developed by Hokkaido CubeSat development team. Its volume and weight is 2.7kg and 12cm cubed. It was fixed in the sub payload space of M-V-7, and was ejected after main satellite separation on September 23,2006. The orbit is sun-synchronous orbit of the altitude of 279-660[km] and the inclination of 98.32[deg]. The purpose is to examine some functions of the bus system. This research report describes an electric al power subsystem design. The major difficulty of Electrical Power System is surely OFF and ON. The OFF needs to be guaran...

HIT-SAT has been designed and developed in order to examine functions of the bus system. It was launched by M-V-7 into a sun-synchronous orbit of the altitude of 279-660 [km] and the inclination of 98.32 [deg]. The volume and weight of HIT-SAT are about 12×13×12[cm3] and 2.7[kg], respectively. HIT-SAT has a flame-panel structure that consists of 6 panels, 4 columns and 2 shelves made of the aluminum alloy that has a high conductivity. The load pass at the launch is their panels and columns. The passive thermal control is adopted. Random vibration tests and impact tests were carried out. It ...

The HIT-SAT had been developed by Hokkaido in order to demonstrate the performance of the attitude control system for &quot;Hokkaido Satellite&quot;. &quot;Hokkaido satellite&quot; is a 50kg small satellite, and the main mission is a remote sensing. The HIT-SAT is size 12cm cubed and weight 2.7kg. Attitude Control is an object of keeping satellite attitude by spin stabilization. It has three parts as de-spin, spin-up and sun acquisition. As an Attitude sensor, we adopt Sun sensor, Magnetometer, and GYRO. Actuator is 3-axis Magnetic Torquer. The HIT-SAT was launched successfully on September, 23, 2006(JST) as a...

&quot;Hokkaido satellite&quot; is a 50kg small satellite, and the main mission is a remote sensing. The HIT-SAT had been developed by Hokkaido in order to demonstrate the performance of the attitude control system for &quot;Hokkaido Satellite&quot;. The HIT-SAT is size 12cm cubed and weight 2.7kg. Attitude Control is an object of keeping satellite attitude by spin stabilization. The HIT-SAT was launched successfully on September, 23, 2006(JST) as a sub-payload of the M-V-7 Rocket. In this paper, we described a design of data handling unit for the HIT-SAT and the result in orbit.

A CubeSat size class &quot;HIT-SAT&quot; is a micro satellite that developed by Hokkaido CubeSat development team. Its volume and weight is 2.7kg and 12cm cubed. It was fixed in the sub payload space of M-V-7, and was ejected after main satellite separation on September 23, 2006. The orbit is sun-synchronous orbit of the altitude of 279-660 [km] and the inclination of 98.32 [deg]. The purpose is to examine some functions of the bus system. This research report describes an electric al power subsystem design. The major difficulty of Electrical Power System is surely OFF and ON. The OFF needs to be gua...

For earth observation thorough hyper-spectral camera, a small satellite &quot;Hokkaido Satellite : TAIKI&quot; has been designed in Hokkaido. To demonstrate the performance of the bus system, a cube-sat &quot;HIT-SAT&quot; was developed as a scale model of the Hokkaido Satellite This paper describes the development and results of launch and operation. The HIT-SAT is 2.7kg and 12cm cubed. The bus system of the satellite consists of five subsystem; power generation system, structure system, data handling system, communication system and attitude control system. The HIT-SAT was launched successfully on Sep. 23, 2...

HIT-SAT was launched as a sub-payload of the M-V-7 rocket on September 23, 2006. The orbit of HIT-SAT is the elliptic one with 98 deg inclination. Altitude at apogee is 648km and perigee 279km.The satellite is operated by the ground station set up by Hokkaido Institute of Technology. The mission of HIT-SAT is to demonstrate the commercial-off-the-shelf component on the orbit. HIT-SAT is an amateur satellite where the amateur radio machine was installed. Operation is being done well on the orbit as for HIT-SAT now. This paper describes the system of the ground control station of HIT-SAT.

Tethered Solar Power Satellite (Tethered-SPS) has been proposed as a feasible and practical Solar Power Satellite. It consists of a power generation/transmission panel suspended by tether wires deployed from single or multiple bus satellite. Especially, the multi-bus Tethered-SPS, recently invented, is highly flexible and expandable. It can be constructed by integrating perfectly equivalent units of miniature Tethered-SPS connected to each other. Each unit folded up is transported from the ground to the geo-stationary orbit and deployed automatically. This concept enables phased construction approach, evolutional development scenario, and coexixtence with other geostationary satellites.

For large space structures, the deformation of the structure due to thermal stress affects the attitude motion. In this paper, we propose a modularized structure which can release the thermal deformation locally. As an application, we study a space solar power system which is stabilized by gravity gradient torque. The purpose of this paper is to suppress overall deformation by the local release of thermal deformation. At first, we analyze thermal deformation of the structure and induced attitude motion under the condition where connecting rigidity between modules is as stiff as module itself. From the result, it is shown that roll and yaw motion becomes unstable due to the thermal deformation. Then, we modify the condition of the connection between modules to release thermal deformation locally. Through the simulation, it is confirmed that large deformation can be suppressed in the modified modularized structure, and thermally induced attitude motion becomes small enough for the mission.

This paper describes the design and performance verification of the attitude determination and control system for the Hokkaido Satellite. The main missions of the satellite are earth observation during sunlight and laser communication during sunshade. The purpose of the attitude determination and control system is to stabilize the attitude around three axes within three degrees. The satellite is stabilized by a momentum wheel (MW). The attitude determination system consists of an earth sensor and an inertia reference unit (IRU). Based on the Kalman filter, the determination system can estimate three attitude angles and IRU bias rates without a yaw sensor. The control modes of the satellite are an attitude acquisition mode, a normal mode and a safe-hold mode. For the normal mode of the wheel-stabilized earth pointing satellite, a new pointing control law is proposed. The proposed law simultaneously achieves nutation dumping and angular momentum direction control relative to the orbital coordinate system. The control law consists of pitch angle control by MW, roll and yaw axes control by magnetic torquers (MTQ) and angular momentum control by MTQ. Through numerical simulations, it was confirmed that the determination laws and the control laws can achieve the required attitude accuracy and stabilization time.

Hokkaido satellite is the small satellite which is being developed in Hokkaido. In this paper, the attitude determination system based on the Kalman Filter is designed for the Hokkaido satellite. The satellite has an earth sensor and IRU. The earth sensor outputs roll and pitch angles. Focusing on coupling between roll and yaw axes in kinematic equation of earth observation satellites, the attitude determination system is designed to estimate roll, pitch and yaw angles using roll and yaw angular measurements and IRU. We estimate accuracy of sensors to satisfy Hokkaido satellite&#039;s requiremen...

Tethered Solar Power Satellite (Tethered-SPS) consisting of a large power generation/transmission panel and a bus system which are connected by tether wires has been proposed as an innovative solar power satellite. The concept Tethered-SPS is highly robust and potentially low cost. This paper presents a new version of Tethered-SPS which is integrated by perfectly equivalent units loosely connected to each other. The new Tethered-SPS, highly flexible and expansible, has a lot of advantages over the past SPS models in attitude stability, construction, modularization, thermal characteristics, and robustness.

In Hokkaido, engineers in companies and researchers in universities have developed a small satellite, Hokkaido Satellite, since two years ago. This paper describes a designed attitude controll system based on Hokkaido Satellite&#039;s requirement. Bias momentum controll is applied to stabilize the attitude of satellite around three axises. The satellite has a momentum wheel on pitch axis and two reaction wheels on roll and yaw axises. Magnetic torquers are aligned with three axises. We simulated the designed attitude control system in complex environment where there are magnetic field, gravity, ...

It has been difficult to avoid falling over for walking robot with only legs. However, by adding arms, the robot is possible to transit from biped walking to more stable quadruped walking when the robot cannot maintain biped walking We demonstrate the limit of stable gait and that the robot can maintain locomotion through the transition to stable quadruped walking despite applied external force.

A biological binocular stereo vision processing was modeled based on Pulse-Coupled Neural Network(PCNN). Then disparity detection can be accomplished in the spontaneous synchronization of neurons corresponding to the correct matching points. Consequently, it is clarified that binocular stereo vision is generated through proposed model. Furthermore, our model is appropriate model based on actual visual processing of biology.

A novel method for extraction of moving objects in an image sequence using multi-tiered Pulse-Coupled Neural Network (PCNN) is presented in this paper. PCNN is a biologically-inspired model which shows highly applicable in various image processing applications, including image segmentation, contour detection, etc. In order to adapt PCNN for moving object extraction, the multi-tiered PCNN model is proposed. This new PCNN model is called E-PCNN, since excitatory term and external linking are its two features. The architecture and algorithm of E-PCNN are presented in detail. It is shown that E-PCNN outweighs the commonly used inter-frame difference algorithm, having three main advantages: utilization of multiple color information, parameter robustness and robustness against noise.

The stability analysis of large space structures such as space solar power system is discussed in this paper. Because these structures are very large and flexible, the mutual interference among position, attitude and structural deformation cannot be negligible. Therefore, a comprehensive analysis of the system dynamics including position, attitude and structural deformation on orbit has been required. In this study, we propose a new method based on potential energy to estimate the integrated stability. Based on potential energy, the integrated stability of deviations in position, attitude and structural deformation on orbit is analyzed. The potential energy, which is caused by gravitational force and centrifugal force, is considered as well as strain energy of the structure. By using the potential energy, not only equilibrium states but also the degree of stability in the neighborhood can be estimated. As a case study, we focus on a solar-array platform with gravity gradient stabilization. At first, the stability about the position and attitude is estimated based on the potential energy. As compared with the numerical results of system dynamics, the validity of the estimation is confirmed. Then, we show the change of stability which depends on the satellite&#039;s configuration. Finally, the stability of structural deformation around the equilibrium point is shown through the potential energy.

Electric wheelchair is an important device to the physically handicapped persons with mobility. The aim of our study is to develop the electric wheelchair which is driven as the human intention, and we tries to extract the human intention from the adaptability of physical characteristic between embodiment system and wheelchair system in various situations. To design the system, we developed the experimental electric wheelchair which can measure dynamic posture changes of electric wheelchair and passenger, simultaneously. These measurements are carried out the straight-line motion and turning motion, etc. Results are shown the various posture change of passenger under the some conditions, and the hunting phenomenon as example of uncontrollable situation. We also derive a mathematical model to analyze this phenomenon, and we explain the simulation results. Finally, we discuss the methodology to realize adaptive operation to human intention.

インターネットを媒体としたロボット遠隔操作システムの構成を提案する。ロボットに行わせるタスクにより各種データの重要性の序列が変化することを利用し, 輻輳検出時にデータの送信頻度を変化させ幅輳適応, 操作の安定化を図る。

筋電図のヒューマンインタフェース (HI) 利用における問題として, 識別には十分大きい能動的な筋力を必要とすることがあげられる。本研究では, 能動的な筋力を必要としないHIを実現するために, 筋刺激応答を応用することを考える。

本研究では, 汎用の加速度センサとPC, およびlinuxを用いた情報ネットワークシステムを提案する。危機管理や状態の把握といった観点から電動車いすでの運用について述べる。遠隔操作やユーザ識別等の展望についても詳述する。

In this paper, chaotic synchronization of pulse-coupled neural network (PCNN) is studied from the view-point of temporal information coding. We extend Eckhorn&#039;s PCNN to realize chaotic inter-spike interval dynamics. First, a condition for synchronous spiking is derived for coupled two-neurons systems. Then, we numericaly analyze a generation of chaotic synchronized assemblies in one dimentional system with locally-excitatory-globally-inhibitory interaction. When multiple assemblies are generated at the same time in the chaotic network, it is shown that there is no cross-correlation between ...

We have proposed a chaotic pulse coupled neural network (CPCNN) to investigate possible roles of high-dimensional chaotic dynamics in information coding using synchronous oscillation. In the present paper, some basic characteristics of CPCNN are examined. On the one hand, in a two-neuron system, CPCNN have rather simple condition for the persistence of synchronization despite of its chaotic dynamics. On the other, in a one-dimensional lattice system of homogeneous neurons, it can exhibit complex and various dynamics such as dynamical clustering, traveling waves and spatio-temporal intermittency.

Based on the analogy of heat and wave equations, novel decentralized control methods of a redundant manipulator are proposed. Because these control methods are based on real physical phenomena, physical sense of control parameters can be understood intuitively. Some traditional control methods can be reconstructed from the viewpoint of proposed methods. Furthermore, stable characteristics of the heat conduction imply stability of the control method. As case studies, three subjects are discussed: position control of the end-effector of manipulator, obstacle avoidance, grasping behavior. Some numerical results are shown to illustrate capabilities of proposed control methods.

本研究では, Global Entrainmentという概念に基づいて, 2足ロボットの歩行運動を生成することに焦点をあてる。その概念によると, 歩行運動は, 神経・身体・環境からなる結合力学系におけるリミットサイクルアトラクタとして自己組織される。本論文では, 計算機シミュレーションならびに実機実験において, 同概念に基づく歩行生成に成功したので報告する。またシミュレーション上では, その歩行が身体・環境モデルの変動に対して適応能力を持つことも調べる。

人-車椅子系の動的制御モデルの構築を行い, 操作性の向上のための資料を得ることを目的に, 本研究では, 人が搭乗している時の電動車椅子の動的な姿勢変化を計測し, その定量的な評価を行った。車椅子には, ヨー, ピッチ, ロールの3軸の角速度と加速度が計測できる姿勢センサーを取り付け, 搭乗者には頭部用の3軸加速度センサを装着して計測を行った。実験は, 発進・走行・停止の直線加減速運動, カーブ走行, その場旋回などの計測を行い, 人-車椅子の姿勢変動の相関を評価した結果を示した。

電動車椅子ロボットにおける人の上半身姿勢の制御を行う。本研究では, 前後左右の2自由度を持つ倒立振子モデルにより人の上半身を表す。急な加減速において, 電動車椅子上の人の上半身姿勢が不安定になることは既によく知られているが, この姿勢変動を横方向も含めて安定化することは非常に困難である。ここでは, 上半身の質量, 長さ等のの身体パラメータが未知である場合に対して, 部分的適応制御を適用し, 姿勢安定化を行う。数値計算によって, その有効性を示す。

In this paper, we show usefulness of Pulse Coupled Neural Network(PCNN) in visual information processing. The PCNN is based on the visual information processing of mammals, and has superior ability like segmentation, edge detection, time resolution, and so on. Therefore, we apply the PCNN to the some visual problems in engineering such as stereo vision, recognition of handwritten characters, and object detection. Each simulations use features of the PCNN, such as robustness against noise, detection ability of foveation point, and segmentation ability using color and form information. Various results of the simulations and usefulness of PCNN are presented.

An autonomous distributed control is introduced as a new control method. The effectiveness of the control is verified using a case study, where the control method is applied to the control of variable geometry trusses that has high redundancy. Through computer simulations, it is shown that various behaviors of variable geometry trusses are realized by very simple control rules of subsystems.

平成18年10月(2006.10)

Multi-cellular inflatable structures were investigated as a candidate of ultra-light space structures with high packaging efficiency. Through numerical analysis and element tests, it was shown that the developed multi-cellular inflatable sandwich panels had sufficient bending rigidity. Furthermore, meter-order multi-layered sandwich panels were also developed as a structural element with practical scale. In addition to it, the dynamical behavior including stable deployment procedure and shape control was also studied.

平成19年度は,構造・環境・制御の相互作用によって形成される宇宙構造システムの研究として以下の3つの課題に取り組み,成果を得た.
課題1.環境力(重力傾斜)による構造形状の維持とその安定性解析
昨年度の結果をもとにして,重力傾斜を宇宙機システムの姿勢維持のみならず構造形状の維持に利用した新しい柔軟多体宇宙機システムを検討した.具体的には,非常に柔軟なパネル構造を複数バス系からテザーで支持する地球指向の太陽発電システムを対象とし,システムの安定性を重力,遠心力,歪みエネルギーからなるポテンシャルエネルギーを用いて評価した.さらに,安定な平衡点まわりにおける固有振動数,モード形状の導出を行うと同時に,重力傾斜を構造形状の維持に利用したシステムの特性を明らかにした.
課題2.環境力(圧力差)を利用した柔軟膜面構造とその動的特性評価
インフレータブル構造物を,構造内と環境との圧力差を利用した構造様式と捉え,内圧維持型のマルチセルインフレータブル構造の提案を行うと同時に,面内剛性の評価を実施した.さらに,展開時の動特性評価を行い,ケーブル要素による制御機構を組み込むことで,安定な展開が行えることを示した.
課題3.柔軟構造要素によって結合された小型衛星群のフォーメーションフライト
本年度は小型衛星群制御の要素技術として必至な,小型衛星の姿勢制御・決定系について,昨年開発・打ち上げに成功した超小型衛星HIT-SATのフライトデータを元に,その性能評価を行った.さらに,シミュレーションベースで,特定平面内をフォーメーションフライトする小型衛星群を柔軟構造要素で結合することにより,必要なスラスタ燃料が大幅に軽減されることを示した.

昨年度は,大規模宇宙構造システムを対象に,構造物の特性と姿勢変動の関係を明らかにした.その結果を基として,本年度は,さらに,軌道・姿勢・構造の3要素の干渉による非線形なシステムの動特性評価を推し進めると同時に,熱応力の影響や,構造変形(振動)や姿勢変動のそれぞれのモード間のエネルギーの伝搬と,モジュール間におけるエネルギーの伝搬についての研究を行った.その知見を元に,分散的に熱応力を解放可能なモジュール構造の提案を行った.その有効性は,シミュレーションにより検証された.具体的には以下の2点に関する知見を得た.(1)連成挙動の支配要因となる構造特性構造システムの柔軟性や形状といった構造特性が,軌道・姿勢・構造の3要素の連成に与える影響についての解析を行った.1次元的な重力傾度安定型宇宙構造物について,解析的にその支配パラメータを特定した.A.軌道運動と構造振動の固有振動数比,B.質量比,C.軌道半径に対する構造物の代表長の比の3点である.これらのうち,A.の要因が最も影響が大きく,その値が約10を越えた場合には,構造振動は,軌道・姿勢運動と独立と捉えて良いことが判明した.(2)エネルギーの伝搬を考慮した熱応力の分散解放構造熱応力存在下のテザー支持による大型宇宙構造物の構造変形及び姿勢変動の解析を行った.熱変形によって,テザーがスラックすると,その固有振動数が著しく低下し,構造振...

In this project, focusing the target to improve the adaptivity of interfacing by considering the chaos dynamics between human and environment, we developed the walking robot, the artificial neural network vision and the electric wheel chair car as a total system. The results are summarized in the followings ;
1. Evaluation of the chaotic skill dynamics within the human walking and speech By application of chaos theory to the measured signal in walking and speech, we made clear of the nonlinear attracting dynamics within the human motions. We developed the 2-legged walking robot with the central pattern generator neurons.
2. Constitution of the articial neural network vision with intelligent information processing Applied the pulse coupled neural networks to the primary visual processing, we developed the simulated system which have the capability to process the segmentation, foveation, target tracking of the objects.
3. Development of the adaptive interfave of electric wheel chair of considering the interactive dynamics between human and machine We developed the electric wheel chair car system to measure and control the dynamical behaviors with human. The 22 sensors are equipped in this system and the measured data are processed synchronously to utilize the adaptive operation. As an example of the undesirable interaction between human and car, we showed the adaptive interfacing method to prevent the hunching phenomenon.

<p>ASTRO-H (hitomi) was an X-ray astronomy satellite in Japan which was launched on 17 Feb. 2016. To meet its science goals, four kinds of instruments and six detectors were equipped on the satellite. The focal length of two soft X-ray telescopes was 5.6 m, and that of two hard X-ray telescopes is 12m. One of the most difficult challenges for the satellite structure was to meet the alignment requirements for instruments and detectors. Through the ground tests and observation results on orbit, it was confirmed that the performance of alignment meet the requirements. In this paper, the results of on-orbit alignment performance of the instruments and obtained techniques to control the alignment are reported.</p>

To meet advanced science missions, large and precise support structures such as truss structures are needed. In this paper, pointing control of a truss structure is discussed. To control the truss structure, thermal expansion of truss members is utilized instead of mechanical actuators. Heaters are equipped to truss members so that the thermal expansion of the members is controlled by heaters. PI control is applied to an experimental model which is box truss with 1.9m height. Through experiments, it is shown that the truss structure can be controlled with good accuracy, for example, within ...

In SCOPE mission, flexible extendable rod antennas are equipped along the spin axis of satellite. For the extendable function, STEM (Stowable Tubular Extendable Member) is used as the rod antenna. The apparent natural frequency of the STEM changes depending on the spin-rate. Furthermore, bending and torsion of the STEM are coupled because the STEM has open section. The dynamic characteristics of the STEM are clarified through analysis and tests. Especially, the coupled vibration of bending and torsion, and the effect of spin motion on apparent natural frequency of the STEM are investigated. As a result, it was shown that the effect of spin motion can be quantitatively predicted by simple analytical model. In addition, it was found that the characteristics of the vibration are strongly affected by the boundary condition of the STEM.

Requirement for shape stability of space structures such as barrel for space telescope tends to become more precisely. In addition to it, large size over 10 meters is sometimes required for such support structure to meet advanced science missions. To realize large and precise support structures, comprehensive techniques including prediction, measurement and stabilization techniques on orbit are needed. In this paper, we introduce some fundamental techniques to keep the precise shape for a slender box truss as a representative support structure. The structural deformation on orbit is induced by thermal distribution, disturbance (RW/MW/SAD etc.) and so on. At first, we analyzed temperature distribution and thermal distortion of the truss structure to predict the thermal deformation. The accuracy of analysis results is evaluated through experiments with a five-bay truss structure. Then, system identification is carried out to identify the stiffness of the structure because such identification of the stiffness becomes important for the precise prediction of thermal deformation in the case of indeterminate structure. As a first step, the stiffness matrix is identified by using particle swarm optimization method from the experimental data of natural frequency. By using the identified stiffness matrix, the natural frequency can be estimated within 1% error. At last, we attempt the shape control of truss structure by using artificial thermal expansion. It is experimentally shown that deformation of truss structure could be controlled with good accuracy, for example, within 30μm error for 1.9m height truss. Copyright ©2010 by the International Astronautical Federation. All rights reserved.

展開構造物のジョイントラッチ部の機械特性として，剛性および熱変形時のラッチ部の滑りに関する研究を行った．各部材の剛性が全体剛性に与える感度を評価し，ジョイント部の剛性寄与度が高いことを明らかにした．また，これらのジョイント部のクリアランスの時間的な変化によって振動が誘起されること明らかにした．熱変形時のカップリング面での滑りに関しては，特に押付力に注目し，その滑り量を管理することを試みた．適切な押付力を電磁石によって制御することで，カップリング面での滑りを管理することが可能となり，展開構造物の形状精度の向上につながることを示した．