This paper analyses stability of discrete-time collocated feedback contorol system of flexible satellite. From the existing studies, the effectiveness of collocated feedback contorol system in ensuring robust stability is known. However, the stability condition is given for continuous-time system, and the influence of discretization to the stability has not been fully investigated. In this study, we propose a method for stability analysis encountered in discretization.

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This report is the introduction of a study of SG-CMG (Single-Gimbal Control Moment Gyro) for agile satellite maneuver in JAXA IAT. In this research, the Rest-to-Rest satellite maneuver by 4-CMG is planned. The feature of the CMG test system is described. Control low of the pair drive of CMGs is explained. It aims to verification of agile artificial satellite maneuver by the experiment and the research of up to date is announced.

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Control moment gyro (CMG) generates higher torque than reaction wheel. Thus it is focused to mount CMGs on future satellites which is required to make fast maneuver. CMGs, however, have singular points. To avoid the singular points, number of CMGs is more than the degree of freedom of satellite. This paper discusses on the minimum energy maneuvers of a satellite using CMGs. The criterion is square of gimbal rate, which is equivalent to energy consumption. The numerical results show that twice of energy is required when one of CMGs malfunctions.

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This paper studies the controller design problem for linear time-invariant systems including on-off type actuators. The controller design is not easy since the actuator has the nonlinear property. In order to cope with the problem, we propose two design methods of statilizing state feedback controller. They are obtained by convex optimization for Liner Matrix Inequalities using comtinuous approximation of on-off function.

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NASTRAN is a computer-aided engineering (CAE) software that major manufacturers worldwide depend on for the important engineering computing needs to create safe, reliable and optimized designs in demanding short turn-around time. For more than 30 years, NASTRAN has been the analysis solution in almost every major industry including aerospace, defense, automotive, shipbuilding, heavy machinery, medical and consumer products-a state of the art for the computer-aided engineering of stress, vibration, structural failure/durability, heat transfer, noise/acoustics and flutter/aeroelasticity. I describe features and functionalities of NX nastran as a subject of software focusing on the space-engineering field, such as aerospace, defense.

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A machine can demonstrate the function demanded by putting various kinds of parts together and moving. A computer performs control and the target operation is realized recently combining the mechanism of the gear, a link, a cam, a belt, etc. in the structure of a motion of an arm and a leg so that it may be represented by the robot. The efficiency of operation of this series, control, etc. are important when designing a machine, and they are also the place which can demonstrate an engineer's idea. The improvement in a performance of a computer and development of algorithm progressed, and structure and the mechanism simulation became possible on the practical use level recently. The space field also has a track record in the deployment action analysis of a solar cell paddle, large-sized antenna deployment action analysis, etc. Here, a mechanism and structural analysis software "SAMCEF MECANO" (Belgium SAMTECH) are taken up, and I introduce about the background, a functional outline, and the example of the space engineering field.

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Advancements in system verification concern both advancements in test and simulation technologies, methods and practices. It is this combined progress in both areas that will be essential to cope with the challenges of system verification on ever more complex structures. This paper will discuss three areas: The Virtual Engineering Process, where our LMS Virtual. Lab solution allows for the integrated multi-attribute analysis of a spacecraft system. This in turn increases analysis accuracy (more physics can be incorporated and optimized) and increases productivity (a single seamless analysis environment). The Hybrid Engineering Process, where we show our Virtual. Lab Assembly and NVH system synthesis capabilities for combining test and simulation models to produce a coupled simulation response. Optimization, where we show our LMS Virtual. Lab Optimization solution, which allows for the target setting and optimization of key parameters for optimal performance design. Each item will be illustrated with an industry example.

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There are some basic improvement of measurement technology and improved application for sound and vibration in modem space engineering, which requests high channel number and reliability of measurement in hard environment. It is, therefore, needed some new technology in transducer and intelligent front-end, such as Transducer Electronic Data Sheet (TEDS), surface microphones and high-pressure microphones, and large dynamic range for AD converter and response equalization of individual transducer and remote calibration technology in measurement front-end instrument. Using these new technology, then, several key application are effective and improved for their performance. In here, these technology and case study of application: Operational Modal Analysis, Beamforming for Noise Source Location and Vibration Check System for aircraft engines, are reviewed for sound and vibration in space engineering.

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We investigated the dynamic chracteristics of the longitudinal (axi-symmetric) sloshing of liquid in a concentric membrane tank. We conducted an experiment using a circular cylindrical tank having a rigid outer wall and a flexible inner wall. The three materials used for the inner walls, rigid acrylic, Kapton film and polyethylene foam sheeting. We found that in the membrane wall, the outer part resonant phenomenon was difficult to clearly discern, because of the heavy motion coupling of the inner and outer liquids through the flexible membrane wall. Consequently the apparent damping ratio was increased with decreasing rigidity of the membrane wall.

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Spacecraft attitude dynamics equations with the structural modes and liquid sloshing are derived. The effect of the flexible structural vibration modes are converted into coupling vectors and the liquid motion in a tank is modeled as a mass-spring-disk model. Then, they are coupled to the rigid-body attitude dynamics of spacecraft.

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The report deals with the inflatable membrane structure with cable. The first, we discuss a non-linear finite element formulation of the menbrane, the cable and the membrane with cable, using the Green strain. Also, we experiment with cable and membrane with cable. Finally, we compare numerical result with experimental one and examine the validity of a non-linear finite element formulation.

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It is well known that musculoskeletal atrophy arises among astronauts and bedridden patients. This is one of main issues on space medicine and clinical medicine. We proposed a "hybrid exercise method" (hereafter, abbreviated as HYB exercise) in which antagonist was stimulated electrically for generating resistance against the volitional contraction of agonist. The HYB exercise, which utilizes electrically stimulated antagonist force as a resistance of joint movement instead of the gravity, would become a useful exercise method in the weightless environment. The HYB exercise was examined in upper and lower limbs under a normal situation and a simulated microgravity. We confirmed its advantages and found it be tedious in a long-term exercise. The purpose of this study is to develop a training system for maintaining and increasing motivation for training. The training system is based on a virtual reality containing entertainment.

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