大槻 真嗣

小型月面探査機OMOTENASHIには，月面着陸時に機器の破損を防ぐために衝撃緩和装置としてエアバッグを搭載する．エアバッグ気室はポリイミド製であるが、従来の樹脂製接着剤を用いた製作方法では目標の質量を超えていた．そこで，気室（バルーン）の軽量化を目的とし，本研究室が有しているポリイミド溶着技術の応用によって新たなバルーンの設計・製作を実施した．本発表では製作したバルーンの性能評価及び構造の改良について述べる．

NASAのロケットシステムSLSに相乗りするCubeSatの一つとして，超小型月面技術実証機OMOTENASHIの開発が進められている．OMOTENASHIではソフトランディングが行えないため，月面との衝突緩和を目的としてエアバッグの使用が提案されている．本発表では，エアバッグへの使用を検討しているポリイミドフィルム製空気室の構造と基礎特性について述べる．

Lunar or planetary exploration is scientifically meaningful because they can give us the hint to throw a light on the origin and evolution of the solar system or the earth, the inner structure of planets, etc. In lunar or planetary exploration missions, it is important to save the weight of spacecraft. Light weight spacecraft leads to low cost and getting more chance to go to the space. Conventionally a lander carries a rover to the surface of the celestial body and the rover traverses the rough terrain to explore in wide region. If the lander and the rover are united, however, the total weight of the spacecraft could be reduced. The authors have already proposed a novel pulley suspension mechanism, which is called Load Equalization Pulley Suspension mechanism: LEPS mechanism, for rovers. The performance of the proposed mechanism as a suspension mechanism of rovers has been evaluated. In this paper, the application of LEPS mechanism to the landing gears of the lander is discussed. By applying the proposed mechanism to the landing gears, the lander can move around the wide region of the surface after landing. The landing dynamics model of the proposed "Movable lander" with LEPS mechanism is introduced. The landing performance is evaluated by 2-dimensional model. The simulation results show that LEPS mechanism has an advantage over normal landing gears.

This paper presents an actively controlled landing gear system and its experimental validations. Active landing gear uses an variable coefficient damper as an shock absorber. We executed landing experiment with the two dimension lander model which introduced an magnetorheological damper as an shock absorber. Damping coefficient is controlled to reduce attitude disturbance during touchdown based on lander attitude and displacement of landing leg. The result of model experiment indicates that the active landing gear can reduce attitude disturbance which causes the lander overturning.

The performance of an integrated navigation system is studied through the field experiments on a four-wheeled test-bed rover, AKI, operated in a terrestrial analogue. The AKI rover employs novel mobility and navigation systems which enable challenging long-range operations in natural terrain. AKI has a vision-based localization system aided by sun sensors and an inclinometer for absolute attitude estimation. The integration with absolute direction sensors improves accuracy in absolute positioning, as well as obtaining 5x run-time improvement of visual pose estimation. The paper reports the results of field experiment conducted in Izu-Oshima island in 2013, and discusses current challenges of the system.

In future lunar, planetary or asteroid explorations, in-situ analysis of rock samples are strongly demanded to obtain many data from various aspects. For precise composition analysis, a sample surface should be smoothed. In this report, a surface shaver with a piezoelectric actuator is proposed and its machining performance in air is investigated. Shaving teeth are mounted at the ends of a lever mechanism. The device is pressed through four springs onto the specimen with a linear actuator. When a sinusoidal voltage of 50 Vp-p and an offset voltage of 25 V ware applied, the natural frequency was 556 Hz and the unloaded amplitude of shaving teeth were 0.77 mmp-p. Basalt samples were machined for 10 minutes in air. The surface roughness was small with an increase of the pressing force. However, the removal amount was smaller with an increase of the pressing force further. The surface roughness varied widely not only due to removal amount but also due to pores.

This paper presents a vibration control method for a wire changing its length such as an elevator cable and a crane wire. We propose a synthesis method of vibration controller considering a time-varying uncertainty directly and having the robustness for a variation of tension, a transition of frequency of resonance and a spillover of high order modes. The performance and robustness of the proposed control method is examined through the numerical calculation on variable conditions.