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The primary goal of the Single-Stage-to-Orbit technology is radially to reduce the cost of access to Space. The Winged rocket developed by Kyushu Institute of Technology, Japan is the test bed and technology demonstrator for this effort. To successfully complete these missions, estimation of air data parameters are vital. FADS (Flush Air Data System) is utilized for the winged rocket. The flight control system requires indispensable air data acquisition with high precision and high reliability. However, under severe thermal environment of re-entry, the failure risk of pressure ports is high and there is as possibility that acquisition of the air data accuracy may not be reliable, which adversely affects the flight control. In this paper, the improved design of Flush Air Data Sensing (FADS) system is proposed for estimation of air data parameters for wide flight range. Wind tunnels tests have been performed for the calibration and calculating the algorithm of FADS. However, the measured and estimated values had little discrepancy in accuracy. Statistical accuracy of the calibration is evaluated by comparing the wind tunnel reference conditions to the air data parameters estimated. This comparison is accomplished by applying the calibrated FADS algorithm to the sensed wind tunnel pressures.

形態: 図版あり, Physical characteristics: Original contains illustrations, Accepted: 2016-10-03, 資料番号: PA1710082000

Kyushu Institute of Technology has been developing fully reusable space transportation system since 2005. WIRES#015, the subscale flight model of suborbital vehicle will be launched from Mojave Desert, California in 2020. The engine employs thrust vector control (TVC) system to improve the control performance during the ascent phase where dynamic pressure is low for instance at the launcher exit. However, natural frequency of the vehicle attitude motion may become higher than the cut-off frequency of the actuator, when the vehicle experiences maximum dynamic pressure, and the actuator performance becomes saturated. In this research, the attitude control law on the longitudinal and lateral motion using thrust vector control and aerodynamic control surfaces in powered flight was designed based on eigenvalue analysis, and the response of pitch angle and TVC actuator performance was evaluated based on non-linear flight simulation. In conclusion, two findings are obtained. At first, the designed control system has appropriate damping ratio on short period mode and enough stability margin of open loop transfer function, which meet the control design requirement. Second, flight simulation shows that the control law stabilizes vehicle attitude with the influence of gimbaling reaction torque, while TVC actuator is not saturated. In future, possible disturbances such as steady wind and combined use TVC and aerodynamic control surfaces for fault tolerance and high angle of attack maneuverer in abort flight will be installed into this flight simulation.

In order to realize reusable winged sub-orbital transportation system, the Space Systems Laboratory, Kyushu Institute of Technology has worked in research, development, and flight test for winged rocket which is called “WIRES” (WInged REusable Sounding rocket) since 2005. Autonomous flight system is one of the most important research fields for space transportation system.

形態: カラー図版あり, Physical characteristics: Original contains color illustrations, Accepted: 2018-01-19, 資料番号: PA1810076000

This study aims at building an evacuation system using audio signals. The feature of the system is the utilization of the precedence effect for a listener to easily perceive the direction of an emergency exit. Two kinds of pre-listening tests were conducted to reconfirm the basic characteristics of the precedence effect which needed consideration in the proposed system. Firstly, the influence of various kinds of background sounds to the precedence effect was investigated in a horizontal plane. The complexity of signal, that is, the difference in levels between the audio signal and background sound, and the variety of the sounds, influenced the precedence effect. Secondly, the generation and disappearance of the precedence effect were investigated in the vertical plane. We confirmed that the generation and disappearance of the precedence effect were clear in the horizontal plane and vague in the vertical plane. The results of the two pre-listening tests led us a new concept of an evacuation system with the loudspeakers set beside a wall in a passageway. In the listening tests of the proposed system, the generation and disappearance of the precedence effect of an audio signal were investigated. The configuration of the loudspeaker setting had a good effect on guidance of evacuees during an emergency. The installation angle of a loudspeaker was shown to be an important factor in the perception of stable sound localization in the direction of the emergency exit. At installation angles of 10 or 20°, the direction of sound localization became more straight ahead than in the case of other installation angles. Furthermore, at the worst listening position for the perception of sound localization, we confirmed that the difference in intensity between the loudspeakers contributed to the improvement of sound localization. Therefore, using loudspeakers with sharper directivity was suggested, which can easily improve the direction of sound localization at the worst listening position to become more straight ahead. We confirmed that the proposed evacuation system with loudspeakers set beside the wall in a passageway was a promising candidate.

A wearable actuator needs to be flexible so as not to injure the human body. The purpose of our study is to develop a flexible and lightweight actuator which can be safe enough to be attached to the human body, and to apply it to a robot arm and rehabilitation device. New types of flexible pneumatic actuator that can be used even if the actuator is deformed by external force have been developed in our previous studies. In this paper, a robot arm using the flexible pneumatic cylinder that can realize a natural flowing movement with multi-motion such as bending, expanding, and contracting is described. The analytical model of the robot arm is proposed for attitude control. In addition, an inexpensive quasi-servo valve using the on/off control valve is utilized in the master-slave control system to improve the control performance. As a result, the usability of the proposed robot arm and the effectiveness of the attitude control method using the analytical model and the quasi-servo valve are confirmed.

A fully-reusable two-stage-to-orbit (TSTO) launch vehicle with ethanol-fueled rocketbased combined cycle (RBCC) engines is a promising option for future space transportation that is currently studied in Japan. In this paper, a conceptual design study is conducted for such a vehicle using a multi-objective, multidisciplinary design optimization (MDO) technique. An MDO framework considering the coupling between vehicle geometry, propulsion system, aerodynamics, and flight trajectory is constructed, and they are optimized simultaneously with the aim of maximizing the payload mass, minimizing the gross mass of the combined vehicle (booster and orbiter), and minimizing the horizontal takeoff velocity. This multi-objective optimization enables a more comprehensive and exploratory design study compared with the gross-mass minimization problem subject to a predetermined mission plan and a fixed takeoff-velocity constraint. The optimization is executed via a novel algorithm, and a set of Pareto optimal solutions with a good spread is obtained. In addition to discussing some representative solutions, knowledge is extracted by applying sensitivity analysis to the solutions. The results provide some insight into the underlying features and trends of the design problem of TSTO space planes with RBCC engines.