The solar observation satellite “SOLAR-B,” which is being developed under the joint cooperation of JAXA and NAOJ with the U.S.A. (NASA) and the U.K. (PPARC), will be launched in summer 2006. SOLAR-B requires very high pointing stability for its three telescopes. In particular, the Solar Optical Telescope (SOT), which has the highest resolution and narrowest field of view among these telescopes, requires 0.06 [arcsec]3σ of short-term (10[s]) stability to meet the observation demands. However, it is very difficult to achieve such levels of stability by only using the satellite attitude control system due to disturbance from the observation equipment. Therefore, we propose using the Correlation Tracker and tip-tilt Mirror package (CTM), which stabilizes the sun observation image. CTM consists of a correlation tracker and a piezo-based tip-tilt mirror with servo control electronics. This paper describes the mechanism and the control and determination methods of the control gain of CTM as well as the results of experiments conducted to clarify its capability.
Motion of aircraft controlled by the pilot is decided depending on the characteristics of man-machine system. Although analysis and study using the mathematical model of the aircraft including the control system is usually done, the method for making mathematical model of pilot, which is necessary for analysis and study of man-machine system, has not been established. Although there was an example of the method for making mathematical model of pilot using transfer function (Kato, A., et al., J. Jpn. Soc. Aeronaut. Space Sci., 50 (2002), pp. 409–415), it was thought that there was a possibility that a more accurate, more flexible pilot model was obtained if neural networks (NN) was applied. Therefore, various studies were done concerning pilot model to which NN is applied. As a result, it has been understood that pilot model with better performance is obtained comparing with the case of applying the transfer function. Moreover, it has been understood also that versatile pilot model, which can deal with various conditions by one model, is obtained by applying NN and studying the control results in various conditions.
A numerical analysis of a piston motion in a free piston driver has been conducted including a diaphragm rupture. Quasi-one-dimensional flow is assumed in the driver. Various losses, which are generated in a compression process, are simplified. A process of the diaphragm rupture is assumed by Outa’s model. Experiments are also conducted by using a free piston shock tunnel. Calculated pressure histories show excellent agreements with experimental results. The numerical analysis shows that the piston motion is strongly affected by the diaphragm rupture. Especially, pressure histories in front of the piston change significantly with compact compression tubes. Diaphragm opening time is necessary to be considered to increase test time and to obtain soft landing conditions in compact free piston drivers.
A flight simulator must exactly simulate the aircraft motion. So, engineers check if the solution of equations of motion, the calculation of flight positions and attitudes, and then, the drawn-up of visual scenery from cockpit windows according to the calculated positions and attitudes are correct. This paper proposes an additional check if the aircraft motion perceived from visual scenery by pilot is same as the calculated motion. This opinion is applied to the simulation case that just lateral-directional flying qualities are evaluated, and it is found that the pitching motion rate (q) and Euler’s pitch attitude rate (Θ) should not be perfectly neglected (i.e. q=Θ=0) but (q and Θ) should be given assuming steady level turn flight should be given. The flight simulator test showed that the pilot felt more real flight motion and controlled some harder than in the condition of q=Θ=0.
DAS (Dive and Ascent Satellite) is a kind of satellite that can approach very close to the earth, which was designed by NAL (National Aerospace Laboratory of Japan) in later 1970’s. Now we paid attention to the function of the satellite that can descend and ascend, and proposed to use it for getting detailed information of the area which is suffered from a natural disaster. In this paper orbital control of DAS with minimum fuel consumption is discussed, where the earth is treated as an ellipsoid of revolution, the atmosphere drag and the second zonal coefficient is considered. The optimal orbital control problems are treated as nonlinear two point boundary problems, and solved by the steepest ascent method. The derivation of equations and results are shown in detail.
An experimental research on supersonic combustion of kerosene in a model scramjet combustor has been conducted. Kerosene was injected normally into a Mach 2 by three types of methods. First, liquid kerosene was directly injected. In comparison with hydrogen, combustion did not take place at low total temperature or in the fuel lean condition. Secondly, “effervescent atomization” method was used. Effervescent atomization method could control penetration height and mass flow rate independently, and improve ignition limits of liquid kerosene. Finally, gaseous kerosene was used. While only intensive combustion mode and choke mode were observed when liquid kerosene was used, existence of transition mode was observed when gaseous kerosene was used.
The problem of low subsonic delta wing flutter was studied experimentally and numerically. Two kinds of oscillation: low- and high-amplitude oscillation modes were observed in experiment. Moreover, the transition velocity between the two modes significantly depends on angle of attack. When angle of attack is high, the transition from low- to high-amplitude mode is made more suddenly. The flutter velocity obtained in the present experiment shows good agreement with other experimental data as well as results of the present computation. In addition, the flow field around an oscillating delta wing with large deformation is made clear, where vortex motion is coupled with wing motion. It is found that aerodynamic force produced by the vortex near the wing leading edge is closely related with the large amplitude wing oscillation.