An Application of Stochastic Control Theory to the Gust-Alleviation System for a Transport Airplane

The optimal control law that minimizes the gust responses of an airplane's longitudinal motion is obtained, making assumptions that the airplane is approximated as a point and that aeroelastic problem is ignored. The airplane gust-alleviation problem has been treated mainly in the frequency domain because of the simplicity of the input-output relations for the power spectra. But in the optimal control problem, the approach in the time domain, applying the optimal stochastic control theory, seems to have more advantages for investigating such a complex control as gust-alleviation. The system state equations consist of the short-period equation of an airplane and the gust shaping filter. The optimal linear control law is derived by applying the Matrix Minimum Principle which minimizes the R.M.S. values of the normal acceleration and the pitch rate at the center of gravity. The results of the numerical calculation for two types of control systems, one being the linkage-control system and the other the independent-control system, are shown in the case of a conventional transport. The latter system is ascertained to have a fairly better performance. The optimal system is also ascertained to have very low sensitivity to the change of the scale of turbulence

Estimation of Annual Average Thermal Efficiency of Modern Steam Power Plants in a Large Hydro-Steam Combined Electric Power System

One of the fundamental problems in planning steam electric power generation is to estimate its annual average thermal efficiencies for a projected plant in a given electric power system. The following discussion is mainly concerned the estimation of thermal efficiency of modern type steam electric power plant to be put into the system operation

A Method for Estimating the Power Duration Curves of the Project Power in a Large Combined Hydro-Steam Power System

In planning electric power generation of a large combined hydro-steam power system, we should determine not only the power and energy but also the power duration curve, which is necessary to calculate the energies, generating hours and start-stop frequencies of each generating unit. The project power, which includes the existing steam power, will be found from the predicted load after subtracting the part assigned to the existing hydro plants. In general, the past data show that the curve, represented by the vertical distance between the duration curves of load and that of hydro power, will be greatly different from the steam power duration curve of the corresponding year. In this paper, the authors try to find out a method in which the duration curves of the predicted steam power, estimated by utilizing the past data of load and hydro power, are closely matching with the actual duration curve of steam power in the corresponding year. The diagrams, calculated by this method from the past data of a certain power system, are expected to be applicable in estimation of the duration curves of project power in near future, at least for the same power system

Aircraft Parameter Identification in the Presence of Atmospheric Turbulence

This paper investigates the method for identifying the unknown parameters in the dynamics of an aircraft from flight data affected by random disturbances due to wind gusts. Two general algorithms suitable for applying to such stochastic environments, i.e. the method of maximum likelihood (ML) estimation and the extended Kalman filter (EKF) technique, are examined for capability by numerical simulations. The advantages and shortcomings of each algorithm are discussed in detail, which leads to the conclusion that the combined use of the two algorithms provides a powerful on-line technique, insensitive to initial parameter estimates

The Selection of the Representative Year of Stream Flow for Electric Power Generation

An analysis of the actual state of the combination of the load and the hydro-and steam-power in a large combined hydro-steam power system is necessary for any economic comparison between various types of hydro- and steam-power generation; and for the power generation by a plant of the run-off-river type as well as of the pondage and storage types, it sometimes involves an inspection of the daily stream flow in connection with the daily load curve throughout a year. In such cases, it being difficult to draw a daily stream flow diagram for the future, it sometimes becomes necessary to select the representative year representing a typical stream flow from the data in the past. This paper describes the method for its selection

The Annual Average Stream Flow for Hydro-electric Power

In a large combined hydro-steam power system as in Japan, it is necessary to know what flowing condition of rivers may be expected to hold on an average for a long term, in order to plan for the economical development of hydro-power. However, the flowing condition not only varies in its total annual stream flow each year, but even seasonally within a given year, which makes it difficult for us to deal directly with the duration curves of stream flow or the daily stream flow curves which have been hitherto employed in developing hydro-power, so that we have to consider as a parameter the annual average stream flow for each year on which these depend. We need not take the average of all the data obtained in the past in order to estimate the annual average stream flow expected to hold for a long term to come, but must resort to the reasonable method of so-called time series analysis with its theoretical foundation, which takes into consideration the periodicity of the fluctuation contained in the stream flow and other factors. In this paper we propose to estimate the annual average stream flow expected to hold on an average for a considerably long term by means of an analysis, as easy and practical as possible, of a stream flow of comparatively small sample size

On-orbit Demonstration of a Sun Sensor on the Micro-Satellite MAIDO-1

A 50-kg-class microsatellite “MAIDO-1 (SOHLA-1)” was launched, along with six other piggyback subsatellites, by a Japanese H-2A rocket on January 23, 2009. The fundamental and detailed designs of the satellite were developed by university students under the technical guidance of the Japan Aerospace Exploration Agency (JAXA). A string-type sun sensor (Fudai Sun Sensor; FSS) was also developed by the students with the technical assistance of JAXA and Advanced Engineering Services (AES) Co. Ltd. The FSS was mounted on the satellite as an experimental component. This paper reports the development of MAIDO-1 and FSS as well as the satellite operation by the students and the results of on-orbit experiments. ABSTRAK: Satu mikrosatelit kelas 50 kg “MAIDO-1 (SOHLA-1)” telah dilancarkan, bersama enam lagi subsatelit gendong, dengan menggunakan roket H-2A (Jepun) pada 23 Januari, 2009. Reka bentuk satelit yang asas dan terperinci dibangunkan oleh para pelajar universiti di bawah bimbingan teknikal Agensi Explorasi Aeroangkasa Jepun (Japan Aerospace Exploration Agency (JAXA)). Sejenis penderia matahari bertali (Fudai Sun Sensor; FSS) juga dibangunkan oleh para penuntut dengan bantuan teknikal dari pihak JAXA dan Advanced Engineering Services (AES) Sdn. Bhd. FSS telah dilekapkan ke satelit sebagai komponen eksperimental. Kertas ini membentangkan perkembangan MAIDO-1 dan FSS, operasi satelit oleh pelajar-pelajar dan keputusan eksperimen semasa dalam orbit