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Volume 8, Issue 1
Displaying 1-17 of 17 articles from this issue
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Setsuzo TSUJI, Hitoshi TAKATA1972 Volume 8 Issue 1 Pages 1-10
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents the new approach to the discrete nonlinear estimation, which enables us to estimate the state of system more accurately, even if there will be rather high nonlinearities in the system.
This approach uses the method of the extended orthogonal projection, in which the optimal nonlinear estimation is assumed to be performed with a polynomial series about the past and present observations.
The estimated values are sequentially obtained by the resulting estimate equation, and are always optimal in the sense of mean square even though the series of observations is truncated at any finite order term.
In the remainder of the paper, an algorithm of a sequential nonlinear filter is derived. This filter contains the observation errors up to the second order term in both the state estimate equation and the covariance equation.
Experimental simulations by a digital computer are also demonstrated, and the results better than those obtained by the ordinary filters are obtained in our special examples.View full abstractDownload PDF (1318K) -
Takayoshi NAKAMIZO1972 Volume 8 Issue 1 Pages 11-17
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper gives a contribution to the physical interpretation of nonlinear filter obtained for continuous-time Markov processes governed by the stochastic (Ito) differential equations. Since the dynamical system for constructing the sample solution of stochastic differential equation is not physically available, results obtained for continuous-time Markov processes must be translated by known formula into results described by the ordinary differential equations. There is however a difficulty involved in such interpretation, since in most cases a truly optimal nonlinear filter i infinite dimensional. A method is presented here in this connection for finding the dynamical equation (in the ordinary sense) for the conditional probability density, from which a set of ordinary differential equations for conditional moments can be directly derived. The present nonlinear filter described by ordinary differential equations displays marked difference to the filter obtained by the finite dimensional approximation and the translation into a set of ordinary differential equations. Incidentally, the analysis shows that no serious problem is introduced whenever the linear observation scheme is available.View full abstractDownload PDF (892K) -
Michio OHTA1972 Volume 8 Issue 1 Pages 18-23
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper starts from the investigations of the two problems about the attached flow written below:
(1) The experimental results show the non-uniformity of the pressure distribution in the bubble, so the radius of the center line of the reattaching jet must not be constant as is commonly assumed in most papers.
(2) Though the novel theories on models such as the attachment point model, the control volume model and some modification of them have their foundations on the momentum law of fluid, the models are inconsistent.
Moreover, in these models σ (Görtler jet-spread parameter) has to change widely from 1 to 20 across σ0=7.67 (free jet), even though the phenomenon is only a “reattachment”.
First, we intend to take the return flow from the attachment point into consideration: this flow brings pressure recovery near the offset-wall and yields the non-uniform pressure distribution in the bubble. The pressure ratio Cp is introduced again to evaluate the distribution.
Next, the curvature of the center line of the attached flow is changed by the values of Cp. An exponentially decreasing radius has been adopted for an example.
Finally a simple model is illustrated to calculate the attachment point distances using constant parameters (Cp=2, σ=7.67) resulting fairly good agreement with experimental data.View full abstractDownload PDF (674K) -
Yasujiro OSHIMA, Osamu KINOSHITA1972 Volume 8 Issue 1 Pages 24-30
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe experimental study has been conducted to investigate the characteristics of the turbulent jet within the liquid fluid amplifier. Dimensions of the fluidic element used are proposed to be aspect ratio: 1.9, main nozzle width b: 10.0mm, offset D: (0∼3.0) b (variable) and side wall angle α: 0°∼30° (variable). The operating liquid is water of about 20°C.
In order to analyze the jet behavior the flow patterns of the attached jet are visualized in an arbitrary horizontal section by means of air bubble tracer and slitted ray of about 0.5mm thickness, and static pressure distributions are measured in various jet velocities, side wall angle and offsets.
The following results of the experimental study are obtained: (1) The attachment stream line and the attachment point are the same in any horizontal section. The attachment point can be defined as the point on which the velocity component parallel to a side wall is zero. (2) The static pressure distributions of vortex on the attached side are obtained. The isobaric curves are almost circular and their distributions are squarely proportional to the radial distance from the vortex center in the inner region of the vortex. From the fact that the jet partly flows into the forced vortex, it is felt that the momentum theory may not be strictly applicable to the attached jet flow. (3) In the turbulent region the attachment length decreases and the vortex center also moves to the upper stream in accordance with the increase of Reynolds number. Both the attachment point and the vortex center gradually approach to constant positions in high Reynolds number. It is remarkable that the position of the vortex relative to the attachment point or to the attachment stream line is independent of the Reynolds number.View full abstractDownload PDF (1597K) -
Masayuki SUZUKI1972 Volume 8 Issue 1 Pages 31-38
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe sensitivity reduction of the optimal control system is discussed. An optimal system is constructed to have two degrees of freedom by using the output feedback and the prefilter. This implementation enables us to reduce system sensitivity without disturbing the optimality. This is a main advantage of the proposed method.
The synthesis procedure is as follows:
i) Using a suitable algorithm, the optimal problem is solved to find an open-loop type solution.
ii) The feedback compensator element which needs only output signals of the plant is designed to minimize a given sensitivity performance index.
iii) The prefilter is determined so that the total input to plant, that is, the output signal of the prefilter plus the feedback signal, coincides with the open-loop input.
The resultant system is called an optimal feedback system.
Several examples are given to illustrate the synthesis procedure.View full abstractDownload PDF (1049K) -
Hiroshi HASHIMOTO, Hajime AKASHI1972 Volume 8 Issue 1 Pages 39-45
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe investigation described in this paper aims at obtaining informations on the control behavior of a human operator in an on-off control system.
The human operator acts as an on-off relay controller in some man-machine systems. However, few investigations have been carried out so far on a closed loop control system inculuding a human operator as a controller.
For the design of such a system the fundamental analysis of the man-machine system as a whole is essential.
To improve the performance score of the human operator, the display system with a switching curve is introduced. Some fundamental characteristics are obtained from the experimental results.View full abstractDownload PDF (1026K) -
Yoshiyuki NISHIHARA, Yasuo KINOUCHI, Sadamu OHTERU, Tomokazu KATO1972 Volume 8 Issue 1 Pages 46-50
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn a present computer system, in order to obtain an arbitrary probability density distribution, we use uniform random numbers and modify them. It is desired to generate any random numbers by a simple equipment.
In this paper, the authors report on a new probability density function generator utilizing stochastic computer techniques.
The equipment is composed of a stochastic integrator (a simple reversible counter with comparator) with a feedback circuit.
The latter performs the important role in obtaining the desired random numbers and controlling their stochastic parameters.
Theory and circuit diagrams are shown together with the interesting experimental results.View full abstractDownload PDF (600K) -
1972 Volume 8 Issue 1 Pages 50
Published: 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSDownload PDF (96K) -
Kozo MATSUSHIMA, Hidehiro KATAGIRI1972 Volume 8 Issue 1 Pages 51-58
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe purpose of this study is to develop simple artificial eyes in order to perceive an object in front of the robot or the unmanned car on which the eyes are installed, and to lighten, as much as possible, the burden of the electronic computer for recognizing the object.
This paper describes the newly devised simple eyes which consist of a couple of TV cameras, a polarity coincidence correlator and servomechanisms to control them.
The experimental results by the above-mentioned eyes offer the fundamental data for design of the equipment for practical use.View full abstractDownload PDF (1560K) -
Katsutoshi TAMURA1972 Volume 8 Issue 1 Pages 59-66
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA computational approach to a class of optimization problem in which subsystems should be dropped out each time when some condition is satisfied in the course of control is mentioned in this paper. Since the optimal sequence of subsystems to be dropped out is not known in advance and the sequence is depending upon the control function, we cannot arbitrarily take a control function as the first estimation of the optimal control. In this paper the optimal sequence as well as the corresponding control function is obtained by means of repeating the setting up of subproblem and its solution. The gradient function needed to solve the subproblem is derived. The solution method is applied to the problem of minimum time unloading operation for oil tanker.View full abstractDownload PDF (894K) -
Tatsuo KITAJIMA, Etsujiro SHIMEMURA1972 Volume 8 Issue 1 Pages 67-72
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper is concerned with solving the free terminal-time optimal problem of a distributed parameter system via gradient method.
In order to transform the time variable to a variable defined on a fixed interval, a new scalar parameter is introduced. Then the original optimal control problem is converted to the new fixedterminal time problem containing a parameter. A computational algorithm for this new problem is developed by using a gradient method in a function space.
An example is given to show the effectiveness of this method.View full abstractDownload PDF (716K) -
Yoshikazu NISHIKAWA, Nobuo SANNOMIYA, Hidekiyo ITAKURA1972 Volume 8 Issue 1 Pages 73-77
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe construction of an optimal state regulator for a linear system involves the solution of a matrix Riccati equation. If the system is time-varying, the closed form solution is impossible to obtain. This paper deals with an approximate construction of the optimal state regulator for a periodically varying linear system with quadratic performance index. In the present discussion, the periodic term is taken to be a perturbation to the time-invariant system equation, and a parameter ε is introduced to stand for the perturbation.
By making use of a power-series expansion in ε, when the control duration is sufficiently large, the solution of the Riccati equation is reduced to solving a nonlinear algebraic equation and obtaining steady-state solutions of a sequence of linear time-invariant differential equations. It is shown that, if the unperturbed system is completely controllable, the steady-state solutions for those linear differential equations exist and are periodic. If, in particular, the periodic coefficients in the system equation are given in finite Fourier series, the steady-state solutions are obtained merely by solving linear algebraic equations. It is further demonstrated that the l-th order approximation for the feedback law results in the (2l+1) th approximation to the optimal performance.
An example is attached to illustrate the present procedure, and the results of the approximation are compared with the optimal solution.View full abstractDownload PDF (600K) -
Kageo AKIZUKI, Takashi SHIGEMASA1972 Volume 8 Issue 1 Pages 78-86
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSRelay control systems subjected to random disturbance and random desired variables have been often analyzed by using statistical linearization method. But the results analyzed by this method are not satisfactory, it is more desirable to know the probability density functions of the error, which are obtained as the solutions of the Fokker-Planck equations representing these stochastic relay control systems.
However, in many cases, it is difficult to solve the Fokker-Planck equations by analytical methods. Numerical calculations based on the finite difference method are useful.
In this paper, the Fokker-Planck equations for the general class of relay control systems subjected to random inputs are derived and the boundary conditions are shown by using the concept of probability flow. Next some numerical techniques are shown. Finally examples of numerical analysis of relay control systems subjected to random inputs are discussed. These results are compared with the digital simulations.View full abstractDownload PDF (994K) -
Hirokazu MAEDA1972 Volume 8 Issue 1 Pages 87-95
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn system theory, one of the most basic problems is to find a reduced form of a system, where the reduced form of the system is a system with minimum dimensional state space which is equivalent to the given system. As is well known, for usual linear systems this reduction problem is solved almost completely, and the concept of irreducibility is closely related to the concepts of controllability and observability.
This paper is concerned with the concept of irreducibility of linear stationary systems with time lag. The necessary and sufficient conditions for controllability and for observability are given in terms of the system parameters. A few concepts of irreducibillity are defined, and it is shown these concepts of irreducibility are closely related to the concepts of controllability and observability. For a type of irreducibility, an algorithm for determining the reduced form of the system is given.View full abstractDownload PDF (1072K) -
Tsugumasa SUTO, Akira TOZUNE, Sakae SHINOMIYA1972 Volume 8 Issue 1 Pages 96-103
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, an equation is derived to calculate the alternating torque of a 2-phase servomotor which is operated with a 2-phase source unbalanced in amplitude and phase angle.
The equation is simplified by introducing the specific relation among the equivalent circuit parameters of the 2-phase servomotor.
The alternating torque of the test 2-phase servomotors in phase control is calculated by using the equation.
The calculated value is compared with the alternating torque obtaind experimentally by using a 2-phase induction type accelerometer. The agreement is satisfactory.
In phase control of a 2-phase servomotor, the alternating torque characteristics and, the relation between alternating torque and average torque are calculated from the above equation.
The alternating torque characteristics in phase-control and in voltage control are compared.View full abstractDownload PDF (741K) -
Takami KOYANAGI, Kazuo AIDA, Keiji GENMA1972 Volume 8 Issue 1 Pages 104-112
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThe characteristics of spherical ionization chamber are discussed here in hope of realizing a faster response than that of cylindrical chamber. It may be easier to increase the ratio (Vα/V) with spherical chamber than cylindrical chamber.
Fundamental requirements are considered for attaining a fast response or a short rise time (0.1∼0.9) in indicial response, following in the previous report on cylindrical chamber.
The rise time (Tγ) increases with increase of the ratio (m) of radius of outer electrode to that of inner electrode and has a peak at m≅3, then decreases to a minimum value, but it makes little changes for m>10. These values of m(≅3, ≅10) are fairly less than that of cylindrical chamber, and these relations between Tγ and m are similarly observed at different values of filling gas pressure and time lag of amplifier.
The characteristics of overall detector system (with a filter circuit) may be expressed by transfer function, and it is revealed that the function may be written with excellent approximation as G(s)=(1+T2s)/(1+Ts)(1+T1s)(1+T3s). By this expression, the effects of m, p (the filling gas pressure) and V0 (the voltage between electrodes) on the dynamic error or the statistical error of the system can be easily investigated.
The dynamic error decreases in inverse proportion to (V0/p), but it is barely affected by m. The statistical error increases in exact proportion to m and (V0/p). When the filter has a small time lag, the effect of m exceeds that of (V0/p), but when the time lag becomes large the effect of (V0/p) exceeds.
The experiments are carried out with a spherical chamber filled up with pure Ar gas, the radius of outer electrode of which is 6cm. The static characteristics of this chamber are similar with those of a cylindrical chamber. As to the indicial responses, the ratio (Vα/V) and the rise time (Tγ) have been proved to be in good agreement with the calculated results, and the excellency in dynamic response characteristics of the spherical chamber has been proved.View full abstractDownload PDF (1056K) -
Susumu HATTORI, Shizuo NARIZUKA, Seiji TAKATA1972 Volume 8 Issue 1 Pages 113-121
Published: February 29, 1972
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSRegression analyses of the characteristics of 4 vacuum and 4 gas-filled tungsten strip lamps which had been manufactured in Japan as the pyrometric standards and calibrated regularly every year since 1967 in the Thermal Measurements Section of the NRLM revealed that their luminance temperature-current relations are expressed by a biquadratic regression equation having on its third and fourth power terms numerical coefficients common to all the lamps of each type. This result indicates that the relation pertinent to any lamp can be expressed by the sum of a quadratic equation specific to that lamp and a common biquadratic equation. Based on these analyses, a set of numerical tables (relating to IPTS-68) is made. This table is available in interpolating the luminance temperature (T)-current (I) data of a generally used tungsten strip lamp in Japan, or in calculating dI/dT.View full abstractDownload PDF (1108K)
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