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Volume 7, Issue 1
Displaying 1-13 of 13 articles from this issue
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Takao OUCHI, Mitsunori FUKUJU, Haruo SUZUKI1971 Volume 7 Issue 1 Pages 1-8
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSTo convert a binary code to a pulse width, in the traditional method is required the double conversion: the code is converted into the corresponding voltage, and subsequently the voltage is converted into the pulse width.
The authors devised a D-A converter which can convert directly seven binary digits to the pulse width. This converter is cascade-connected with the pulse width modulator with magnetic cores. The output pulse width of this modulator corresponds to one digit of a binary code. The pulse widths representing the binary “one” are “weighted” or multiplied by factors according to the conversion factors of the seven binary digits and are summed to obtain the equivalent pulse width.
The influence of saturation flux on the generation of undesirable pulse could be eliminated by choosing the suitable circuit. Therefore, the conversion circuits with a high degree of accuracy could be produced. The characteristics of this modulator corresponding to each digit were analized theoretically by using the equivalent circuit.View full abstractDownload PDF (1677K) -
Taro TAJIMA1971 Volume 7 Issue 1 Pages 9-16
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSStudied is the relation between the temperature slope at room temperature and the current density of forward biased silicon diodes, for the purpose of precise temperature compensation of semi-conductor devices.
Results are:
A) When the forward voltage V, the current density j, temp. T are related by the equation j=isexpqv/ηKT (1)
1) The mean temp. slope in the range 250∼350°K M0 is nearly equal the temp. slope at 300°K=m0 and is proportional to 0.2η log j.
2) When impurity is diffused in a silicon wafer whose specific resistivity ρ and the life time τ assume the prescribed values, and then when pn-junction and the ohmic contact are performed in the prescribed condition, a) M0-j diagram of the silicon diode is appoximately parallel, b) M0 becomes small as the junction area becomes small.
B) If the equation (1) is not valid, j becoming either too small or too large, the mean temperature slope M0 becomes larger than the value calculated assuming (1) is valid.
C) If τ0=[τ] 300°K is hardly affected by the surface condition, m0 is approximately represented by m0=0.2ηlogj-β (2)where β=1.87, 2.00, 2.10, 2.20, 2.25 corresponding to ρ=0.01, 0.1, 1, 10, 100, respectively.View full abstractDownload PDF (1409K) -
Ryuji TAKANUKI, Iwao MORISHITA1971 Volume 7 Issue 1 Pages 17-24
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper describes a self-learning algorithm for two-category pattern classification and an experimental classifier made using the algorithm. The algorithm decomposes a sequence of patterns presented into a family of orthogonal signals called the principal components in the factor analysis, and picks out, in the steady-state, the largest-power principal component as the output. The two-category pattern classification is carried out according to the sign of the output.
An experimental classifier with 25 self-adjusting weights has been made, and satisfactory results have been obtained in the several classification experiments carried out using the classifier.View full abstractDownload PDF (3885K) -
Gen-ichiro KINUSHITA, Kunikatsu TAKASE, Masahiro MORI1971 Volume 7 Issue 1 Pages 25-30
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper proposes an artificial-tactile pattern recognition which is composed of the recognition by touching the object surface with the artificial-tactile sense and the recognition by grasping the object with the artificial-hand.
The hint of this proposition was found in the function of the tactile sense of a human hand.
The fundermental principle of the artificial-tactile pattern recognition is to process a stress distribution that the unknown object produces in the artificial-tactile sense elements.
In the proposed method, the 3-dimensional stress distribution is partitioned into the 2-dimensional peripheral pattern and the threshold decrement by an analogy with the threshold phenomena in the living body. The object surface is recognized as a sequence of the peripheral processing at each threshold decrement.
A simple experiment classifying cylinders and square pillars was performed by the artificialhand with on-off switches instead of the presure sense elements. As the result, a high reliability of recognition is obtained.View full abstractDownload PDF (2377K) -
Masayoshi KAKIKURA, Kohei SATO, Mitsuo YAMAGUCHI1971 Volume 7 Issue 1 Pages 31-38
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIf the conventional industrial robot is given a tactile sense and an ability for dexterous motions, the following remarkable improvement will result.
a) The burden of the operator is decreased to a great extent because he has to instruct the robot less often in teaching as well as in giving orders for the next move.
b) Various problems, such as measurement error, positional error, displacement of the object are solved by properly processing the signals from the sensors attached to the industrial robot.
c) The mechanically difficult work can be circumvented being handled by software techniques.
In this paper, two topics to achieve the above mentioned goals are discussed:
(1) To give the industrial robot some kinds of sensors, an ability for judgement and an ability for decision making, so that it can cope with the change of situation and complete its work.
(2) To make the system capable of changing easily the details of the work to be done by the industrial robot.View full abstractDownload PDF (2523K) -
Hiroshi KASHIWAGI, Kazutaka NADAYOSHI1971 Volume 7 Issue 1 Pages 39-46
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWhen the autocorrelation function of an input signal to a system is Dirac's delta (δ-) function, the impulse response of the system is obtained as the crosscorrelation function between the input and the output of the system. In practice, however, there exist some cases where such an input signal cannot be used because of its lack of power, or because of poor frequency characteristics of the devices actually applying the input. In these cases the impulse response is not obtained simply from the crosscorrelation, but indirectly by a troublesome deconvolution. In the present paper a simple deconvolution method is proposed in which the impulse response is determined from a linear combination of the derivatives of the crosscorrelation function. The method is particularly simple when the autocorrelation function φxx(τ) is given as φxx(τ)=e-λ|τ| or φxx(τ)={1-|τ|/T(|τ|≤T) 0(|τ|>T)
This method does not require the function φxx(τ) to be the δ-function, but to be not differentiable at some τ's. Essentially, the method utilizes the δ-functions appearing when φxx(τ) is differentiated in the sense of the distribution proposed by L. Schwartz. The experimental values obtained by the computer simulation agree well with the theoretical ones, and the errors estimated are negligibly small.View full abstractDownload PDF (808K) -
Takuya KATAYAMA1971 Volume 7 Issue 1 Pages 47-54
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSGeneration of the band-limited white noise x(t) on a digital computer is discussed. The method for generating x(t) is: (1) to expand x(t) into a series according to the sampling theorem, and (2) to truncate the series at some finite term, that is, the following xN(t) is composed on the digital computer.
xN(t)=NΣn=-N+1xn+[t/t0]φn(t/t0-[t/t0])
where φn(t)=sinπ(t-n)/π(t-n), {xi}: random numbers, t0=π/ωc
(ωc: cut-off angular frequency).
The autocorrelation function and the power spectral density of xN(t) are studied theoretically. It is shown that the effect of truncation and incompleteness of random number {xi} is negligible in an ordinary condition if N≥50.
The method for speeding-up of generation is also discussed. The sample autocorrelation function and the power spectral density are calculated from xN(t) generated by the above method, and the results are shown to coincide with the theoretical analysis.
From these analyses, we can conclude that the band-limited white noise can be generated satisfactorily on a digital computer.View full abstractDownload PDF (859K) -
Ken ITO1971 Volume 7 Issue 1 Pages 55-62
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSThis paper presents the research to introduce an on-off speed control system of a gasoline engine coupled with a dynamometer, in order to make simple and easy the performance test of the engine.
The on-off control device consists of two parts, one being a conventional on-off control element that is an electromagnetic water valve, and the other being an integral action element that is an electric motor valve. The latter is connected with the on-off element in parallel and operated by a three position acting relay. In a transient state, the two parts of the control device operate simultaneously. On the contrary, in a steady state, only the on-off element operates.
It is found that this control system has an excellent merit as compared with the conventional on-off control system, as both the setting time and the limit-cycle amplitude of the control system are short in a step response.
It is mentioned that, for the experiments on the effect of controllability, satisfactory results are obtained.View full abstractDownload PDF (969K) -
Akira SANO1971 Volume 7 Issue 1 Pages 63-70
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSTo control distributed-parameter systems subject to external, disturbances, the information about the state of the systems is required. In practice, because of the physical and economical constraints on the system, it is very convenient to estimate the state by the measurement data from a finite number of measuring devices and to apply a finite number of control inputs to the systems. In this case it becomes significant to choose the optimum locations for the measuring devices and the control inputs.
This paper discusses the structure of the optimum controller with the finite number of output measuring devices and control inputs, and determines analytically the optimum locations of the measuring devices to minimize an estimation error cost. The optimum location depends on the statistical characteristics of the disturbances and on the boundary conditions, and when they are known the location can be determined a priori. Furthermore, this paper discusses the adaptive algorithm of measurement optimization by which the uncertain characteristics of the disturbances are estimated. This method is available when the covariance of disturbances is unknown.View full abstractDownload PDF (982K) -
Tohru KATAYAMA1971 Volume 7 Issue 1 Pages 71-78
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSIn this paper, the stochastic bang-bang control problem that maximizes the average first passage time for the state to reach the boundary of a certain safe region is considered. It is assumed that the dynamics of the system is described by the linear stochastic differential equation. By use of dynamic programming, the problem is reduced to the boundary value problem of Dirichlet type for the Bellman equation. The difference scheme is applied in order to obtain the numerical solution of the boundary value problem. It is found that for first order systems the difference scheme gives excellent numerical results. Some switching curves are also obtained for a second order plant 1/s2 with additive gaussian white noises.View full abstractDownload PDF (925K) -
Yoshikazu NISHIKAWA, Nobuo SANNOMIYA, Hidekiyo ITAKURA1971 Volume 7 Issue 1 Pages 79-85
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA method is developed for the approximate design of an optimal state regulator for a nonlinear system with quadratic performance index. The nonlinearity is taken to be a perturbation to the system. By making use of a power-series expansion in a small parameter, matrix equations are derived for the stepwise determination of a suboptimal feedback law. Given a polynomial nonlinearity of an arbitrary form, explicit solutions have been obtained for those matrix equations. A necessary and sufficient condition for the existence and uniqueness of the solution is also shown. Further, the performance analysis reveals the fact that the l-th order approximation in the feedback law leads to the (2l+1) th order approximation in the optimal performance index. The method may effectively be used in a computer programmed computation.View full abstractDownload PDF (906K) -
Tatsuo KITAJIMA, Etsujiro SHIMEMURA1971 Volume 7 Issue 1 Pages 86-90
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSA computational algorithm is developed for the optimal control of a system having lumped parameter subsystems coupled with distributed parameter subsystems. Constraints are given on the terminal state of the system. The algorithm is based on the gradient method in the function space.
This method is composed of two steps: in the first step, the control function which gives the trajectory satisfying the terminal constraint is found; in the second step, this control function is modified so as to reduce the value of the performance index while the terminal constraint is still satisfied.
An example is given to show the effectiveness of the developed method.View full abstractDownload PDF (561K) -
Takeshi YOKOI1971 Volume 7 Issue 1 Pages 91-97
Published: February 28, 1971
Released on J-STAGE: March 27, 2009
JOURNAL FREE ACCESSWith the development of science and technology, large scale systems are produced. The number of elements in a system grows large and the relations between the elements also grow complex. When we intend to construct and control these systems, it is impossible to treat them by the ways which are on the viewpoint of microscopic observation. Therefore it is necessary to introduce a new expression and a general performance index of the system on the viewpoint of macroscopic observation.
In this paper, the system is limited to be a network system such as a traffic system. We introduce the idea of entropy into the stationary state of that system and consider the significance of the evaluation of network system by entropy.
As a result, it is proved that the negative entropy introduced has the same character as the entropy increasing law of statistical mechanics and that the negative entropy also expresses the degree of confusion of the network system. Therefore by making use of the negative entropy as the performance index, we obtain the construction theorem which is intuitively understood. We believe the usefulness of entropy as the performance index of a network system. Last of all we obtain a useful decomposition theorem for the construction of a large scale network system.View full abstractDownload PDF (855K)
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