Design and experiment of an Automatic Maximum-Searching Machine is described. Recently, a great many number of adaptive and/or optimalizing control systems has been developed. To say nothing of the performance index itself, they make use of some searching procedure for the maximum or minimum of the performance index as a function of manipulated variables. Most of these extremum searching procedures are based on the measurement of the differential coefficient of the function. On the other hand, Sequential Search being a procedure sequentially narrowing the interval containing the point at which a unimodal function possesses. a maximum, its remarkable feature is that no other restriction than unimodality is neccesary.
An experimental machine which performs sequential search with golden section automatically was constructed from elements of analog computer and relays. Experiments on analog computer resulted in expected performance. Further studies are neccesary before applying this machine to on-line optimization of continuous systems.

View full abstract

The magnetic scale is an incremental pattern device which is utilized as position encoder to measure linear displacement digitally.
It has two tracks of the sinusoidal remanence pattern of the same period, the phase of which is shifted 90°each other, hence both the magnitude and the direction at a displacement can be determined.
The remanence pattern is written by the magnetic recording head onto the thin magnetic layer which is coated on a square glass rod.
The sinusoidal pattern is obtained by making flow a signal current of frequency f superposed with the ac bias current into the recording head which moves at a constant speed v relative to the magnetic coating. The period of the pattern 2 is determined by λ=ν/f.
The pattern is detected by a flux-sensitive head, hence the detection is possible even at rest.
The output signals from the detector are shaped squarely. One of the squared signals branches out to two buses which emit pulses each time when the signal rises up or falls down, respectively. These pulses are gated by the signal from the other track, hence the pulses in the two buses pass the gates according to the direction of the displacement each time when the detecting head comes to the points of zero remanence.
These pulses are counted by a reversible counter.
The period of the pattern can be made as small as 30 /μ.
An improved read-out circuit which can be easily constructed utilizing the above mentioned circuitry can interpolate digitally the period into one-fourth.
The precision of the read-out of the pattern is about 0.6 μ.

View full abstract

In this paper, the optimum controller which minimizes the meansquare error of a linear control system with a very long transportation lag and with a stationary random disturbance, is designed and simulated on an analog computer. The controller which is found to be optimum provides itself with a model of the controlled process. It measures the disturbance and predicts its future values in order to make an optimal manipulation.
Two example cases of design are shown in detail, where the transfer function of the controlled process is given by
_??_
and the power spectral densities of the disturbance are
_??_
In both cases, the optimum controller can be constructed by using a respective model of the process incorporated with a P or a PD controller. Thereof irremovable, minimum meansquare errors are calculated and are verified on an analog computer.
From a viewpoint of control ability, the defference between the optimum and the optimally set PID controllers is discussed, and the latter is found to be as equally able as the former in some cases.
The Smith's controller is also discussed on its capacity of control.

View full abstract

A new linear positioning transducer, called the DELPAX-63 L, has been developed.
This new transducer, is a stable electronic analog-digital standard scale providing the linear distance measurment ability of high accuracy for machine tools and other machine industries.
The DELPAX-63 L, as shown Photo. 1, consists of one detector coil which is the precisely spaced two single layer solenoid on stainless steel bobbin and scale which is a square shaped steel screw thread with precisely 2mm lead on long lengths. It is advantageous feature that moving element as scale has not coils and lead wire.
Movement of the detector coil along the scale gives an output with sinusoidal amplitude which is variated from zero to maximum value as every pitch of the scale.
Any positioning between scale pitches is obtained by rotation of the scale.
Useful results have been obtained in experiments, as follows:
Eccentricitz of the scale in detector coil and variation of external electromagnetic field are neglected for accuracy.
Accuracy has not been influenced by the residual pitch error in the detector coil and the threaded screw so that a number of turns in coil averaged pitch error over all length of the coil.
Accuracy: measured total pitch error over the scale (350mm) is less than 0.01mm
Sensitivity: output voltage of the detector coil is about 0.01 volt at maximum, output of amplifier is 1. 4 volt/10μ
Repeatability: repeated error is less than 0.001mm

View full abstract

Various methods for the calculation of boiler control system have been contrived by many investiga-tors.
We developed the theoretical expression for the dynamic characteristics of steam temperature control system of boiler and derived some approximate transfer functions.
In this article, it is shown that our method, considered the mutual interference in steam, pipe and combustion gas, have been experimentally confirmed in the test of dynamic characteristics of 520 T/H boiler.
This expression for the dynamic characteristics may be useful to the design of steam temperature control system of boiler and to the study of performance when the load of boiler is changed.

View full abstract