This paper analytically compares three types of regulated power supplies for new fuel cells. In the near future, telecommunication systems will make use of fuel cells. The fuel cells must have their output voltage regulated. The comparisons are based on the efficiency of the regulated power supplies. The results show that the chopper-type and the boost-converter-type power supplies are better than the converter-type one as regards efficiency. Furthermore, the efficiencies of the chopper-type and the boost-converter-type power supplies are high when the difference between the output voltage of the fuel cells and the output voltage of the power supply is small.

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In this paper, a novel single-phase sinusoidal PWM voltage source inverter (VSI) is proposed. The inverter has an additional arm to the normal single-phase bridge circuit. The two auxiliary self-turn-off devices of the branch avail to adopt the composite PWM control, which contributes to reduce the ripple in the ac output current. Also, the inverter has a LC series resonance circuit tuned to twice the system frequency f, which is connected in parallel with the smoothing capacitor on the dc side. This absorbs the ac component included the dc pulsating current with 2f. Consequently, the capacity of the smoothing capacitor is drastically reduced. As an example of the application of this VSI, the utility connected residential photovoltaic power generation system is shown. In the system, the smooth dc current without pulsation is supplied from PV array, and the VSI provides a sinusoidal ac current for domestic lords and the utility line.

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There are many requests for selecting freely the moment of inertia, even though moment of inertia is determined with the materials, structure, shape, and size of the motors. From the stand point of control, reducing the moment of inertia will make it possible to construct well-controlled drive systems and expand the applications in which a motor may be used to replace another non-electric machine. We developed an “inertia-lowering control” system that uses disturbance observer to reduce inertia apparently.
To realize this control system with vector controlled induction motors, we clarified the equations and machine constants needed for designing the systems. A digital signal processor and a micro processor were adopted for induction motor control, and good results were obtained through the experiments.

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In servomotor control systems, it is difficult to obtain the accurate speed information by using a low resolution encoder because encoder pulses are very rare in a low speed range. To overcome this problem, we proposed the instantaneous speed observer to estimate the instantaneous speed and improved the system stability and also realized the disturbance rejection control. However, when the inertia moment changed, the estimated instantaneous speed had an error because the observer used the nominal inertia to calculate the speed. For this reason, the identification method of the inertia moment was proposed but it operated at about 50rpm speed command. In this paper, we propose novel identification methods for the average speed type instantaneous speed observer and identify the inertia moment in a very low speed range below 1 rpm.

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A high repetition rate, long-pulse TE-CO₂ laser has been developed for hard material processing. A new type of pre-ionization circuit with damping resistor made it possible to stabilize the long-pulse laser discharge. Maximum laser energy is 1.1 J and maximum repetition rate is 500Hz. The 16 μ sec (FWHM) optical pulse of low initial spike is obtained by controlling the discharge current and the gas composition, and the output mirror reflectivity. The initial spike power is reduced below 95 kW and the tail output power is increased to 56 kW. The laser power density at the focal point is about 1.9×10⁸ W/cm², making it possible to use the laser without causing the breakdown of air insulation. Using the laser, we succeeded in fine-cutting a 0.5mm thick Al₂O₃ ceramic.

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In this paper, a steering control of automatic guided vehicles (AGVs) by a successive learning neural network is proposed. In the proposed control strategy, the learning procedure of the neural network is carried out in some trials. Then, the excellent steering control strategy can be established and the exellent results of the AGV travelling are obtained. At the first step, the teaching signal based on the PI control is proposed. The experiment in the steering control of the right and left turning is put into practice. Then, it is clarified that the excellent learning and the steering control of AGVs is realized by adjusting the coefficients in the teaching signal according to the degree of learning. The proposed strategy using the successive learning neural network is proved to be of much practical use for the steering control of AGVs.

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For the linear displacement measurement in industrial machines, a linear scale using a magnetic phenomenon is superior to environment-resistance. An absolute type magnetic scale has the feature to give us safety a position information with high reliability. Until now, an absolute type magnetic scale writes a position information at plural parallel tracks. The scale becomes large-sized for a long measuring length. Furthermore, a fine magnetic pattern of the scale is needed for a high-resolution. From the practical point of view, however, the fine pattern makes the clearance of detecting head and scale small. For the solution of these problems, we propose a new magnetic scale where an absolute position information is written at series on one track accompanying with a parallel incremental track. The scale is expected to be in small-sized and to show a high efficiency having a long measurement range without decreasing accuracy and resolution. From the above, we made the new absolute type magnetic scale with absolute track where the position-information is written in at series by using non-repeated codes and with a parallel incremental track.
Furthermore, make the operation and structure, performance characteristic clear. We measured the operation characteristics of the scale and discussed the response speed and the position accuracy.

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The route guide sign system is one of the route induction system in the road traffic. However, there are partially miss-match notation in the network because it includes contradiction in each notation addresses.
Under these background, we are going to study on the method of notation addresses decision for the route guide sign boards, and will evaluate its network.
In this paper, we describe the methods of evaluation for the route guide sign system and detection of stray crossing points in a network, using the induction route by drive-simulation. In the method of evaluation, we use the standard induction routes. The standard induction routes are imaginative one by route guide sign system. By comparing the standard route's distance with the result of drive simulation's one, evaluation values are calculated and stray crossing points are detected.
By using this method, the route guide sign systems are evaluated in quantity, and the wrong route guide sign boards are likely detected.
Finally, we show an application example of this evaluation method and detection of the stray crossing points for the route guide sign systems at the Northwest CHIBA area.

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The authors have been developing a high speed hydraulic linear servo valve (LSV), a dynamic response of a 90° phase lag at 500Hz, with a high response linear dc motor to improve the accuracy and the productivity of sheet metal machines. This paper describes the considerations on high precision bending using the LSV. The following points are obtained:
(1) The bending machine using the LSV has sufficient positioning accuracy and rigidity for high precision bending with the positioning accuracy of 2μm and the hydraulic rigidity of 7.5kN/μm.
(2) The repeatability of bending angle by the bending machine using the LSV is ±5 minutes. The high precision bending, above 6 times higher accuracy than that of the conventional bending machine, has been realized by adopting the LSV.
(3) The drift of bending angle with the compensation for the piston displacement drift caused by temperature changes of hydraulic fluid is 30 minutes and it is 10 times higher precision than that of the conventional bending machine. For more precise bending, it is necessary to consider the drift of the distance between punch and die caused by thermal expansion of the frame.

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