The figure and the table, that conditions of signals and switches and others needed for train traffic operation are summarized, are called the interlocking chart. Untill now, the production of interlocking chart is carried out by the expert who has long time experience. Great labor and time are necessary to produce interlocking chart.
In the case that interlocking chart is producted by using a computer, input of data and the calculation of interlocking table corresponding to it are important. According to an experimental system that is described in this paper for producting interlocking chart, the interlocking chart is obtained when rough sketch is input from a screen of a display. The rough sketch shows connections of lines and various kinds apparatus. At first, the system generates the data of the tree structure type, called the route search tree, from the rough sketch data that was already input. The calculation of interlocking table is carried out on the basis of the route search tree that was generated. Usually the route of train needed for interlocking table is given beforehand. However, in this system the route is requested from the route search tree to decrease the trouble of input. The search of locking condition and others to each route are carried out, and the interlocking table is summarized. Finally, the interlocking chart that consists of figure and table is output.

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A new digital control technique is proposed to synthesize arbitrary three phase PWM inverter output. Sensing two line-to-line voltages, the required pulse patterns for deadbeat response are computed in real time manner, based on the predicted voltage by an observer at 18kHz sampling frequency. When used for the uninterruptible power supply, this closed loop voltage control inherently results in a very low THD and a very quick transient response with the less filter capacity. Also with repetitive compensator, the proposed scheme has advantages in improving the output waveform for non-linear load. This paper describes modeling technique, theoretical analysis, simulations and experimental results.

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Conventional passive filters have been broadly used to suppress the harmonics in power systems. However, they have the following disadvantages; (1) Source impedance affects the compensation characteristics. (2) Antiresonance between the source and the passive filter amplifies the harmonic current of the source at the specific frequency. (3) No harmonic compensation is performed at the frequency to which the passive filter is not tuned. On the other hand, active filters which have been studied and put into practical use have the ability to overcome the disadvantages mentioned above, but their initial and running costs are high, because they need voltage-or current-source PWM converters having high speed current response.
This paper presents a novel harmonic compensator consisting of an active filter and a passive filter which are connected in series with each other. The passive filter removes the harmonics of the load, and the active filter improves the compensation characteristics of the passive filter. So the proposed filter system can eliminate the problems of the passive filter used alone and needs a small rated active filter, compared with a conventional active filter used alone. Control schemes and compensation characteristics are discussed, and experimental results of a laboratory model are shown.

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Up to now, the performance of current control for field-oriented control of the induction machine using pulsewidth-modulated (PWM) voltage source inverter have the problem that it can not provide high-accuracy and quick-tracking response simultaneously. For improvement, two variable structure approaches are proposed in this paper. One is the so called Discontinuous Damping System method implemented by software alone, which is suitable when switching frequency of inverter is higher. The other is a combination of software PI controller and hardware hysteresis comparator, which is necessary in the case of lower switching frequency. Experimental results show that both approaches have the dynamic response as fast as that of a hysteresis controller as well as an accurate static response with the least harmonic currents. An optimum PWM pattern of the inverter based on the space vector concept was also implemented so that not only the harmonic currents are limited but also, with the proposed methods, it becomes easy to compensate the dead-time of the inverter and to sample motor current eliminating the distortions.

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A new output voltage control method for PWM-controlled cycloconverters with space vectors is proposed in this paper. Results are as follows:
(1) The classification and the systematic behavior of the space vectors of PWM-controlled cycloconverters are clarified through the analysis.
(2) A new output voltage control method which makes the excellent output voltage waveforms is proposed using the results of the analysis.
(3) Feasibility of the proposed output voltage control method is confirmed by simulation.
(4) Output voltage waveforms of the PWM-controlled cycloconverters are compared with those of the PWM-controlled inverters, using the performance index of variance of time-integral of higher harmonic components. Therefore, the proposed control method has possibility to reduce acoustic noise and torque ripple of induction motors.

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The control method for the squirrel cage induction generator system without speed sensor driven by wind turbine has been studied. The estimation of the generator speed is realized by feedback of torque component of the generator current. To determine the control gains, the transient responses of the system with respect to the change of wind velocity, are evaluated theoretically. As a result, it is clarified that the speed and torque response of the system is dominated by the time constant of the speed estimation divided by generator slip. The upper limit for time constant of the speed estimation is found, which limits the converter capacity and suppresses the strength of the generator shaft.
In this system, to eliminate the start-up failure due to the stall of the wind turbine, the generator must start from a running state of rotor, where the starting speed is determined by the terminal voltages generate from the residual flux of the generator.

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In order to clarify the usefulness of traffic demand predictors to be used in traffic management and control system, tested with actual field data were thirteen prediction algorithms consisting of UTCS-2, UTCS-3, methods of employing as estimates current measurements, historical means and measurements made a week before and models applying multi-variate regression analysis, time series analysis developed by Box and Jenkins, spectral analysis and Kalman filtering (made up of three models, Kalman-1, Kalman-2 and Kalman-3). The extensive tests were performed to see the applicability of the predictors for 5 to 60 min prediction of 5 min, 15 min and 30 min traffic demand. For the sake of ensuring the robustness of the predictors the tests were made for the case where the traffic demand of the day in question roughly follows the average historical pattern as well as the case where the deviation of the traffic demand of the study day from the historical average is substantial.
The test results for two cases of prediction, 15 min prediction of 15 min demand and 30 min prediction of 30 min demand (which are most likely to be interesting from practical viewpoint), suggested that in the former prediction the Kalman-3 model (which employs, as state variables, not only traffic demand on the link in question but also on other relevant links, updating the transition matrix on a real-time basis) and the multi-variate regression analysis model (which also utilizes traffic demand informations on some links inclusive of the subject link, with parameters fixed throughout the study day) perform better than the remaining predictors while in the latter prediction only the Kalman-3 model yields the most reliable prediction algorithm.

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In order to realize an advanced motion control for robot arms, many control algorithm have been proposed. Now, for applying the trajectory control to the robot arm, the influence of identification errors concerning physical parameters of the robot arm on both unstable problem and tracking accuracy is the most significant matter.
In this paper, we clarify the consideration points for applying the trajectory control, that was already proposed by Mita, et al., and propose an evasion method of unstable problem. To put it in the concrete, the influence of the identification error of inertial terms or viscous damping on both stability and tracking accuracy is clarified, and it is shown that by tunning the design parameter socalled weighting factor, unstable problem caused by the identification error can be avoided, but the tracking accuracy can not be guaranteed. Moreover, it is shown that the unstable phenomenon occurs in the tracking though the stability concerning the equilibrium point is assured, and its reason is explained by giving attention to the output of the integral compensator. In order to avoid the instability phenomenon, we propose that the disturbance caused by the parameter error should be esimated by using the observer and that the feedback mechanism so as to cancel the disturbance should be constructed.

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This paper describes a controller design for a water temperature system, aiming at an accurate control. If we control the system based on the pole placement regulator, the water temperature oscillates around a desired value and has some steady state deviation. We propose a method for eliminating the oscillation and the steady state deviation.
The oscillation phenomenon was found to be caused by a drive delay of heater, We eliminated the oscillation by using the drive delay compensation control method in which a future state value of the system was predicted through a real time simulation. However, some steady state error was noticed in the system and the cause was traced to the stational heat value in the mathematical model of the system. We replaced this value by an imaginary stational heat value as calculated on real time, hence, we got rid of this error. Combining these two control techniques, we obtained an experimental result of water temperature system in a high accuracy of 0.01°C

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A DC tacho-generator has been widely used in such applications as computer peripherals and machine tools. However, this generator has some problems which are the ripple voltage involved in the output voltage and the abrasion of the brush and the commutator. It is said that the ripple voltage of a general DC tacho-generator is from 1.5 to 5% of the output voltage. This ripple voltage must be reduced to very small value in consideration of the influences on control systems.
A compensation network of the ripple voltage on this generator was proposed in the previous paper. In this paper, the network is so improved as to operate effectively without losing the high response even when the rotating speed is changed slightly. The performance of the proposed network is discussed in detail, and the method for the design of the network to satisfy the requirements both of the ripple voltage and of the response time is proposed. The experimental results show that the ripple voltage is eliminated perfectly at the steady state, and that the high response is not lost.

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The thrust force of moving magnet type linear direct current motor (MM-LDM) is analyzed in this study. The moving magnet type MM-LDM consists of a stator and a mover. The stator is composed of two stick shape electromagnets and the mover consists the movable permanent magnet that is located in two electromagnets.
One of the methods to calculate the thrust force of the MM-LDM is analyzed by the energy gradient which is decided by the distribution of magnetic flux. But this method is very difficult for calculating the thrust force of these kind of LDM. This MM-LDM can be considered as a transformer, when the magnet of the mover is assumed to be a one-turn coil carrying large current. The stored energy in the MM-LDM can be gotten by measuring the self-inductance and the mutal-inductance of the equivalent circuit of the MM-LDM. And this energy gradient gives the thrust force.
The calculation of thrust force induced on this motor shows that the mutual inductance has much influence on the generation of thrust force.

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The authors have named dT_e/dδ synchronizing torque and have shown a step-out discriminant by using this, where T_e is the torque generated by a synchronous generator. Next, we have introduced a measurement method of the synchronizing torque based on the measurement of T_m-δ characteristics, where T_m is the torque generated by a prime mover. By using this method, we have proved that a step-out occurs where synchronizing torque has become zero. We have measured the magnitude of the inverse frequency transfer function in 0.1Hz, that is the synchronizing torque considering the hysteresis of T_m-δ characteristics. Next, we have deduced the synchronizing torque formula considering the nonlinear magnetic phenomena. Differential constants x_d*, x_q* are necessary to obtain the synchronizing torque calculated values related to the synchronizing torque measurement values based on the measurement of T_m-δ characteristics. Incremental constants _??__d, _??__q, are necessary to obtain the calculated values related to the synchronizing torque measurement values based on the inverse vector locus measurement method. Both constants agree in the ordinary region, so both calculated values agree. As _??__q is less than x_q* in the neighborhood of the steadystate stability limit, the calculated value based on the incremental constants is greater than the calculated value based on the diffarential constants. And, the calculated values almost have agreed with the measured values. Finally, we have predicted a steady-state stability limit by the synchronizing torque calculated values using diffarential constants, which limit substantially has agreed with actual limit.

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The authors have developed two types of stepping motors with a function of magnetic suspension. Since the motors have, in their relatively simple and compact structure, the function of magnetic suspension and positioning at once, they are suitable for use in cleanrooms, vacuum chambers and hostile environments. Due to the characteristic toothed pole structure of the motors, attractive force fluctuation per tooth is inevitable as the motors are propelled. However, the authors have succeeded in designing the motors so that the sum attractive force becomes relatively constant and insensitive to the position of the slider in the direction of propulsion, resulting in the realisation of stable suspension by a conventional servo circuit used for ordinary magnetic bearings. The paper will discuss the following: (i) structure of two types of stepping motors; (ii) magnetomotive force of coils; (iii) attractive force calculation; (iv) control circuit, (v) experiment and performance; and (vi) comparison of two types.

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It is well known that the suppression of howling is one of the most important problems in the realization of a teleconference system. Usually, acoustic echo cancellers have been employed in order to cancel the howling. Due to the extremely long impulse response of the acoustic system, however, this kind of howling canceller requires a large hardware and a lot of computation. This paper considers a new type of howling suppressor. Namely, noting that howling signal can be well approximated by the sinusoids, we propose a howling canceller using an adaptive notch filter. The proposed howling suppressor has following two special features: (i) It is realized by a very small hardware and requires less computation compared to the conventional cancellers. (ii) It does not require any special training period. Finally, by implementing the suppressor on a DSP (Digital Signal Processor), the effectiveness of the proposed suppressor is confirmed.

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Magnetically levitated rail cars are expected as a new transportation system in Japan. The author used a model of magnetically levitated vehicles with many normal conducting magnets. This paper discusses the dynamics between the three coupled rail cars and the elastic rails.
In this paper, I propose two types of control method; The one is Rail Oscillation Damping Control method (RODC-method), the other is Feedback Coefficients Changing Control method (FCCC-method). From an economical point of view, a light, elastic and oscillatory rail be used. In addition to this, from many geographical restrictions, a long span beam out of the standard type should be used. So I propose the above mentioned control system in which the feedback coefficients are changed one after another with the aim of damping the oscillation to match each beam by the information of it's characteristics.
According to the results of digital simulation, we found out; when the vehicles keep the feedback coefficients determined without RODC and FCCC methods to be constant and run on various rails, the supporting magnets come in contact with the rail; when the control circuits change the coefficients one after another with the aim of damping the oscillation so as to match the long and elastic rail on which the vehicles are running, the maglev system is stable.

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Reluctance Generator (RG) can be operated at super high-speed because of its simple, robust rotor. Thus it is found acceptable for its high ratio of power/volume or power/weight as a small power source in airplanes, vehicles, etc., where electricity cannot be transmitted from external power source.
While describing the output characteristics of RG, equivalent circuit or phasor diagram is generally applied. But although the iron and copper losses are caused by different mechanisms, they were treated by using a constant equivalent resistance in the past papers. In viewpoint of loss, it was same to that only the copper loss was considered. On the other hand, the iron loss is variable with the change of voltage and frequency. And the iron loss makes up the great part of the total losses especially when the machine driven at high speed. Therefore it is natural that the iron loss should be treated precisely.
In this paper, the following points are discussed.
(1) A new equivalent circuit with taking iron loss into consideration is developed by introducing an iron loss conductance. A measurement method (circuit diagram method) of the circuit parameters is also proposed.
(2) The circuit parameters of the test machine are measured by applying the proposed circuit diagram method. And experimental results on the test machine show the validity of the new equivalent circuit.
(3) Based on the new equivalent circuit, the relationship of the RG output characteristics and circuit parameters is studied. Thus the bases to choose the circuit parameters are given.

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