In a web process control system, such as for film, textile material and paper, strong couplings between the subsystems of speed and tension control exist. Then it is difficult to determine the parameters of controllers and accordingly much experience is often needed for setting up the large scale and complex system. The paper deals with the analysis and control of web tension control system. First it is pointed out that there are distinct differences between steel process and the web process dynamics. A block diagram for an experimental web tension control system is constructed, and the stabilizability test for decentralized control for the system is described. From the computer simulation, it becomes clear that the tension control subsystems have poor tracking performance in the case of conventional PI control. In order to improve the tension control performance, the author introduces a high gain adaptive control with the structure of PI. The adaptive controller compensates the disturbances from the other neighboring subsystems, and shows a satisfactory performance.

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A new control method is presented using holonic concept on Universal Learning Network (U. L. N.). Holonic concept was proposed by Arthur Koestler in 1905. Its aim is to harmonize hole systems with partial systems, which have hierarchal structures. On the other hand, U. L. N. which models and controls large-scale complicated systems such as industrial plants, economic, social and life phenomena is proposed. In this paper. holonic control system based on holonic concept and U. L. N. is presented. From simulation results of a nonlinear crane system, it has been proved that holonic control can harmonize the system rather than optimize it, which used to be the conventional method of control engineering.

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Characteristics of control system design using Universal Learning Network(U. L. N.) are such that a system to be controlled and a controller are both constructed by U. L. N. and that the controller is best tuned through learning. U. L. N. has the same generalization ability as N. N._??_ So the controller constructed by U. L. N. is able to control the system in a favorable way under the condition different from the condition of the control system at learning stage. But stability can not be realized sufficiently.
In this paper, we propose a learning robust control method using U. L. N. and second order derivatives of U. L. N._??_ The proposed method can realize better performance and robustness than the commonly used Neural Network. Robust learning control considered here is defined as follows. Even though initial values of node outputs change from those at learning stage, the control system is able to reduce its influence to other node outputs and can control the system in a preferable way as in the case of no variation. In order to realize such robust control, a new term concerning the variation is added to a usual criterion function. And parameter variables are adjusted so as to minimize the above mentioned criterion function using the second order derivatives of criterion function with respect to the parameters. Finally it is shown that the controller constructed by the proposed method works in an effective way through a simulation study of a nonlinear crane system.

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Control probrems on the large-scale complicated systems such as optimal distributed control and optimal hierarchical control have been extensively studied in the 1960's. On the other hand, recently, multi-objective optimization problems have been studied in the field of Linear Programming and Non Linear Programming problems. In this paper, a new control methodology called fuzzy weighting factor method is presented that automatically determines the weighting factors of the criterion function of the large-scale multi-objective non linear systems which are made up of plural subsystems with their own criterion functions. Hitherto, weighting factor method, ε constraint method and fuzzy Min Max method etc. have been presented as the method of optimizing the multiobjective systems. Most of them are applied to static optimization probrems, and they have the problem to be solved such that as the methods are converted to linear programming problems, the membership functions of the plural criterion functions should be approximated linearly and the methods need a fairly amount of computations. In this paper, the controller's parameter variables in the dynamic multi-objective non-linear control systems are determined by using Universal Learning Network (ULN) and a new fuzzy weighting factor method. And the new method can solve the above mentioned problems and is also different from the usual fuzzy Min Max method in the point that the new fuzzy weighting factor method can arbitrarily adopt the membership functions. The Universal Learning Network is a super set of all kinds of neural network paradigms with supervised learning capability and in this paper both control objects and its controllers of the large-scale complicated systems are represented by ULN. Finally, characteristics of the fuzzy weighting factor method are studied by simulations on a nonlinear tank network.

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This paper describesa new parameter tuning method for an elevator group control system. In an elevator group control system tuning parameters describing elevator use and the building environment are important. The new tuning method uses improved genetic algorithms to follow environment changes and to give robustness. Keeping diversity is important in following environment changes. The paper also describes the adding random chromosomes method and adding other estimationsmethod to keep diversity. Their effects are shown by simulations.

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For promotion of low-priced and reliable PWM converters, it is important to decrease the number of parts which comprise a PWM converter. The proposed control method realizes an integrated control circuit using inexpensive DSP (Digital Signal Processor) to offer unity input power factor without a source voltage sensor. In the method, an observer estimates voltage instead of sensing it. Then, the phase-angle error between the estimated voltage wave and a sine wave generating input current command is made zero by a phase controller based on the Fourier series. The stability of the system is shown by the Popov's method. Experiments demonstrate the system achieves sinusoidal input current and unity power factor.

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We proposed the three phase active filter by controlling the ripple power based on the instantaneous AC line power detection. And we showed that the proposed system had many excellent features such as simple construction, high accuracy, high efficiency and so on.
In this paper, we apply this control principle to the single phase power line compensator such as active filter, reactive power compensator. In this case, we must control the instantaneous current waveform instead of ripple components of 2 axis quantities of three phase current or power. The proposed system can be easily constructed and controlled only by detecting the AC line side current and the DC side voltage of the PWM converter. The system has many functions such as a PWM converter, an active filter, a reactive power compensator at the same time without any modifications in addition to the above excellent features.
In this paper, we describe the proposed system comparing with the conventional one and confirm the feasibility of the system by simulation and experimental results.

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There are many torque measuring methods for an induction motor. Some applications require a simple and easy method to detect torque change rather than a precise method to measure the torque of the motor. The torque of an induction motor is roughly estimated by the input current. This is the most simple method of measuring torque.
The input current of the induction motor is the sum of the torque current and the exciting current. The torque current is proportional to the synchronous-watt and the motor torque. The exciting current has a phase difference of almost 90 degree lag to the torque current, is variable with the input voltage and is larger than the torque current especially at a light load. Therefore, it is difficult to find motor torque from the input current of the motor at a light load.
In this paper, we propose a simple and easy torque measuring method with a synchronous rectifier circuit. The synchronous rectifier circuit can find a vector component at the detecting angle from the input current of the induction motor and detect the torque current in the input current of the motor. Adjusting the detecting angle of the synchronous rectifier, the rectified signal is mixed with the torque current and the exciting current in proper persentage and compensated for the fluctuation of the input voltage. It serves as a simple and easy torque measuring method suitable for trouble detection of the load such as under the life test.

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Brushless DC Motor (BLDCM) systems, which consist of a permanent magnet synchronous motor (PMSM), an inverter, and a position sensor mounted on the motor shaft, have recently become widely used in many industrial applications. However, when trying to make a high precision control for the BLDCM, such as making the steady state error less than 0.01% of the rating speed, the effect of the small torque ripple which does not appear in the DC Motors cannot be ignored. This torque ripple in BLDCM is mainly due to fluctuations of the field distribution, the influence of the switching dead time and the cogging torque. The offset error and the unbalanced gain between each phase of the current detector also contribute to the periodical disturbance.
This paper presents a new control method for small vibration suppression. We propose a new disturbance torque model which consists of several kinds of periodical components and a DC component. As the state space observer theory can be applied to this model, an observer based approach is used to estimate the amplitude and the phase of these periodical disturbances assuming that the frequency is known. The estimated torque is fed to the current reference to suppress the vibration. This method can be applied not only to a constant speed control system but also to a variable speed control system.
Experimental results show the validity of the proposal method.

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This paper proposes a new method of color-gray image transformation. In comparison with gray image processing, color image processing is not often applied to appearance inspections because of its high cost and complexity of processing. To solve this problem, we have developed a method for rapidly transforming a color image into a gray-scale image by the use of a look-up table without losing useful information for inspection. In this method the gray level is decided by the distance between representative points of clusters. To extract an object clearly, all background clusters are transformed to an equal level and the borders of objects and backgrounds are enhanced.
The experimental results indicated detecting edges to a level of subpixel precision in the transformed images. This method is presented to show its validity for appearance inspections.

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In the market for miniature 2.5-inch hard disk drives and smaller sizes, there exists a growing need for faster drives with larger capacities. The demands for the robustness of the head positioning control system are becoming severe.
Generally, a high bandwidth servo loop or a feedback control system designed for optimum protection against external disturbance is necessary to realize robust performance. However, a limited servo bandwidth by the resonance of a voice coil motor or the strict estimation of the external disturbance makes it diffcult to realize a robust head control system using the linear feedback controller only.
In this paper, a head control system using a sliding mode controller with linear feedback controller is presented. The control method enables to realize the higher robustness and the smaller chattering caused by the sliding mode controller than the conventional feedback controller.
The validity of the proposed method is confirmed by the numerical and experimental results in the miniature 2.5inch hard disk drive.

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A new method is proposed to determining the cutting layout of two-dimensional patterns in a sheet by genetic algorithms (GA) to attain the minimum required length of the sheet. In applying the GAs to two-dimentional problems, if genes are designed to represent two-dimentional positions as normally adopted, required search spaces become wide, thus resulting in large calculation time. In the proposed method, since it becomes possible to deal the problem as an one-dimentional order one by incorporating layout determining algorithms (LDA) into GAs, the saving of the required calculation time is attained. The LDAs arrange each pattern on the sheet without opening and overlapping according to the order given by the GAs and return the required sheet length to the GAs. On the other hand the GAs determine the order to make the length minimum. The results of simulation show good performance.

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This paper describes variations of turbine generator steady-state reactances for load conditions. When the turbine generator is a small size, magnetic saturation of the stator and rotor core is a problem. Therefore it is important to understand the variations of the reactances for load conditions. The reactances of a 592MVA turbine generator are calculated with d- and q-axis equations considering magnetic saturation and two-dimensional numerical magnetic field analysis. The results are as follows.
(1) The equivalent synchronous reactances considering cross-magnetizing phenomenon are smaller than the original synchronous reactances for load conditions.
(2) Numerical values of the d- and q-axis mutual reactance and the field and q-axis mutual reactance are at their maximum when the d-axis linkage flux is nearly equal to the q-axis linkage flux under constant voltage.
(3) The d-axis synchronous reactance drops with increasing reactive power under constant voltage and active power, but the q-axis synchronous reactance increases.
(4) The variation of the equivalent d-axis synchronous reactance with increasing reactive power is similar to that of the d-axis synchronous reactance, but variation of the equivalent q-axis synchronous reactance is different from that of the q-axis synchronous reactance.

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The authors have developed high-power electrostatic motor called Dual Excitation Multiphase Electrostatic Drive (DEMED). This motor possesses 230W/kg of power/weight ratio and this is much higher than those of conventional electromagnetic motors. However, the motor has some problems with the quality of its output, such as low positioning resolution or much viblations, since its force generation is rippled. In case of electromagnetic motors, torque or force ripple is removed by skewing slots of their armatures. Similaly, the force ripple of DEMED is expected to be removed by skewing their electrodes, instead of slots. In this paper, the effect of skewing electrodes of DEMED is analyzed, and the analytical results show that appropriate skewing will suppress the ripple considerably and will raise effective force of DEMED.

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Permanent magnet (PM) motors, which have a simple and maintenance-free structure and high performance, have been used widely in the fields of industry applications. The PM motor, however, has some problems on the cost and weight in high power usage.
In this paper, we propose a method for optimizing surface PM synchronous motors (SPMSM) using non linear optimization technique. In the formulation, the performance characteristics are estimated using space harmonic analysis. The accuracy of the formulas is investigated by experiment. The exterior point transformation method and the simplex method are applied to solve the constrained nonlinear programming problem. Eight parameters are chosen as the independent variables, such as number of poles, the stack height, the number of slots per pole per phase, the coil pitch, the ratio of slot width to slot pitch, the width of magnet, the height of magnet and the height of rotor yoke. The SPMSM design is analyzed under four objective functions; the primary weight, the cost of materials, the input KVA and the power rate.

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The thin iron plate is needed to be transported without the degradation of the quality of surface, and magnetic levitation technology is one of the solutions to satisfy these requirements. Magnetic saturation in the objective, however, is a severe problem for the levitation of the thin iron plate. Design and evaluation method of the electromagnet is studied to avoid the saturation. In this paper, the shape of the electromagnet is studied to design the electromagnet shape for the levitation of the thin iron plate. The magnetic saturation occurs in the iron plate especially when plate is very thin. Therefore, the preferable shape of electromagnet should be investigated to secure the large cross sectional area of flux path in the plate. The authors suggest the evaluation factor. The evaluation factor of magnet shape for thin iron plate is studied experimentally. In conclusion, the evaluation factor of magnet shape, however, is not sufficient to decided the optimum shape of electromagnet for thin plate levitation. Thus the another evaluation factor is the electric power consumption. The design of the electromagnet shape for levitation of the thin iron plate is possible by evaluation factor of magnet shape and the power consumption.

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