We consider the problem of applying H^∞ optimization techniques to design a TDOF controller for robust servo systems. We introduce a two-step H^∞ optimization procedure: a feedback controller is designed to satisfy feedback properties and a prefilter is used to improve reference tracking performance. We describe a mixed sensitivity optimization scheme that is used for the feedback controller design, and propose a frequency shaping philosophy that highlights key issues for the prefilter design. We discuss the uncertainties in DC motor model and explain how to treat the parametric and non-parametric uncertainties in H^∞ optimization framework. We also show a design example for a DC motor with parametric uncertainties and analyze the tracking property in terms of design strategy and parameters change.

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This paper describes fixed-frequency variable-speed motor/generators with voltage source converter cascade, which are used in a wide power range between 1MW for wind energy generation and about 400MW in pumped storage power plants. Structure and design criterias of the controls are shown, based on the system equations. The simulation of the whole system with “SABER” shows the behaviour under normal operation conditions and the “ride through” during line faults. This simulation was the basis for the dimensioning of a 30MW 50-16 2/3Hz rail way supply system which was commissioned in February 1995 in Karlsruhe, Germany.

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In development, design and operation of photovoltaic power generation systems, a technique for constructing I-V curves under different levels of solar irradiance and module temperature condition susing basic characteristic values of photovoltaic modules is required.
For this purpose, we have already developed a practical I-V curve construction method and are using it in the evaluation of the output of a photovoltaic power generation system as well as in the core section of a simulation program to determine the amount of powor generated by a photovoltaic power generation system.
This time, we have developed an I-V curve construction method based on a different viewpoint from the above, namely, we developed an I-V curve construction method using current-oltage characteristic equations under photovoltaic cell irradiated conditions. Using this method, we can obtain I-V curves not only in the first quadrant but also in the second and fourth quadrants.
In this report, we discuss the outline of the I-V curve construction method using current-voltage characteristic equations of photovoltaic celles, as well as verification test results and application examples.

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It has been said that the nominal system is realized in low frequency region when disturbance and parameter variation are compensated by feedback of estimated disturbance signal from disturbance observer. According to analysis of the realized system, however, it is found that there are some cases in which the nominal system isn't realized. The nominal system is realized by choosing the order of the disturbance observer in accordance with disturbance and transfer function of control object. This paper shows the relationship among the order of the disturbance observer, the realized system, and the stability of the system.

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This paper deals with leakage current and it's high-frequency zero-phase-sequence equivalent circuit in an induction motor driven by a PWM inverter. The leakage current flows through stray capacitances between stator windings and iron core (frame) of an induction motor at the switching instants of the inverter transistors. The high-frequency zero-phase-sequence equivalent circuit is derived based on the frequency characteristics of the high-frequency zero-phase-impedance of the induction motor. The validity of the derived equivalent circuit is confirmed by simulation and experimental results.

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The effective usage of the power facilities can be realized by leveling the fluctuating active power and compensating the reactive power. The fuzzy control strategy of superconducting magnet energy storages (SMES) was proposed for this purpose. The control results depend on the values of scaling factors in fuzzy reasoning. Therefore, it is desired to obtain better control results that the scaling factors are successively adjusted according to the load power fluctuation.
In this paper, the control strategy based on an auto-tuning of scaling factors and a fuzzy singleton-type of reasoning method using the back propagation of neural network is proposed for leveling load fluctuation. The prediction and revision of teaching signal with energy of SMES is proposed. The coefficients of learning rate and the revision of the teaching signal is discussed. Then, we can achieve the better leveling of load power fluctuation by using fuzzy logic and neural network.

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The research of intelligent traffic management systems or intelligent traffic information systems has become to be a important subject in all over the world. There are many projects of intelligent traffic systems, some of which are now in practical stage, but the effect and evaluation of the systems are not disscussed very well. That is why an effective tool to simulate the systems is needed.
In this paper, discussed is the modeling and the structure of a software simulator developed as a tool for the study on intelligent traffic management systems. The simulator is given the following two features: One is to apply micromodel, which enables it to collect detailed data of each car. The other is to adopt object oriented method, which makes the simulation system clear and easy to extend in the future. The simulator has so flexible flame with object oriented method that it is a useful tool for the study of dynamically changing traffic flow.

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This paper deals with aa merging section of the Automated Guided Vehicle System under time limit for merging. At near the merging section, one flow of traffic must form a queue to avoid collision of vehicles. The vehicle behavior is analyzed using approximate analysis with Markov chain approach and the analysis is based on an idealized model. It is important to discuss the behavior of traffic at merging sections in the design of the overall AGV system, also in realization of the system. We derive the average queue length and the average waiting time using the recurrence. The relationship between queuing delay and traffic density is examined. Therefore, we can make particular consideration about the behavior of traffic quantitatively.

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From a systems point of view, railway crossings are the weakest point in the railway system, accounting for a major part of fatal operational accidents in spite of various countermeasures taken. As always, high priority continues to be given to safety countermeasures. With a view to more effective and elaborate accident prevention, the authors have developed the simulator using a personal computer to analyze complicated traffic situations near a railway crossing caused by train/road traffic, crossing installation, etc. It is aimed at reproducing the traffic conditions such as traffic jams or accidents, visually, real-time and conveniently in order to evaluate safety, effects of equipment improvement or new control strategy of gate and alarm, eventually contributing to establishment of proper standards for signal design. This simulator consists of two subsystems: (i) traffic flow analysis simulation system and (ii) visuality analysis simulation system. (i) is to analyze quantitatively traffic flow around a railway crossing, by means of a micro model based on construction and causal model. (ii) helps human sensitivity assessments such as visuality using 3DCG (3-dimensional computer graphics). The simulator is linked to the nationwide crossing database covering about 40, 000 sites. Thus it realizes a highly flexible and useful system capable of both general and individual analyses.

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The ultrasonic motor is a newly developed motor and it has an excellent performance and many useful features, so it has been expected to be of practical use. However, this motor has a heavy nonlinearity which varies with driving conditions. Therefore, the precise position control of the ultrasonic motor is difficult.
This paper proposes a new position control scheme for the ultrasonic motor using a neural network. The proposed controller can approximate the nonlinear input-output mappings of the motor using the neural network, and can compensate the characteristic variations by online learning. The usefulness and validity of the proposed control scheme is examined in experiments.

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Recently, robots have been required to inspect the insides of nuclear reactors with an environment of high temperature and radiation flux. In a FBR (fast breeder reactor), the viewing system of the robot is particularly important because the reactor vessel of the FBR is filled with opaque liquid sodium. To drive the robot, servo motors have to meet such special requirements. Above 220°C, organic materials cannot maintain their properties for long periods. In addition, the air gap length of the motor varies, because metals expand at high temperature. Thus, the characteristics of induction motors with an air gap length of 0.2_??_0.4 mm may vary. Furthermore, the rotor may come into contact with the stator.
In this paper, a newly developed permanent magnet motor which can withstand high temperature and radiation is presented and the characteristics of the motor at high temperature are discussed.
Coils which wind ceramic magnetic wires are installed in the stator. Sm₂Co₁₇ permanent magnets are embedded in the rotor yoke. This motor is suitable for application at up to 400°C because of the use of inorganic materials. In addition, the permanent magnet motor can have a long air gap length, which has little effect on the characteristics of the motor.
The test results show that the motor has excellent characteristics at high temperature.

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