This paper describes the characteristics of the cogging torque based on four factors through the coordination between analysis and experiment. Four factors are air-gap of fitting part of divided core, annealing, a shape of inside diameter of stator, and eccentricity. This paper clarifies the influence of each factor. It is noted that air-gap of fitting part of divided core, annealing, and eccentricity have an influence to the cogging torque based on the least common multiple of pole number and slot number in 8-pole 12-slot PM motor. On the other hand, the shape of inside diameter of stator has the influence to the cogging torque of pole number order. The adequacy of the analysis model is proved by experiments.

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Passivity theory is a very useful tool for the stability analysis of bilateral teleoperation with communication delay. Many researchers use passivity-based stabilization method such as those based on scattering theory or wave variables. However, passivity-based stabilization is too conservative for the design of a high-performance teleoperation system. The term “high-performance” implies that people who operate this system can experience a highly accurate reaction force from environments. In this study, we analyze the L₂-stability of some bilateral control systems with time-varying communication delay by using the small-gain theorem. The small-gain theorem is known to be a stability condition for multi-input multi-output feedback systems. Additionally, a novel control structure for the bilateral control system with communication delay is proposed. The bilateral control system with the proposed structure satisfies the L₂-stability condition of the small-gain theorem. The experimental results show the utility of the proposed control structure.

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Bilateral control is one of control methods used to achieve haptic teleoperation between remote places. If the bilateral system is utilized for small or large environments such as those in brain surgery and space development, it is necessary that the system takes into account scaling factors between the master and slave. In this paper, we propose the bilateral control of master-slave system with different scaling on the basis of reproducibility and operationality which are one of the evaluation indices of bilateral control system. The proposed control system contains two kinds of scaling factors. One of them is scaling factors of position and force responses that are used to determine the scaling ratio between the master and the slave. The other one is used to adjust the control gains at the master and the slave, respectively. In this paper, some scaling types depending on the nominal masses of the systems are proposed. In order to compare the scaling methods, the analysis results of the proposed method on reproducibility and operationality are shown. Moreover, experimental results confirm the validity of the proposed method.

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This paper presents a phase angle control method of coil currents in a zone-control induction heating (ZCIH) system, which has split work coils on a susceptor. The ZCIH system controls the amplitude and the phase angle of each coil current to adjust the heat and temperature distribution on the susceptor. In order to control the current amplitude in a wide range from 0 to 100%, the phase angles of the coil currents are adjusted to be in phase with each other. This paper theoretically deriving the phase angle change of the coil current in transient states, and reveals that the phase angle change can be considered as a first-order response. Experiments have been conducted to verify the validity of the theoretical analysis. Based on the analysis, a phase angle controller was designed and examined in experiments using a two-zone ZCIH system. It is clarified that the designed controller makes it possible to adjust the current phase angle not only in steady states but also in transient states.

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Some of the position sensorless vector control methods of IPMSM use the back electromotive force and require accurate values of motor parameter. Their stability is influenced by motor parameter errors. Particularly, it becomes a problem in the case of extreme temperature variation and operation at low speed. In this paper, the online identification of stator resistance and permanent magnet flux is proposed for performance improvement. The proposed method uses only an observer signal without any additional sensor or signal injection. Both parameters are identified simultaneously using an appropriate error function. The principle of the proposed method is presented in the experimental results.

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This paper presents an application of ANFIS approach for automated fault disturbance detection and classification in transmission lines using measured data from one terminal of the transmission line. The ANFIS design and implementation are aimed at high-speed processing which can provide selection real-time detection and classification of faults. The ANFIS has been proposed not only to detect all shunt faults but also to identify the type of faults for digital distance protection system. The proposed technique is able to accurately identify the phase(s) involved in all ten types of shunt faults that may occur in a transmission line. The ANFIS's were trained and tested using various sets of field data. The field data are obtained from the simulation of faults at various points of a transmission line using a computer program based on Matlab. Various fault scenarios (fault types, fault locations and fault impedance) are considered in this paper. The inputs to ANFIS's are phase current and voltage measurement available at the relay location based on Root-Mean-Square values. The outputs of ANFIS's are 1 or 0 for detection of faults and type of fault. Through simulated process, the results indicate that the speed and selectivity of the approach are quite robust and provides adequate performance for a transmission and distribution monitoring, control and protection applications.

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This paper presents a novel position command shaping approach for mechanical vibration suppression in mechatronic systems. Although conventional command shaping approaches can suppress the specified mechanical vibrations, mechanical and/or electrical perturbations in a plant may deteriorate the motion performance because the commands are generally shaped in a feedforward control manner. In this research, a linear matrix inequality (LMI) design framework is applied to eliminate the deterioration in positioning, where the robust command shaping against the plant perturbations can be directly achieved under the constraint of state variables in a system. The effectiveness of the proposed shaping has been verified by numerical simulations and experiments using a prototype.

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The load characteristics of induction motor manufactured by soft magnetic composite (SMC) are presented. We manufactured three kinds of induction motors experimentally. One is a conventional laminated iron core motor. The others are SMC motors. One of the SMC motor uses SMC only for stator, while the other SMC motor uses SMC for stator and rotor. The experimental comparisons of load characteristics and loss analysis are shown. As a result, the difference between the efficiency of the SMC motor and the conventional laminated motor is 4.6%, in spite of the permeability of SMC being 20% lower than the conventional electromagnetic steel.

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This paper deals with a single-phase utility-interface power converter using no ac inductor to eliminate switching voltage/current ripples and electro-magnetic noises. The main circuit of the proposed converter consists of a diode-clamped linear amplifier (DCLA) and a dc-voltage balancing circuit. The DCLA has a circuit configuration similar with a diode-clamped multi-level inverter, except for using complimentary MOSFETs as power devices. As a result, the DCLA makes it possible to generate a sinusoidal output voltage without any ac filter. This paper presents new output voltage/current control methods to connect the DCLA with the utility grid. The experimental results show a conversion efficiency as high as 93% and a current THD less than 2%.

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In this paper, a body trajectory planning method of a biped robot based on ZMP (zero-moment point) is proposed. In the proposed method, the body of the biped robot is maintained at a constant height during walking. By this body trajectory, the biped robot walks stably without moving up and down the body height. Higher energy efficiency can be achieved by the proposed method than the conventional method that maintains a constant COG (center of gravity) height, since the biped robot walks with a higher body position and with less torque of joints. Additionally, the validity of the proposed method was confirmed by experiments of walking.

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A flexible actuator that consists of a thrust wire and a linear motor realizes the flexible arrangement of an actuator and an end-effector. The flexible actuator is able to transmit force sensation through a thrust wire. Thus, it is expected to be utilized in haptic motion systems. However, there is a non-negligible error between the generated force of the actuators and the actual force that is transmitted through the thrust wire. This is because of the disturbances such as friction and mechanical play of a thrust wire. In a bilateral system with thrust wires for haptic motion, the disturbance must be compensated. A new method for the compensation of the disturbance in the bilateral system with thrust wire is proposed in this paper. The effectiveness of the proposed method is investigated through experimental results.

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This paper proposes a dynamic analysis method of the linear resonance actuator under PWM (Pulse Width Modulation) control employing the 3-D finite element method (FEM). The effectiveness of this method is shown by the comparison with the experimental results. Moreover, the influence of the load on dynamic performances is clarified.

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Information on road surface conditions is important and helpful for road users such as automobile drivers, particularly in snowy seasons. In practice, the surface conditions depend greatly on the weather, road users, location, and other relevant factors. This report is concerned with the reliable detection of the surface conditions using tire noise from road vehicles. The road/tire noise emitted from moving vehicles varies momentarily depending on the road surface properties. Then, it may be possible to passively and easily detect the state of the road surface: i.e., dry, wet, or snowy state. To detect tire noise, we used a commercially available microphone as an acoustic sensor, which enabled us to easily reduce the cost and size in realizing a practical system for detecting road surface conditions. We propose a couple of simple detection methods to classify the conditions into several categories of state and to improve the classification accuracy. From the experimental results obtained in snowy areas, it has been demonstrated that an accuracy of up to about 81% is attained in predicting the road surface states using only tire noise data.

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In Tokaido Shinkansen, the power of a feeding substation increases in a short time because the train schedule is of high density and the acceleration performance of the rolling stock has improved. If the load power of the feeding substation increases further, the feeder voltage cannot be maintained when the power converter supplies only the reactive power. Because such a case was assumed in the frequency conversion section, we developed the Electronic Frequency Converter controls the A. C. voltage using the fixed power factor method. The Electronic Frequency Converter is under construction in the Numazu frequency conversion substation. We describe the domination of A. C. voltage control using the fixed power factor method.

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