Simultaneous localization and mapping (SLAM) is the latest technique for constructing indoor maps. In indoor environment, a localization method using the features of the walls as landmarks has been studied in the past. The past study has a drawback. It cannot localize in spaces surrounded by featureless walls or walls on which similar features are repeated. To overcome this drawback, we developed an accuracy localization method that ignores the features of the walls. We noted the fact that the walls in a building are aligned along only two orthogonal directions. By considering a specific wall to be a reference wall, the location of a robot was expressed by using the distance between the robot and the reference wall. We developed the robot in order to evaluate the mapping accuracy of our method and carried out an experiment to map a corridor (40m long) that contained featureless parts. The map obtained had a margin of error of less than 2%.

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This paper proposes new methods of data validation that targets configuration data prepared for train protection systems as represented by the automatic train control (ATC) systems that are applied to the Shinkansen and other heavy-duty trains. This configuration data is assigned to a generic application program in order to realise specific applications according to track layouts and different local conditions. The potential of introducing errors to the configuration data can lead to undesirable events; the safe separation of trains and safe speed are not ensured by such errors. Therefore, it is a safety-critical issue to eliminate errors from the configuration data.
Because of this, the author developed the data validation methods not depending on human works, utilising Extensible Markup Language (XML) technologies. This paper illustrates that XML is useful to represent the configuration data to which flexible expressions are required, and that XML Schema is valuable when performing syntax validation. Subsequently, the semantic validation methods are proposed by means of Extensible StyleSheet Language Transformations (XSLT) to provide a way to realise the semantic validation without custom application programming. Additionally, reliable processes to ensure the checking of validation results are proposed, and the effectiveness of the proposed methods are demonstrated by applying to actual configurations.

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The purpose of this study is to establish the stable operation of the sensorless induction motor drives with stator resistance adaptation using estimation error index. The stator resistance estimation is difficult at no load and zero frequency. These problems are solved by decoupling adaptive schemes and adjusting the adaptive gain. The stability analysis by pole placement and the experimental results show the effectiveness of the method.

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This paper proposes a novel control system to improve the operationality of a multilateral control system under constant communication time delay. A multilateral control system can be used to transmit haptic sense to remote places. Operationality indicates the magnitude of the operational force, which refers to the force that the operator of a robot experiences other than the reaction force from the environment. If the operational force is large, the operator of a robot feels heavy operational feeling. Time delay is one of the factors of heavy operational feeling. In this study, we investigate the relationship between the operationality of robots and the mutual transmission of their position signals in a multilateral control system under constant communication time delay. In the proposed control system, there is no transimission of position signals between the master robots. We verify the validity of the proposed control system by performing experiments.

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This paper presents the simple pulse width modulation (PWM) technique of a five-leg inverter to drive two three-phase AC motors independently. Normal PWM techniques in three-phase voltage source inverter cannot be used for the five-leg inverter with the independent drive. In this paper, two kinds of simple and novel PWM techniques of the five-leg inverter with two three-phase AC motors are introduced. Experimental results are provided to illustrate the validity of the proposed PWM technique.

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In this paper, we propose a method in which sliding mode control is used for improving position control. In industrial equipments, a pulse encoder is generally used for the determination of their positions, but the positions determined are unstable due to quantization errors that vary with the resolution of the encoder. It is known that this problem can be solved by employing an analog clamp method that uses two analog sinusoidal signals. However, the transmission capacity increases when the analog signals are transmitted serially.
Therefore, we propose an analog clamp controller that can be used for determining a control condition on a sliding mode plane. Experiments confirm the effectiveness of the proposed method.

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This paper presents a method for estimating the torque and rotational speed of line-start induction motors for motor-operated valves. Routine inspections of the valves are carried out because motor-operated valves are used in momentous plants such as power plants where securing, the reliability of the valves are very important. Movement environments in these plants are characterized by high temperature and humidity and therefore, it is difficult to position sensors near motors. In such a case, we must troubleshoot the system without using torque or speed sensors. The proposed method can estimate the torque and speed of an induction motor by using currents and voltages near the switchboard. Furthermore, we propose the parameter identification of mutual inductance by comparing the scalar and vector products between currents and voltages. The proposed method is validated by experimental results.

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Continuous path tracking control is an important technology for the position control system such as factory automation field. Particulaly, large torque is required for continuous path tracking control at its start position and its goal position. Each AC servo motor of continuous path tracking control have limitation of current and voltage. Therefore, in controlling a multi-degree-of-freedom continuous path tracking control system, even if only the motor torque of one axis has the current limitation, the actual position response is not often equal to the desired trajectory reference. In order to overcome these problems, this paper proposes a new continuous path tracking control algorithm by considering both the saturation of voltage and current. The proposed method assures the coordinated motion by considering the saturation of voltage and current. The effectiveness of the proposed method is confirmed by the experimental results in this paper.

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This paper presents an intensive discussion on modeling an adjustable-speed motor drive system consisting of a voltage-source PWM inverter and an induction motor that are connected by a three-phase symmetric, long cable with a grounding wire lead. Then, it describes a design procedure for a parallel-connected R-L filter in each phase that can mitigate the overvoltage appearing at the motor terminals. The model developed in this paper focuses on the inherent “ringing frequency” of the cable, where the ringing frequency is inversely proportional to cable length. When no filter is used, the so-called “impedance mismatch” causes the reflection of a voltage-traveling wave at both the inverter and the motor terminals. As a result, the impedance mismatch generates an overvoltage that may reach twice the inverter dc-link voltage at the motor terminals. The overvoltage may damage the motor-winding insulation, and may cause it to breakdown. Although an R-L filter installed on the ac side of the inverter can reduce the overvoltage, it would be difficult to design the filter effectively for long cables of different lengths. The effectiveness and validity of the simple design procedure described in this paper are confirmed on a 400-V, 15-kW experimental system with either a 100-m or 200-m-long cable.

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This paper proposes a large-capacity capacitor simulator consisting of a chemical capacitor and three-leg converter. One of three legs performs a bi-directional chopper. The others are used for a PWM rectifier. In the charging mode the most of the power stored in the chemical capacitor is injected to the utility through the PWM rectifier. In the discharging mode the power is supplied to the chemical capacitor side from the utility through the PWM rectifier. Thus the proposed simulator performs a large-capacity capacitor. The basic principle of the proposed simulator is discussed in detail. A prototype experimental model is constructed and tested. Experimental results demonstrate the validity and excellent practicability of the proposed simulator.

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This paper proposes a charge method using motor inductance for the boost driver with EDLCs. This method can be realized by the vibration of an exciting voltage in space vector modulation and enables the driver to charge EDLCs in itself without an additional charge circuit. The simulations confirm that the charge operation performs well without degrading the motor drive performance.

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Single-phase boost rectifier with snubber energy recovery feature operating under the current-mode control with a turn-on at constant clock time is studied. In this rectifier, the resonant circuit consisting of small inductor and capacitor is added in DC circuit. The snubber energy is transferred to an additional resonant capacitor and can next be transferred to the load circuit when an insulated-gate bipolar transistor as the active power device is turned off. The experimental prototype is implemented to investigate the operation. The experimental results confirm that the proposed snubber energy recovery scheme has the feasibility.

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