Nowadays agile market is in common, and the fundamental technology supporting next-generation production system requires further development of machine and information technologies to establish “human friendly technology" and a bridging of these technologies together. IMS-HUTOP project proposes a new product life cycle that respects the human nature of individuals, and establishes the elemental technologies necessary for acquiring, modelling and evaluating various human factors in an effort to achieve the HUTOP cycle. In this paper we propose a human centred and human friendly manufacturing system, which has been proposed in the IMS-HUTOP project.

View full abstract

Recently, manufacturing systems have become large scale and complex. Social scientific approach is one of the promising methods to facilitate effective operation for the resource allocation problems in manufacturing systems, since the approach takes an analogy of social systems with optimality and robustness in nature. In this paper, we firstly propose a modelling methodology of oligopolistic virtual market, and develop an oligopolistic virtual market as an experimental model. Then we clarify the several important characteristics of the oligopolistic virtual market by computer simulation experiments, and try to apply the proposed method into a utility computing operational problem to validate its effectiveness into resource allocation problems.

View full abstract

It is very important to guarantee the quality of the industrial products by means of visual inspection. In order to reduce the human error in the manufacturing process, this paper proposes a 3D visual inspection system based on a stereo vision with single camera. It is technically noted that the base line of this single camera stereo was precisely calibrated by the image processing procedure of template matching. Comparing its performance with that of human inspection using OGP microscope, the proposed 3D inspection could be an alternative in precision and in processing cost. Since the practical specification in 3D precision is 0.02mm and the experimental performance was around the same, it was demonstrated by the proposed system that the human error in inspection, especially in 3D inspection, was decreased.
In order to realize the Total Production Cycle called HUTOP, this paper will suggest how the human inspection of the products could be modeled and be implemented by the computer system especially in manufacturing process.

View full abstract

In the field of manufacturing, the importance of utilizing knowledge and know-how has been growing. To meet this background, there is a need for new methods to efficiently accumulate and extract effective knowledge and know-how. To facilitate the extraction of knowledge and know-how needed by engineers, we first defined business process information which includes schedule/progress information, document data, information about communication among parties concerned, and information which corresponds to these three types of information. Based on our definitions, we proposed an IT system (FlexPIM: Flexible and collaborative Process Information Management) to register and accumulate business process information with the least effort. In order to efficiently extract effective information from huge volumes of accumulated business process information, focusing attention on “actions” and communication patterns, we propose a new extraction method using communication patterns. And the validity of this method has been verified for some communication patterns.

View full abstract

Human is able to exchange information smoothly using voice under different situations such as noisy environment in a crowd and with the existence of plural speakers. We are able to detect the position of a source sound in 3D space, extract a particular sound from mixed sounds, and recognize who is talking. By realizing this mechanism with a computer, new applications will be presented for recording a sound with high quality by reducing noise, presenting a clarified sound, and realizing a microphone-free speech recognition by extracting particular sound. The paper will introduce a realtime detection and identification of particular speaker in noisy environment using a microphone array based on the location of a speaker and the individual voice characteristics. The study will be applied to develop an adaptive auditory system of a mobile robot which collaborates with a factory worker.

View full abstract

This research intends to develop the basic concepts of an experimental “human-friendly” robot, which flexibly moves and supports cell-based production. The development concept is to design a robot capable of autonomic transfer and intelligent operation by responding to a call by an operator and performing the instructed operations. In this system, the robot follows the human teacher to learn the safe basic path, and plays back the taught information while independently moving along the taught path. We call it ‘playback-type navigation’.

View full abstract

Because visual inspection systems are difficult to tune, they create many problems for the kaizen process. This results in increased development costs and time to assure that the inspection systems function properly. In order to improve inspection system development, we designed an easy-tuning system called a “Program-less” visual inspection system.
The ROI macro command which consisted of eight kinds of shape recognition macro commands and decision, operation, control commands was built. Furthermore, the macro command editing executive system was developed by the operation of only the GUI without editing source program. The validity of the ROI macro command was proved by the application of 488 places.

View full abstract

This paper proposes new sensorless vector control methods for permanent-magnet synchronous motors (PMSMs), which are based on a new minimum-order back-EMF state-observer taking acceleration into account, and examines potentiality of the improved back-EMF observer through experiments. Conventional sensorless vector control methods for PMSMs using an estimate of back-EMF are established under the assumption of constant speed or zero acceleration, consequently cannot operate properly at modes requiring rapid speed change especially in low speed region. On the other hand, the proposed back-EMF observer has the following features: 1) it is a new back-EMF state-observer taking acceleration into account and requiring no additional approximation to motor mathematical model; 2) it is a minimum order state-observer; 3) it utilizes motor parameters in the simplest manner; 4) it can be applied to both of salient-pole and non-salient-pole PMSMs; 5) it can be realized in both rotor and stator reference frames. Detailed designs and analyses for the improved state-observer and the sensorless vector control systems in both rotor and stator reference frames are given. In relation to the sensorless vector control systems, this paper newly proposes a double-integral type PLL method and an integral-feedback type acceleration/speed estimation method. Their potentialities are examined through experiments.

View full abstract

A double converter of modified three-phase bridge full-controlled rectifier with improved power factor is presented and analyzed for its commutation processes and operating condition. Both the mathematical model and the minimum inverting angle for safety commutation are derived. A comparison is carried on with the conventional twelve-pulse bridge. The waveforms and data tested from the experimental converter agree with the theoretical analysis.

View full abstract

This paper describes a direct-power-controlled current-source PWM rectifier, and presents its experimentally examined operation characteristics. The most important feature of this strategy is a direct selection of switching states of the PWM rectifier on the bases of instantaneous control errors of active and reactive power. In addition, this paper describes a theoretical analysis on relationship between the instantaneous power and the switching states, which is essential to compose a switching-state table in the controller. Feasibility of the proposed strategy is verified through experimental tests, using a 2-kW prototype setup. As a result, the maximum total input power factor of 99.86% and the maximum total efficiency of 92.72% have been confirmed in the tests as well as high-speed responses of the power.

View full abstract

A gap arrester is being used for ground fault protection in AC Feeding System. However there are faults in which a conventional gap arrester burns down in a normal state of circuit. We investigated the cause of the fault in which a gap arrester burns. Then, it was found out that the cause of the fault was the discharge of AC current from the surge voltage. Therefore, we developed a new type gap arrester which does not burn down. The new type gap arrester is composed of a discharge tube and a zinc oxide element which are connected in series. Unnecessary AC current discharge is prevented by this structure. The new type gap arrester is actually used at the railroad track.

View full abstract

In recent years, many WBT systems have been proposed and developed by the progress of computer networks. However, there have been a few WBT systems treating experiments and training. Therefore, our laboratory developed WBT system for logic circuit experiments. The WBT system has problems in instruction using a chat. Since the instructor always needs to monitor the student's wiring state, instructor's burden is heavy. Students and the instructor have to share the time for chat instruction. In order to perform more efficient study, the WBT system needs the environment that students can progress study without the instructor. The tutoring function instructs students instead of the instructor by appropriate advice using the student's wiring state. The tutoring function always monitors the student's wiring state. When the wiring state changes, the advice suitable for the wiring state is searched from the database, and searched advice sends to the student. There are two kinds of advice for the tutoring function, the advice prepared beforehand and the advice automatically generated from the chat log. The advice automatically generated from the chat log increases in proportion to the number of chat instructions. We implement the tutoring function, and evaluate the WBT system.

View full abstract

In this paper, we propose the getting up detection and report device which can be installed in middle-small facilities and ordinary houses. This device combines a mat sensor which detects rising and a power line communication (PLC) device as a reporting system. This device does not need any additional construction for installation as long as facilities equip electric power supply 100V for ordinary businesses. At first, the mat sensor in the system detects rising of an elderly person or lying down to bed. The PLC system sends ON/OFF signal and reports to nurses and staff members in their rooms. Since the main objective of the PLC system is to keep exact detection and transmission of the mat-sensor ON/OFF signal, high-speed network is not necessary. It is required that the system should be robust against noises of household electrical appliances. We used the selected-career method as a transmission method in which we located 2 lines of tone frequency (132kHz or 115kHz) for the power line transmission in the device. The effectiveness of the proposed device has been confirmed by the field experiments in welfare facilities for elderly people.

View full abstract

In the flip chip junction, void in the solder bump has serious influences on reliability and electric characteristic. In this paper, we propose an automated detection technique of micro voids in solder bump. The void makes hollow on the bump shape in X-ray image. We developed subtraction-based method by means of combination of morphology filter and image subtraction to detect the voids. Furthermore, we introduced noise elimination method using some void feature values and discriminant analysis. We evaluated this technique using simulation model and real bump. As a result, a correct rate reached 99.2%, which demonstrates this technique has very high detection ability.

View full abstract

In Japan, carbon dioxide (CO₂) emissions caused by vehicles have been increasing year by year and it is well known that CO₂ causes a serious global warming problem. For urban traffic control systems, there is a great demand for realization of signal control measures as soon as possible due to the urgency of the recent environmental situation. This paper describes a new traffic signal control for reducing vehicle CO₂ emissions on an arterial road. First, we develop a model for estimating the emissions using the traffic delay and the number of stops a driver makes. Second, to find the optimal control parameters, we introduce a random search method with rapid convergence suitable for an online traffic control. We conduct experiments in Kawasaki to verify the effectiveness of our method. The experiments show that our approach decreases not only the emissions but also congestion and travel time significantly, compared to the method implemented in the real system.

View full abstract

The position sensor-less drive technique based on the back electromotive force (EMF) has been widely used for brush-less DC motor drives. However, it is impossible to detect the rotor position at low-speed by using this technique. Therefore, the motor must be accelerated by the open loop based synchronous drive up to the middle speed. The open loop based synchronous drive extremely influences the motor performance. The torque pulsation and the over current can be occurred by using that.
This paper proposes a new start method for the brush-less DC motors. In this method, the rotor position can be detected the moment the motor is driven. As a result, the open loop based synchronous drive can be eliminated, rapid acceleration and high performance of the motor drives are achieved. Effectiveness of the proposed method is shown by experimental results.

View full abstract

A method to detect MURA, which is defined as irregular lightness variation on uniformly manufactured surface, is necessary to keep quality of the display devices. The MURA is inevitable matter for devices relating to image processing. Input devices, output devices and display devices have MURA of various levels which determine acceptance of device quality. We report the level of the contrast and resolution which is required to the MURA detection, through MURA detection of shadow masks as an example.

View full abstract

We have developed a stable control method for a large capacity tubular ozonizer. To make a high power factor operation, it is necessary to know the electric characteristics of the discharge phenomena of the ozonizer. In this study, we theoretically discuss the discharge stability with the consideration of the effect of the matching with the driving circuit, and successfully find the operation condition for a robust control of the ozonizer discharge. To make a stable control over a wide input power range, we invent a frequency variable control method, and proved the validity of the method by measuring the voltage and current waveform of the developed ozonizer system.

View full abstract

Hybrid magnetically levitated transportation system has been developed. The magnetic rail is set on the ground, and the carrier with permanent magnets and high-Tc superconductors (HTSC) levitates on the rail. In this system, pinning force of HTSC and repulsive force of permanent magnet is combined. Repulsive force of permanent magnet is introduced to support weight. Pinning force is used to support weight of the frame of the carrier and to achieve lateral stability of the carrier. To decrease influence of weight on the levitation gap of the carrier, the weight stage is fixed to the carrier frame by linear sliders, and moves freely for vertical direction. As a result, there is little influence on levitation gap of the carrier. Basic levitation and guidance characteristics of the system are shown. Repulsive force generates very large levitation force. It also generates unstable lateral force. Weight added to the carrier has some influence on lateral stability. Although lateral position recovery force by pinning effect decreases at a heavier weight, the carrier shows enough force to keep lateral stability.

View full abstract

A shaft generator system is widely used in a ship to provide sufficient power for the electric apparatus by using a part of the power produced by the main engine. We have already analyzed the steady-state characteristics and open-loop transient performances of the system. In this system, the output voltage and frequency should be kept constant. Hence, the closed-loop control systems for constant voltage and frequency of the system need to be investigated.
In this paper, transient performances of the shaft generator system for the case with closed-loop control system are analyzed first. The effects of the duplex reactor for eliminating the output voltage distortion and the controller constants of the system on the transient performances are clarified. Also, experimental transient responses are compared with simulated results. In order to give generality to the results, average constants of the shaft generator system are used in the investigation and the transient responses of the system with these constants are simulated. It is clarified that although the transient responses become oscillatory for the case with basic closed-control system, the responses are improved remarkably when the current minor-loops are incorporated into the system.

View full abstract

This paper proposes a new sensorless vector control method for salient-pole permanent-magnet synchronous motors. In regard to rotor phase estimation, the sensorless vector control method is featured by a new high-frequency voltage injection method distinguished from the conventional ones by a unique ellipse shape of the spatially rotating, and by a new PLL method whose input is a high frequency current auto-correlated signal. The new vector control method established by two innovative technologies can have the following high-performance and attractive features: 1) it can allow 250% rated torque at standstill; 2) it can operate from zero to the rated speed under the rated motoring or regenerating load; 3) it accepts instant injection of the rated load even for zero-speed control; 4) it accommodates a load with huge moment of inertia; 5) phase estimation is very robust against inverter dead time; 6) computational load for estimating rotor phase is very small, would be the smallest among the methods with comparable performance. This paper presents the new vector control method by focusing on two innovative technologies from its principles to design rules. Usefulness of the new vector control method is verified through extensive experiments.

View full abstract

We examined the claw type teeth motor as one application of the soft magnetic composite to a motor core. In order to understand quantitatively the characteristics of the claw type teeth motor, we used the 3-dimensional electromagnetic field analysis to predict its characteristics in advance and manufactured a trial motor to estimate it. And we examined the advantages of the claw type teeth motor comparing with a conventional slot type motor. The results are: 1. By using the 3-dimensional electromagnetic field analysis, it is able to estimate with high accuracy the characteristics of the 3-phase permanent magnet synchronous claw type teeth motor having a core composed of the soft magnetic composite. 2. The claw type teeth motor is able to achieve about 20% higher output than a conventional slot type motor having an electromagnetic steel core, while both volumes are equal. 3. The motor efficiency of the claw type teeth motor is about 3.5% higher than the conventional motor.

View full abstract

This paper proposes effective and practical design method of higher quality heating for induction-heating cooker. The IH cooker which has the simple pancake-shaped coil arrangement produces slightly nonuniform temperature distribution along the heating plate. The object of this research is to achieve the better heating performance by adjusting the arrangement of the coil. Easiness of coil winding is added to the evaluation basis. Eddy current analysis is made by the finite element method for calculating the heat distribution of the heating plate. After this, heat transfer analysis is made by the finite element method for calculating the temperature distribution of the heating plate. Multi-objective genetic algorithm is employed for obtaining the optimum arrangement of the coil. The two objectives that mean the uniformity of temperature distribution and the easiness of coil winding are both evaluated. By using the proposed method, we could obtain the expected coil arrangement easily. The temperature distribution approaches closer to uniform distribution by using the obtained coil arrangement which is not difficult to wind.

View full abstract

The immittance converter has the input impedance that is proportional to the admittance of the load connected across output terminals. Therefore, in this converter, the output current is proportional to the input voltage and the input current is proportional to the output voltage. Consequently, it converts a constant voltage source into a constant current source and a constant current source into a constant voltage source.
In this paper, we propose a new type immittance converter, named half-bridge type immittance converter, consists of a tapped transformer and a pair of L, C. The new immittance converter is developed from the hybrid type immittance converter, and has almost same characteristics of that.

View full abstract