Many researches have proven that the vibration signal of rolling element bearing can be considered as a kind of cyclostationary signal (CS) since its periodically time various characteristics especially when fault occurs. In this paper, the basic theories of second-order cyclostationary signal processing is introduced. Then, a method so called slice analysis based on spectrum correlation density function is proposed, and it is employed in fault feature extracting to the vibration signal of rolling element bearing. Simulation and application results demonstrate that the slice analysis method is available and effective in fault diagnosis of rolling element bearing.

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This paper describes the trend of inter national standards for condition monitoring and diagnostics (CMD) of machines by ISO/TC108/SC5. Some typical standards of CMD are introduced in this paper include the standard for training and certification of personnel of CMD engineer. JSME established the certification system of vibration CMD engineer.

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We have developed fiber optic strain and vibration sensors (FOSVS) suited for simultaneous monitoring of strain and vibration. A fiber optic gap sensor made of two optical fibers, a broad-band light source, two photo detectors and an FBG filter were used to compose the sensor system. The gap sensor was composed of two fibers. One of them fixed like a cantilever beam. The axial displacement of the sensor was measured from the reflected interfered signal. The amplitude of the transmitted signal through the reflector fiber was used to measure the transverse vibration of the cantilever fiber. The sensor was applied to measurement of quasi-static tensile strain, vibration under tensile strain and bending vibration. From the experimental and theoretical results, it appeared that the FOSVS could measure the axial strain and the transverse acceleration correctly. Furthermore, from bending vibration test, it was found that FOSVS could measure strain and vibration simultaneously.

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Chain Curing Polymers (CCP) cured with ultraviolet rays have many advantages over heat-cured polymers. Especially, an energy saving feature is remarkable. But it is not easy to know whether they have cured completely, because the temperature is governed by the heat generation during chain curing which can't be controlled directly. Cure monitoring is one of the best methods to solve this problem. In the present study, a cure monitoring method using optical fibers embedded in the polymers has been proposed for CCP. In the monitoring method, the refractive index of resins which changes during cure process is measured and the cure progress is monitored. The cure monitoring experiments were performed for CCP and the obtained results showed that the proposed method was promising for its cure monitoring.

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The objective was to apply a structural health monitoring concept to detect loosening of a bolt without human involvement. The smart washer has with a part of the cantilever is able to detect the bolt loosening by using flexibility of cantilever and self-sensing/actuation function. The precision in case of the bolt loosening detection is necessary to confirm the influence of the temperture variation in the environment. Experimental results were shown about the influences of frequency characteristic depending on the temperature changing in this paper. This paper proposes a design method of the smart washer by using ANSYS, due to the smart washer is not yet enough to detect high sensitively the loosening.

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Time reversal processing for the measured sensor signal can be applied to detect not only structural damage but also impact loading of the structure. After measuring the electrical sensor signals corresponding to scattered wave filed of the plate in experimentally, the time reversal processing is applied to the measured signals in the numerical wave back propagation simulation for localizing the impact loading point on the plate. The time-reversed wave travels back through the plate and is focused on the region around a point where hit by the impact hammer. Effect of the number of surface bonded piezoceramic sensors on the quality of the impact identification is experimentally investigated here.

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Authors show the wireless sensor network system was for diagnosing facility. If the general wireless sensor network system is applied for facility diagnostic, many problems arise about communication distance, interference, data lost and power consumption. This system realizes long-range communication, high reliant communication, low power consumption by specified low power radio module and sleep function.

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Milling is one of the most important metal cutting processes. If we measure the cutting force, we can make cutting process optimum, prevent tool breakage, and improve efficiency of process. Especially, in the case of using an end mill with small diameter, it is very difficult to identify whether cutting process is good or not. In this paper, we proposed the cutting force measurement technique by using image processing. In the technique, we captured the image of the end mill during cutting process, determined the deflection of the tool and finally estimated the cutting force. Proposed technique can be applicable for any small size end mill and did not disturb the cutting process.

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The authors have endeavored to newly develop a monitoring technology used for detecting abnormalities in machinery at an early stage during which signs of abnormality appear, and for promptly determining the cause of abnormality. A technology verification test was practiced using the Mahalanobis-Taguchi System, which is defined as a multivariate data analysis technique. Based on measurement data obtained from a simulator, the individual characteristics of data gathered under conditions of normal, rated operation and data gathered under abnormal conditions were analyzed and evaluated. As a result, it was confirmed that all verified abnormal conditions can be detected during the stage in which signs of abnormality appear. It was also found that all abnormal conditions can be detected before the simulator gives off an alerts indicating an abnormal level ; and, in the case in which the simulator does not give off an alert, the proposed early detection technique can be used to detect problematic conditions deviating from those of a regular, normal state.

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In the present maintenance system for cogeneration systems (CGS), simple diagnosis techniques are often used. To operate the CGS with higher reliability and efficiently, an advanced diagnosis system is required. One of the techniques for an advanced system is model based diagnosis, in which system load and outside air temperature etc. are taken into account and the location and the type of trouble can be identified. In this paper, we built the CGS model including thermodynamic and kinetic characteristics, and proposed a diagnosis technique by identifying characteristics of systems.

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Differential pressure transmitters with an orifice are widely used as a reliable flowmeter in process industries. The most frequent problem with this type of flowmeter is blockage in impulse line: it causes a severe deterioration of measurement accuracy. Hence, this paper develops a new detection method of impulse line blockage with digital differential pressure transmitter in a steady-state steam line. This method, which utilizes inherent pressure fluctuations of the steam line, consists of two functions: (i) detecting impulse line blockage by evaluating standard deviations of differential pressure, and (ii) specifying which side of impulse line is blocked from the phase difference between two impulse lines.

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This paper proposes torsional vibrations of the loosened clearance problem in coupling and joint for a rotating shaft system. When the coupling and joint are loosened due to deformation, or wear and tear, the torsional stiffness of the rotating shaft may be assumed by a bilinear model for the clearance in coupling and joint. To make researches into the vibrational phenomena of the system, bilinear spring stiffness models are developed. The dynamic behavior of this system is investigated by using a numerical simulation. The possibility to detect the loosened clearance is studied by using nonlinear vibration analyses of the system in this paper. The investigation is based on frequency response, time response, bifurcation diagram, FFT, phase plane diagram and Poincare map.

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The authors have studied the applicability of the AE technique for detection of abnormalities in sliding bearings in a hydraulic power generator. The results of the experiment revealed that the AE method is effective for identifying the status of the lubricant film of sliding bearings with a superior sensitivity as compared to other kinds of diagnosis techniques. Furthermore, the integrity of the sliding bearings can be evaluated through definition of the detected AE signals as the amount of characteristics.

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This study is that it watches operating state of the fishing boat engine and diagnoses the condition as a torque rich operation. The combustion analysis in a torque rich was done by first using the heat release rate for that. Next, to detect a torque rich, the analysis that used the performance data of the engine was done. In addition, the method of detecting a torque rich in handily and high accuracy based on the vibration acceleration in which a single acceleration pick up was able to be installed in the surface of the a cylinder head was examined.

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The purpose of this study is to develop the monitoring and diagnosis methods for distributed energy system using fieldbus technology, which makes it possible to share much information of field devices. The authors constructed an experimental apparatus of a hot water supply process, which is one of the key components of distributed energy systems. The targets of abnormal conditions are not only air accumulation, which was also the target of previous works, but also drain accumulation in the shell. An algorithm of the process diagnosis based on monitoring process values and device operating conditions using the statuses in FOUNDATION fieldbus is developed and its effectiveness is confirmed experimentally.

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So far the authors have presented a technique for detection of breathing cracks in a beam. The presented technique uses the incremental transfer matrix method. In some cases, due to the problem in treatment of the opening and closing condition for a breathing crack, the incremental transfer matrix method can not analyse a cracked beam. In this report, a detection technique which uses the finite element method based on the mixed variational principle instead of the incremental transfer matrix method is proposed. In the proposed technique the opening and closing condition for a breathing crack can be treated without any problems The applicability of the proposed technique is presented via numerical simulation.

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A simplified and practical method of evaluation of the local bending flexibility of structures employing the measurement of angular rate is presented in this paper, by making an approximation of the previously proposed concept of local flexibility index. Experiments using a desktop-scale test structure are carried out to show that the proposed algorithm can detect the extent of the local damage that does not affect the global feature such as natural frequencies. Because the proposed damage index is evaluated from dynamically-identified mode shapes without calculating mass-normalization constant, this methodology can be realized by installing two or three gyroscopes and accelerometers per one location of interest, not deploying many sensors throughout the whole structure. This would be advantageous when considering the implementation of this algorithm in the wireless sensor network environment, so that the progress as a distributed computing structural health monitoring strategy is expected in the future.

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In metallic surfaces, highlights are very strong and light shape is often observed as a specular reflection. A number of methods have been proposed to remove or reduce specular reflection components of inhomogeneous objects and quite a few methods are applied to metallic surfaces. This paper presents a method that can reduce specular reflection components of metallic surfaces. A set of real images are taken in various lighting conditions and Photometric Linearization method is introduced to control diffuse reflection components as well as reducing specular reflection components. It separates specular reflection components and converts input images to imaginary images that contain only diffuse reflection components. The experimental results show that specular reflection components can be effectively reduced in realistic images of metallic surfaces using this technique.

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In this paper, considered the judgment standard value in the rotation machine which was operation with an actual petrochemical plant by the thing to analyze the distribution of the normal value data of 20 years or more. The following matter was clarified by this research. That is, (1) An standard value of the vibration of the rotation machine showed the thing assumed to be a standard value with high accuracy by the thing calculated from the rotational speed, the motor output, and the axis diameter. (2) The standard value calculation type with high accuracy was shown compared with the law so far by the thing to use the multivariate analysis. (3) It did not depend on the rotational speed, the motor output or the axis diameter, etc., and assuming it was constant touched an absolute value standard value of the speed value about the possibility that management with high accuracy in the real operation was able to be done. Moreover, the standard value was 3.2mm/s.

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Environmental concerns have increased demand for induction motors with low noise characteristics. Electromagnetic noise has been a particular concern. In this study, the relationship between electromagnetic noise and temperature was analyzed quantitatively. It was found the relation of electromagnetic noise and temperature as follows. In temperature 20-70℃, noise level does not varies, but in temperature 70-140℃ noise level decreases drastically by 6dB (A) at first and then increases by 3dB (A). Natural frequencies of 273Hz and 350Hz appear at 20℃, and two natural frequencies unites at 70-140℃ in the experiments. A two-degrees of freedom system with core and coil end considering temperature effects was used for calculation of natural frequency. These calculated values agreed with experimental result. The relation between variation of natural frequency and temperature in

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The object of this study is to investigate an on-board diagnostic method to detect the deterioration of a three-way catalyst under actual vehicle operating conditions. For this purpose, we analyzed the signal waves generated by two oxygen sensors placed on upstream and downstream positions of the catalytic converter. Transient operation experiments were carried out using engine dynamometer system equipped with a fresh catalyst or an aged catalyst. The signal data of two oxygen sensors were processed by the fast Fourier transformation method. As a result, we found that the difference between the power spectrum of the upstream oxygen sensor signal and one of the downstream oxygen sensor signal, which was named the Δ Power, is effective index for the detection of deteriorated catalyst under acceleration conditions.

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[in Japanese]

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