Optical fiber cable for the broad bands communication is usually covered by plastic pipe and buried under the ground. Then, we are required to grasp its real buried position before digging at the construction or the maintenance in order to prevent from the cutting of the optical fiber cable. However, once the optical fiber cable is buried under the ground, it is very difficult to confirm the buried position of the pipe. This research aims to identify easily the buried position of the pipe, using the information of the buried position from the pipe. We use two rotary encoders that have pulleys contacting right and left walls of the buried pipe in order to detect directly the information of the buried position of the pipe. Output of the rotary encoder contacting the wall shows the length of the wall. Average of summation of the outputs of the right and the left rotary encoders shows moving distance of a surveying mechanism of the position surveying system. The curvature of the buried pipe is obtained by difference of the outputs of the right and the left rotary encoders. The position of buried pipe is identified by the moving distance and the curvature of the pipe. It is confirmed that the new position surveying system can identify the buried position of a pipe that is 20 m long and has loose curvature in the error of 5.9 mm.
This paper presents a novel particle detection method for evaluating a defect on patterned wafer surface by detecting “Scattered Evanescent Light Fringe Pattern (SELFP)”. In order to apply this optical measurement method to in-process measurement at high speed, scanning measurement is proposed. The scanning measurement process is performed by identifying defect position and evaluating SELFPs. The scanning basic experiments are performed using a tip of AFM probe with the size of 110nm. It is found that P-polarized evanescent light is better applied to illumination light than S-polarized evanescent light and that the defect position can be identified according to the peak value of intensity variation at scanning area. The measurement of defect with a size of 170nm on the patterned wafer surface comprising about 180nm Half Pitch is conducted, under the condition that illumination light has P-polarized evanescent light. The results suggest that the proposed scanning method can be effective for in-process measurement.
The multi-probe scanning method has been researched widely for evaluating the profile of large size ultra precision specimens. Several data processing methods, such as inclination method, integration method and combination method, etc. have been developed using two or three-sensor measurement systems. In this paper, the spatial frequency domain 2-point method, which combines two data sets of 2-point method with different sensor intervals, is discussed. Firstly, the algorithm of the two sets of 2-point method is introduced without considering the systematic and random error. Then, the influence of the systematic error is analyzed and an accurate software calibration method of the systematic error is proposed in the presence of the systematic and random error simultaneously. The uncertainty of evaluated profile is also estimated quantitatively after calibration. Although the uncertainty is introduced by both the random error and the systematic error, it is shown that its result is only decided by the magnitude of the random error. Simulations are performed to confirm the theory analysis finally.
In order to inspect the strength and reliability of structures, measurement using a strain gauge is widely adopted. However the measurement of real structures using a strain gauge requires dangerous preparatory work such as fixing strain gauges onto the structure and connecting them via cables to strain meters located in a remote place. Moreover, strain gauges detect strain only at the points where they are attached. Therefore there is a growing demand for a more reliable and accurate strain distribution measurement of structures. The purpose of this study is to develop a strain distribution measurement system based on the sub-pixel digital image correlation (Sub-DIC) method. However, the Sub-DIC method has several problems concerning accuracy; an out-of-plane deformation of structures has an adverse effect on the measurement accuracy. In this study, the effect of the out-of-plane deformation is taken into account. We formulate a model of the out-of-plane deformation, and discuss the effect of the theoretical equation given on the strain measurement accuracy. Furthermore, we show the effectiveness of the theory by a model experiment. Moreover, a compensation method for the out-of-plane deformation is proposed. It is found that the Sub-DIC method with the proposed compensation system is superior to existing strain distribution measurement systems, on the basis of a series of experimental examinations using the four-point bending test.
This paper addresses Scanning Electron Microscope (SEM). There is the quality problem that the image noise caused by the acoustic noise disturbs observation for correct shape of the specimen. Thus, SEM be less influenced by the acoustic noise is expected. This paper approaches to this image noise problem from the mode shapes of the base plate, and the transmission path of the acoustic noise and vibration. Firstly, the mode shapes of the base plate with conventional rib are compared to those of the plain base plate, and no remarkable increase in natural frequencies and no change in mode shapes are shown. Secondary, new base plate, which has two twisting mode as 1st and 2nd mode by arranging position of the rib, is developed. In those two twisting modes, vibration amplitude around the center of the base plate is smaller than that in bending modes. Thus, less vibration is transmitted to the specimen chamber and to the specimen in twisting modes than bending ones. Finally, the developed base plate is assembled to SEM, and remarkable reduction of the image noise under the condition of the acoustic noise below 250Hz is shown. This base plate has already applied to the products on the market.
In the previous paper, the authors achieved a 3D motion capture system by using one camera with triangle markers, named as Mono-MoCap (MMC). MMC has two features. One is that MMC can measure 3D positions of subjects by using one camera on the basis of the perspective n point (PnP) problem. Another is that MMC does not need to recalibrate the camera parameters. In this paper, the authors apply MMC to binocular stereovision system for expanding its measurement range. Stereovision system can not measure 3D positions of objects when even one camera does not capture the objects. Experimental results show that the proposed method is effective for expanding of the measurement range of the parallel binocular stereovision system.
This paper describes a new approach for detecting image rotation angles with a high accuracy. Frequency amplitude distributions of input and reference images are transformed to the polar coordinate expression and then the position shift between the polar spectra is detected. In the shift detection, weights depending on the frequency and the amplitude at each frequency are used to precisely calculate the shift. In experiments, four types of synthetic and real image patterns were used as reference images. The average and standard deviation of absolute errors for the rotation mode where synthetic reference images are synthetically rotated are 0.007 and 0.0048 degrees, respectively. Those for other modes where real images are rotated synthetically or with a mechanical stage are within 0.004 and 0.003 degrees, respectively.
Tip of thin tungsten electrode is transformed into a thinner, needle-like shape in single, high current discharge of some tens of amperes and a few hundreds microsecond duration. This self-sharpening phenomenon has been studied by a newly designed, home-made stroboscopic imaging system, which is constructed from a fast CCD camera and a high repetition rate, short pulse laser as an illuminating light source. Using this imaging system, one hundred pictures at 16 or 64 microsecond interval were taken in one discharge event. From these images, we could observe temporal change of the electrode shape during and after the discharge. Special attention was paid on movement of the molten part at the electrode tip. The upper position of the melt part climbs up along the electrode at constant speed after the discharge ended. The move continues for more than one hundred microseconds after the discharge. It is highly probable that the surface tension of the melt is the source of that movement. Based on our observed results, a model of self-sharpening phenomenon has been proposed.
Needs of digital devices are increasing rapidly in recent years, and the demands of a micro Fresnel glass lenses are increasing especially in a DVD pick-up and dark field systems for automobiles. The glass lenses are molded with a glass press molding process with micro ceramics molds and dies, and then ultra-precision grinding technology of ceramic molds and dies becomes to be a core technology. Authors have successfully developed the simultaneous 2-axes (Y, Z) controlled grinding method, and it was clarified that ultra-precision micro Fresnel shape could be ground using a diamond wheel with sharp edge. In this paper, in order to improve the form accuracy, a new truing method with rare metal truer is proposed and the effects of the molybdenum truer are tested. Finally, with the developed truing system the micro diamond wheel was trued, and an aspherical mold of Fresnel glass lens for infrared DOE is ground to evaluate grinding performances.
A study on life distribution and reliability for a roller guide with cage type is carried out with total number of 90 test samples of two lots (Ns=38 and 52) and fatigue life distribution functions, such as two and three parameters Weibull distribution and log-normal distribution, are used for discussion. The basic dynamic load rating formula standardized by ISO in 2004 is also compared with the life test data in relation to the effect of crownings of carriage raceway end portions. As a result, (1) the best fit for the life test series is obtained by 3-parameter Weibull distribution introduced a minimum life as a third parameter, having Weibull slope m=27/20 and load life exponent p=10/3, followed by the log-normal distribution as second, and 2-parameter Weibull distribution as the third. (2) The 2-parameter Weibull distribution with Weibull slope m=9/8 as used in ISO linear bearing standard dose not fit with the experimental results. (3) The fatigue failures of roller guide is initiated near the crowning start points of carriage raceway both end portions, and almost 70% of test specimen are uneven and inclined contact situations of rollers. (4) The basic dynamic load ratings between theory and life test result fit well each other, and λbm factors are also fallen into suitable value range.
This paper presents a smoothing method for a triangular mesh with feature preservation. In order to obtain a smooth surface from a scanned mesh where noise is contained because of measurement errors, we developed a feature preserving smoothing method. At first, we simplified the scale-dependent discrete Laplacian and defined boundary Laplacian to deal with an open mesh. Then, a method for feature detection is constructed. Furthermore, utilizing this feature detection method to determine a suitable parameter, we have developed a feature preserving smoothing method based on anisotropic diffusion. Vertices that consist the feature lines are detected by our feature detection method, and smoothing is conducted for the whole mesh including feature lines. We demonstrate the presented method and the results give a well-smoothed mesh with its features preserved.
Manufacturing feature is key information to achieve data sharing between CAD and the following manufacturing process. It is well known that the data of the feature is first generated by feature recognition from CAD geometry, and then applied to the process planning. Our study has examined the process planning based on Feature Dependency and have demonstrated the way to create and implement the feature dependency. First report demonstrates that representing the feature dependency which contains feature hierarchy when applying the data to the process planning leads the following process to be more efficient and accurate. In the second report, features including division and/or unification, i.e. dynamic feature, are discussed. Previous two papers focus on the features which have explicit relationship with geometry, i.e. explicit feature, are discussed. In this paper, feature dependency that has no explicit relationship with geometry, i.e. implicit feature, such as a thread, surface finish, removal thickness and finishing allowance are also discussed and the method of integrating explicit features and implicit features into one feature dependency is introduced.
In recent years, to meet demands for high efficiency, the use of concentrated winding motors, in which the coil is wound around every magnetic pole tooth, has increased. By using a separate core structure, the coil fill factor of the motor, and the motor efficiency per unit volume, are improved. However, since the assembly error is large compared with non-separate cores, a separate core can produce an imbalance in the flux distribution during motor rotation and cause cogging torque to increase. Usually the core assembly precision is determined by the circularity of inner core, however, it is difficult to predict the cogging torque of a separate core from its circularity because the circularity does not correlate well with the cogging torque. So, in this paper, with reference to the inner core shape, one or several points of deformation were intentionally introduced and the relationship with cogging torque was investigated. Consequently, it became clear that cogging torque caused by the inner core shape is the main component of cogging torque. Moreover, it turned out that cogging torque when there were several points of deformation was the vector sum of the cogging torque resulting from each one. From these results, a new evaluation method which predicts the cogging torque more precisely than evaluation using the circularity of inner core has been established. Furthermore, a new core, which we call a “joint-lapped core” is proposed as a core structure which can reduce cogging torque. Because the joint-lapped core was made by a press, similar to a conventional cylindrical core, the circularity and the cogging torque of the joint-lapped core were the same grade as non-separate cores.