On the precision positioning device of semi-closed control type which is driven by a ball screw, the expansion of the ball screw generates the positioning error of the stage during the stage repeated movement. The expansion is mainly caused by 2 heat sources of relative rotation of the ball screw/nut and angular ball bearings which support the thrust and radial force of the screw. In this study, the expansion measured by a gap sensor at the ball screw end is fed back to Peltier module to cool the screw/nut. Other Peltier modules cool both sides of housing made of pure cupper of large thermal conductivity to keep the housing temperature at the room temperature of 20℃. The angular bearings are cooled through the housing. At the same time, the datum point of minute displacement in the longitudinal direction of the device is corrected by the Peltier modules indirectly. As a result, the expansion of the ball screw in length of 400 mm is reduced from 18 µm under the repeated stage movement of 150 mm/s to 1 µm.

抄録全体を表示

Rolling elements are widely used due to their low friction properties. However, it is not easy to observe whole cylindrical surfaces with an optical microscope because they are out of plane. In a previous study, we could observe whole cylindrical surfaces in a very short time with the wide-field laser microscope we developed. The confocal scanning laser microscope can produce clear, high-contrast images because the reflected laser light comes from only a laser-irradiated point and there are no stray lights from other points than the laser-irradiated point. However, inner surfaces of cylinders are more difficult to observe than the outer surfaces of cylinders. Cam surfaces are not perfectly cylindrical and are also difficult to observe. In this study we tried to acquire surface images of such inner surfaces and cam surfaces. The inner surface of cylinder and the cam surface could be observed with the aid of a 45-degree inclined mirror and two motor driven linear stages respectively

抄録全体を表示

A new design method for a refractive-type laser beam shaper with an asymmetric shape is proposed. This beam-shaping technique is useful in pattern marking (e.g., logo marking or character marking), and also in local heat treatment. These applications could be realized using high-power lasers with beam intensity converters. A refractive-type shaper is superior to a diffractive-type shaper for these applications because of its lower optical power loss and simple fabrication method, which involves only conventional machining processes such as milling, grinding, and polishing. For a desired beam pattern, the shaper form is designed automatically using iterative calculations by applying the behavior of electrically charged particles. The beam elements are assumed to possess the same polarity of charge, which generates a repulsive force depending on the intensity of electric charge and distance between elements. Furthermore, the desired pattern elements are assumed to possess contrary polarities, so that every beam element is effected of attractive force from all desired pattern elements. For no optical path crossing, the adjacent relations of elements are maintained throughout iterations. This design method was verified via testing in order to redistribute uniform collimated radiation into a single focused point. As a result, a paraboloidal surface was obtained, which performs the same function as a convex lens. Furthermore, the marking function was demonstrated by redistributing the character string “CIT” with 10,000 elements; the light pattern of the string was observed by the shaper.

抄録全体を表示

In Japan, aerial cables in residential areas are complexly installed. In addition, aerial cable heights change as time passes. Therefore, the aerial cable heights must be regularly maintained. In recent years, the Mobile Mapping System, which is equipped with a laser scanner, has been used to capture geospatial point cloud data, including aerial cables. The mobile mapping data include over 100 million points. Thus, a technique that automatically extracts aerial cable data from the large mobile mapping point cloud data is very important. In this paper, we propose a new method for automatic aerial cable data extraction that considers the position of power poles and local linearity of cables. Our method can extract data of cables that are complexly and closely installed in residential areas. The evaluation test result of our method shows an extraction accuracy of 76.9%. In this paper, we describe the detailed method and the evaluation test result.

抄録全体を表示