Reuse of mechanical parts is required to reduce the environmental load of the products. However, the unpredictable wear of the reused parts may increase the number of the defective products. This causes the difficulty of design when planning the product suitable for reuse. To reduce this difficulty, we propose a simulation method by integrating the wear information with tolerance analysis. The method calculates probability distribution of dimensions of worn parts based on the wear information of parts. The quality of assembled products can be predicted through the simulation. Experimental software is developed based on the method and results on an example of simple mechanism show its effectiveness. A strategy how worn parts should be used is also discussed based on the simulated results.

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Equi-density surface like MetaBall is widely used in Computer Graphics so far. In this paper, we describe Sphere Density Method, a new equi-density method to represent shapes for industrial design. It uses skeleton for the base shape to control the result shape. Though the skeleton is restricted to a closed shape, it can include not only planes but also surfaces like NURBS. Therefore Sphere Density Method can generate a shape using the solid models represented by B-reps in any CAD system as a skeleton.
And we can constrain a part of the shape by the Sphere Density Method while manipulate the other part of the shape. Constraining the shape is the important advantage of this method to use in industrial design area.

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This paper presents color uniformity evaluation model based on color contrast effect for electronic displays. Inspectors in production lines perform the evaluation, but the results depend on persons doing the inspection. In order to realize automatic evaluation, accurate evaluation algorithm that includes color contrast effects among color defects is strongly expected. The experiences of inspectors are analyzed, and some knowledge of color white uniformity inspection is introduced in this new evaluation model. In the new evaluation model, the total uniformity of a display consists of two kinds of effects. They are the effect of each color defect region itself and the mutual effect of color contrasts among defect regions. The relation of compensation colors makes the defects more noticeable. Pseudo color defects that hues and saturations are different are displayed on a CRT monitor. Human evaluations are performed by paired comparisons method. The human evaluation results were put in the equation of the evaluation model, and the coefficients of the equation were determined by the results of regression analysis, and the validity of the new white uniformity evaluation model was verified.

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This paper proposes a method to detect rectangular objects that have free sizes, aspect ratios, locations and inclinations in a scene image. The positions of candidates for vertexes of rectangular objects are measured by the combinational Hough transform that uses the geometrical features of a pair of edge pixels. Each rectangular object is detected by evaluating the geometrical relations between the candidates for vertexes. The experimental results show that various rectangular objects with free sizes and free poses were detected successfully in gray-scaled images by the proposed method. The proposed method is supposed to be useful for practical applications because it has good reliability without large computational cost.

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A practical cooling ability of air spouted out of C-D nozzle is evaluated on a simple model for heat transfer analysis. An average heat transfer coefficient of the air measures h_Ave=1540W/m²K in range over 1βz/L_PCβ2 independent of nozzle configuration and conditions of supplying air to the cooling area under the correct expansion condition. Cooling air from the C-D nozzle installed at the optimum position z/L_PC=1 maximizes its cooling efficiency around grinding point. Practical Nusselt number Nu of the air is also correlated with Reynolds number Re at the exit part of the C-D nozzle to predict the cooling ability in the case of arbitrary supplying air conditions. Surface temperature on work-piece being ground by supplying cooling air is measured to clarify usefulness of practical cooling air grinding. The surface temperature is compared with that by supplying conventional used grinding fluid. The primary consideration shows that the cooling air, Nu of which is above 306, should improve its cooling ability and can cool the grinding point more than the conventional used grinding fluid does. The optimum supply condition of the cooling air is experimentally verified.

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In through hole drilling of hard and brittle materials such as ceramics, glass etc., cracks occur at the exit surface. This paper deals with a miniature drilling of Al₂O₃ (1600HV) using an electroplated diamond tool. The main purpose of this research is to find out tool geometries and drilling conditions in which the exit cracks are very small and the tool life is very long. A tool with rectangle section and bowl end is effective on the chip removal and the control of fracture size. A method assisted by step feed, in addition, produces a numerous drilling number of 100th or more at a workpiece with a thickness of 3.4mm. The desirable drilling speed should be 50-100m/min and the preferable feed rate arrangement should be 5mm/min at the entrance while 1.5mm/min at the exit. When the tool end reaches the position about 40μm from the exit surface, a hole passes through and large cracks occur around the hole. At the same time, the thrust force falls rapidly. As the tool end moves further, the hole diameter increases and the fracture size decreases. However, large cracks may occur rarely in the progressive process.

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In Chemical Mechanical Polishing (CMP), pad conditioning is a very important technique. Chip Manufactures have problems with semiconductor wafers getting scratched by diamond fragments and slurry waste particles on the surface and inside the pad. Fragments in the pad cause pad life to be too short. In this report, we will mention the development of a new cleaning system that uses water in a high-pressure micro jet system (HPMJ), which controls the kinetic energy of the droplets to solve these problems. We measured the velocity distribution and the size distribution of the fluid droplets sprayed from the HPMJ. The kinetic energy of each water droplets was calculated from velocity, droplets size, and flow rate within the sprayed pattern. Further more, we have confirmed the kinetic energy result by studying the effect of the HPMJ as a conditioning tool on an unwoven fabric polyester type pads and a bubble urethane type pads that are widely used in CMP process.

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A new system, which can simulate the cutting process with a variety of tool shapes such as the chip breaker, was developed. This developed system is composed of tool model making module, cutting simulation module and GUI module which helps to carry out the simulation. Frictional boundary condition on the curved rake face is also formulated and it enables to simulate the cutting process of various type of tool with chip breaker. It was shown that the chip curl state, chip flow, cutting force, temperature, and residual stress/strain could be predicted. It was also shown that the favorable cutting state is realized when the tool-chip contact length is suppressed effectively and the chip exhausts smoothly.

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On the working surface of grinding wheel, dulling, loading and shedding occur in complicated way with progress of grinding. In this paper, we propose the novel evaluation method to separate those complex changes into the typical changes such as shedding, depositing and welding types of loading, and dulling definitely. Furthermore, in order to examine the validity of the method, the grinding experiments is carried out, and then following results are obtained: The relative frequency distribution derived from the peak height of the working surface profile generates peculiar changes as follows with same sensitivity to the typical changes respectively. The two types of loading decrease the relative frequency of the distribution at inside of the wheel and increase it at periphery. Contrary to this, the shedding and dulling increase the frequency at inside and decrease it at periphery. In addition, the dulling and welding type loading only vary the distribution at narrow region of the wheel periphery. On the other hand, the shedding and deposition type loading vary the frequency almost whole region of the wheel. From above mentioned results, it can be said that the complex changes of the working surface condition can be separated into the typical changes based on the width and central position of changing region and order of increase and decrease within the region in the peak distribution.

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Equipment that uses a wire and an acoustic emission sensor in measuring the form of a ball-end mill on a computerized numerical control milling machine is developed in this study. The contact between the wire and the cutting edge of the ball-end mill is detected by sensing the AE wave caused by the cutting of the wire. The use of the wire as a line-type stylus rather than as a pin-type stylus, makes it facilitates the reestablishment of the contact point when the stylus generates scratches. Therefore the measurement of the profile of the rotating cutting edge can be continued in spite of wire damage. In the trial, the new equipment measured the radius, circularity deviation and coordinates of the center of the point of the ball-end mill. It was confirmed that the equipment can measure the form of a ball-end mill as precise as the copying method.

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The present paper deals with the LD-pumped YAG laser processing technique for transparent conductive oxide, which has been used in solar cells as a transparent electrode. The effect of pulse width on damage caused to the glass substrates is investigated theoretically and experimentally. And then laser power and the distance between focal point of the lens and the substrate (defocused distance) are investigated. It is found that LD-pumped YAG laser, which has a short pulse width, can be used to pattern SnO₂ without damaging the glass substrate. And the characteristics of the machined groove can be changed by changing the laser power and defocused distance. Consequentially, a high quality groove, which has high electrical resistance and aspect ratio, can be obtained.

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Real-time motion error correction of a rotor driven by a non-contact ultrasonic motor (non-contact USM) was achieved. The rotor is installed in the cylindrical stator with a small gap designed to have a resonance frequency of 23.9 kHz at the 8th flexural mode of vibration. The multi-layered piezoelectric actuators excite the flexural wave traveling in the circumference direction. The ultrasonic vibration produces a sound field to levitate the rotor and the traveling wave induces near-boundary streaming to rotate the rotor by viscous force. Herein, we report the experimental performance of the non-contact USM. When the amplitude of the flexural vibration was 0.3 μm, the rotational speed was 4 rpm. The rotational speed and starting torque were proportional to the vibration amplitude. The staring performance of rotational speed was consistent (time constant = 2 sec) for various vibration amplitudes, hence the rotational torque is independent of the rotational speed and the resistance forced on the rotor is governed by viscosity. In addition, the non-contact USM allows contact-free micro positioning of the rotor by control of the deformations of the piezoelectric actuators. A PI controller was constructed to compensate the detected motion error of rotor in the radial direction. As a consequence, the motion error of 0.8 μm for a rotor revolution was reduced to within ±0.1 μm.

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This paper proposes a reinforcement learning system that uses fuzzy ART neural networks for segmentation of state space. One of the problems in reinforcement learning with a real robot is to need a large number of trials. In reinforcement learning, some efficient method for the state-space segmentation is necessary to improve the learning quality and to reduce the learning time. By using an incremental state-space construction method with fuzzy ART neural networks, we are able to economize the software resources and reduce learning time. Whenever the fuzzy ART neural network encounters a new situation, it adds a new category unit to the state-space. We propose adding methods of a new category unit that inherit the state-value and the policy from a similar unit. This system estimated from simulation of a two-link robot and experiment of a multi-link mobile robot. It is shown that the state-space has become small and the learning time has decreased.

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This paper describes the method of measuring a point on a three-dimensional space with a stereo camera using geometrical invariants. An affine invariant and a projected invariant are used as geometrical invariants. The measurement space is sandwiched by two planes which consist of eight points. The eight points are called reference points. The process of measurement is as follows. The geometrical invariant is calculated from the reference points on the images. The geo-invariant is applied to the reference point three-dimensional space, and the three-dimensional point is set on the two planes. The measurement point is calculated using the points set on the reference planes. The experiment is performed using affine invariants, projected invariants, and camera parameters which are calibrated as a stereo camera system. The conclusion of the experiment illustrates that by using projected invariants the same results as when using camera parameters can be found.

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[in Japanese]

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