Forcefree control is a kind of robot arm control method as if it existed under non-gravity and non-friction conditions. In this paper, the forcefree control with independent compensation was proposed, in which inertia, friction and gravity torque were compensated independently. The proposed forcefree control with independent compensation was assured by simulation and experimental results. Furthermore, experimental results of pull-out-work and direct teaching of an industrial articulated robot arm were shown as applications of the proposed method.

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Electro-magnetically enforced rotary barrel finishing system has been developed for finishing rectangular quartz crystal blanks into lens-like shape (bi-convex). In our previous works, the fixed abrasive method, in which abrasive papers are used instead of powder abrasives, has been introduced as a new finishing method for fabricating the bi-convex type rectangular quartz crystal blanks. Our previous works also have shown that, the use of the fixed abrasive method make possible to realize accurate shape transferring, dustless clean working environment, and shortening process time (20 hours for complete shape transferring). In this paper, we have developed an electro-magnetically enforced rotary barrel finishing system for finishing the rectangular quartz blanks into bi-convex within a shorter process time. It can be reasonably expected that the use of electro-magnets generate additional machining pressure, and enable to further shorten the process time. As a result, almost complete shape transferring has been realized by 9 hours processing, which corresponds 45% of previous process time. Shape and frequency responses of the fabricated resonators have also been measured and discussed.

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Spin angle controlled ball lapping method developed recently, is to have an excellent performance to finish the ball, in which V-groove lapping plate is separated into two parts and three plates are able to rotate independently. However, lapping of ceramic ball such as a silicon nitride one is very hard. Present paper focuses on both of the grinding characteristics and polishing ones of a silicon nitride ball. Grinding is conducted using the diamond wheels with grain size degradation, and then polishing is performed with very fine diamond of average grain size of nano-meter. It is found that the grain size degradation grinding method has very effective performance of finishing of the silicon nitride ball. Polishing of the ceramic ball with slurry mixed super fine diamonds into an ion-exchanged water yields higher decrease of nano-meter level of surface roughness. Spin angle controlled finishing method describes that higher finishing performance rather than conventional one.

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This paper deals with controlling approaching and escaping paths for the fixed circular machining pattern on NC machine tools. Recently accuracy of circular motion on NC machine tools has extremely improved. One of the reasons is that servo control gain became higher. Several servo errors caused by motor cogging or guide friction were reduced. The other reason is that the KGM measurement system has been developed in addition to the DBB. Different radius circles became able to be tested. However, there are two errors that do not appear on circularity measurement with the DBB or the KGM. The first one is servo error due to different acceleration between approaching path and shaping path in circular machining pattern. The error cannot be observed because circularity measurement pattern is different from circular machining pattern. The second one is tool deformation due to cutting force. Circularity measurement is done without cutting, so the measurement cannot observe the error. In this study, the errors are analyzed and a new path pattern is proposed to reduce the errors.

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In this study, we proposed a fabrication process of diamond array tool for micro-to-nano machining. The diamond array tools are fabricated by depositing polycrystalline diamond using CVD on silicon molds which are made by anisotropic wet etching of the single crystal silicon. It has a characteristic which can control a tip shape of cutting edge with different silicon planes. Moreover, the sizes and the arrangements of cutting edge are decided minutely by changing mask pattern on silicon substrate. The diamond array tools are expected to have a possibility of industrial applications as a micro-to-nano machining tool.

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Should the fabrication of microparts by casting become possible, the range of possible methods applicable for the fabrication of three-dimensional parts will widen further. Thus far, we have examined a method of producing precision metal microparts through the fabrication of casting molds using a temporary disposal three-dimensional model, followed by transfer of the mold shape by casting. However, in a method in which casting molds are fabricated by increasing the density of ceramic powders by the application of centrifugal force to ceramic slurry, the model itself is deformed due to the centrifugal force when the model rigidity is low. Accordingly, it is impossible to fabricate casting molds for model shapes that are precisely prescribed. In this study, casting molds were fabricated by electrophoresis, which is a method that does not deform the shape of the original model. The results indicate that casting of cilia of 1μm diameter was possible when an ant was used as a model for shape transfer.

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Multi-layer thin film, which consists of hydrogenated amorphous silicon (a-Si:H) and thin metal films, is used to form solar cells. Laser beam processing is one of the most important techniques to create the integrated structure of a-Si:H solar cells. Unfortunately heat affection of a-Si:H, a serious problem for solar cells, occurs during laser processing. However, it is possible to remove multi-layer thin film without heat affection by back-side irradiation with a SHG YAG laser, in which the laser beam irradiates a-Si:H through glass. This method is being investigated experimentally and the mechanisms of the method are discussed. It is found that the removal of multi-layer thin film is preceded by the creation of hydrogen pressure, which evolves from the decomposition of a-Si:H.

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Using the atmospheric pressure plasma CVD (AP-PCVD) technique, polycrystalline silicon (poly-Si) films were deposited at high rates ranging from 0.4 to 7.6nm/s. In order to clarify the deposition process of poly-Si films, the influences of VHF power, concentration of the reactive gases (H₂, SiH₄), substrate temperature (T_sub) and deposition gap on the deposition rate were studied. Simultaneously increasing VHF power and hydrogen dilution ratio of SiH₄ (H₂/SiH₄ ratio) was found to be the crucial method to improve the crystallinity and also to increase the deposition rate of the film. In addition, it was found that L_P was sensitive to H₂ concentration in the plasma atmosphere, while it was not affected by SiH₄ concentration within the present deposition conditions. These facts suggested that supplying sufficient VHF power enhanced dissociation of H₂ molecules, which leaded to effective generation of atomic hydrogen in the plasma, and that the atomic hydrogen played important roles in both dissociation of SiH₄ molecules and crystalline Si film growth. It became clear that the deposition rate had positive temperature dependence with extremely small activation energy of 0.036eV. Additionally, the extremely small activation energy implied that a T_sub-independent process partly contributed to the surface reaction. It was also revealed that the deposition rate increased exponentially with decreasing the deposition gap, indicating that the deposition precursors were supplied to the surface by diffusion.

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In the report, the effect of grinding fluid on the newly devised ultra-smoothness grinding of silicon carbide and silicon nitride ceramics using the #140 diamond wheel is examined additionally following the previous report on the ultra-smoothness grinding of silicon carbide. The three types of grinding fluids are used for the examination. The main results obtained are as follows : (1) Grinding fluid supply is effective for the ultra-smoothness grinding of. silicon nitride ceramic as well as silicon carbide ceramic (2) The type and dilution of grinding fluid have the great influence on surface roughness in ultra-smoothness grinding of those ceramics. It is important to select the suitable grinding fluid for obtaining the ultra-smoothness surface. (3) Supplying the suitable grinding fluid, the surface smoothness of silicon nitride ceramic in measuring area of 256μm x 256μm attains below 60nm (Rz) or 3nm (Ra).

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The ever-increasing improvement in the speed, scale and function of electron devices is attributed to the rapid spread of information by society. In an effort to meet the demands for improvement in the sector of electron device technology represented by semiconductors, inspection with high sensitivity for complicated patterns is desirable. Herein, we report optical inspection technology aimed at high sensitivity inspection, which is expected to have applications to bright-field systems. Effective detection method of high order diffracted light using polarization control is described. This method was verified to have high contrast detection sensitivity for defects.

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In this article, we propose a technique for highly stabilized atom-tracking control of a scanning tunneling microscope (STM) tip by referring to an atomic point (or atomic array) on a regular crystalline surface. Graphite crystal, whose lattice spacing is approximately 0.25nm, was utilized as the reference. To enhance stability of the atom-tracking control against external disturbances, a new atom-tracking controller, which consists of integrator, tracer and limiter units, was developed. The integrator unit is designed to eliminate the steady-state error due to thermal drift. A phase-lag low-pass filter is utilized as the tracer unit to compensate the disturbance due to vibration/acoustic noise. To improve the phase margin of the controller, the limiter unit consists of a phase-lead high-pass filter and a saturator whose output is less than one-half of the lattice spacing. The performance of the stabilized technique, which is to combine the new tracking controller with enhanced STM stiffness, was evaluated using internal/external artificial disturbance generators. The experimental results show that the proposed method has a high capability for maintaining atom-tracking control without any jumping of the STM tip to neighboring atoms, even in a noisy environment. The method was also applied to atom-stepping control of the STM tip by referring to some crystalline axis. The atom-stepping control atom by atom along the crystalline axis over a range of 200 atoms, at a rate of 10 atoms/sec, was performed without missing the atomic array.

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Recent requirements for semiconductor equipment and robots that can proceed in their tasks without returning to a starting point have increased the demand for absolute encoders, including higher resolution and longer scale. This paper deals with the development of a high-resolution, long-range absolute linear encoder. To obtain the absolute position this encoder combines three signals : 1) the M-code signal, based on the 9-bit M-code; 2) the Gray-code signal, based on the 4-bit Gray code; and 3) the interpolation of data of sinusoid waves by the grating. This absolute linear encoder achieves an accuracy of 0.16μm and 1m detection range.

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An active anti-vibration apparatus is widely used in the field of precision measurement and precision positioning. In these fields, the realization of apparatus with low natural frequency is expected because the transmissibility from floor vibration to isolated table is especially improved in the high frequency region. In order to lower its frequency furthermore, it is necessary to change the mechanical impedance by means of mechanical or control ways. In the latter case, the following fact, namely, the characteristics of air spring roughly behaves as an integrator, is used for feedback control. However, since the break point frequency actually exists in very low frequency region of air spring, the conversion of mechanical impedance is restricted.
Then, in order to freely manipulate the mechanical impedance, this paper proposes to implement the pressure feedback for air spring. At this time, the complete integrator appears to optimize the whole control system. Using this integrator in place of pseudo-integrator of air spring itself, the conversion of the mechanical impedance can be easily manipulated. Finally, experimental results show that the natural frequency is lower than that of the conventional control using air spring characteristics.

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In this paper, a new architecture is proposed to realize autonomous machining operation unconstrained by NC program. A flexible process and operation planning system is developed to generate cutting parameters dynamically for flexible machining operation. The flexible process and operation planning system can generate the production plan from the Total Removal Volume (TRV). The TRV is extracted from initial and finished shapes of the product, and the TRV is divided into machining primitives or machining features. The flexible process and operation planning system can generate cutting parameters according to the machining features detected. In addition, a technique called digital copy milling is developed to control the NC machine tool in real time. The digital copy milling system can generate the tool paths in real time based on the principle of copy milling, and it permits to change the operation sequence and the cutting parameters during the machining operation. A prototype of autonomous machine tool was implemented, and actual cutting tests were carried out to verify the effectiveness of the proposed system. It was proved that the direct machining operation which does not require any effort and time to prepare the NC program can be achieved.

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This paper proposes an advanced multi-step optimal design method composed of topology optimization and shape optimization, for designing practical compliant mechanisms. The proposed method consists of two steps. First a topology optimization is conducted to provide an optimal topology and rough shape outlines of the structure. In the second step, shape optimization is performed using the result of the first step as an initial solution and a detailed optimal shape is then obtained by the optimization procedure, during which a wide range of engineering requirements such as stress concentration and non-linear deformation can be considered. The integration of topology and shape optimizations as proposed in this paper uses the specific advantages of both optimization methods, providing useful and practical designs of compliant mechanisms.

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