This paper describes a representation method of a single closed loop defined by two-dimensional CAD system based on G-type Fourier descriptor. Traditionally, equal length polygonal approximation method is used to get sampling points for calculating discrete fourier descriptor. However, this approach requires many sampling points depending on the complexity of the shape. This study describes a method for the reduction of the number of sampling points and discusses the geometrical error between the original sampling points and the reconstructed points using inverse fourier transformation. First, an equal angle polygonal approximation method is proposed to reduce the number of sampling points. It means that the length between neighboring two sampling points is unequal. As a result of experiments with thirty-one shapes, the equal angle method is concluded to be sufficient for the reconstruction of the shapes. Second, to improve the geometrical error of inverse fourier transformation of the shape with acute angle, a fourier descriptor with multiple vertices is proposed. Using this method, it is possible to reconstruct the shape without higher order harmonics. Finally, it is proposed that the fourier synthesis method for generating a new shape from fourier descriptors of two shapes.

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This paper describes the process of recovering a 3D shape from stereo image. Two CCD cameras are set up and a parametric curve is on an epipolar plane. A superconic function is used as the parametric curve. This curve causes disparity among the right image and left image. The visible part of the curve shows the object's profile which is cut by an epipolar plane. The estimation function is defined using the disparity including parameters. Parameters of the curve are controlled to optimize the estimation function. The estimation function is defined in the following steps : 1st : the visible part of the curve is calculated. 2nd : the visible part is projected to the right and left images. 3rd : the length of the projected curve is calculated and it is compared with the two images. 4th : the length and difference of the two images' intensities are used as the estimation function.
Parameters of the curve are controlled to optimize the estimation function using the polytope method. This algorithm is tested with experimental image data. The results are similar to the DP matching method which resolves the correspondence problem.

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While many of welding tasks are automatized nowadays, there is still much demand for skillful manual welding tasks. Therefore, the inheritance of manual welding skill and, safe and efficient training of unskilled welders are important. As a solution for them, a simulator by means of mixed reality technique and a training system with it have been proposed by now. In the simulator and training system, however, there were problems such as registration error of virtual objects, measurement error of gap between the electrode tip and the workpiece, slow refresh rate of image displayed to trainees, obscure teaching function of skill improvement, etc. In this research, first, the problems in the simulator have been solved by changing the camera lens, gap sensor setup and so on. As the result, reality of the simulator has been improved considerably. Secondly, in the teaching function, teaching items have been refined from the viewpoint of novice welder training. Applying the modified system to the training of ten unskilled subjects, it has been confirmed that the system is effective in the training.

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This paper deals with the evaluation and analysis of the relation between two different materials of the encoder's slit disk and angle precision. We found that when a glass slit disk was used, the encoder had twice the angle precision as when PET (Polyethylene terephthalate) was the material, we also obtained the relation between dispersion of the slit width and accuracy of the encoder. This, tern in, this paper is useful for deciding the material selection of the slit disk and the specification of encoder's precision.

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An optical fiber array is an optical communication device that consists of multi-core optical fibers and a V-grooved substrate. Due to the use of DWDM systems, the demand for optical fiber arrays has increased significantly. In this research, for the mass production of optical fiber arrays, we considered and proposed technology that automates the insertion of fiber into the V-groove. For automatic assemble of optical fiber array, a fiber must be put a precise position of V-groove. It is dependent on the friction coefficient of a optical fiber with the V-groove's slope whether precise positioning can be performed. A friction coefficient of a optical fiber and the V-groove's slope influences the positioning greatly. It is necessary to develop the measurement method of friction coefficient for assemble of optical fiber array. This paper deals with the equipment measuring coefficient of friction easily, and the relation of a friction coefficient and grinding processing of V-groove was obtained.

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Using the atmospheric pressure plasma chemical vapor deposition (CVD) technique, further investigations were performed to improve the density of silicon nitride (SiN_x) films deposited at extremely high deposition rate. The films were prepared on Si(001) wafers at atmospheric pressure in a very high frequency (150MHz) plasma of gas mixtures containing He, H₂, SiH₄ and NH₃. Si-N, Si-H and N-H bond densities of the SiN_x films were studied as functions of NH₃/SiH₄ ratio and the H₂ concentration by Fourier transformation infrared (FTIR) absorption spectroscopy. Etching rate with buffered HF (BHF) solution, refractive index and relative permittivity of the SiN_x films were also studied as a function of Si-N bond density of those films. It is found that by decreasing NH₃/SiH₄ ratio or increasing H₂ concentration, Si-N and Si-H bond densities increase, while N-H bond density decreases. It is also noticed that N-H bond density is larger than Si-H bond density within the present deposition conditions, indicating that the SiN_x films are N-rich. These facts suggest that elimination of excessive hydrogen atoms bonded with N atoms at the film-growing surface is an important factor to form SiN_x film with a dense Si-N network. The highest Si-N bond density and then the lowest hydrogen content are obtained for the film deposited with the H₂ concentration of 20% and the input power of 1000W.

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This study provides a useful guideline for design of supersonic convergent-divergent nozzle (C-D nozzle) of rectangular cross-section for the cooling air grinding. The C-D nozzles as trial products in various sizes are produced on an assumption of the isentropic flow of the perfect gas. Distributed total pressure of the air flow out of the nozzle is measured to estimate the potential core length L_PC. Dependences of L_PC on air flow parameters are validated under the correct expansion condition. The frictional exclusion caused near the inner wall is correlated with Reynolds number in physical state of the exit part. It appears behavior of the air flow without the frictional exclusion is in agreement with that of the isentropic flow. Both effects of the taper in the divergent part and aspect ratio of the cross-section at the throat on L_PC are clarified experimentally. A proper design procedure, which can determine configuration of C-D nozzle, is shown by arranging the experimental results and is related with required L_PC with the optimum air supply condition.

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A conventional robot arm has the joint coordinate system constructed with an equal number of actuators to the number of its joints, whereas a two-joint link mechanism reported for human extremities has the muscle coordinate system constructed with the three pairs of antagonistic muscles consisting of one antagonistic pair of bi-articular muscles and two antagonistic pairs of mono-articular muscles. We have reported that motion control through the coordination of bi-articular and mono-articular muscles has been confirmed using electromyography and verified using a robot arm equipped with bi-articular actuators. This study describes the motion control of humanlike two-joint robot arm based on the muscle coordinate system to dissolve the contact task problem. The mechanical properties of endpoint operated with the muscle coordinate system consisting of three pairs of antagonistic actuators including the bi-articular actuators, were comparatively examined theoretically and experimentally in terms of robotics, and simple robotic experiments were designed to show how the humanlike two-joint robot arm with muscle coordinate system could dissolve the contact task.
The results obtained here demonstrate the moment arms and elastic coefficient of the bi-articular actuators and the mono-articular actuators at the first joints contributes to control the elastic ellipse and the trajectory exerted at the endpoint, and the two-joint robot arm provided with these mechanical properties on the muscle coordinate system could dissolve the contact task.

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Grinding mark such as spiral or concentric circle pattern is usually generated on ground axi-symmetric aspherical surfaces. The grinding mark on most machined-parts usually does not incur any serious problem. However, grinding marks generated on optical parts such as lenses cause image distortion. As the image quality of optical instruments becomes more rigorous, the effect of the grinding marks becomes conspicuous. In this research, the relationship between grinding conditions and grinding marks is investigated theoretically. The result of theoretical analysis shows that the slight vibration of wheel spindle causes the grinding marks. The result of theoretical analysis also shows that a spiral circle pattern grinding marks are generated under a constant spindle speeds. On the other hand, a concentric circle pattern grinding marks are generated under fluctuating grinding spindle speed. In addition, grinding marks of higher order are analyzed. The order of the most conspicuous grinding marks depends on grinding conditions, such as spindle speeds and wheel feed rate.

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The mesh-type polishing tool, the backing of which is knitted with almost flat cross-sectional shaped polyester fiber (average diameter : 125μm) is a newly developed polishing tool. The polishing tool has meshes of size about 100μm. And fine abrasive grains are coated on both sides of the backing. Chips generated during the grinding process can easily go through the mesh. As a result, the tool can grind the surfaces of the workpiece under constant conditions as loading does not occur. To clarify the grinding characteristics of this polishing tool and its features, in this research, the tool performance was evaluated by comparing the experimental results with the most used conventional polishing tool. Moreover, in order to find out the optimum grinding conditions of the mesh-type polishing tool, finishing experiments were carried out by changing the effective grinding parameters and observing the experimental results such as accumulated stock removal, surface roughness, tool surfaces and so on. Finally, the important grinding conditions affecting the amount of stock removal and surface roughness were clarified from the analytical results of multiple regression analysis.

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This paper presents a motion control method for a nonholonomic omnidirectional vehicle moving on undulating area. The vehicle has four wheel units, each of which is equipped with a nonholonomic mobile base and a chassis tilting mechanism with 1 DOF active prismatic joint and 3 DOF free rotary joint. The motion control system consists of chassis-unit controller and wheel-unit controller; the chassis-unit controller decides the desired motion of the vehicle, while each of wheel-unit controllers controls its own mobile base and chassis tilting mechanism to produce the desired motion of the vehicle. A path-tracking controller in the chassis-unit controller is designed based on the Ackerman geometry. The wheel-unit controller is designed based on the resolved velocity control method. The proposed control method makes it possible to keep the chassis in a horizontal position while the vehicle tracking its prescribed path on undulating area. Experimental results validate the effectiveness of the control method.

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This paper investigates how to use cylindrical shape memory alloy (SMA) as chucking part because tool holder can be simplified and miniaturized. Ni-Ti alloy for SMA was used and its critical point by changing heat treatment conditions were experimented. SMA cannot be utilized as chucking tool since it is one-way direction, but it is possible to attach and take off a tool by changing temperature in case cylindrical SMA is made combing cylinder with carbon steel (S30C in JIS). Tensile stress and torsional stress whether it can resist cutting force in real cutting or not was experimented. As a result of this study, it is clear that combing cylinder with cylindrical SMA could resist cutting force in real cutting. Therefore, prototype tool holder that used combing cylinder with cylindrical SMA as chucking part was developed and tried real cutting process.

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Homogeneous nonequilibrium low temperature plasma was generated under atmospheric pressure by an RF (13.56MHz) excitation of He and O₂ gases. Using this cold plasma, ZnO thin films were deposited on glass substrate exposed to air at room temperature by feeding Bis-Dipivaloylmethanato Zinc into the plasma with He carrier gas. Dependence of RF power and gap of electrodes on thickness and optical transmittance of the ZnO films were investigated. In addition, crystallinity and microstructure of the films was studied by XRD measurement and FE-SEM observation.

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To assemble the micro-parts includes many varieties of the operations. So, to realize easy assembling, the “Imaginary triangle plate” algorithm is proposed. The shape and size of micro-parts are simplified using a proposed plate. The vertices of an imaginary triangle plate are selected as the handling points using triple micro-arms; this collision avoidance control operation can be replaced with the motion control of proposed triangle plate. Also, this plate is operated with each arm simultaneously. Then, an assembling robot with triple micro-arms has been developed, in which these arms move simultaneously in a single working area. To reduce the inertia of the arm and motor, each arm is driven through the five-bar linkage mechanism. Also to generate a vertical motion, this linkage is attached on a swing motion mechanism. The proposed algorithm is verified using a prototype system. The testing micro rectangular parts can be operated in an arbitrary three-dimensional working area.

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