As a recent trend, composite materials are used in many parts of structural components for the newly developed aircraft and launch vehicles. The main structures of aerospace vehicles are semi-monocoque construction, which are composed of skins, stringers and frames. The composites are used as laminated stiffened panels for the wings and fuselages. During the service of aircraft and launch vehicles, their outer surface such as wing, fuselage and engine covers are exposed to severe acoustic environment due to their engine exhaust noise. Therefore, it is important to consider vibration characteristics in the structural design of airframes. This paper describes a simple analysis method of free vibration of rectangular plates and stiffened plates. This method can deal with isotropic and anisotropic plates with several boundary conditions under in-plane stress. The accuracy of the analysis of this method was verified by comparing with theoretical analysis and finite element method (FEM) using NASTRAN. The natural frequencies obtained by the present analysis are within the allowable error bounds of those by detail analysis method. Consequently, this method was designed to be an effective calculation tool for the vibration analysis in the early phase of airframe design. As an example, this paper describes analysis result of the relation between in-plane stress level and natural frequencies of a laminated composite plate.

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Differentiation steering assistance offers potential measures by which the control stability of a vehicle can be rapidly improved. However, for all differentiation steering methods, the inconvenience caused by the need to keep turning the steering wheel during cornering is significant. Because the steering return phenomenon of the steering wheel stop like this is not so preferable, it is preferable that the differentiation steering assistance is extremely weak (almost 0) in such a usual grip cornering driving. Alternatively, in the drift area of cornering where the grip area of the tires has been exceeded, differentiation steering assistance is helpful because the driver can control his counter steering extremely well. Furthermore, only a small amount of differentiation steering assistance is required in the drift area. And, because the amount of differentiation steering assistance required is minor, there is little in the way of control disconnection sensation during the transition from grip cornering to drift cornering. Moreover, because the response and settling of a vehicle shows strong improvement when differentiation steering assistance is used during lane changes, use of the technique is preferable at that time. In this background, steering method controls into which the differentiation steering assistance constant has been applied, along with perception changes in anticipated driving situations was examined.

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This paper presents the theoretical procedure to predict the vibratory response and radiated noise of the engine block coupled with the rotating crankshaft and gear train shafts which drives the fuel injection pump and valve system. The exciting forces acting on the engine block and shaft system are combustion pressure, inertia forces of the moving parts, piston slap forces, fuel injection pressure and valve driving force and torque. Theoretical procedures consist of the following four steps; (1) Dynamic characteristics of the engine block and shafts are detemined separately by FEM or experimental modal analysis, (2 ) Normal mode expansion technique is employed to derive the equation of motion of the total system in which rotating shafts with gear train are combined to the engine block by the oil film and contact stiffness, (3) The time histories of the vibratory response of the engine block and rotating shafts are calculated by the numerical integration technique., (4) Engine noise radiated from the engine block surface is evaluated using the Boundary Element Method. This method is applied to estimate the effect of the backlash of the gear train on the engine block vibration and radiated noise.

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This paper describes a method of measuring the surface condition of thermally sprayed materials and its three-dimensional position with a new laser rangefinder. The feature of this rangefinder is to equip an optical position sensor which has the ability to simultaneously detect the position of a light and its incident angle onto the sensor. Moreover, the sensor has an autonomous exposure time control function with a microcomputer. Therefore, our laser rangefinder can detect the 3-D positions of an object with unknown reflectance. We constructed a prototype system and performed some experiments. First, we inspected the surface reflection of each element in thermally sprayed materials and established the measurement procedure using our rangefinder, which can identify the surface condition based on the optical properties. Next, we measured the thermally sprayed materials with several kinds of delaminations. From the measurement results, the error of the 3D position measurement was Δz/z=0.7%, which was independent of the surface reflection of the measured objects. Regarding the detection of the surface condition, we could identify four types of delamination conditions with accuracy. The proposed method has great potential for a wide range of industrial inspections.

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A vena cava filter is a device inserted percutaneously into a major vein to prevent a blood clot from entering the lungs. A thrombus clot traveling to the lungs is called a pulmonary embolism. Many types of vena cava filters, such as the Greenfield filter, are available. Although their insertion seems to be a safe and effective method to prevent recurrence of pulmonary embolisms, patients in whom the filter has become tilted may experience pulmonary embolism recurrence because of a decrease in the filter's thrombus-trapping performance. However, there are little quantitative data about the mechanical properties of these filters, such as the ease of filter delivery. In this study, we therefore evaluated the mechanical properties of the Greenfield filter by numerical analysis. This model of filter is constructed with viscoelastic springs and segments for the dynamic deformation of a flexible structure. The blood vessel is an elastic tube. The contact forces between the filter and the vessel are calculated according to the stiffness and friction of the vessel wall. Using these models, the position and the configuration of the filter were calculated to represent the deployment of a Greenfield filter inside the blood vessel and its prsence for a fixed time under a constant force. When the introducer catheter does not align with the axis of the vena cava, the inserted filter tilts. When the filter does not expand uniformly, the inserted filter tilts as well.

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This paper deals with response vibration in single-degree-of-freedom excited by periodic displacement with arbitrary functions. The analytical model is steady collision vibration in spring-mass system with viscous damping. When the system is subjected to an exciting vibration by displacement and amplitude of the mass increases farther than collision clearance, the mass collides elastically to clamped spring. Then, the restitution force of the mass is assumed an asymmetric piecewise-linear system. In order to clarify harmonic, superharmonic and subharmonic resonances of the collision system, the resulting vibrations are analyzed extending the Fourier series method which is proposed by authors. Following this theoretical analysis, the numerical calculations are performed and the resonance curves are constructed using the resulting vibrations. The numerical results show effects on the damping ratio, the stiffness of clamped spring and the amplitude of forced vibration for resonance curves. Experiments are also carried out to verify the theoretical results. Comparing the theoretical results with the experimental ones, it is shown that they show a fairy good agreement.

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The design of Gas Turbine High Temperature gas cooled Reactor with a power output of 300MWe employed magnetic bearings for supporting gas turbine rotor composed of turbo-compressor and generator rotors, which are connected by a flexible coupling each other. The generator rotor is a flexible rotor, which passes over the forth critical speed below the rated speed. The total length, bearing span, mass and rated speed of the rotor is 18m, 8.19m, 67t and 3600rpm, respectively. For designing a controll system of magnetic bearing, a simplified rotordynamics model was proposed based on Timoschenko beam model by adding a rotational spring which simulated deformation of plane at stepped parts of rotor. The model predicted adequately the bearing stiffness dependency on vibration mode shapes of rotor at critical speeds in comparison with numerical results by 3-dimensional FEM analysis. As opposed to the conventional model, the model predicted adequately the increase of inclination at the center of rotor where mass was concentrated because bending stiffness was lowered by the deformation of plane at stepped parts of rotor, which affects whirling motion by Jayro effect at the forth critical speed.

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Lure fishing and fly-fishing have been positioned as sports deliberately different from the traditional Japanese fishing-style. In the case of fly-fishing, casting is the element which anglers must master in order to cast a fly, done so by using the weight of a line. This study uses experimental and computational analysis to investigate the dynamic behavior of a fly line. Fly-fishing constitutes various elements, but the importance that casting holds is large. However, the behavior of the line after the casting is also the important element in the fly-fishing. There are two types of fly line. One is floating-line that is used for the dry fly or the wet fly at shallow field such as creek. And the other is sinking-line that is used for the streamer at lake or sea. When an angler uses floating-line, the fly is on the surface of the water. So the fish under the deep water can not find the fly. Therefore, the sinking-line is used. In case of sinking-line, the line shape is important. The line should not sink before the fly sinks. And the line should have been given the tension in order to find the signal of the fish hooked. In this study, the behavior of the sinking-line is taken into consideration.

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In this study, vibration characteristics of mechanical structure having high natural frequency are investigated from the viewpoint of energy balance. Mechanical structures having high natural frequency in a nuclear power plant are generally designed statically and elastically. However it has been reported that fracture of ordinry piping is produced not by momentary large load but by cumulative fatigue damage. Therefore it is very imortant to grasp seismic performance dynamically by considering cyclic load. This paper deals with an investigation regarding seismic performance evaluation of high natural frequency mechanical structure. The energy balance equation that is one of valid methods for structural calculation is applied through the investigation. The main feature of the energy balance equation is that it explains accumulated information of motion. Therefore the energy balance equation is adequate for the investigation of the influence of cumulative load such as seismic response. In this paper, vibration experiment and simulation using sinusoidal waves and artificial seismic waves were examined in order to investigate relationship between natural frequency of structure and energy. As a result, we found that input energy decreases with an increase in the natural frequency.

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This paper discusses research on the strength analysis and damage experiments of a universal joint. The Kashiwazaki Kariwa nuclear power plant suffered damage under the Niigata Chuetsu-oki earthquake, which occurred on July 16, 2007. The earthquake motion damaged a driving shaft coupling of an overhead traveling crane of unit 6 nuclear reactor building. The damaged portion consisted of a universal joint. In this research, the cause of damage of the universal joint is studied, and damage experiment and stress analysis of the miniature model of a universal joint are conducted. As a cause of the damage, it is thought that the universal joint was loaded with torque under the earthquake motion. In the experiment, a miniature model of the universal joint is loaded with the torque to be damaged. The torque of damage is measured. The failure modes are observed. Similarly, in the analysis by 3DCAD (Three Dimensional Computer Aided Design) and CAE (Computer Aided Engineering), the miniature model is loaded with the torque to be damaged. The analytical result is compared with the experimental result. The analytical result agrees with the experimental result.

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Analysis method of resonant frequency and leg's load of cylindrical vessel with cracked legs is proposed. Cylindrical vessel supported by legs is installed in shaking table, and is excited to investigate resonant frequency and leg's load. During the vibration tests, some of the legs have simulated penetrated cracks. So, the resonant frequency reduced from original case. The test data coincide well with analytical one, and so the proposed analysis method is verified. It is clarified that the resonant frequency has good correlation with the crack location coefficient. It is also shown that resonant frequency reduction is less than 10% even if there are 3 cracked legs.

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The concrete placing of a concrete dam by a large-scale crane is carried out by the skill operator based on the long experience. To apply an automatic driving of a crane in the construction of dams, shortening the cycle time of carriage and placing concrete is demanded. The rolling up and down of the hanging load while running of the trolley is needed for the improvement of the cycle time. Because the length of the hanging load rope changes, antisway control becomes difficult. We proposes a control technique of trolley considering the change of the phase velocity dependig on the length of the hanging load rope. The residual vibration after the trolley reaches the concrete placing position is not produced. Moreover, the validity of the proposed control technique was confirmed from the numerical simulation.

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This paper presents a response evaluator which evaluates the response of the system and decides the control input to the system. It is applied to a base isolated structure with a semi-active oil damper whose damping coefficient has large or small values. Absolute acceleration of a top story and displacement of an isolated layer are the input signals of the response evaluator, and switching parameter for the damping coefficient is the output signal of the response evaluator. The response evaluator consists of a layered neural network, and a genetic algorithm is used to adjust the neural network parameters which decide the performance of the response evaluator. A computer simulation is carried out using several kinds of earthquake motions, and absolute acceleration and displacement of each story which are trade off relations of each other are reduced to the intermediate value of the response in case where constant damping coefficients are large or small. From the result of simulations, the effectiveness of the response evaluator is verified.

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Simultaneously separating and transporting works by using elliptical vibration with vertical vibration over the jump limit is described. In the condition of vertical vibration from 1.2 to 2.0G, works with a smooth contact surface and those without a smooth contact surface can be separated and transported by adequately controlling the phase difference of elliptical vibration. Experimental results show that electronic parts with electric terminals can be separated at high speed in accordance with the difference between the shapes of the face and reverse sides. A change in the transportation characteristics of electronic parts without a smooth surface increases the speed of the separation and transportation. The difference between the transportation characteristics of parts without a smooth surface and those of parts with a smooth surface has increased. We clarified that the change in the transportation characteristics was derived from the jumps of parts by observing the behavior of electronic parts during separation and transportation with a high speed camera.

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This paper deals with robust stabilization of running self-sustaining two-wheeled vehicle with varying running speed and mass variations. Recently, there have been a lot of research results about stabilization of two-wheeled vehicle. These researches have achieved the stable running only by the steering control. However, an actual two-wheeled vehicle is stabilized by not only the steering control, but the control of a vehicle's center of gravity. We have proposed the stabilization control method of two-wheeled vehicle in the state of stillness, and have shown the effectiveness of proposed approach. In this research, we construct the control system for the running stabilization of two-wheeled vehicle. H_∞ control problem is used to design the controller to achieve running stability even if the running speed and the mass of two-wheeled vehicle would change. The experimental results show effectiveness of proposed approach for robustness.

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It is hard to reduce the noise trasmitted through the internal panel of the railway vehicle by any existing active control methods, which are necessay to identify the vibration-modes of target structure, because the vibration characteristics of the interior panel changes while running. We propose a new noise control system that the noise insulation panels with piezoelectric material arrange. The system enables the noise transmitted through the target plate to reduce by suppressing the vibration of the noise insulation panels with a simple analog control circuit. In this paper, after the equivalent mechanical models for a number of the piezoelectric material are shown, we demonstrate the analytical and experimental results about the control effects of the noise insulation panel and the noise transmitted through a target plate by the control system without identification to the vibration or transmitted noise characteristics of the target plate.

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In this paper, the authors propose a passive type MR damper which has hardening type resisting force characteristic. The damper consists of a piston, a cylinder, MR fluid and rare-earth magnets which are attached symmetrically about the center of the cylinder. A trial damper was made and the resisting force characteristic was measured. A semi-active type MR damper with a bypass was also made to compare the passive type MR damper. The frequency and seismic responses of a single-degree-of-freedom system supported with the MR dampers were measured with a shaking table using permanent magnets. The effects of vibration suppression of both dampers were compared, and the equality of the passive type MR damper with the semi-active type MR damper was substantiated. The experimental results were compared with calculated results, and the validity of the calculations was confirmed.

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Various measurement methods using an ultrasonic sensor are generally used for inspecting the strength and reliability of actual structures. Therefore, there is a growing demand for developing accurate and precise ultrasonic sensing techniques. In this study, we aim to examine the precision of the ultrasonic sensing technique using a chirp burst pulse wave and a pulse compression methodology based on the leading edge technology of radar signal processing. In this paper, we present details of the pulse compression methodology, the analysis of the measured data, and the experimental results of the performance test of this method. The performance test demonstrated the plate thickness measurement under a series of experimental conditions. The results of the performance test, based on a comparison of the pulse compression method and conventional rectangle pulse emitted method, are as follows. (1) The effectiveness of pulse compression method is confirmed. (2) The pulse compression method enables high-precision measurement compared with the conventional rectangle pulse method.

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In the near future, the mechanical systems using hydrogen energy such as a fuel cell vehicle will be widely used. From the point of safty measure, the hydrogen sensors are the necessities. In this paper, a new acoustic method of detecting hydrogen leakage is proposed. This acoustic method is effective in wide space such as a basement parking lot. Three-dimensional computer simulations of sound propagation using finite difference time domain FDTD method is carried out. A basic experiment using helium, instead of hydrogen is also carried out. The validity of the proposed method is shown from the results of simulation and experiment.

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In recent years, the tilting vehicle of air spring type, which uses air springs as the car-body tilt mechanism, has been employed even for Shinkansen trains to speed up on curved sections. On the test train with the tilt mechanism running at the speed of about 300km/h, however, it was found that the car-body roll and lateral vibrations increased in a compound curve where plane and vertical curves were overlapping. In this study, with an analytical model of the tilting vehicle of air spring type, numerical simulation is carried out to investigate the high-speed curving behavior in the compound curve. Then, anti-roll damper, which is equipped between the car-body and the existing anti-roll device, is examined as a counter measure. As a result, it is shown that the vibration phenomena occurred in compound curves is caused by the centrifugal force due to the vertical curve and the unbalanced stiffness between the right and left air springs for the car-body tilting, and that the anti-roll damper has a potential to reduce the car-body vibration increased in the compound curve.

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In order to run safely and smoothly though curved tracks, the gauge of track has been widened in curved sections. In recent years, however, the gauge widening (GW) was reduced due to some causes, such as, the decrease of three-axle bogies, the increased accuracy of track maintenance, etc. But the GW has the original purpose that gives the rolling radius difference of inner/outer wheels which produces the steering effect. The reduction of GW may lead to the decrease of running ability, especially curving performance, and increase of abnormal wear, such as rail corrugation. In this study the authors examine how GW affects running performance by using numerical simulations and full-size stand tests. Through these results we conclude; (1) the increase of GW produces more rolling radius difference and improves curving performance, and these tendencies become more remarkable for large value of GW, (2) for more than some value of GW, the running stability also increases according to GW expansion because of the reduction of the equivalent conicity of wheels.

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The behavior of driver is formed by recognition, decision and operation. Driver have to grasp parameters such as changing of surroundings and movements of the automobile. These are chances that vehicle movements might be drivers' mental-workload and cause them to make mistakes in judgment and to disturb their operation of the car. In this report, we measured drivers' physical reaction, and vehicle movements such as velocity, acceleration, yaw rate and roll rate through the steady-state cornering test. In order to consider time-series factors of physical reaction, we used Wavelet Analysis from R-R interval of heart beat variability to clarify activities of autonomic nerve. As a result, we could specify the parameters of vehicle movements which cause drivers' mental-workload. In addition, we could make a specific group of drivers who easily get the mental-workload from vehicle movements by using HQL Workload Sensitivity Questionnaire based on drivers' individual characteristics.

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We have previously showed that microparts can be fed along a sawtooth surface using simple planar symmetric vibration. Microparts move forward because they adhere to the sawtooth surface asymmetrically. We studied also the effects of sawtooth pitch and vibration frequency on the movement of 2012-type capacitors (size: 2.0×1.2×0.6mm, weight: 7.5mg). In the present work, we studied tribological characteristics of smaller 0603-type capacitors (size: 0.6×0.3×0.3mm, weight: 0.3mg). We analysed the contact between a micropart and a sawtooth surface based on measurements. A microscope was used to obtaine precise surface models of 0603-type capacitor and feeder surface. A three dimentional model of each surface was synthesized from pictures at various values of focus height, and obtained a section model along vertical plane. Section models of both surfaces were approximated by linear polynominals, and then contact of both section models was analysed to examine adhesion. A statics including adhesion was defined and identified by friction angle measurement experiments.

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This paper presents a method for controlling the position and stiffness of a pneumatic planar parallel manipulator in which the pressure and force sensors are eliminated by replacing them by observers for the purpose of cost reduction. Generally, since pneumatic manipulators are characterized by high nonlinearities such as air compressibility and friction arising in their joints and sliding parts, conventional PID controllers are insufficient for precise control. Using advanced controllers aiming at higher performance requires various sensors, but their dependence on a lot of costly sensors makes pneumatic manipulators less competitive with other power source manipulators in terms of cost. Based on our previous papers, a position controller for the pneumatic manipulator is first discussed in this paper, which introduces observer-based friction compensation for enhancing motion accuracy and pressure observers as substitutes for pressure sensors. The designed controller is further extended in order to control simultaneously the position and stiffness of the manipulator. In this controller, friction observers estimated the contact force between the manipulator's end-effector and a target object, and from these results a force sensor was removed to save costs. Several experiments were carried out to verify the performance of the proposed low-cost controller.

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In this paper, we perform the on-chip assembly of microstructures with dimensions of 〜20μm. The fabrication method is proposed to polymerize the photo-crosslinkable resin to form the arbitrary shape by the illumination of patterned UV-ray through the mask on the microchip under a micro-scope. The polymerized micro-objects, which we call as "Microtools", can be used for the single cell analysis. By the proposed method, the microtools are fabricated at the desired place on the micro-chip in less than 1s. Additionally, the microtools are assembled by the laser manipulation on glass surface. The assembled microstructures are driven by the laser manipulation as rotational structures.

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Our previous paper presented a method for relaxing adhesion forces by oscillation and showed the adhesion state can be checked by analyzing the data obtained by laser displacement meter. However, there are several problems in laser measuring method. 1) The endeffector must be located at the specific point where laser displacement meter can measure oscillation. 2) The adhesion state can not be checked if something blocks the light/laser or the target leaves measuring point. 3) The total system becomes very large. To resolve these problems, this paper firstly presents a method for checking the adhesion state by piezo-transducer. Next, to achieve more precision manipulation, we propose a method to deform the endeffector by adding DC input to the piezo actuator which is also oscillated simulaneously for endeffector for relaxing adhesion forces. Furthermore, we find that the first mode resonance frequency shifts with the increase of the amount of pushing the object by the endeffector. Using the amount of shift, we develop a method for checking the adhesion state.

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A power assist system is operated by a human operator, so it is very important to consider the human element in the control loop. In order to evaluate the performance of power assist system at the design process, usage of the simulation, which includes the human factor, is quite effective. In this study simulation of industrial arm type power assist system is developed for system design. The mathematical model consists of an AC motor model, a link model, and a controller that inclues a human model to operate the power assist system by operating force. The human model consists of the feedback control and feedforward control that consisted of an inverse system of the power assist system. The human model's inverse system learns using a neural network. The feasibility of the simulation was demonstrated in comparison with measurement results from operating force and acceleration.

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Dynamics of toner particles in the magnetic single-component development system of electrophotography have been investigated to utilize for the improvement of the system. Two approaches have been adopted for the investigation: One is the direct observation of the toner motion in a development area with a high-speed microscope camera and another is the numerical simulation with the distinct element method. We have manufactured the mock-up apparatus that consisted of a pseudo-photoreceptor, development roller, stational magnetic roller inside it, and doctor blade to form thin toner layer on the development roller. The development roller, magnetic roller, and blade were diverted from a commercial printer. Thin line electrodes were embedded on the pseudo-photoreceptor drum to substitute for electrostatic latent images. The apparatus enabled high-speed observation of toner motion at the development gap with satisfactory image quality. Observed images showed that (1) toner particles formed chain-like clusters in the vicinity of the gap, (2) these chains vibrated at the development zone synchronized with an applied alternative electrostatic field, (3) at the latent image, chains crashed on the photoreceptor and then fell apart from the photoreceptor, and (4) at this moment, some of toner particles returned to the development roller but some adhered to the latent image to form a real image. Three-dimensional shapes of toner piles on the latent image were measured after the development by a scanned laser displacement meter. It has been clarified that both the width and height of the toner pile increased with an increase in the development voltage but these were saturated at the voltage higher than a threshold. Numerical simulation has been conducted to confirm the experimental results. The simulation method is based on a hard sphere model of the distinct element methtd with cyclic boundary condition. The method can be applied for the dynamics of small toner particles within reasonable calculation time.

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We have studied friction force of magnetic carrier brushes to the photoconductor drum in two-component magnetic development system of electrophotography by a model experiment and the numerical simulation with the Distinct Element Method. Axial and lateral forces of chain-like brushes applied to the photoconductor were measured to clarify the relationship between the lateral friction force and the diameter of carrier particles, magnetic flux density, and the brush length. It was observed that the force was increased in accordance with the increase of the magnetic flux density and decreased with the brush length but the particle diameter did not affect the total force. On the other hand, the numerical calculation deduced that although the total force is not affected by the particle diameter, the individual differential force of the chain was small and the density of contact points of the brush was high for small particles.

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In the early design process, diverse design ideas must be obtained from global solution search under the constraint of unclear design conditions. Because it is difficult to apply the conventional engineering design in the early design process, the emergent design method is proposed as a design method that can be applied in the early design process by a conventional research. Moreover, the emergent design system that can generate diverse three dimensional forms is proposed as an application of the emergent design method. To obtain diverse design solutions, this system should appropriately set the parameters with the application case. However, it cannot judge whether the value of the obtained parameters are the best because the parameters are decided by trial and error. In this research, the parameters that influences the diversity of form was extracted, and it aimed to show the knowledge of extracted parameter for the diversity of generated form and the setting method of these parameters. Therefore, the parameter of this system was assumed to be a factor, and an analysis of variance was conducted, and the parameters, which influence the diversity of generated form, were extracted. Moreover, it was analyzed to clarify the relationship to the diversity of form and extracted parameters, and the conditions about these parameters setting were shown.

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Multimedia services such as an audio and visual media have been advanced rapidly. And now we can employ several multimedia services via the Internet in which audio and visual information is exchanged. In addition to them, physical force information is expected as the next multimedia service. However, there are several fundamental issues for interactive force telecommunication, which do not appear in the conventional teleportation. We study on basic issues of force telecommunication from human sensory aspect by using two haptic interfaces with 3' DOF that have an orthodox parallel linkage, and propose a hybrid control of Master/Slave system for force telecommunication between Human beings, which has position/force feedback loop directly. Results show that both hybrid and compliance control of Master/Slave System are suitable candidates for the force telecommunication system because both force and position serve functions are essential for the system. Moreover, recognition of an operator coordinate system is clarified to be important because of force communication strong interaction, which is discussed from human sensory aspect.

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Recently, environment that visually impaired persons are capable of getting electric information is being developed. By using Braille display, visually impaired can get various electrical information on network. Therefore, Braille display rapidly spread in the foreign and domentic country. However, when Braille display is used continually, the base material of Braille display becomes worn. It has been pointed out that Braille readers find it difficult to read Braille on worn base material which their forefingers cannot slide easily. In this study, to reduce this friction, we reinvent a thin low friction film cover on worn base material to reduce friction during Braille reading. And also we carried out a study to investigate influence of base material features of Braille display on Braille reading and the effect of its use. We compared the discriminability of Braille when covering two films with excessive and less kinetic friction on the base material. As the results, subjects could read Braille significantly faster and more correctly when less kinetic friction film (powder compounded film) cover was used on the base material. In short, by use of powder compounded film cover, we found that Braille readers' forefingers can slide easily and discriminability of Braille was improved. From this study, we suggest the covering less friction this film on Braille display with worn base material as method of being able to improve the discriminability of Braille.

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This paper presents the experimental results of photoelasticity for determining the magnitude and distributions of stresses on the polyetheren insert of typical three types of posterior stabilized knee prostheses designed to attain high/deep knee flexion. Three prostheses used in the experiment were a conventional posterior stabilizer knee, Scorpio NRG (Stryker Co., USA), Bi-surface knee (Kyocera Inc., Japan) with a unique design with a ball-and-socket joint and CFK (Complete Flexion Knee, Japan Medical Material Co., Japan) which we have developed by further improving the Bi-surface so as to make a complete knee flexion. Epoxy resins were selected to fabricate the tibial insert models. Special equipment was used to apply 2kg force on the model by setting knee flexion angle at 0°, 30°, 60°, 90° and 120° respectively. After that the stressed model was sliced in parallel with the saggital plane and photoelastic fringes in each slice were observed. The results demonstrated that while knee angle was smaller than 90°, shear stress on the lateral slice became highest for Bi-surface, followed CFK and NRG was lowest, indicating NRG has high conformity as to the condylarinsert articulation. After knee angle bacame larger than 90°, shear stress on the mid-posterior slice became highest for NRG, followed Bi-surface and CFK was lowest. We may conclude that CFK has the optimal configuration especially at deep knee flexion from a load bearing viewpoint.

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The number of patients with chronic respiratory deficiency, such as Chronic Obstructive Pulmonary Disease (COPD) or Sleep Apnea Syndrome (SAS), is increasing. For patients with comparatively serious symptoms, the Non-invasive Positive Pressure Ventilation (NPPV) may be prescribed. However, pressure necrosis or anaclisis could affect treatment by occurring at the contact area of nasal mask. In response to this problem, the construction of a simulation environment can be applied. The system consists of leaser measurement technology and ultrasonic and the Free Form Deformation (FFD) technique. The shape of the face is measured by laser technology, while ultrasonic technology is used to measure he shape of soft tissue and bone. This personal simulation model was created based on these measurement results and the interpolation results using the FFD. A fundamental numerical analysis was performed, and Von Mises stress distribution was shown when the NPPV nasal mask made contact with the face. This also compared with the actually measured results. In conclusion, the finite element model made by the proposed system can reproduce the actual stress state. By using this system, the shape of a nasal mask suitable for each patient can be determined.

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Japan's progressing aging society increasingly emphasizes the need for evaluation of equipment for human assistance. Earlier studies have evaluated the use of wheelchairs. However, how the equipment moderates the generated consumption energy of helpers has not been sufficiently described. This study performs mechanical evaluation of a helper's walking using a wheelchair on a slop. We use the Musculo-Skeletal Model to estimate the joint moment and the consumption energy. Fourteen volunteers assisted these wheelchair experiments. Results were considered for cases in which the energy consumption of the wheelchair increased by 13% from that of a normal gait when moving up an incline. This evaluation method is useful for developing practical assisting equipment.

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"Barrier-free New Law" was recently enacted in Japan. Therefore, many Braille signs and tactile guide maps have been installed at various buildings, stations and other public facilities. However, many unsatisfactory tactile guide maps appeared around us. Therefore, Japanese Standards Association enacted Standardized Method of Displaying Tactile Guide Maps in March 2007. However, rules and regulations about perception of texture with dot pattern and striped pattern for tactile guide maps were not contained. In this study, for the purpose of proposing useful texture with striped pattern for tactile maps, we examined the perception of texture with dot pattern and striped pattern on human forefinger. We made dot pattern and striped pattern test pieces with varying dot-distance and line-distance by screen-printing and asked ten subjects to clarify texture with striped-pattern (such as high density and low density) by the method of successive categories. As these results indicate, relation between dot and line distance and "perception of texture with dot pattern and striped pattern" on human forefinger became clear.

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The purpose of this study is to obtain the quantitative indices of evaluation for standing stability during anterior-posterior tilt movement. We assumed human body in standing position which is modeled as a inverted pendulum, and two parameters based on control engineering, namely, natural frequency and damping ratio were estimated from the model for the quantitative indices. Twelve healthy volunteers participated in the experiment. Subjects inclined forward as large as possible around axis of the ankle joint mainly from upright standing, and recovered to the initial standing posture again. This task was executed in four conditions on the assumption that the standing stability decreased respectively as follows; both legs standing with eyes open, both legs standing with eyes closed, one leg standing using a tiltable step that prevents lateral sway, one leg standing without the step. The angular data at hip and ankle joint while the subject performed tilt movement followed by recovery were measured, and natural frequency and damping ratio were estimated using theoretical model about all conditions. The estimated parameters were compared among four conditions. As the results natural frequency was more increased and damping ratio was more decreased according to the decrease of standing stability if the subject could execute the movement task by ankle joint mainly. On the other hand, when the larger movement at hip joint was measured, estimated indices suggested more unstable situation. It is confirmed these two parameters are useful as the quantitative indices of evaluation for standing stability.

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In this paper, a novel desktop NC machine tool with compliance controllability is presented for finishing metallic molds with small curved surface. The NC machine tool consists of a robot with three axes. A small ball-end abrasive tool is attached to the tip of z-axis of the robot. The control system of the NC machine tool is composed of a force feedback loop, a position feedback loop and a position feedforward loop. The force feedback loop controls the polishing force consisting of tool contact force and kinetic friction force. The position feedback loop controls the position in pick feed direction. Also, the position feedforward loop leads the tool tip along cutter location data. It is expected that the NC machine tool delicately removes small surface cusps on a mold, and finishes the surface with high quality. In order to first confirm the application limit of a conventional industrial robot to a finishing task, we evaluate the backlash which causes the position inaccuracy at the tip of the abrasive tool, through a simple position/force measurement. The basic position/force controllability of the proposed NC machine tool is demonstrated by a similar position/force measurement and by a surface-following-control experiment along a lens mold. Finally, the proposed NC machine tool is applied for finishing a LED lens mold to evaluate its performance qualitatively.

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Bolted joints are widely used to assemble various parts in both machines and mechanical structures since the disassembly for maintenance is easy with low cost. However, vibration induced loosing due to dynamic loading has been an unsolved problem for a long time. We have developed a new type of nut named "Torque Mate", which realizes anti-loosening performance without complicated tightening process and tool. In this research, we have investigated the mechanisms of bolted joint with Torque Mate, and tightening behavior is analyzed by mean of three-dimensional finite element method and experimental investigation. The results are compared with the experimental results. Good qualitative agreement is observed between the analytical results and the experiments with respect to tightening force and tightening torque. We found some new aspects and superior points for bolted-joint with Torque Mate than that of standard nuts. It is found that tightening torque of Torque Mate is higher than that of standard. It is also found that the antiloosening performance can be realized by the thread contact force at the angular facing on bearing surface. Moreover, by mean of loosening test and tightening test, it is concluded that Torque Mate involves sufficient anti-loosening performance in practical use.

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The heat generation due to friction between tooth flanks and hysteresis of plastic material greatly affects the load capacity of a plastic gear especially in operation without lubricants. And the heat radiation of plastic gears generally decreases with the increase of facewidth and module under the same gear rotation speed. Therefore, tooth temperature increases in case of large facewidth and/or module. Friction and hysteresis that causes heat generation are not proportional to gear rotation speed, so that tooth temperature should be determined considering facewidth, module, and gear rotation speed. However, the effect of tooth temperature is usually not considered in the load capacity evaluation of a plastic gear pair. The temperature-rise factor for the load capacity calculation has been proposed considering facewidth of a plastic gear. In the present paper, the effect of module and rotation speed on the heat generation and radiation in plastic gear pair is investigated on the basis of three-dimensional analyses using a developed computer program with measured results obtained from experiments using POM gears with various modules and under various gear rotation speeds. As a result, On basis of these results, a method of determining the temperature-rise factor was proposed, and it enables not only facewidth but also module and gear rotation speed to be considered.

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The novel mechanism CVT (Shaft Drive CVT, S-CVT) was developed by the authors. The improvement of the power to weight ratio, namely the increase of transmitted power with downsizing and lightening of the transmission is important applying the S-CVT to automobiles. To achieve this objective, the zero-spin disk/roller was devised. By using this disk/roller, the spin decreased to less than 0.9% and the contact pressure also decreased domparing with the ordinary concave one. In this report, the effect of the zero-spin disk/roller was confirmed by the calculation and the experiment. The efficiency of the zero-spin disk/roller was calculated by considering the power transmission of the backup roller based on the traction curve. The calculated efficiency and speed efficiency were 87.7 to 92.7% and 99.0 to 99.4%, respectively. These efficiencies were measured by the experiment using the prototype S-CVT equipped with the zero-spin disk/roller. The results of 79.6% to 95.2% and 99.0 to 99.1%, respectively, were in agreement with the calculated results.

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Recent investigations have confirmed that CN_x (Carbon Nitride) coating showed superlow friction coefficient when it slid against a Si_3N_4 ball in N_2. However, superlow friction was not kept when it lubricated. It was considered that lubricant oil swept the transfer film. To clarify superlow fiction possibility of CN_x coating using under PAO (poly-alpha-olefins), we prepared 4 different friction pairs as (a) as-deposit CN_x vs. a Si_3N_4 ball, (b) as-deposit CN_x vs. CN_x transfer layer on a Si_3N_4 ball, (c) CN_x surface rubbed under N_2 blowing vs. a Si_3N_4 ball, and (d) CN_x surface rubbed under N_2 blowing vs. CN_x transfer layer on a Si_3N_4 ball. We investigated the effect of running-in, or to do the effect of CN_x transfer layer, on friction coefficient under PAO. In the case of using CN_x surface rubbed under N_2 blowing to friction test, the lowest friction coefficient was obtained approx. 0.017 in PAO. In order to know the differences of CN_x coatings' surface energy, which was before and afer rubbing under N_2 blowing, we measured contact angles of water and CH_2I_2 droplet on as-deposit CN_x and inside of wear track to calculate hydrogen bond component and dispersion force component. The CN_x coating after sliding under N_2 blowing indicated higher dispersion force component value than as-deposit CN_x. It seemed to be a hydrophobic surface. We assumed that the hydrophobicity made the CN_x low friction coefficient surface rather than as-deposit CN_x.

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A hypothesis was presented concerning the effect of the axial residual stress at the first thread root of a bolt on its fatigue strength. However, this has not yet been verified since the residual stress which may exist locally around the thread root cannot be measured or estimated with sufficient accuracy. This study aims to clarify the effect of the axial residual stress on the fatigue strength quantitatively by using newly developed technologies. As the first step, the residual stress at the root of groove-rolled specimen was measured by X-ray method with CCD positioning system, and two-dimensional FEM simulation for groove rolling process was performed by using DEFORM with simple plane strain model. The experimental results show that the compressive residual stress of 700MPa level exists at the root surface, and the maximum residual stress of 1200MPa level is generated at the inner layer of about 0.5mm from the surface. Such a residual stress distribution can be simulated by FEM although it is affected by the coefficient of shear friction and the restraint conditions which may affect the circumferential material flow in groove rolling process.

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Ski deflection with its torsion and the ski-snow contacting pressure have been measured simultaneously during the actual turn on the snow surface. Ski deflection and the torsion were measured by the deflection sensor beam that was developed by the authors. Ski-snow contacting pressure was measured applying commercial pressure sensors. In the long carving turn on the well pressed snow surface, pressure showed a hill distribution that pressures were high around the boot center area. The deflection of the ski in the front side well corresponded with the pressure applied in front of the boot center. The deflection caused by the torsion was small. Applying the average ski deflection profile on the remained snow groove, it is estimated that the region between the top and the boot center area makes the carved groove by partly compressing and partly excluding the snow. The tangents of these surfaces have counter angles with the turn trajectory tangent and the applying pressure on this area produces the turning force.

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In recent years, it is strongly demanded that edge roll off of workpiece be diminished in polishing silicon wafers and glass disks and, however, the conventional polishing technologies cannot meet the demand. In this study, using finite element method of a polishing model, the influences of the mechanical properties of a polishing pad on the contact stress distribution near the workpiece edge surface were investigated. As a result, it was found that a double-layered polishing pad had a possibility of suppressing the stress concentration significantly near the workpiece edge, namely, the edge roll off of workpiece. Based on the analytical result, a double-layered polishing pad having extra-fine fiber layer as upper layer and hard polymer layer as lower layer was developed. A series of polishing experiments for silicon wafers and glass plates revealed that the finishing efficiency was much higher than that obtained with conventional polishing pad and the edge roll off of the workpiece could be significantly improved.

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This paper makes it possible to predict the output motion of a parallel mechanism and proposes a method for generating a tool path of a machine tool consisting of the parallel mechanism. As a numerically controlled machine tool generally processes a work by interpolating an ideal shape with linear lines, a deviation between a path of tool and the ideal shape can be estimated easily. However, an input-output relation of the parallel mechanism is nonlinear, and accordingly an output pose of the parallel mechanism can be hardly determined by the direct kinematics. A prediction of the deviation of the parallel mechanism machine tool is therefore extremely difficult, so that a generation of its tool path that ensures a given allowance is not easy. Thus the present study proposes a simple method to predict the tool path of the parallel mechanism by approximating its motion with a spiral path. By using a prediction result, the study determines an efficiently optimal cutter location data to realize the tool path that ensures a required deviation.

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Sapphire has high hardness, chemical stability and high wear resistance. When a sapphire is used as a product, it must be machined into a desired shape. However, it is very difficult to machine the sapphire because of its high hardness. By the way, the sapphire can react with silica at high temperature and under high pressure. The purpose of this research work is to machine sapphire by tool wear during cutting of glass which contains the silica. An apparatus for this machining is developed. Next, machining experiments are performed. The sapphire can be machined by silica and the finished average surface roughness of 0.01μm is obtained.

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A linear-motor-driven table sustained by constant-flow hydrostatic water bearings which are free from environmental pollution is developed. The static characteristic of the developed table system is experimentally investigated. Since the constant-flow hydrostatic bearings needs no restrictor, such as orifice or capillary tube, blocking of the restrictor by bacteria, sludge, and rust of steel can be avoided. A miniature gear pump applied showed good constant flow performance for the hydrostatic bearing without pump pulsation. A simple one-side-recess type bearing is chosen for the system. In order to obtain high sustaining stiffness, preload is given to the bearings using attractive force of a core-type linear motor. The preload is effective in both vertical and horizontal directions by using the slant arrangement of the linear-motor magnet. The measured sustaining force is 4.5kN and static stiffness is 0.66kN/μm under bearing clearance h=16μm and flow rate Q=0.92mL/s.

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