In this paper, two kinds of the Hydrodynamic Grooved bearing with and without oil circulation port are discussed. (1) 15,625 kinds of bearing designs that combined six parameters with five stages that influences in the cavitations were analyzed. (2) The optimized design that filled plural required performances of the Hydrodynamic bearing (the radial stiffness, the thrust stiffness, the thrust flying height, the friction torque, and the vapor pressure area rate) ware simulated by computer. (3) The optimizing policy of the Hydrodynamic bearing design was made clear. (4) The direct calculation method was applied to the analysis of the Hydrodynamic bearing.

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High coefficient of friction and wear resistance are required for a mechanical brake. Especially in a wet type brake, a rotor has necessary to contact with a pad directly to acquire high frictional force. This research is carried out to investigate the surface property with high friction coefficient of force in wet condition. The micro wavy and high hardness surface combined machining laser heat treated carbon steel. Laser heat treatment on the surface is undertaken by carbon dioxide laser. The characteristic of friction of this micro wavy surface is investigated to compare with the surface finished. The surface finished by cutting after laser heat treatment have higher static coefficient of friction compared with the surface finished by polishing or cutting. The smaller laser scan pitch becomes, the larger static coefficient of friction is obtained. When the angle between friction direction and laser scan direction is 45°, the largest static coefficient of friction is obtained.

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A pressure wave propagating in a tube often changes to a shock wave because of the nonlinear effect of the fluid it is traveling through. The purpose of this study is to establish a practical analytical model to analyze this phenomenon. In the first report, a concentrated mass model was proposed to analyze a nonlinear pressure wave phenomenon in a straight cylindrical tube. In this paper, the modeling of an enlargement and a contraction is proposed. The model at the enlargement and the contraction consists of masses, nonlinear pressure elements, base support dampers, and nonlinear dampers. The nonlinear damper is derived from pressure loss at the enlargement and the contraction. To confirm the validity of the proposed model, an experiment on a sound tube with an expansion-chamber muffler is performed and the experimental result is compared with the numerical result obtained by the concentrated mass model. The numerical computational result agrees very well with the experimental result. Therefore, it is concluded that the proposed enlargement and contraction model is valid for the numerical analysis of nonlinear pressure wave problem in a tube with an expansion-chamber muffler.

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It is well known that zero and one nodal diameter (k=0 and k=1) modes of blade system interact with shaft system. The former is coupling with torsional and/or axial shaft vibrations and the latter with bending shaft vibrations. This paper deals with the latter. With respect to k=1 modes, we discuss experimentally and theoretically in-plane blades and out-of-plane blades attached radially to rotating shaft. If we excited the shaft at the rotational speed of Ω=|ω_b-ω_s| (where ω_b=blade natural frequency, ω_s=shaft natural frequency and Ω=rotational speed), we examined that the exciting frequency v=ω_s induced shaft-blade coupling resonance. In addition, in the case of the in-plane blade system we encountered the additional resonance attributed to deformation caused by gravity. In the case of the out-of-plane blade system, we experienced two types of abnormal vibrations. One is the additional resonance generated at Ω=ω_b/2 due to unbalance of the shaft and anisotropy of the bearing stiffness. The other is a flow-induced self-exited vibration caused by galloping due to the cross-section shape of blade tip, because this instability disappeared at rotation test inside a vacuum chamber. Both occurred at the same time and both leads to the entrainment phenomenon, which was identified by our own frequency analysis technique.

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Acoustic environment during the launch, which results in the severe random vibration of satellite components and large surface structures, is the one of major design consideration. Empirically, spacecraft box-like component is usually critically sensitive to the random vibration from the attachment point rather than acoustics, because the vibration path to component is more superior to that of acoustic path. However, spacecraft subsystem with large surface area such as antenna and radiometer may have equal sensitivity to both ambient diffuse acoustics and random vibration from attached joint to spacecraft structure. These spacecraft subsystems have been designed and verified by tests of random vibration or acoustics. Unfortunately, there has been no analysis method which is simple and effective to be used for the evaluation of the test severity, instead of empirical approach. In this paper, a simplified approach using joint acceptance to calculate the structural vibration under diffuse acoustical excitation is proposed. The numerical examples used to validate the method are shown.

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We conducted full scale experiment to study the derailment mechanism of high speed railway vehicle by earthquake ground motion. The experiment was arranged to mimic the vehicle/track conditions of Tokaido Shinkansen by using the bolsterless bogie and the track materials both presently in use for Tokaido Shinkansen. Large excitations enough to derail the test vehicle were given, so that derailment motions were fully captured. Through the tests, (1) Total 34 cases of derailment were observed by the sine wave excitations in the frequency ranges of 1.1Hz to 1.5Hz. The test vehicle was derailed as the result of rocking motion. (2) Wheel lifts of around flange height without derailment were observed by the sine wave excitations in the frequency ranges of 0.5Hz to 1.0Hz. (3) By comparing the vehicle motions of two cases of different ballast conditions, we learned that dynamic features of the ballast track brings no significant difference on the vehicle dynamics of those cases. (4) Finding reasonable match between the experimental results and analytical results obtained from the simulation developed by the authors, we further investigated the possibility of derailment by the sine wave excitations in the frequency ranges of 0.5Hz to 1.0Hz and found that vehicle was to be derailed by giving larger excitation amplitudes than those given in the experiment.

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In the field of precision positioning and measurement, air-type anti-vibration apparatus are widely used. Nozzle flapper servo valve is commonly used for control of supplied air to air-type anti-vibration apparatus due to the linear characteristic of its valve. However, this valve always exhausts most of supplied air. Therefore the use of spool servo valve has been proposed. This valve little exhausts supplied air, however has non-linear characteristic. As compensation of the non-linear characteristic that this valve has, the model following control was proposed in the reference. The effectiveness of this control was shown in the paper, however the concrete adjustment method of this control is not clarified. This paper's object is to clarify the above problem.

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When a shaking-table of an earthquake simulator is driven for the seismic experiment of a specimen, its motion is affected by a reaction force caused by the specimen on the table. This paper presents a reaction force compensation methodology for shaking tables in earthquake simulators. This methodology is designed by using the RFC(Reaction Force Compensation) based on the disturbance observer method in real time. RFC observes the reaction force and compensates the observed reaction force by using a phase lead compensator. The effectiveness of the proposed technique is verified by using a two-dimensional large shaking table.

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This paper considers a system identification procedure of multi-degrees-of-freedom anti-vibration apparatus. A general procedure of system identification requires the determination of some parameters such as model structure, model order and sampling frequency of I/O signal. Although general guidelines for the determination of these parameters have been studied and reported, some of the parameters should be selected and determined through trial and error in practical engineering fields. Discussing the determination guideline of these parameters is quite useful in order to make a system identification technique applicable in practice. In this paper, the influence of some parameters on system identification results are discussed through the comparison of frequency responses of the models obtained by subspace method under different conditions. These consideration contribute to the application of a system identification technique in practice.

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The purpose of this research is to suppress the inclination of the pneumatic isolation table caused by the relatively quick movement of the servo stage set on the isolation table. Pneumatic isolation tables are widely used in ultra precision machineries, such as steppers and precision measurement apparatuses. This is because they can support a high payload with a relatively low energy. Recently, pneumatic isolation tables for the semiconductor manufacturing devices have required higher performance as the line widths of semiconductors become finer. Therefore, the size of isolation table including the counter-mass is becoming larger, and the characteristics of the air springs are becoming softer. When the servo stage on a soft isolation table quickly moves, the table inclines and the recovery takes some long time. In this paper, a new compensation method of the inclination of isolation table using pressure differentiators is proposed. The pressure change in the air spring is detected with the pressure differentiator and it is positively fed back to realize higher pressure response. The performance of the proposed method is evaluated using an isolation table having 4 air springs in vertical direction, and a pneumatic driven servo stage on it. The effectiveness of the proposed method is demonstrated experimentally.

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The inverted pendulum is often used for confirmation of control theory and a new control design, because it is an unstable system and experiments of it are easy. This paper discusses a swing-up problem of the inverted pendulum. While an inverted pendulum is usually swung up with the horizontal movement of a cart, we propose a new swing-up method by using both a horizontal and vertical movements of a cart. The movement of a cart is designed to increase the energy of the pendulum. With the proposed method, a time for swing-up is reduced. Effectiveness of the proposed method is confirmed through the experiments. Because the proposed swinging-up control does not use system parameters (mass and length of pendulum etc.), that has robustness against parameter uncertainty.

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This paper considers the problem of controlling a class of nonholonomic systems in second-order chained form, which is described by a set of nonlinear differential equations. Our novel approach is based on coordinate transformations and sampled data control. First, the nonholonomic system is discretized by a zero order hold and a sampler. A time-varying discrete-time coordinate transformation is utilized to reduce the stabilization problem to a standard pole assignment problem for a linear time-invariant discrete-time system. Both a new state feedback controller and a new dynamic output feedback controller based on state-observer are presented for obtaining global exponential stabilization of the system. Moreover, the proposed design methods are simple and straightforward. Some simulations are performed to validate the effectiveness of the proposed controllers.

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This paper discribes a method of fault detection and isolation of internal and external sensors for mobile robot. Soft faults, which appear as change of sensor gains, are handled for three internal sensors (two wheel-resolvers and one gyro). They are diagnosed based on estimating the robot velocity with a fault-free external sensor (a forward-looking laser range sensor) via scan matching method. Abrupt faults of the external sensor are also handled, and they are detected based on errors related to the scan matching. False or missed detection of sensor faults in dynamical environments are improved based on occupancy grid method. Experimental results in indoor environments show the performance of our method.

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In this research, an autonomous robot system is developed for a table transportation, which is motivated by the fact that tables are heavy and frequently transported in daily life. As the process of the table transportation, the robot recognizes tables, moves under the table, lifts up the bottom side, and transports it. In this strategy, the robot must hold around the center of gravity of the table to avoid falling. Therefore, the robot is equipped with pressure sensors to measure the center of gravity and adjust the lift up position. The robot is also equipped with lift up mechanisms with independent four support points developed for stably lifting up the table even when there are something on the table. Thus, this paper describes the details of the developed robot system, the equipped functions, and the experimental results for an automatic table layout.

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The research of image-based control for nonholonomic mobile robots is a recent topic of mobile robots. There are few researches about image-based control of mobile robots with a central catadioptric camera. A central catadioptric camera is very effective to keep target objects in the camera field of view because of its wide area view. In this paper, a new image-based path following control method for a nonholonomic mobile robot with a central catadioptric camera is proposed in the image parameter space. It is confirmed by indoor experiments that the designed system has high performance in real world.

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In this paper, for an ego-motion estimating problem of mobile robot, we propose plug and play type ego-motion estimator that user can freely select sensor type and flexibly install the sensor. In this algorithm, each sensor is dealt as a sensor unit that has computing equipment, and each sensor unit estimate ego-motion and the sensor parameter. Moreover, sensor units are connected via network, ego-motion estimate of each unit are exchanged each other. Then the exchanged information is fused by Covariance Intersection method, which is one of a decentralized estimator. By this, this algorithm can estimate ego-motion not affected by number of sensors and sensor type. Furthermore, user can flexibly install the sensors by this algorithm because sensor parameters are estimated in each unit and compensated information are exchanged each other. In addition to this high flexibility, an experimental results denotes that our method estimate ego-motion with adequate accuracy.

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This paper describes the improvement of the multi-directional micro switching valve chip with ten outlets. This switching valve chip has a special rotary mechanism, allowing this chip to quickly switch among ten outlets under high pressure (higher than 500kPa). However, users needed to adjust the positioning of the push-rod against the rotor and the positioning of the bias spring against the plunger, when users utilized the switching valve chip. Therefore, we developed the bias spring mechanism that doesn't need adjustment. The switching valve succeeded to built the bias spring mechanism into the chip. Moreover, the valve performance such as flow rate vs. pressure property was evaluated experimentally.

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There are many cosmetic companies and visual appreciation is undertaken by human expert though, skin texture has not been investigated quantitatively and automatically so far. In this study, image processing method for analyzing skin texture is proposed. Since sulci is very important for expressing skin texture, we apply cross binarization method for extracting sulci and by matching short lines onto sulci extracted, sulci is expressed by short lines. By analyzing short lines in terms of number, direction, and so on, quantitative indices are suggested for displaying feature of sulci. We then investigate whether it is available or not to predict visual appreciation score by quantitative indices. By using multiple linear regression analysis, we find that visual appreciation score is predictable in high rate by using quantitative indices we have proposed. This method comes into practical use since January 2009.

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This paper presents the detection of sliding with integrated piezoelectric vibration tactile sensors. A tactile sensor is important for robotics to find a mechanical pressure and contact condition between grippers and objects. We have proposed the piezoelectric vibration-type tactile sensors to realize a high sensitivity and a wide measurement range. This type of tactile sensor is proposed by embedding the piezoelectric vibration sensors in a PDMS basis for stable responses. The basic experiment of sliding detection is also presented using proposed tactile sensor between the aluminum protrusion and the sensor surface covered by soft-material to detect the sliding and its direction.

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In order to improve the operation precision of the remote manipulation systems, it is necessary to clarify the human characteristic of length perception by using fingers. In previous studies, the length perception has not been investigated using multi-fingers grasping. Therefore, we developed a tactile length measuring system in this study. By using this system, some experiments were made to clarify the human length perception for fingers (thumb, index finger, middle finger). These results suggest that human tactile length perception in case of three fingers using is better than that of two fingers (thumb and index finger) condition.

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Rehabilitation for upper limb is important for stroked patients and the aged people with motor disorder. In recent years, the rehabilitation system using robot and virtual reality is expected to quantify the effect of rehabilitative training. Furusho laboratory of Osaka University has been developing many rehabilitation systems with high safety by using virtual reality technologies. On the other hand, the rehabilitation focusing on the neuro-science is more effective. Dr. Miyai (Morinomiya Hospital) has established observation system of the brain activities during treadmill exercises for healthy adults. In this paper, we describe about the development of evaluation system of motor function for upper limbs using 3-D rehabilitation robot "EMUL" and brain function imaging method "NIRS". On this system, we developed a tracking training program called "Eight Vertex Reaching Program". 7 healthy adults excised this program and we recorded motion data and brain function data of these subjects during this training. Then, we could observe subjects' learning processes against the training. And we could know which place of cerebral cortex activated about leaning processes of the training.

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A numerical analysis method for elastic contact mechanics between a spherical slider and a flat disk with a sub-nanometer roughness is presented by taking account of Lennard-Jones(LJ) surface forces. In contrast to conventional theories, the elastic deformations and LJ surface forces of both mean surfaces and contacting asperities are taken into account. Calculated results for 2-mm radius glass slider are shown and compared with experimental dynamic indentation characteristics. Convergent solutions obtained by a simple under-relaxation iteration method are shown for low roughness contacts with sub-nanometer mean surface distance and asperity height of 2-mm radius glass slider and 20-mm radius head slider contacting with a magnetic disk. It is found that the increase in adhesion force with a decrease in mean surface distance can be suppressed by deceasing asperity radius and increasing asperity density and Young's modulus.

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The pulse plasma CVD method with self bias discharge was applied to Diamond-Like Carbon (DLC) film coating of the die used under dry conditions. When DLC film was deposited on the die with deep hole, a uniform thick film was observed down the depth of the inner wall and the hardness and adhesive force of the film was adequate. Then, the tribological properties of DLC films against aluminum were studied with a ball-on-disk type tribometer under dry conditions. After repeated friction over a long period, the surfaces of DLC films derived from both methane and acetylene became smoother and the coefficient of friction for DLC film from methane in the initial sliding decreased. Lastly, the life of DLC film coated die was evaluated in ironing process of aluminum cup under dry conditions using an actual press machine. The die from methane gas showed significantly longer life than that from acetylene. It was inferred that longer life of die from methane was brought about by antiwear properties due to high hardness of DLC film during the continuous ironing process of aluminum cup.

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In railways, when trains run through sharp curves at some low speed, there is a possibility to have wheel climb derailment. Previous researches said that the increase in the friction coefficient between a rail and a wheel is one of the reasons of the derailment. In this study, the variation of friction coefficient with the number of rolling was investigated. In order to identify mechanisms of the variation of friction coefficient with the number of rolling cycles, some surface analyses were conducted. The results of sliding tests showed that the friction coefficient was low as 0.3 below 10^2 cycles, then it reached the maximum value of 0.6 at 10^5 cycles. The results of surface analyses suggested that the variation of friction coefficient was caused by the variation of composition of oxide with the number of rolling. If the oxide on the rolling track governs the friction, the increase of friction coefficient with the number of rolling contact can be detected by the measuring the electrical resistance of the oxide made during rolling contact. In order to investigate the relation between electrical resistance of oxide on the rolling track and friction coefficient, the electrical resistance of the oxide on the rolled track was measured. It can be found that friction coefficient was a function of electrical resistance and estimated from the electric resistance.

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Nickel may erode diamond efficiently because carbon diffuses into nickel. We conducted erosion tests by bringing a pure nickel wire into contact with a diamond in a vacuum. The results revealed that as the erosion mark on the diamond surface became larger, the carbon content in the surface layer of the nickel wire increased. This implies that a diamond can be thermochemically polished by nickel. On the basis of this result, a diamond cutting tool was polished by bringing its rake face into contact with a nickel plate heated at 523K for 6h in a vacuum of 4.2×10^3Pa. Approximately 4nm-thick layer was removed from the rake face. However, this technique had an unexpected adverse effect on the tool durability. The tool had low resistance to chipping of the cutting edge. Therefore, its tool life was extremely short compared with that of a mechanically polished diamond cutting tool. Thus, this implies that diamond cutting tools should be polished by a heated copper plate, that is, by the oxidation-deoxidization reaction discussed in our previous study.

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Recently the achievement of further high flatness of workpiece is strongly required in mirror finishing. Especially the edge roll off of silicon wafers as the substrates of semiconductor devices is demanded to decrease in polishing process for raising the yield of IC chips. However, the conventional polishing pad cannot meet the demand. In the previous study, a double-layered polishing pad having extra-fine fiber layer as upper layer and hard polymer layer as lower layer was developed to overcome the problem and it was found that the pad brought the high-flat edge and high finishing efficiency. In this study, constitution of the polishing pad was analyzed and investigated by using finite element method of a polishing model and considering the relative dynamic motion between the pad and the workpiece for improving the edge flatness further. A series of polishing experiments for silicon wafers revealed that the flatness of the edge shape is improved significantly with the newly developed pad based on the analytical results.

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The four-body polishing in which polymer particles are applied as a carrier of abrasives solved many problems of conventional polishing but some problems remained such as bubbling phenomenon and time-dependent deterioration of removal rate. In order to solve these problems, we advanced some experiments by employing some hydrophilic polymers and inorganic particles as the carrier particle. As a result, a hydrophilic polystyrene particle which was given a hydrophilic group on the surface accomplished better removal rate than untreated polystyrene particle. The bubbling problem was relieved completely by application of amorphous calcium phosphate particle. Though the removal rate decreased by employing some kind of porous inorganic particles, a distinguished surface roughness and edge geometry was obtained. Meanwhile, the removal rate was improved compared to the conventional polishing by using a molten-silica and an aggregated-silica particle. There are two maximum removal rates when the concentration of the silica particle was regulated. Furthermore, an exceptional removal rate was attained by optimizing the concentration of molten silica particles and changing the polishing conditions.

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This paper describes the system that can decide the efficient parts layout for assembly cell-production before setting up the real cell-production line in a factory. The system is called Virtual Assembly Cell-production System (VACS). VACS consists of two module, a parts layout decision GA system and a virtual production system. Especially, the GA system adopts the original crossover method called Twice Transformation Crossover. It is ascertained that VACS is useful by applying it to a cell-production line of a personal computer assembly.

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To maximize designers' creativity during collaborative design processes, this paper focuses on designers' individual differences, especially differences in their idea evaluations, and proposes an analytical method for revealing their differences. During creative group activity, when a designer represents an idea using some words or a short sentence, the others imagine the concrete image of the idea form the presented words and evaluate the concretized idea in their mind. However, the results of their concretizations and evaluations vary among designers in most cases. Such differences or diversities seem to be undesirable, but they have a huge potential for leading new ideas during divergent processes of exploring ideas. Therefore, the method proposed here reveals designers' individual differences by analyzing the results of their idea evaluations and encourages their further idea explanations. In addition, to confirm the effectiveness of the proposed method, the case study is carried out and its results and detailed processes are analyzed.

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Qualitative risk assessment such as preliminary hazard analysis (PHA) is extremely crucial in promoting inherent safety design in the early phase of development. Compared with previous developments, inherent safety design is being pursued more thoroughly as product development becomes larger and/or more complex. On the other hand, many engineers share their work loads and have more interfaces in their projects. Under these situations, hazard identification and risk evaluation in qualitative risk assessment should be improved with quantified expression. The authors proposed the methodology of quantification and approximation formulas in the other presented paper. This paper presents actual effectiveness of the presented methodology with the results of questionnaire survey for engineers of satellite development as a case study. Furthermore, this paper includes considerations for application to improve information sharing and risk communication of qualitative risk assessment with obtained parameters of the approximation formulas.

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