In order to obtain a highly accurate periodic solution for systems based on strongly quadratic nonlinear oscillators, an averaging method improved through the use of the Jacobian elliptic function is proposed. In the improved averaging method, the Jacobian elliptic sine function is incorporated as the generating solution. The stability criterion for the approximate solutions obtained by this method is also presented. The proposed method is then applied to several different typical nonlinear oscillators. The efficiency of the proposed method is demonstrated by comparing the computational results with those obtained by the shooting method and the conventional averaging method. It is confirmed that the proposed method provides a more accurate solution than the conventional averaging method, which uses a trigonometric function as the generating solution.

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In rotating machinery, the unbalance of the rotor causes many resonances at the critical speeds corresponding to various modes. In this paper, a method of vibration control for rotor systems utilizing the disturbance observer (D.O.) is proposed. The nonlinear terms, unbalance, parameter variations and uncertain terms of a rotor system are lumped into a disturbance term, and this term is cancelled by using D. O.. As a result, the vibrations of the system are controlled to a small amplitude in all over the rotational speed range. Using the information of disturbance obtained by D. O., the unbalance of the first mode is estimated simultaneously. Moreover, the effects of some parameter errors of the control system are also investigated. The validity of the proposed method is verified through numerical simulations and experiments.

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Dynamics of a ball bearing retainer of the reaction wheel is investigated through experimental tests and numerical simulations. Disturbances of normal and abnormal RWs are compared, and then relation between retainer mass imbalances and their dynamics are investigated. As results, a trade-off relation between instability reduction and disturbance reduction is verified and one of the criteria to decide the appropriate mass imbalance is proposed.

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Health monitoring of slabs is generally carried out on the basis of their stiffness. So, in the first report, the method to identify spring constant, mass and damping coefficient separately by wavelet transform of an excitation force and response accelerations was proposed and examined. To develop the research, the method to identify spring constant is, in the second report, theoretically investigated on condition that the measured data of the excitation force and the response acceleration include noises. The method is to find the specific value of constant α in the analyzing wavelet which gives the most reliable value of the spring constant according to the graphic shape of the relation between identified mass and constant α. In this report, it is examined to expand the method to five degree-of-freedom models.

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This paper presents an evaluation method of coupling structures for high frequency vibration by Statistical Modal Analysis. For low frequency domains where the modal analysis is effective, Substructure Synthesis Method (SSM) has been studied as a modeling technique for coupling structures. However, with modal analysis based on finite element models, it becomes difficult to maintain the accuracy with increased frequency. Additionally, Statistical Energy Analysis (SEA) has not been established yet as a method of high precision for the prediction of noise and vibration because of the assumptions and approximations. From this point of view, a statistical method using modal analysis (called Statistical Modal Analysis; SMA) was proposed. However, the SMA only applies to a flat plate and a L-form structure. In this paper, the SMA is applied to a coupling structure that is part of the Gas Heat Pump Outdoor Unit. As a result, it is shown that the SMA is applicable and effective to analyze the complex and coupling structure vibration.

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Several packages analyze a set of eigenvalues of rotor-bearing systems at given speeds. But it is still hard to identify each eigenvalue behaviors depending to speeds. We propose a solver which can continuously follow an eigenvalue modification by speed change. In our method, an eigenvalue and eigen vectors are replaced by state variables which difference are defined by the sliding mode control. Hence, the numerical integration provides variables grasping the exact value in any speed. A several case studies on rotors supported by oil-film bearings, a time-lag bearing and the critical speed calculation to demonstrate the effectiveness of our tenacious solver.

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Impacts spheres are one of the basic problem in engineering field. The severity of impact is generally characterized by Coefficient of Restitution. This paper intends to investigate the effects of inelastic deformation on the Coefficient of Restitution in direct central impact of two equivalent spheres. The experiments of diret central impact of two spheres were conducted for bearing steel balls (JIS SUJ2). The steel balls were impacted by pendulum motions. Static tensile tests and split Hopkinson bar tests were conducted to obtain the static and dynamic stress-strain relations of SUJ2. The test pieces and the spheres were annealed under same condition before the experiments. The rise of yield stress with the strain rate was confirmed. The author han already dealt with the elastoplastic impact of SUJ2 balls. The elasto-plastic analysis underestimated the Coefficient of Restitution. Present paper deals with the elasto/visco-plastic impact of SUJ2 balls. Coefficients of Restitution and contact duration obtained from the experiments and those obtained from Finite Element Analysis were compared. It was shown that the experimental results were simulated well by elasto/visco-plastic analysis considering the dynamic stress-strain relation for SUJ2. It was recognized that the effect of dynamic stress-strain relation could not ignore in the low speed impacts.

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Incompatibility between two colliding cars is becoming an important issue in passive safety engineering. Indicating signs of incompatibility, “over-riding and under-riding” and “forking” are likely caused by geometrical incompatibility in vertical and horizontal directions. The issue is, therefore, not only.a problem for partner-protection but also a possible disadvantage in self-protection. One of the possible solutions of this dual contradictory problem is to have a good structural interaction between the front-ends of two cars. In this study, it was hypothesized that homobeneous front-end could be a possible better solution for good structural interaction. Stress distribution at the front-end surface can be taken as possible indicators to quantitatively evaluate homogeneity. A multiple load-cell berrier enables to analyze stress distribution by measuring force through crash tests. In addition to digitizing stress distribution on the load-cell surface, statistical techniques can be used to quantify the deviation. Both simulation and experiment were conducted on actual front-end frame structure to examine the validity of the hypothesis and the capability of the proposed indicators. Finite element results (RADIOSS-CRASH) match with experimental result. Effect of curvature in dispersion of loads was also studied.

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This paper deals with experimental identification of the stiffness and damping in dynamic collision between a slider and a stationary magnetic disk. In experiments, the collision motion of a spherical slider on the disk surface is measured by LDV. We used an Al₂O₃TiC spherical slider with a radius of 1 mm and two kinds of magnetic disk whose substrate is Aluminum (Al) and glass. The contact force and damping were identified so as to minimize root means square value of error between the experimental data and the analytical results of a single DOF slider motion calculated from the six different damping force models. As a result, we found that the contact force due to penetrating depth can be accurately estimated by Hertzian contact theory using the elastic parameters in the substrate. The damping coefficient is proportional to the real contact area and is different between in the penetrating and repulsing processes of the slider. The damping coefficient in repulsing process is more than two order larger than that in penetrating process in the Al disk. The damping of glass disk is almost zero.

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The radiation efficiency of a plate carrying concentrated masses has been studied. The variation of the radiation efficiency of a plate occurs due to attaching a mass to the plate at frequencies below the coincidence frequency. The reason of the efficiency variation can be interpreted physically by using the concept of volume velocity cancellations. The volume velocities on the plate surface except the regions near the four corners are canceled out when the plate is uniform, while the cancellation of the volume velocities is disturbed around the mass attached on the plate. Attaching a mass increases the radiation efficiency of a plate. In this paper, the approximate expression has been developed for the variation of the raiation efficiency of a plate due to attaching concentrated masses in case where a large number of modes are excited. Experimental results show that the approximate expression is valid and useful.

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This paper addresses the active power flow control of a flexible beam. Unlike conventional modal-based vibration control, power flow control falling into a category of active wave control has the potential for suppressing all the vibration modes of a target structure. From a viewpoint of wave propagation, this paper presents a novel power flow control using vibration intensity as a criterion of vibration energy flow. By expanding the conception of the approach presented in the work, a control method to generate a quiet zone on a designated area of the target beam is then proposed. Finally, a numerical simulation as well as an experiment using adaptive feedforward control was conducted, demonstrating the validity of the proposed active power flow control.

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The quastitative condition starting flutter vibration of a pipe was studied experimentally which is caused by the flow parallel to a pipe in fluidized bed. The pipe was designed and set by wires so that it has freedom of both torsional and bending motion, which resembles to the system of the cooling pipe model used for chemical plant. The occurrence of self-excited flutter vibration was observed over the critical flow velocity in fluidized bed. The dependence of critical velocity was found to be proportional to the natural frequency of torsion. This fact is simply explained by the aeroelastic vibration theory. This vibration is a self-excited mode, which is a coupling of torsional and bending motion. From the result of the experiment, the coefficient, which determines a critical condition of flutter vibration, was obtained quantitatively.

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The lifetime of a rotary blood pump as an artificial heart is mainly determined by the durability of mechanical parts such as bearings and seals. The purpose of this study is to develop a durable centrifugal blood pump with self-bearing motor techniques. A magnetically suspended centrifugal blood pump by using an axially levitated motor is reported. The axially levitated motor consists of a top stator, a levitated rotor, a bottom stator, and a permanent magnet bearing. The levitated rotor is set between the top and the bottom stator. The axial position of the rotor is controlled by using the electromagnets. The maximum head pressure and the maximum flow rate of the magnetically suspended centrifugal pump were 200 mmHg and 8 1/min, respectively. The developed pump displayed good magnetic suspension performance and sufficient pump performance as a ventricular assist device.

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It is important to reduce consumption of biomedical reagent, since some of them are quite expensive or some may cause environmental pollution. There have been reported on the biochemical micro-chips in the field of μ-TAS (micro total analysis systems), and they contributed to reduce the amount of sample liquids as well as reagent. However, most of the reagents are injected into the chip from outside through a tube. There is large dead volume in such operation. Therefore, here we propose a novel micro-injection port to minimize the dead volume. We employed a micro-valve which utilizes thermal sol-gel transformation of thermosensitive hydrogel. The valve is closed by heating the microelectrode. The three-dimensional microchannel structure is fabricated by the newly developed microfabrication technique employing the Ink-jet Rapid Prototyping Method. We succeeded in reducing consumption of reagent for more than 99% compared with the conventional operation.

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In the design of rail vehicle, the compatibility between high speed running stability and good curving performance is quite important. Various railway vehicles with steering mechanism have been considered. Even though some steering bogies are realized on service operation, there still remains some improvement in the passive vehicle design for more tight curved track. The proposed bogie with power-steering yaw damper enables the vehicle to realize ideal curving performance on tight curved track with active control while achieving high speed running stability with passive nature of the suspension. In this paper, the theory of power-steering bogie is explained. In order to verify the performance of the newly developed steering bogie, the scaled model experimental platform with 1/10 model vehicle is originally made and experimental results show the running performance.

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The Superconducting Maglev system is conceptualized as a next-generation high-speed transportation system. For practical use, it is important to achieve adequate ride comfort particularly in high-speed running. Maglev vehicles are composed of lightweight car bodies and relatively heavy bogies which are mounted with devices such as superconducting magnets (SCMs), on-board refrigerating system. In this magnetically levitated system, the passive electromagnetic damping in the primary suspension between the SCMs and ground coils is very small. Therefore, it is effective to add active electromagnetic damping to this primary suspention, and to adjust the secondary suspension between the car body and bogie. This paper examines vibration control systems of the Maglev vehicle using actuators for the secondary suspension. Moreover, the estimated electromagnetic damping, which interacts between the SCMs and the guideway, is also considered in the model to improve the ride comfort.

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To enhance ride comfort in the superconducting Maglev system, vibrations were reduced by controlling secondary suspension between the car body and bogie. To reduce vibrations at the relatively high characteristic frequencies of primary suspension, attention has been directed toward control using power collection coils of the on-board distributed-type linear power-generator system. Because this control can apply damping directly to primary suspension, it is considered optimal in reducing high-frequency vibrations. Using a Maglev model focusing on vertical motions, this work describes the effectiveness of reducing vibrations using damping force control of the linear generator system for primary suspension and LQ control in the actuators for secondary suspension.

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It is well known that a vibration control problem using semi-active suspension for automobiles and railway vehicles is formulated as a control problem of a bilinear system. And the body of a bullet train which is one of railway vehicles is lightened for the speedup, and then its vibrations due to rigid and elastic dynamics are easily caused by various disturbances. Hence, for the present countermeasure, passive dampers such as air suspension and axle spring are located on the truck of railway vehicle. For the practical use and to promote the efficiency of vibration reduction, therefore, this study presents more suppression of vibrations and a synthesis method of robust controller for the bilinear system considering unstructured and scaled structured uncertainties of controlled system. The bilinear robust controller is designed based on H-infinity theory, the scaled structured uncertainty due to parameter variation and error is considered as performance weightings in the time domain, and the unstructured uncertainty due to modeling error is taken into consideration by shaped filters enveloping it in the frequency domain. The vibration reduction performance of semi-active suspension and the robustness for the uncertainties are verified through the numerical calculations for the case that the railway vehicle is subjected to the disturbance due to vertical uneven railway track, the mass variation and the modeling error caused by non-controlled modes. Consequently the effectiveness and robustness of the proposed control method are obtained in comparison with the conventional optimal one.

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In this paper, a new active suspension control scheme is developed so that ride comfort at any specified place becomes best. To achieve this end, two ideal models are designed so that ride comfort becomes best at each different place. Then, linearly combining the two ideal models, a combined ideal model is proposed. It should be noted that by using only one design parameter, we can easily make ride comfort at a specified place become best in the proposed combined ideal model. To achieve the good property stated above in real vehicles, a robust tracking controller is proposed. It is shown by numerical simulations that ride comfort at a specified place can be easily improved in the closed loop system using the proposed combined ideal model.

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The purpose of this study is to determine the nonlinear vibration characteristics of a spring in order to analyze the vibration response of a vehicle. In the present paper, we constructed the hysteresis restoring force models dependant on amplitude and frequency from experimental results of a dynamic hysteresis test of the tapered leaf springs, and the spring constants and damping coefficients could be calculated by using a power-function-type restoring force model. Finally, we proved the accuracy of this method by directly comparing the analytical results with the experimental results on the vibration characteristics (spring constant, damping coefficient). Using the above method, it will become possible to calculate more precisely the nonlinear vibration response of vehicles.

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This research presents an optimal design of active suspension, simulated on random road surface. In this work damper and spring are considered as sky-hook control gain and mechanical parameters of active suspension. Besides, the 8-DOF vehicle model is used for calculating the simulation. The function of energy consumption and vehicle vibration is defined as the criteria. Hence a research on the design parameters of the above mentioned criteria gives an optimal result on the vehicle vibration and energy consumption.

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This paper describes the attitude control problem of a flexible parameter varying spacecraft. Considered herein is the spacecraft consisting of the main rigid body and some flexible solar paddles which rotate at the orbital rate in order to generate more electricity. In this case, the interference characteristics of the elastic vibration of the paddles and the attitude motion of the body changes depends on the paddle angle. Therefore, the attitude control system of such spacecraft becomes parameter varying. This paper is intended to establish the systematic robust control synthesis procedure for this problem by applying gain scheduling control using descriptor equation. Capability of the method is investigated by the numerical study using the model of the ETS-VI spacecraft.

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In order to realize universal 8-legged walking of just as creatural spiders and adapt to environments, this paper is concerned with cooperative walking control for a spider-type robot. At first, we examine how a spider walks on the floor to ascertain its gait. Second, a spider-type robot which is possible to walk by 8-legs is made experimentally. And using our trial robot, we perform walking experiments to check whether various walking types are possible. The walking types are forward, beck, diagonal, revolution and R-advance. Next, we observe whether a spider reacts well to the environment and then how a spider walks. A creatural spider responds to environmental information by adapting various walking forms, in cases of escaping from natural enemies or fear, wandering around for hunting game and so on. Finally, the mechanisms of these walking forms are examined and verified through simulation experiment. And, we discuss 8-legged cooperative control. The experiment uses various information such as fatigue, fear and distance. Moreover, fuzzy theory is used for controlling the walking velocity by expressing obscure environmental information.

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The concept of robot vehicle using variable configuration segmented wheels is proposed and the mechanism has been designed and tested successfully. The rim of the segmented wheel is divided into 6 segments which can be deployed and retrieved periodically by moving the hub to an eccentric position. This robot vehicle is able to climb up obstacles and move from land to water surface by controlling the deployment of the segments. Thrusting force can be obtained in water by cyclic motion of the segments. The angle and the direction of deployment of segment are mechanically controlled by duplicated eccentric shafts. Outer eccentric shaft is driven by a body-mounted motor through an idle gear. Steering is achieved by changing the joint angle of divided body. Load contact force equalizing mechanism is simply achieved by a rotation free longitudinal shaft. The experimental data shows that these mechanisms are functioned effectively.

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Cutter location (CL) data with normal vectors can be used for not only a desired trajectory of tool's translational motion but also desired force directions for a mold polishing robot. In this paper, such normalized tool vectors are systematically generated from 3-axis CL data. The resultant CL data allow the polishing robot with an abrasive tool to realize a teaching-less operation of position and force. The present robot can also control the polishing force consisting of the contact and kinetic friction forces. During the polishing of a mold, a position feedback loop has a delicate contribution to the force feedback loop in Cartesian space so that a stable force control and an accurate pick feed control can be simultaneously achieved. The effectiveness and validity of the proposed robot have been proved by actual polishing experiments using a duralumin mold with curved surface.

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This paper describes a new control method for a redundant parallel manipulator using an internal force sensor. In conventional control methods of a redundant parallel manipulator, optimal torque minimized actuator torque or maximized manipulability by using evaluation function is decided and used. However, these methods have to use a torque controlled actuator. It's torque is small, also it is expensive. So, we propose a new control method using a conventional geared actuator in this paper. In our method, internal forces produced by actuator redundancy is detected by an internal force sensor and controlled to be zero. We demonstrate about the proposed control system and the structure, the principle, and the experimental result of the redundant parallel manipulator using the internal force sensor.

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SSM (Sensor Steering Mechanism) vehicle realizes high speed moving and high accuracy following the guide way of the road. A conventional experimental setup of SSM is equipped with a sensor arm and a deceleration gear system which controls the ration of arm and steering angle. The existence of this sensor arm prevents to realize SSM for conventional vehicles. This paper tries to replace the sensor arm with 1 kHz Smart Camera which is developed recently. By using of the difference between left and right pixel values over the each edge of the center line, the following control is applied to SSM-vehicle model. The vibration of the control system caused by the long sampling interval is reduced by using the dynamic absorber. Finally, the experimental results show the stable cornering even if the rear part of the vehicle is drifting.

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The piping inspection sometimes must be performed in places such as areas of radiation contamination and at dangerous heights, etc. In an environment in which a human cannot work, a robot is needed. Up to now, many robots that inspect the inside of piping have seen practical use. On the other hand, a robot intended to inspect the surface of piping has not been realised. It has been impossible for a robot to inspect a pipe's surface due to obstacles such as flanges, valves, curves, vertical piping, etc. The present study examines a mechanism intended to allow an inspection robot to move automatically along the outside of a pipe. We have also designed a mechanism that enables the robot to correspond to traverse flanges. This robot moves by means of magnetic wheels, and is composed of three connected units. This robot can traverse flanges by moving each of its three units; i. e., one unit moves up and down while another moves horizontally.

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This paper proposes a kinematic calibration method with simplified measurement for parallel mechanism. Since it is difficult to measure full 6 degrees of freedom of the end-effector accurately, especially orientation, the calibration method which uses as little orientation measurement as possible is discussed with simulations and experiments for a rotary type parallel mechanism. The results show the calibration performance can be improved by increasing the position measurement when orientation measurements are reduced.

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This paper presents a method for evaluating output errors of multiple degree-of-freedom mechanisms by forces applied to the output link in arbitrary direction. The output errors evaluated in this study result from elastic deformations of the driving parts. The evaluation values can be obtained by solving the eigenvalue problem of the matrix introduced from the compliance matrix which reveals the relations between the output error and force applied to a mechanism. The method will facilitate to improve the rigidity of a multiple degree-of-freedom mechanism such as a parallel mechanism in their design. Practically, the present paper designs a spatial 3-dof parallel mechanism by the proposed method. The spatial 3-dof parallel mechanism comprises 3-RPS chains and board-like links for suppressing bending deformation induced in the prismatic pairs. The paper describes the proposed method can consider elastic deformation induced in the structures partially as well as the driving parts and practically considers the shape of the board-like links for improving the output errors caused by the translational and rotational deformation in the prismatic pairs.

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For photo resist processing in semiconductor manufacturing, the precise temperature control of wafer has been demanded to realize a more fine device in recent years. However, it is difficult to achieve the precise temperature control by a current wafer heating and cooling system, because the system cannot control the temperature of transient state including wafer movement from the nature of the system. An integrated heating and cooling plate was developed to overcome above problem. On the other hand, it is difficult to achieve the precise temperature control of the plate because of its mutual intervention and unstable non-steady heat conduction. For that reason, we propose the control system based on thermal model with finite element in this paper, which is the state feedback control with scheduled gain to the process progress. Moreover, we propose the in-process estimation of wafer temperature based on system identification. Experimental results illustrate the effectiveness of the proposed method and the arbitrary thermal history control of wafer.

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Exhaust gas regulations for harmful components have been established in most countries of the world. In order to establish reduction technology for harmful components in exhaust gas, technology is required for the real-time detection of trace heavy metal components. In this paper, a method for the detection of trace heavy metal components using laser induced breakdown spectroscopy (LIBS) was examined with respect to powder and gas phase samples. Detection characteristics were obtained for Pb and Cr in real ash, and measurement sensitivity under 500 mg/kg was confirmed. Detection characteristics were also obtained for As, Be, Cd, Co, Cr, Hg, Mn, Ni, Pb, Se, and Sb in gas, and measurement sensitivity under 0.1mg/Nm³ was confirmed for these elements, except for As and Se. Future use of high sensitivity techniques is expected to reach a sensitivity level under 0.1mg/ Nm³ for As and Se.

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Maneuverability of wheelchair depends not only on mechanical efficiency but also on the environmental condition where the wheelchair runs. So, we have been aiming to comprehend mechanism of influences of road/floor conditions on maneuvering the wheelchairs quantitatively. In this paper some information obtained through many test runs of experimental wheelchair on longitudinal slopes are reported. The load/distance rate that is momentum needed to move 1 m, is useful to evaluate difficulty in maneuvering the wheelchair quantitatively. Furthermore, knowledge about factor that causes failure in negotiating a longitudinal slope by the wheelchair was acquired. Making use of the knowledge, the indicator that can estimate whether a wheelchair rider will be able to negotiate a longitudinal slope on the basis of measurement of his/her traction force using simple push-pull gauge for example.

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Purpose of epidermal ridges of humans have been said to avoid slippage and to increase sensitivity of tactile perception. In the present study, meaning of detailed geometry of each epidermal ridge is investigated. First, cross-sectional geometry of epidermal ridges are measured using imprint material. It is found that the geometry of epidermal ridges are between that of arc and trapezoid. Then, finite element contact analyses between finger section model and a flat plate are conducted. It is found that normal contact forse distribution of human epidermal ridge is much uniform compared with those for arc and trapezoid. It is also found that rapid entire slippage of an epidermal ridge occurs when tangential traction is applied. Finally, eigen value analysis is conducted. It is found that eigen frequency of the epidermal ridges agrees with FA I mechanoreceptor's sensitive frequency.

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Numerical tooth profile analysis of finish rolling process of sintered Fe alloy gears using screw-shaped tool are carried out to obtain some useful information for optimum design of the tool. P/M gears are approximated by a continuum model of a ductile porous material. Two kinds of 3 dimensional FEM models are proposed and the analytical results are compared with the experimental ones. In particular, the influence of the elastic deformation and the motion of the tool on the deformation of the workpiece are investigated in detail. The rotation motion of the tool during rolling cannot be ignored when evaluating the distribution of the amount of stock rolled of the workpiece precisely. An equivalent Young's modulus is adopted to the material properties of the workpiece to take into account the elastic deformation of the rigid tool indirectly. The analytical results about the amount of stock rolled and the tooth profiles of the rolled gear teeth are agree well with the experimental ones.

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Bevel gears are greatly influenced by the deflection of gear shafts and bearings. The reason is that both gear shafts cross and one of them is at least cantilever. Those have great influence on the transmission error which is related to the vibration and noise. In the previous report, the transmission errors were calculated, when gear shafts were supported by two bearings. However, these transmission error were greatly influenced by tooth profiles. Therefore, in this report, transmission error was calculated, when tooth profiles were spherical involute tooth type and Gleason tooth type. It were clarified how transmission error on tooth profiles were influenced by assembly errors, torque and crowning.

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To clarify leakage characteristics of the flat metallic gasket, the leakage rate of a gas and real contact area of the seal surfaces were measured under several closing loads. The static seal used in this study consisted of the ring shaped copper gasket and the two steel flanges which held the gasket. The contact surfaces of the flanges were finished by the lathe. So far the following two directions on the gasket surface were pointed out as the leakage flow paths. One was the radial direction perpendicular to the lathe turning groove and the other was circumferential direction along the groove. As the closing loads increased, the leakage flow in the radial direction ceased and only the leakage flow in the circumferential direction remained. To determine the closing load, that is the contact pressure, at which the radial leakage flow ceases, the real contact situation on the gasket surface should he observed. In this paper the real contact area between the copper gasket and the steel flange was measured using the thin polymer film of 1μm in thickness. As a result the contact pressure over which the radial leakage ceased could he predicted from the observation of the thin polymer film. In addition, the cross section of the aperture for the leakage flow in the circumferential direction was evaluated from measured real contact area, and the leakage rate was estimated by the assumption of laminar flow. It agreed well with the measured leakage rate.

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This paper deals with the running torque for ball hearings with polymer lubricant. In this study, two types of ball bearings with polymer lubricant were used. Type I featured a bearing cavity packed with a greater amount of polymer lubricant, and the ball surface, except for around the contact points of the ball and the bearing rings, was covered with polymer lubricant. Type II featured the polymer lubricant packed only on the rivet parts of the cage, and the balls were not covered with polymer lubricant. First, the running torque formulas for ball bearings with polymer lubricant were proposed as the sum of the running torque caused by the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant, the elastic hysteresis, the differential slip, the spinning friction of the balls, the EHL viscous rolling resistance, and the friction between the balls and the polymer lubricant (or the cage). Second, the calculated running torque of the proposed running torque formulas was compared with the measured running torque, within the experimental conditions (rotational speed 500-2500rpm, axial load 29.4-98.0N) of the previous report. The calculated running torque almost matched the measured running torque. In addition, the validity of the proposed running torque formulas was confirmed. Finally, the effects of the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant, the elastic hysteresis, the differential slip, the spinning friction of the balls, the EHL viscous rolling resistance, and the friction between the balls and the polymer lubricant (or the cage) on the running torque were investigated. In the case of Type I, the running torque caused by the friction between the balls and the polymer lubricant, the EHL viscous rolling resistance, and the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant affect significantly on the running torque. In the case of Type II, the running torque caused by the EHL viscous rolling resistance, and the shearing resistance of the mineral oil between the bearing rings and the polymer lubricant affect significantly on the running torque.

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A micro-contact model for chemical mechanical polishing (CMP) of Si wafer is presented. The model is developed on the basis of the Greenwood-Williamson micro contact mechanics. The atomic force microscope (AFM) is used as a polishing test apparatus to evaluate the removal rate by a single particle in CMP slurry. Using this model and AFM, the simulation on polishing of SiO₂ is performed. The model is evaluated by comparing the simulated polishing rate and that experimentally determined by real CMP processes. The validity of the AFM wear test and the contact model proposed is discussed.

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It is very easy to cause loading on a fixed-abrasive tool in the grinding process of soft metal materials such as aluminum substrates, and this leads to difficulty in the smooth running of the grinding process. Hence, a porous PVA (polyvinyl alcohol) stone is the only fixed-abrasive tool that is generally used until now. However, the PVA stone has some disadvantages that it is easy to be softered because of absorbing water during grinding, and high-density abrasive grains cannot be used due to precipitation in the polymerization process. In this research, a new high-porosity fixed-abrasive pad for grinding aluminum disks was developed. The method proposed to manufacture a high-porosity fixed-abrasive pad while TiO₂ ultra-fine powders are added into the pad. This pad made of SiC or Al₂O₃ abrasive grains not only provided for a loading-free grinding process, but also had a better finishing roughness than PVA stones.

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It has been reported that the chip breaking during lathe machining could be improved by the addition of Si and/or Cu in Al-1.0 mass%Mg-0.8 mass%Si alloy (A6061 alooy). To find out the information about the nucleation of chip-break and the mechanism of chip breaking, the surface morphology of chips was examined by using scanning electron microscopy for A6061, Si and Cu added A6061 (A6061 + SiCu) and 99.7 mass%Al (A1070). Although the chip surface of A1070 was rather smooth, shear bands and micro-cracks were observed on the free surface and the side surface of chips, respectively, in both A6061 and A6061+SiCu alloys ; they may bring about the notch effect. Taking previous results on the microstructure of the alloys into consideration, the improvement of chip breaking during turning by the addition of Si and Cu was ascribed to more frequent crack formation due to the notch effect, and it was also ascribed to faster crack propagation due to increase in the number of inclusions and in the matrix hardness.

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In order to clarify the flattening process of the high-temperature and high-speed droplet due to its impact on the substrate in an atomic level, a three-dimensional molecular dynamics simulation was conducted. The droplet and the substrate were assumed to consist of pure aluminum, and Morse potential was postulated between a pair of aluminum atoms. By visualizing the analytical result, the processes of melting and solidification, temperature distribution, deformation velocity and potential energy of atoms of the droplet were clarified. As a result, following conclusions were obtained : (1) The transfer of the droplet atoms to the horizontal direction in flattening process increases in proportion to the horizontal distance from the central axis of the droplet. (2) The solidification of the droplet starts from the outside edge of the droplet, and finishes as the flattening ratio increases.

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Scroll compressor components have spiral grooves known as scroll wraps. Since their shape is determined by an involute curve and their accuracy dominates the compressor performance, they are produced by precise contour milling using end mills. The progress in NC device for milling involute shape has enabled a feed speed control at a cutting point and a position control, keeping a cutting point constant relatively to the end mill center. Instead of the conventional method reported formerly which controls the feed speed at the center of the end mill, more precise milling process has been required, which is based on a new control. While milling the inside face of the curve, even if the feed speed is controlled so as to keep the projection cutting area constant, the cutting force increases in connection with the tool contact length. This increase in cutting force deteriorates the profile accuracy. Though controlling the radial depth of cut is one solution, the minimum depth of cut near the involute center is so small as the surface roughness, and the accuracy is not stable. In the present paper, the relationship among cutting area, tool contact length and cutting force is analyzed by the multiple linear regression analysis, and the cutting force was simulated. The result of the cutting force simulation showed a good coincidence with the experimental result in tendency. Using the result of calculation to control the feed speed at the cutting point so that the cutting force can be kept constant, it was possible to improve the profile accuracy from 8μm to 3μm.

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MQL (minimal quantities of lubricant) was applied to grooving to clarify its performance in high speed and high efficiency cutting. When grooving a bar of carbon steel with coated carbides at high cutting speeds of 4 and 5 m/s, the corner wear and flank wear in MQL cutting were improved drastically as compared with dry and wet cutting. They decreased with increasing pressure of the compressed air even if the oil was supplied at a constant rate of 7 ml/h. In addition to the ordinary blow of the oil mist, the controlled blow for changing the blowing direction of oil mist through prolonged pipes along the flank face was applied to high efficiency grooving with a cutting cross section of 1.275 mm². When the flow rate is the same, the controlled blow of oil mist reduced both the corner wear and flank wear of cemented carbides effectively.

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A method for measuring the height and thickness of drilling burr profile using image-processing techniques is presented. The system consists of a base, a CCD camera and a personal computer for image processing. The base for measuring the burr specimen is configured so that the burr is surrounded by four prism mirrors to enable simultaneous viewing of the planer and profile surfaces of the burr by a vertically-mounted CCD camera. The images of the captured burr are translated into a binary format for calculation of the thickness and height data. Measurement tests for gages with various thicknesses and heights show that measurement results were good agreement with the actual thickness and height. In theses tests, a measurement error was about 50 μm.

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The attenuation characteristics of a slit resonator that combined the adaptive feedback ANC system at a ventilation aperture of the package for leakage noise is investigated. The discrete tones radiated from an AC axial flow fan are controlled by DSP using Filtered-X Least Meane Square algorithm. The attenuation is found at the range of : 3dB-14dB with circular slit resonator, 2dB-15dB with elliptic slit resonator. Results of measurement show that the proposed system can achieve TNR (Tone to Noise Ratio) and PR (Prominence Ratio) under threshold effectively.

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This study proposes a technique to relate design intentions with each figure in a drawing. The technique will contribute to information sharing among designers and manufactures reducing in design errors by misunderstanding of design intentions. A CAD is developed by applying the technique with the functionality to draw basic figure elements necessary for mechanical designs. The information of the change of each figure, which is composed of drawing data and history data including design intentions, is stored in a XML format. The applicability of the CAD is subjectively evaluated by five evaluators comparing with the ordinal method of describing design intentions in documents through the task to understand an improved design of a simple robot arm. The CAD has higher evaluation points in the viewpoints of understandability of figure change history and efficiency. It also has equivalent points to the ordinal method in the viewpoints of understandability of change points and understandability of relation with other changes.

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In this paper, a new method of recyclability evaluation is proposed. In this method, the recyclability of a product is given by summing up recyclabilities of all units to which the product is manually disassembled. The recyclability of a unit is calculated, if all names and amounts of materials of which the unit is composed are known. The recyclability of a disassembled unit, consisting of multiple materials, is judged on the grounds of removability of impurities, miscibility and marketability of polymer blends. Recyclability of a long-lifetime product can be estimated from recyclabilities of units, which are modeled as probabilistically distributed degradation of materials. The proposed method is applied to recyclability evaluation for a refrigerator with several scenarios of disassembly levels. The practical disassembly scenarios limit maximum recyclability rate of the product. Therefore recyclability rates calculated based on the proposed method are considerably lower than those of the recyclable materials of which the product consisted.

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