This paper presents an experimental study on the vibration control of a viscous liquid-filled rotor using two active magnetic bearings. The magnetic bearings are placed at both ends of a rigid shaft connected to the rotor. In order to support the rotor system and to suppress the unstable whirling motion, the gain-scheduled system based on conventional PD control law is proposed. In addition, a first-order delay filter is also introduced to improve noise sensitivity. The gain schedule system was formed in the experiment by scheduling control parameters of the PD controller with the related rotating speed at which the rotor System is stable. The validity of the control system has been verified by the experiment.

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It is well known that magnetic levitation using permanent magnets without control is impossible. However, just as in the case of a sleeping top, if the body to be levitated has some amount of rotational velocity, the situation will be changed. In this paper, a new type of system which utilizes both the repulsion force of permanent magnets for vertical levitation and a null-flux coil system for horizontal restoring force is proposed. A method of decreasing the required radial restoring stiffness is given. Asymptotic stability of the top is discussed using eigenvalue analysis. Two different types of eddy current dampers for asymptotic stability are proposed. Some preliminary experimental results are also shown.

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Active suspensions are usually applied for control of secondary suspensions because of the restrictions of hardware. Since magnetic levitation vehicles have heavy unsprung masses of superconductive magnets and have no viscous damping at high velocity, it is supposed that the characteristic of their vibrations is worse than that of ordinary vehicles. On the other hand, magnetic levitation vehicles have the advantage that primary suspension can also be actively controlled. This is because the force in the primary suspension is generated by electro magnetic force. In this paper, it is shown that unsprung mass resonance is decreased by use of direct control of primary suspension. Frequency responses which are calculated for an optimal regulator are compared, and the characteristics of secondary suspension control and of primary suspension control are clarified.

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For a traveling steel belt (SUS430) which is supported in a contactless manner by attractive forces of electromagnetic actuators, a theoretical and an experimental study on a control performance at the traveling speed of more than critical value were performed. And a suboptimal control theory was applied to minimize effects of spillover of residual Vibration modes of the belt. As a result, the levitation and transport control of the steel belt were realized to the traveling speed of more than critical value by using a simple digital optimal control technique. And it was further observed that the control performance was improved by applying the feedback gain taking the spillover of residual modes into account.

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The object of this paper is the application of the theory of the optimal control with feedforward link and the frequency-shaped optimal control for the vibration isolation system using magnetic levitaion. The vibration isolation system is a single-degree-of-freedom system and the vibration of it's table, which is levitated by repulsion force of a permanent magnet, is controlled by attraction force of an electromagnet. By carrying out experiment, it was experimentally verified that the control efficiency can be improved by the application of the theory of the optimal control with feedforward link and can be further improved by adopting the frequency-shaped optimal control.

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Magnetically levitated (MAGLEV) vehicle systems have been researched for future high-speed transportation. It is especially important to investigate the dynamic characteristics from the viewpoint of running stability, safety and ride quality ht high speed. This paper deals with repulsive-type MAGLEV systems using electro-dynamic suspension (EDS). Although the EDS is inherently stable, the damping force is not large enough to suppress the vibration excited by guideway irregularity and other disturbances. Therefore, this paper investigate theoretically and experimentally the damping force control of EDS systems with a hybrid magnet configuration of a permanent magnet and an additional electromagnet of which the current is compensated by a feedback control loop. The dynamical characteristics are analyzed by an experimental set-up in which a one degree-of-freedom mass is suspended above an aluminum rotating plate. According to the experiment, the damping coefficient is significantly increased by the additional control circuit.

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Magnetically levitated (MAGLEV) vehicle systems have been studied as the future high-speed transportation. It is especially important to investigate the dynamic characteristics for running stability, safety and ride quality at high speeds. This paper deals with the vibration control problem of a two-degree-of-freedom vehicle-suspension model of repulsive MAGLEV systems; Although the repulsive MAGLEV system is inherently stable, the damping force is not large enough to suppress the vibration excited by guideway irregularity. In order to improve the vibration characteristics, there are two approaches; one 6f them is through secondary suspension design and the other, primary suspension design. The first approach gives a limit of vibration control because of the existence of an invariant point in the frequency response of car-body acceleration. This paper investigates the second approach, that is, direct magnetic force control of the MAGLEV systems. For this purpose the primary suspension is designed as a hybrid magnet configuration of a permanent magnet and an additional electromagnet of which the current is optimally controlled by LQG theory. The experimental and theoretical results show that the car body and levitation gap vibrations are significantly improved with the additional control circuit.

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Many studies on the magnetic levitation (maglev) suspension of electric dynamic systems have been reported. Most of them are concern about systems in which ground coils for levitation are arranged on the bottom of the guideway. In the new type of maglev suspension, ground coils for levitation are arranged on the sidewall of the guideway. This kind of suspension has not been investigated precisely yet. In this paper, we apply the strategy for the previous system to the new system and design a experimental device to measure electromagnetic forte in the new system. The results of calculation and measurement are clarified; and the effectiveness of the strategy of analysis for the new system is verified.

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In recent years, miniaturization of mechanical systems has made remarkable progress. Manufacturing systems for minute parts are necessary to advance miniaturization further. Each such system is composed of sections for material feeding, machining and transferring of parts. The handling technique of these workings is the essential point in system construction. This paper proposes that the handling device consists of a pair of bimorph piezo .members rigidly connected with other in series and fingertips attached to the pointed end, which is like a hooked finger. The device is able to move two-dimensionally by application of an independent voltage to each of the members. It is noted that there is an optimum value for height of the feeding plane and optimum combination of the attaching angle of the device and connecting angle of the members, which enhance quasi-static feeding performance. Experimental results agree well with the theoretical ones.

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Generally, a peristaltic pump and a syringe pump have been used to feed about 2(m1/min) of liquid. But, as neither a continuous flow nor a low fluctuation flow can be realized simultaneously, a new type of microquantity pump is required in the field of pharmaceutic manufacturing. Therefore piezo-elements were applied to make a 2-dimensional pump suitable for multichannel and multistage pumps. The experiments have revealed that the pump successfully works and its head reaches a maximum of 18(kPa).

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The longitudinal vibration of piezoelectric elements is analyzed using the wave equation. The element is fabricated of multilayer piezoelectric ceramics which are applied to such devices as actuators because of their capacity for electrical to mechanical energy conversion. The fundamental equations of electricity, based on the constitutive equations for piezoelectric elements, are derived by considering the longitudinal vibration. The dynamic behavior of the elements is presented in terms of the general solution of longitudinal vibration. The calculated results are verified by comparison with the current excited by the longitudinal vibration in the driving circuit.

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The control system of an active dynamic vibration absorber with an electromagnetic servomechanism, is designed based on the theory of output regulation with internal stability. The absorber system consists of a lever generating an inertial reaction, two electromagnets driving the lever, sensors and a controller. The object of the control is twofold. First, it is to reduce the vibration of the primary system equipped with the absorber to a nonresonant level in the whole range of frequencies. Second, it is to reduce the vibration to zero at a specified frequency. It is shown that the latter property is preserved in the face of small parameter variations in the primary system, but is not preserved when the parameters in the absorber system are perturbed. Experimental results emphasize the effectiveness of the proposed control method, and support the analytical predictions well.

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This paper describes vibration control using electromagnets without displacement sensors. An electromagnet for vibration control has two natural feedback loops. One feedback loop is from the gap length to the magnetic flux; the amount of the magnetic flux depends on the gap length. The other is from the magnetic flux to the coil voltage; the back electromotive force is derived from the time derivative of the magnetic flux. Through these two feedback loops, information about the gap length pours into the magnetic flux and the coil current; therefore, the gap length can be detected from there two state variables of the electromagnet without a displacement sensor (self-sending). The displacement, being the fluctuation of this gap length; can be estimated with the magnetic flux subtracted by the coil current. The vibration control using this estimated displacement consists of the negative feedback of the magnetic flux and the positive feedback of the coil current. The PD feedback of the estimated displacement can produce a damping effect and positive stiffness.

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Numerical and experimental results on the dynamic behavior of a thin electrically conducting plate under strong magnetic field are described in this paper. Thin electrically conducting plates are used as the structural components of high-magnetic-field machines. When a transient field acts on thin structures, induced current produces electromagnetic force and thin structures vibrate. An additional current arising from the movement of a vibrating structure is induced and an additional electromagnetic force acts as a damping force. The dynamic behavior of thin structures can be evaluated by considering the electromagnetomechanical coupling effect. In this paper the authors present experimental as well as numerical results for the dynamic responses of a thin plate under electromagnetic force. Both results show good agreement in deflection amplitude and frequency. The magnetic damping effect for maximum displacement and stress was evaluated. The results suggest that the effective use of the effect might decrease the maximum stress in the thin structures.

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Fluidic devices for space experiments require an effective degasser to remove gas from gas-liquid two-phase flow. To meet this requirement, a new type of degasser has been developed. The degasser is composed of a vacuum chamber, magnets and a hydrophobic membrane, and removes gas through the use of electromagnetic force instead of gravitational forte: The ground experiment reveals the degassing performance, which indicates the possibility of gas removal under the micro-gravity conditions.

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A new method is presented for analysing so-called mid-frequency resonance in a step motor, which is an unstable vibration arising from the interaction between rotor motion and coil current. Firstly, state equation in the time invariant form is derived using the rotating coodinate which is synchronous with the rotor. Secondly, a reduced-order model of 2nd order is obtained from the 4th-order state equation through modeling of a rotor fluctuation mode, in which a particular emphasis is placed on the low-frequency band of the torque transfer function. As a result, mid-frequenty instability can be analytically predicted from an approximated algebraic expression in closed form. Capability of the above approximated algebraic expression is demonstrated with an explanation for the difference of mid-frequency resonance between the hybrid-type motor and claw-type motor.

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Combination tones in a nonlinear beam subjected to two harmonic excitations are investigated for cases in which the resonance conditions of two different types of combination tones are satisfied simultaneously. For theoretical analysis, the perturbation method of multiple scales is used. It is found theoretically that for such cases combination tones can occur in multiple modes. The validity of the theoretical analysis is confirmed experimentally.

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Nonlinear liquid motion in a circular cylindrical tank partially filled with liquid, in response to a pitching excitation, is investigated. The nonlinearity of the liquid surface oscillation is considered in the response analysis of the sloshing motion. Basic equations are derived by employing the variational principle. The nonlinear ordinary differential equations governing the liquid surface oscillation are then derived by applying Galerkin's method to the basic equations. The nonlinear characteristics of liquid surface oscillation are discussed. The time histories of the liquid surface displacement are calculated to the harmonic pitching excitations. An experiment was conducted using a model tank. A good agreement was found between the theoretical and experimental results. It is shown that the nonlinear analysis is important for estimating the sloshing responses.

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This paper deals with instability for inclinational vibrations of an asymmetrical shaft rotating with a fluctuating angular velocity. For this rotor-shaft system, the equations of motion are derived and solved using an approximation which was previously proposed by the authors. As a result of the approximations ; the position of a widely unstable region caused only by shaft asymmetry moves to higher angular velocity as effects of the gyroscopic action become stronger. Furthermore, the position and width of instability regions caused by the coexistence of shaft asymmetry and an angular velocity fluctuation change markedly with the effect of gyroscopic action.

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Vibration and noise problems are common to small, high-speed rotating machines such as electric vacuum cleaners and small blowers. When these machines are used in the home, reduced vibrations and noise are very desirable, Engine order analysis is a well known method to measure vibration and noise characteristics of rotating machines. However, for small rotating machines, attachment of a rotating pulse generator to the rotating shaft to detect rotating frequency is generally difficult. Even if attachment is possible, much time is taken in preparation for the measurements. A new rotating frequency estimation method without a rotating pulse generator is proposed and its accuracy is discussed. Then, a new engine order analysis technique using the frequency estimation method is introduced and applied to analyze vibration and noise from an electric vacuum cleaner.

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The oil-flooded screw compressor rotates as the corresponding male and female rotors make contact. As gas pressure builds in the grooves of the rotor, periodically fluctuating torques and thrust forces occur. Also, the rotor is an axial and torsional coupled system. In this research, the torques and thrust forced are calculated, and the vibration of the rotor in this axial and torsiond coupled system is analyzed theoretically.

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In this study, we experimentaly examined the characteristics of unsteady fluid forces acting on the downstream cylinder of a two-tandem-cylinder system in the lift direction at P/D=3.0 subjected to two-phase bubble cross flow. The downstream cylinder was oscillated to measure the unsteady fluid force at the frequency (f_P) which is a natural frequency of the upstream cylinder in water. Experiments showed the following major results : ( 1 ) At low reduced velocity, we could not observe the differences in the characteristics of unsteady fluid force, that is with respect to void fraction and oscillation amplitude ; ( 2 ) air bubbles decreased the fluid force for the reduced velocity over the value of that in lock-in the state ; ( 3 ) the fluid force was reduced by air bubbles at the void fraction of α≤ 5% for high reduced velocities.

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This paper deals with the active control of structure-borne sound radiating from a vibrating plate. It is the purpose of this paper to clarify the characteristics of the system response when the sound radiation is suppressed by controlling structural power flow. As a result of applying power flow control, the authors have already shown that there are basically three resultant response patterns in vibration intensity flow: straight, S-shaped and vortex. Relationships between the acoustic intensity and vibration intensity of these patterns are investigated in this paper. Particular emphasis is placed upon the vortex-type response pattern, which has the potential for realizing mode localization. A novel method for producing a power flow vortex at an arbitrary position on the plate is introduced. Furthermore, it is shown that there exists a situation where the direction of the acoustic intensity and vibration intensity vortices are completely opposite. It also turns out that there is a sound pressure null above the vortex center.

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In this paper nonlinear control of an inverted pendulum system with unknown parameters is discussed. First, the unknown parameters of the pendulum and the cart are identified. Then, using the identified parameter values, swing-up control of the pendulum is carried out and stabilizing control at the inverted position is applied. Thus, automatic operation of an unknown inverted pendulum system was achieved. The swing-up control law is given by an optimal regulator method and the stabilizing control law by nonlinear eigenvalue assignment. The stability of the closed system is proven.

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A new magnetic gear transmitting system with an actuator made of an electromagnet is proposed in this paper. The vibration due to the system parameter variations or external disturbance is absorbed by means of changing magnetic fluxes of the electromagnet and the controller is designed by variable structure system (VSS) theory. The theoretical expressions of the transmitting torque, magnetic spring constant and control force versus electric current in the electromagnet were derived. Both the simulations and experiments of this magnetic gear system were carried out by means of the sliding mode regulator and were compared with the PID linear control method. The experimental results confirmed the theoretical analyses.

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Zhou and his co-workers proposed an "intelligent controller" that simulates the control behavior of a human operator. The controller has multiple control modes to simulate a human operator switching several control actions according to the state of a target plant. In this paper, we discuss an application of the intelligent controller to swing up a one-link pendulum under driving torque limitation. To design the controller, we examine the action of a human operator who controls the swing-up motion of a one-link pendulum, and obtain three control modes with six parameters. Then the parameters are adjusted using a pendulum simulation system. The experimental results show that the designed controller achieves successful swing-up control even if the plant parameters are changed.

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In stochastic optimal control with a feedforward link, there are two problems, one is the difficulty of design by frequency-shaped cost functionals, the other is the problem that the level of the frequency response increases beyond the frequency range of an assumed disturbance dynamics. In this study, to overcome these defects of the stochastic vibration control, methods for design of frequency cost and robust control are presented by applying the theory of H^∞ control. In the numerical calculation using a single-degree-of-freedom system, the usefulness of the presented method using the H^∞ control was verified.

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The paper describes an approach for extending the potential to estimate unsteady flow rate through oil hydraulic pipelines and components in real time, in combination with two previously proposed approaches. In this method, unsteady flow rate at an arbitrary point along the pipeline is estimated by using hydraulic pipeline dynamics and only two measured pressures at two distant points along the pipeline. This method has some advantages, that is, it is more convenient to install without disturbance and highly responsive to flow rate changes. We proposed the following two minor methods: an interpolation method and an extrapolation method. This paper mainly describes the interpolation method. In the interpolation method, unsteady flow rate at an arbitrary internal point between two points to measure the pressures is given by convolutions between the weighting functions and the two measured pressure values of the two distant points. High-speed operations of the convolutions in real time using a microcomputer can be simply achieved with the use of only software. Under unsteady laminar oil flow conditions, good agreement between the estimated and directly measured flow rate waveforms illustrates the validity of the method proposed here.

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The paper describes an approach for extending the potential to estimate unsteady flow rate though oil hydraulic pipelines and components in real time. In this method unsteady flow rate at an arbitrary point along the pipeline is estimated by using the hydraulic pipeline dynamics and the only measured pressure values at two distant points along the pipeline in high responsiveness. This method has some advantages, that is, more easy and convenient to install without flow disturbance and with high responsiveness to unsteady flow rate changes. There are two minor methods, an interpolation method and an extrapolation method. This paper mainly describes the extrapolation method. In the extrapolation method, unsteady flow rate at the arbitrary external portions between two pressure measuring points is obtained by an inverse Fourier fast transform between the weighting functions and the measured pressure values. And this method is considered to be most useful for practical purpose. Under unsteady laminar oil flow conditions, the good agreement between the estimated and directly measured flow rate waveforms illustrates the validity of the method proposed here. In addition, a real time flow monitor applying this method is proposed and the validity is ascertained.

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A method of measuring the angular displacement of the human eys is investigated through the use of a simple system comprising a 2-D CCD and a personal computer. The data that are on a rectangular coordinate are transformed into the data on a polar coordinate, and some examples of the angular displacements of the human eye obtained by calculating a cross-correlation function between the iris pattern and its reference pattern are shown. We conclude that it is possible to measure the counter- rolling of the human eye by the above method.

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A new control method for positioning the end effector of a flexible robot arm has been developed using experimental modal analysis. Based on the fact that robotic motion can be described by transfer functions between the input and the output at the representative positions of the piecewise linearized section, prediction of motion and control of motion have been achieved with good results. In this study, the following three themes are discussed : 1) a new method which advances previous methods, 2) prediction of motion by a new method and its comparison with experiments, 3)experimental results of motion-control designed smooth motion.

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Intelligent/adaptive structures can change their geometrical configuration and mechanical characteristics by themselves. In order to construct large space structures, it is important to plan how to operate them effectively. In this paper, a neural network is used in order to plan effective operation for a multijointed link structure which is a simplified model of intelligent/adaptive structures. The task considered here is to generate an effective joint trajectory for development of a multijointed link structure from the packaged state to the final configuration. Numerical simulations and experiments show that a neural network can solve such a problem under minimum torque.

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Various simulations have shown that stability in walking robots of 2, 4, 6 legs, etc., can be achieved by adopting appropriate controls. In these simulations, however, two-dimensional treatment is commonly applied, and besides, there remains some vagueness as to whether the analytical treatment is propdr for cased such as multiple legs simultaneously touching the floor or functioning as thd supp6rt legd in the shifting period. The equations of walking robot are very; complicated because of the mdny links and joints involved and the changeable conditions of constraint. In this pdper, the aims, characteristics and basic concept are introduced for a comprehensive simulator of.robotmotion, called "MOSURA", which is now under development at Kobe University. The simulater is applicable to various wdlking robots and will treat dven cup and ballgame robots in the future. It is designed to be of high extdnsibility.

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Self-organizing systems and distributed systems have recently been studied by many researchers. The authors have studied a cellular robotic system called CEBOT as a dynamically reconfigurable robotic system. CEBOT consists of many sorts of functional units, which have simple functions, knowledge, and a database. CEBOT is required to perform many given tasks in various environments by reconfiguring the structures of both hardware and software. If CEBOT does not possess a proper subsystem, called a module, in its own system, it must create a module by combining dells. In the process of the cell production, we apply the genetic algorithms (GA) to the CEBOT. We propose the algorithm called the genetic cell production algorithm, (GCPA) in this paper. We also propose a performance index based on the theory of entropy in order to estimate the performance of distributed systems. To assess the GCPA and the estimation method, we conducted on experiment using a robot manipulator contorolled by self-organizing knowledge system based on the GCPA.

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In this paper, a solution for the two-point boundary value variational problem, whose basic algorithm was published earlier by us, is formalized completely and universally. The optimum solution of the variational problem is obtained as a uniform B-spline curve by parallel and iterative computation. The degree of the B-spline used can be selected to correspond to the specified problem, and the solution is derived as a set of the control points of the B-spline. The algorithm is very simple and easily applicable to various engineering problems. As an application, trajectory planning of a manipulator with redundant degrees of freedom and a specified end effector path is selected, and the objective function which takes account of both the smoothness of the trajectories and the accuracy of the end effector path is constructed using the relative weighting coefficients. The effectiveness of the algorithm is well confirmed by the numerical examples.

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This paper presents a study of the transient response of HDA subjected to a half-sine shock pulse in the axial and pitching directions. The solution is obtained using the multi-modal expansion approximation and applying the Galerkin method of the resulting equations. Numerical results are obtained using the Newmark β method for a 3.5" hard disk-head system. It is found that the relative distance between the disk and the head becomes maximum when the input duration γ is about l.5times the natural half-period of the fundamental (0, 0) mode. Results also show that the air film stiffness between the head and the disk should be high in order to realize a shock-proof head.

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Stress analyses of harmonic drive are carried out. Since the structure of harmonic drive is very complicated, several typical components are modelled simply and are analyzed first. They are ( a )estimation of stiffness of the bearing ball by contact, ( b ) contact problem between the bearing ball and belts, ( c ) contact problem between the bearing belt and flexspline, and ( d ) contact problem between the gears of the flexspline and circular spline. Each problem is analyzed using FEM or BEM, and contact problems are approximated by an elastic spring based on these analyses. Then the full model is analyed and the stress fields at the base of the gears of flexspline are evaluated.

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A method of levitation control of a permanent-magnet-type rotating motor is proposed. It is assumed that the rotor has sinusoidally distributed magnetic poles, while the stator has a current sheet to produce arbitrary distributed flux. The levitation force can be independently controlled with the proposed ±2-pole algorithm. This can be applicable to both a synchronous motor and a servomotor. A simple experimental apparatus is made and controlled with a synchronous algorithm. The results clarify the validity of the proposed method.

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A method of measuring the air gap of the magnetic levitation system from the pulse width modulation (PWM) carrier frequency component is presented. It is intended that an electromagnet be used as a gap sensor and a levitation control actuator. The inductance of the magnet is a function of the air gap which can be estimated from the PWM carrier component of the driving voltage and current. The estimated air gap is used to control the duty ratio of the PWM driving voltage. The proposed method is applied to a simple experimental apparatus and its capability is tested.

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A new numerical scheme for the finite element method for calculating the interface phenomena of VCR, namely, between the magnetic tape and the magnetic head of the drum, is presented. To enable estimation of the characteristics of the designed VCR system and the effects of design parameters on the performance, it is absolutely necessary to reduce the CPU time and the memory storage without losing accuracy. We divide the analysis area concerned into two subareas, a whole drum area and a head circumference area. The analysis is carried out in one after another, and the result is used for the other analysis. The analysis results are in good agreement with the experimental one. Moreover, the CPU time required to carry out the analysis is short.

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Damping characteristics in vibration transfer through deep-groove ball bearings are precisely measured using single-bearing structure (equivalent to the 6200 type) and compliance transfer function resulting from impulse hammering the bearing. To eliminate unnecessary effects caused by bearing setting and preloading, the single-bearing is specially fabricated to unite its inner ring and a shaft in one body, and also its outer ring and a rotor. This structure enables to be preloaded by an externally pressurized air bearing. Experimental damping ratios are found to range from 2-4%, and damping coefficients from 0.15-0.35 Ns/mm. Damping is found to decrease with increasing preload, and to be larger for larger clearance and for larger ball number. Decreases in damping owing to superimpose of the inclined mode and owing to increase in clearance lead to the fact that ball rolling motion rather than sliding motion is apt to decrease damping. Also, bearing rotational effect is found to be small, and grease hardly provides damping function during rotation.

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In this paper, the static characteristics of infinitely long high-speed slider bearings lubricated with non-Newtonian fluids are examined theoretically by considering the fluid inertia effect. In the derivation of the modified Reynolds equation, the fluid inertia terms in the momentum equation for the lubricant film are averaged over the film thickness, and the Rabinowitsch empirical model is used as a constitutive equation of non-Newtonian fluids. Applying the modified Reynolds equation to the infinitely long slider bearings, the film pressure, load carrying capacity, friction force and inlet flow rate are obtained under various values of the dimensionless nonlinear factor and film thickness ratio, and the effect of fluid inertia on these static characteristics is discussed.

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An investigation was carried out to elucidate the nature of the natural vibrations on the outer ring of the cylindrical roller bearing. In this paper, the vibrations of six outer rings of the cylindrical roller bearing were studied. In the experiments, the outer ring itself was struck in the radial or the axial direction. The sound generated by the strike was measured by a condenser microphone. Natural frequencies of the outer ring itself were determined from the frequency spectra of the sound. Moreover, some theoretical approaches were taken toward the measured natural frequencies. From the experiments, analysis and considerations, the natural vibrations on the outer ring itself of the cylindrical roller bearing were clarified, and it was found that the natural vibrations could be calculated by the theory of Love and the extended theories of Kirkhope.

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Hypoid gears are the most general form of gearing, and their theoretical solution has been long in coming. Many guesses or theorems about gearing have been proposed, some of them correct and many of them wrong. The tooth surfaces are parts of general curved surfaces and they must have principal directions and principal curvatures on every contact point. But there have been no discus-sions on such fundamental elements of the surface. This paper develops necessary conditions for determining these curvatures and principal directions for gearing with a contact line, introducing the concept of geodesic torsions.

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Nondestructive inspections of surface flaws of zirconia in grinding were investigated by using the available method submerged Rayleigh Wave detection. Shockwave transducers with two different characteristics of resonance frequency (15 MHz, 25 MHz) and focusing diameter (1 mm, 0.4 mm) were selected. Flaw calibrations of the system have been carried out for artificial flaws instead of real grinding flaws. The results obtained are itemized as follows. ( 1 ) The depth of the flaw represented by a scratch could be estimated quantitatively, and the detectable limited depth would be 2.5μm. ( 2 ) For small defects inspected by means of Vickers indentation, smaller focusing diameter of the transducer made for higher inspection sensitivity, still inspectability was explicitly decreased in comparison to the case of the scratch. ( 3 ) Compressive residual stresses remaining on the surface made for lower estimations of length. ( 4 )Real surface flaws caused by heavy grindings, as a factor of strength degradation, could easily be detected.

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This paper details experimental research to determine problems that should be eliminated to realize ultraprecision machining of ceramics. The performance of a diamond tool with a radiused cutting edge is verified through the measurement of flank wear and cutting force that are created under face turning on partially stabilized zirconia. The same evaluation, varying the cutting conditions, is performed on a tool with a straight cutting edge to restrict the tool wear and accompanied increase of the thrust force. It is shown that the growth of the flank wear on the tool with a radiused cutting edge is accelerated with the decrease in feed rate. This growth occurs because the major cutting edge situated between the nose wear and the groove wear is worn by the increase in rubbing force. Furthermore, it is clarified that the tool wear and the cutting force can be restricted by using a tool with a straight cutting edge, in spite of the fact that the crystallographical orientation of the tool fate id not sufficient to perfectly brotect the growth of the flank wear.

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Almost all empirical formulae for estimation of blank-holding force (or pressure) proposed thus far are examined with respect to circular cup drawing from circular blanks. A theoretical formula proposed by Kawai is checked to find that it gives a too low value in a practical Sense. There exists no formula for estimation of blank-holding force to prevent flange wrinkling in the case where the circular cup is partially drawn from irregularly shaped blanks, and especially where the square cup is drawn from square or circular blanks. A new empirical formula for such cases including, of course, circular cupping from circular blanks, is proposed. By many experiments, formula is verified to be quite useful from the viewpoint that the blank-holding force should be the minimum necessary so as to prevent wrinkling. The effective area of the irregularly shaped blanks for estimation of blank-holding force is also discussed.

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Thermal spraying of self-fluxing alloy is quite effective for good bonding in cast-in inserts of mild steel pipe by flake graphite cast iron. To clarify the thermal conditions for the bonding, the freezing process around the interface was analyzed by a finite difference method. The analysis showed that there are three types of boundary freezing: a)slow freezing where the solid fraction increases gradually; b)rapid freezing followed by remelting with temporary decrease in the solid fraction; and c)rapid and complete solidification without remelting. Successful bonding required a steel surface at high temperature to contact a solid-liquid coexistent melt for a certain period. Sprayed alloy fused at the interface increases the maximum solid fraction and shortens the minimum contacting period greatly.

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In automated search of a design database to support mechanical design, it is necessary to recognize a shape pattern which represents a design object. This paper introduces the concept of d surface relation graph (SRG) for recognizing shape patterns from a 3D boundary representation scheme of a solid object (a B-rep model). In SRG, the nodes and arcs correspond to the faces and edges shared by two adjacent faces, respectively. An attribute assigned to an arc is given by an integer which discriminates the relationship between two adjacent faces. The +sign of the integer represents the geometric convexity of the solid, and the -sign the concavity at the shared edge. The input shape is recognized by comparison with the predefined features which are subgraphs of the SRG. A hierarchy of the database for supporting the design is presented. A search for the design database is also discussed. The usefulness of this method is illustrated by some application results.

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