In this paper, free vibrations of twisted plates with thickness varying in two directions is investigated analytically and experimentally. A numerical procedure based on the Rayleigh-Ritz method is presented. Frequency parameters and modes of vibration are analyzed for typical twisted plates and the influences of plate thickness variation are discussed. Then, the resonance frequencies and modes of vibration measured by means of holographic interferometry are compared with the analytical results for three kinds of test specimens. Comparison reveals that the analytical results are well explained the experimental and the proposed method is useful for analyzing the free vibrations of twisted plates with variable thickness.

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Experimental investigations are presented for nonlinear (large amplitude) fundamental vibrations of eccentrically stiffened square plates with a small initial deflection. The stiffened plates made of copper by photoetching are excited by an acoustic speaker. The effects of an initial deflection on the characteristics of the natural frequency depending on the amplitude are clarified. The experimental values for the ratio of nonlinear frequency to linear frequency agree well with the theoretical results obtained by applying the method of successive approximations.

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In previous papers, the authors proposed an experimental identification technique for nonlinear beams. In this paper, an attempt is made to generalize the technique so that it can be used to identify nonlinear two-dimensional structures such as plates and shells. First, it is shown that analysis of the equations of motion for such structures is always reduced to analysis of the modal equations. Then a technique is proposed which enables us to determine the modal equations by use of experimental data. Numerical simulation is conducted for some nonlinear plates, and the validity of the technique is confirmed.

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A pair of nonlinear simultaneous differential equations which govern the unsteady bouncing and pitching oscillations of a simple levitated body, are solved by using the method of multiple scales, for the special case in which the fluctuation of the magnetic lift force changes harmonically in the neighborhood of twice the natural frequency of the bouncing oscillation Ω_z, and in which the natural frequency of the pitching oscillation Ωo is equal to Ω_z/2. As a result, it is shown that there are three types of oscillations ; periodic, quasi-periodic and complicated. Furthermore these three types of oscillations are observed with a simple experimental apparatus.

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In this study, chaotic behavior of a single wheelset rolling on a rail has been examined numerically. The single wheelset model is assumed to be elastically restrained from an imaginary truck frame moving in parallel with a straight track. In the simulation, nonlinear forces of the flange-rail contact and the wheel-rail creep are involved. When the elastic restraint is decreased, self-excited lateral oscillation occurs even in the practical speed range ; then the oscillation bifurcates into chaotic behavior. The chaotic features are confirmed by the correlation dimension, bifurcation diagram, power sepctrum and Poincare map.

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Development of a vibration feeder was performed as one application of a vibratory machine with a self-contained vibration-reducing function by means of interference of transmissive force. The most important conditions for a vibration proof of a vibratory machine are compatibility of functions which oppose each other, reduction of transmissive force on the machine base and amplification of vibration on the body. This study deals with application of the proposed design to the feeder. The machine consists of coupling of a pair of one-degree-of-freedom mass-spring system. An excitation spring is devided as a part of a coupling spring for generation of excitation force on the two bodies. One end of the spring is excited by harmonic displacement with a reciprocating mechanism such as a crank. In this paper, we present vibration characteristics with full consideration of transmissive force and the optimum design procedure of the system. The transmissive force is reduced by 30 dB in the linear feeder which is excited by the excitation spring in the first trial.

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Natural modes and natural frequencies of a "track-type" ultrasonic motor, one of the "travelling-wave-type" ultrasonic motors, is discussed. For generating the out-of-plain travelling wave which rotates in the track-shaped ring, we must design the vibrator so as to obtain two natural modes whose rank (number of nodal diameters and nodal circles) and natural frequencies are the same, and whose natural modes are shifted 90 degrees in phase and in time. In general, the natural frequencies of these two modes are different. We study the change in the natural modes/frequencies by changing the length of the straight part of the vibrator using finite-element analysis. Consequently, we find some specific cases where the two natural frequencies correspond. We also fabricate the vibrator in order to confirm the calculation.

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The induction motor is used in many industries. These days motor noise reduction is often required due to environmental concerns. This paper is concerned with the reduction of motor noise. The relationship of exciting force and vibration mode of the stator core is analyzed. An exciting force as an electromagnetic radial force was applied to the stator core. Analysis was performed for the case of a continuous distributed force and the case of a discrete multipoint exciting force. The vibration behavior of the core was analyzed theoretically, numerically (FEM) and experimentally with respect to modes, frequency and phase of exciting force. It has been confirmed that : 1. in the continuous distributed excitation, the core vibrates when M=±N and the exciting frequency coincides with the natural frequency, 2. in the discreted multipoint excitation, the core vibrates when M±N=mK. Here, N is the natural frequency mode, "is the excitation frequency mode, m is an integer, and K is the number of applied points of the exciting force.

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In the case of thermo-acoustic oscillation in a tube by heat supply, progressive pressure waves are generated by local expansion of gas at the beginning of heating. After several reflectios of the waves at the tube ends, standing waves are formed, and their amplitude gradually increases. In order to clarify the mechanism of this type of oscillation, one-dimensional vibratory fields in the tube are simulated by a numerical method. As a result of computation, it was found that the standing waves of pressure and velocity are generated in the tube and oscillate in the fundamental frequency. The stability of this phenomenon depends on the model of the heat source. A new heat source model, in which the leeward temperature fluctuations are taken into account, is proposed.

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An upright stainless steel circular cylinder with an attached mass at midlength is excited seismically in the horizontal direction using a shaking table. A well-known seismic wave called E1 Centro 1940 NS is used for the excitation of the test specimen. Fourier components over 10 Hz of the seismic wave are cut off and the duration is shortened to 30, 40, or 50%. Eccentricity of the center of gravity of the attached mass is changed and excited by the modified E1 Centro 1940 NS increasing the amplitude of the seismic wave incrementally. Parametric excitation is observed for each combination of eccentricity of the attached mass and time scale of the seismic wave.

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In this paper, the authors propose a drastic improvement with regard to the force-response window function, which is commonly used on impact vibration testing. The customary force-response window function pairs a rectangular window function for impulsive force signals and an exponential function for vibration response signals. The three dynamic characteristics : inertia, damping and stiffness, are measured with distortion since neither is an actual force signal an exact impulse, nor is data acquisition triggered at t=0 for the exponential window function. Consequently, modal parameters are necessarily identified with bias errors that cannot be ignored in the measured data. Bias errors cannot be removed by any post-treatment techniques because an actual force is never an exact impulse. An improved force-response window function frees the experimental results obtained by impact vibration testing from the problem of the bias error.

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The performance of a tennis racket with the coefficient of restitution (COR) is closely related to the impact phenomena. In this paper, the distribution of the coefficient of restitution of a tennis racket when the racket vibrates is predicted using an approximate nonlinear impact model and an experimentally identified vibration model of a tennis racket on the basis of the idea that the COR can be derived from the energy loss during ball-racket impact. The calculated COR, considering the main sources of energy loss such as the impact between the ball and strings, rotation of the racket and vibration of the racket-frame, can explain the experimental results very well.

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The dynamic behavior of a railway vehicle, such as the hunting motion of a bogie, is often tested on the roller rig of a vehicle test plant. The contact geometry between the wheel and roller rig is, however, different from that between the wheel and rail which is not curved longitudinally. Because the dynamic behavior of the railway vehicle is influenced by the difference in contact geometry, we developed a program which enables calculation of the 3-dimensional contact geometry between the wheel and roller rig. In this paper, the contact geometry between the wheel and roller rig was analyzed using 3-dimensional contact program, and the result was compared with that for the wheel and rail. It is made clear that the contact geometry of the roller rig is different from that of the rail.

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On microvibration isolation systems, three performance requirements are imposed : ( 1 ) isolation from ground vibration, ( 2 ) suppression of direct vibration, and ( 3 ) stabilized positioning. These requirements have some trade-off relationships when are applied conventional passive technologies or feedback-controlled active technologies. In order to obtain high performance and to break through the trade-off limitations, a double-active control method with feedforward control is proposed. Feedforward control is effective for cancelling disturbances and for positioning the controlled object. Thus, this control method realizes all three requirements for the isolator. Experimental results show the usefulness of the proposed control scheme.

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In the case of carrying heavy cargo, which tends to be easily damaged by vibration caused by a vehicle or a ship during transportation, stopping the vibration of the board loaded with the cargo is achieved by means of hydraulic servomechanisms which are placed between the board and the hull. However, the behavior of a hydraulic servomechanism under a vibrating condition differs from that of a hydraulic servomechanism on a stationary base. The aims of this research are to stop the apparent movement of a massive load (vibration insulation) and to clarify the behavior of the hydraulic servomechanism under the vibrating condition. In this paper, the effectiveness of vibration insulation is shown for sinusoidal input and an earthquake-waveform input through the use of an experimental apparatus, and the stability of the servomechanism on the vibrating table is also discussed analytically and experimentally. Experimental and analytical results show good agreement, and the appropriateness of this analytical method is confirmed.

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In order to control the vibration of a rotating shaft, we propose a rotor-shaft system supported by flexible bearing pedestals which are installed in electromagnetic actuators. These actuators are controlled by the PID-type algorithms and can apply an electromagnetic force to the bearing housings. When a rotor is mounted at the midpoint of a shaft, the rotor-shaft system can be modeled by a two-degrees-of-freedom system. The principle of a dynamic absorber is applied to this system and the optimal dynamic parameters of the pedestals are calculated. In the experiment, the stiffness and damping coefficients of the pedestals are regulated to the optimal values by setting the gain of the controllers up, and very effective vibration control of the rotor-shaft system may be confirmed by using this apparatus.

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The swing of a gondola lift is easily caused by wind and is very difficult to reduce. In this paper, several types of dynamic absorbers for a gondola are analyzed theoretically, and a general theory is formulated. The method of optimum tuning is obtained, and the index (equivalent mass ratio) which indicates the effect of the absorber is defined. When the dynamic absorber is located at the center of gravity of the main mass, the swing is not reduced at all. This is because the moment due to the spring of the absorber is canceled by the moment caused by the gravity which acts on the mass of the absorber. The absorber should be located as high as possible.

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On a passive electromagnetic damper, optimum shapes of both a conducting slab and magnetic poles are determined by an optimization technique designed for compaction. Firstly, the optimum rectangular dimensions of the magnetic pole and the conducting slab were determined by this technique for several objective values of damping coefficient. Next, optimum shapes of the magnetic pole and the conducting slab were determined with reference to optimum rectangular shapes. Furthermore, these optimum shapes are verified experimentally.

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A topology and shape optimization technique, which utilizes the concept of microstructure and the homogenization method, is developed for structural dynamic problems. First, the structural optimization problem is transformed into an OMD problem (optimal material distribution). A new objective function is then suggested for eigenvalue optimization problems. An improved updating algorithm which was derived by the authors through a convex linearization approach and the dual method is employed for the optimization problems. Finally, three examples are given to demonstrate the feasibility of the approach developed in this paper.

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This paper deals with the stability analysis of commercial vehicles with front steering and rear driving systems using two control methods, i. e., the front wheel steer control method and the rear wheel traction distribution control method. A "model following control" method is applied in yaw motion control to make the controlled vehicle perform in the desired manner even under critical driving conditions. An optimal regulator is applied in traction control so that the traction force can be controlled in its entire working range. Computer simulations under certain conditions such as driving on a split-μ road and driving through a strong side wind are carried out to verify the effectiveness of the control methods. The simulation results show that the handling and stability of the controlled vehicle are improved significantly.

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Recently many kinds of four-wheel steering (4WS) systems have been proposed and studied. Design of these control systems is based mainly on the two-degrees-of-freedom model. However, vehicle motion is influenced by various nonlinear factors, for example tire characteristics and road conditions. Thus, it is difficult to express the vehicle motion perfectly with the two-degrees-of-freedom model. In this paper, a new 4WS control system with application of the neural network theory is presented. The design of the controller consists of two learning procedures for identification of the system and synthesis of the controller. In order to investigate the effectiveness of the proposed method, computer simulations and control experiments were carried out. As a result it was demonstrated that application of the neural network for motion control in 4WS systems is useful.

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In a mechanical system, such as a master-slave manipulator systems, a power-steering system, an extender, or a robot system for man-robot cooperation, interactions occur between the system, the operator and the environment. Control of the interactions is one of the key issues for the control of such a system. We discuss the control of mechanical systems with man-machine interactions in this paper. We first model the mechanical system, having interactions with its environment and operator, then propose a control algorithm so that the desired interaction is realized. The proposed control system consists of two controllers : one generates the desired motion of the mechanical system based on the force applied to the system, and the other controls the interaction between the system and the environment. The proposed control algorithm specifies both force augmentation and the dynamic characteristics of the system. The algorithm is applied to a planar manipulator with one degree of freedom and the experimental system illustrates the concept of the system.

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This paper deals with modeling and control problems of the three joints robot handling a flexible plate in the vertical plane under gravity. The dynamics model is obtained using Hamilton's principle, and the ordinary differential equations are obtained using modal analysis. According to the desired tip position and orientation, we present an iterative algorithm to solve the inverse kinematics. The design method of the feedforward position and orientation control system is presented in two ways : ( 1 ) By solving the inverse dynamics based on the desired trajectory, we can obtain the desired torque. ( 2 ) By the use of neural networks, we can obtain the desired torque. The second method involves the use of four three-layer neural networks to reduce the feedback errors of three joints angles and the first bending vibration based on the feedback error learning method with the desired trajectories including the static bending deflection curve. We present trajectory control results for both methods. A comparison between the two methods is presented in this paper. From the simulation results, the second method, using neural networks, is useful for reducing position and orientation errors. Moreover, the second method has ability to learn and thus improve control performance against some parameter errors in the model.

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This paper describes the position and force neuro-adaptive control of a two-link flexible robot arm. First, the equation of motion of the flexible robot arm consisting of the first rigid link and second flexible link is shown. The end of the second flexible link is constrained by a rgid wall. Second, the position and force neuro-adaptive control system is composed of two-layer neural networks and proportional feedback control loops. Furthermore, from the experimental results and the numerically simulated ones, it is confirmed that the control error of position and force with the neuro-adaptive control is markedly smaller than the control error without the neuro-adaptive control.

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For the manipulation of an underwater robot affected by large inertia force due to the added mass and nonlinear fluid drag force, it is necessary to take into consideration the flexibility of the manipulator in order to position it accurately and quickly. In addition, a manipulator gripping a body of unknown shape at the tip is affected by unknown inertia force and fluid drag force of the body. Therefore, an estimation of the body mass and fluid drag force coefficient is needed. In this study, a positioning system for a flexible rotating arm with a body at the tip in water is developed using the optimal control theory. In this system, the arm is rotated with constant torque at first to estimate the parameter of the tip body. Using this parameter, optimal feedback gain is calculated, and the arm is controlled in order to attain the target position. Then, model experiments are carried out and the performance of the developed control system is confirmed.

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In this study our objective is high-speed positioning of a pneumatic robot. To realize a high-speed drive, the control algorithm should be as simple as possible to reduce the calculation time of control input. A posicast control scheme may be considered an effective control strategy which satisfies such a requirement. However, the original scheme is not sufficient for a pneumatic drive system which is usually of an order higher than the second, and has an operating delay in the electro pneumatic valve, etc. We improve the original posicast control scheme so that it can be applied to positioning of the pneumatic robot. In this control scheme, the regulation of both the height and the switching time of reference input is important. Thus, we provide a learning function which can regulate these parameters with respect to the configuration of the last response during repeated operation. We describe the proposed control algorithm and discuss its availability through simulations and experiments.

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This paper proposes FDM (Fur Driven Micro-mobile-mechanism) robots, using an electro magnetic actuator. The FDM moves by means of the difference in inertia and friction between forward and backward motion. We developed two types of the FDM robots. FDM 1 can move foward and is smaller than 10 mm³, while FDM2 can make a right turn and a left turn, as well as move forward. Both of FDM1 and FDM2 can be separated into two parts (body and leg). The leg is fitted with fur on the surface that faces the ground. Because this fur has the inclination to the ground, a friction difference between forward and backward motion is produced. As a result, we can observe a stick-slip motion which is well known in tribology. In this paper, the design of the micro mobile robots, the mechanism of motion, the analysis of motion, and the characteristics of this mobile robot based on the mathematical model are shown with some experimental results, which agree with the simulation results.

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We have studied a micro-cellular robotic system (μ-CEBOT), which is applied with the distributed robotic system. μ-CEBOT consists of many small robots which we named cells. Each call controls itself and carries out the tasks cooperatively with other cells. Characteristically, cells adapt to the tasks or environment by changing their structure. This problem is called the cell configuration problem. In this paper, we propose two algorithms for cell configuration using the sequential method and the parallel method. In these algorithms, the cell selects its pair of connections by distance evaluation. In order to allow adaptation to the dynamic environment, we define the conditional function. The conditional function shows the degree of communication and interruption. We show the algorithms of cell configuration and simulation results, and compare the two methods.

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Motions of human arms are analyzed kinetically and kinematically with respect to smoothness. A kinematic arm model with 6 degrees of freedom is suggested and spatial motions are simulated considering the sum of the weighted square of joint displacements, which approximately equals kinetic energy of the whole arm. A low-pass filter is applied for smoothing the kinetic state variables, i. e., displacement, velocity, and acceleration, and the smoothing transfomation is optimized from the aspect of characteristics of response and vibration. Such transformation is also applied to the human arm model, and the effects are investigated through simulations.

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A prototype failure diagnosis system has been developed using neural network technology for the actuator of air-operated valves. Because actual failure data were not easily available, the data of 30 failure patterns were experimentally obtained using more than 10 sensors. The time series of sensor signals are Fourier transformed. The data of the magnitude spectrum, phase difference and others are used as the characteristic parameters in our failure diagnosis. From the data, appropriate information for use in the failure diagnosis was extracted. Furthermore, similarities among the failure characteristics were found by fuzzy clustering and statistical analysis. The new system which we developed consists of plural subnetworks and one main network. Each subnetwork is related to one specific sensor signal, and deals with the magnitude spectra from the sensor signal. The main network makes the final decision according to the outputs from the subnetworks and other data. In our system, the number of network connections can be reduced by approximately 40% without degradation of the recognition capability in comparison with the conventional system which uses only one neural network.

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An optimal operational planning method, using the decomposition algorithm, for cogeneration systems with thermal storage is proposed. The daily operational strategy of constituent equipment is determined together with the charging and discharging history for thermal storage so as to minimize the daily operational cost subject to the energy demand requirement. This optimization problem is formulated as a large-scale mixed-integer linear programming problem, and it is decomposed into a large-scale linear programming problem and a set of small-scale mixed-integer linear programming problems for hourly operational planning. The solution of the original problem is obtained by solving these problems iteratively. Effects of thermal storage on the operation of cogeneration systems are examined through a numerical study. The method proposed here is a useful tool for evaluating the economical and energy-saving properties of cogeneration systems with thermal storage.

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The Helmholtz resonator reduces the noise by making use of the antiresonance. The damping of the resonator must be small at the antiresonance and large at the resonance. The damping can be controlled by feedback of sound pressure detected by a microphone in the resonator to a speaker on the wall of the resonator cavity. When the feedback gain is increased, the damping becomes negative and the system becomes unstable. In order to avoid instability and to have small damping only in the vicinity of the antiresonance, a 1/3 octave band pass filter is set in the feedback loop. Theoretical and experimental investigation was carried out of duct noise, and it was found that a resonator with frequency dependent damping can reduce the noise by about 20 dB.

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This paper describes a theoretical study of active control of blade rotational noise radiated from an axial flow fan when using a secondary source which consists of several point sources. The primary source analyzed here is a circular multipole source in phase rotation. Additional point sources are arranged on a concentric circle at regular intervals. The optimal strength of the secondary source and minimum sound power output are deduced. The characteristics of total power radiated from both sources are discussed by means of numerical analysis, and attenuation in total power is also investigated. It is found that significant attenuation can be achieved if the phase velocities of the sources are lower than the sound speed. The effect of the radial distribution of the circular source on the attenuation in total power is examined, and is found to be almost negligible.

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This paper treats the pumping characteristics of a herring-bone grooved gas journal bearing when this bearing is used as a viscous vacuum pump in order to reduce windage power losses of a laser scanner mirror. In the theoretical analysis, the Reynolds equation for a herring-bone gas journal is derived, considering the effect of slip flow. The optimum design method for a vacuum pump is discussed by showing the influences of various design parameters on the pumping characteristics. It is consequently shown that this type of bearing functions well as a vacuum pump and is very useful for the reduction of windage power losses of the laser scanner mirror.

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This paper describes the frequency response of a hydrostatic thrust bearing which can attain very high static stiffness using a new type of self-controlled restictor. Many design parameters affect the frequency-response characteristics of this type of bearing. Here, the influcences of each parameter on the frequency response are theoretically investigated, and the theoretical results are compared with experimental ones in order to confirm the validity of the theoretical predictions. It is found that the hydrostatic thrust bearing with the self-controlled restrictor consistently shows a stable frequency response.

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An investigation was carried out to elucidate the vibration on the outer ring of a ball bearing under a radial load. In this report, the vibrations of three ball bearings were studied. The ball bearings were operated at a constant speed under a radial load. The radial and the axial vibrations on the outer ring of each ball bearing were detected by an accelerometer. The vibrations were examined using a fast Fourier transform analyzer. From the experimental results, analysis and considerations, the frequency characteristics of vibrations on the outer ring of ball bearings were clarified, and the causes of main peaks were specified.

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An investigation was carried out to elucidate the vibration of the outer ring of a ball bearing under a radial load. In this report, the rigid-body natural vibration of the outer ring was studied. The ball bearings were operated at a constant speed under a radial load. The radial vibrations of 13 points on the outer ring were detected by two accelerometers. Analyzing the radial vibrations, we obtained the mode shape of the rigid-body natural vibration of the outer ring. From the experimental results, analysis and considerations, the existence of the rigid-body natural vibration of the outer ring was clarified, and the frequency expression for the rigid-body natural vibration of the outer ring was derived. Moreover, considerable accuracy of the frequency expression was demonstrated.

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The contact condition and performance of a crossed helical gearpair of line contact for a spinning machine are researched. In this pair, the driving gear is a plastic helical gear with the working flank profile transferred from the counterpart, the driven gear is a steel involute helical gear, and the shaft angle is 90°. A method for computing the gap between two working flanks in a plane perpendicular to the axis is given, and the contact lines on both working flanks are obtained numerically. Their shapes differ considerably in terms of the helix angle, and some of them are illustrated. The working flank of a plastic gear is produced by cutting the flank of a plastic involute helical gear with a specially designed gear hob having an involute tooth fiank. The improvements in the noise level, power transmission efficiency and wear compared with the case of point contact are confirmed experimentally.

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The overall aim of this research is to establish an effective method for accurately estimating the noise power radiating from gear blanks. For this purpose, the basic theory for estimating the frequency response of radiated sound power was proposed in previous papers, and was applied to a circular plate with a solid shaft subjected to an axial load, in which the circular plate was a simple model of gear blanks. The basic theory was extended in previous papers to the circular plates excited three-dimensionally similar to that for helical gears. In this paper the basic theory has been further extended to include the rigid-body modes of vibration as well as the natural modes of flexural vibration of the circular plates. Consequently, the estimation of radiated sound power was much improved in a low-frequency range below 3 kHz, where the rigid-body modes existed.

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ADI (austempered ductile iron) has superior mechanical properties and shows a strength nearly identical to that of hardened steel. In view of such advantageous properties of ADI, research has been carried out in order to apply ADI to gears. However, it had long been thought impossible to develop ADI gears, because ADI is a difficult-to-cut material and tool failure occurs in a short time. This study aims at developing a method of hobbing ADI with a hob of high-speed steel. The results obtained are summarized as follows : ( 1 ) A tool of 5° rake angle and 15° relief angle was best, undergoing very little wear of the cutting edge without failure. ( 2 ) The conditions of 1-thread hob, hob feed of 1.0 mm/rev and cutting speed of 63 m/min are suitable for hobbing ADI gears. ( 3 ) The wear obtained with cutting oil was larger than that obtained in dry cutting. ( 4 ) By cooling the cutting portion with compressed air, tool life was improved.

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Oil mist leakage through a viscoseal under laminar flow conditions is experimentally investigated in relation to the pressure difference across the seal. The leakage cannot be confirmed when the pressure difference is smaller than a limiting value of around 40 to 50 percent of the maximum pressure difference generated by the pumping action of grooves. At a higher pressure difference, oil mist leakage appears, and the leakage rate increases in proportion to the increase in the pressure difference. Under the assumption that oil mist leakage occurs due to the backflow of pumped air in the grooves, the route of oil mist flow is studied. A correlation between the velocity distribution and the occurrence of oil mist leakage has been recognized. The limiting pressure difference where no oil mist leakage occurs can be obtained within a certain degree of accuracy from the velocity distribution in a groove with certain assumptions.

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The dynamic interation between snow-ice and various sheet materials, which is important for the development and design of machine structures and snow-removing equipment used in snowfall regions, is not very well understood. In this study, the dynamic interaction is discussed from the viewpoint of dynamics of machinery and elastic-plastic mechanics. This study is the first to explain the interaction theoretically and experimentally. The study of snow-ice from a mechanical engineering approach as mentioned above has been named "glaciodynamics", and as a part of this, research on glaciotribology is performed. In this report, the dynamic friction resistance that is practically important in dynamic interaction is measured in a low-temperature room and the results are discussed. The purpose of this report is to clarify the properties of various sheet materials on snow sliding and to construct a basis for theoretical explication of the dynamic friction mechanism.

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This report deals with an investigation of the results of basic experiments of tribology characteristics between diamagnetic CuB 2 copper and ferromagnetic S 45 C carbon steel in alternating field, after which experiments on the dry sliding wear were made. In the alternating flux parallel to the wear surface, the value of induced voltage generated was increased and it showed a violent variation, the AC and DC voltage were generated at the wear surface. The DC voltage showed change in polarity. The mean value of the coefficient of friction was 0.6 to 0.85 in alternating field. The EPMA analysis showed that oxygen concentration of wear surface became increased in alternating field.

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This report describes an analysis of the steel ball lapping process by use of lap plates with V-shape grooves. An evaluation of three-dimensional sphericity in terms of spherical functions enables quantitative analysis of this process. The angle of the contact points between the steel ball and the lap plays an important role in this process because the interference value between the ball and the lap is related to this angle. The rate of sphericity improvement is strongly dependent on the contacting point angle. Experimental results show that the contacting point angle increases with increasing wear of lap. This increase in the angle increases the rate of sphericity improvement in second-order waviness, and decreases that in third-order waviness, which are included in the form error. Furthermore, the rate is also related to the total number of balls processed at one time.

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It is known that the compensation of the fluctuating torque on the input shaft of indexing drives minimizes the transient and residual vibration of the driven member. Previous study was based on the energy exchange between mass and mass. The disadvantages of this method are higher cost and bigger size. To solve this problem, we developed mass-spring torque compensation, in which energy is alternatively exchanged between mass and spring. The basic mathematical procedure to obtain the normalized motion diagram of the torque compensation cam was established. The disadvantage of this new method is that perfect torque compensation only occurs at a certain speed (target speed). For industrial use, however, if most of the torque is compensated at that speed, it is still useful. To minimize the torque at that speed, the initial length of the spring should be adjusted. We also obtained the most suitable relationship between the arbitrary speed and initial compression of the spring.

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A new suspension system that uses a swinging mechanism to reduce the forces which occur during a frontal collision of a motorcycle was proposed in the previous paper. The motorcycle equipped with the suspension device exhibited excellent shock isolation properties compared with that in ordinary motorcycles. It is necessary, however, to satisfy the vibration isolation and running performance conditions when the new device is practically utilized in motorcycles. The properties of the vibration were experimentally analyzed using drum-type testing machine with sinusoidal wave plates in both a motorcycle model with structural similarity and an actual motorcycle. The running tests were done on an artificial rough road. The results of the studies confirmed that the swinging mechanism suspension system had superior vibration isolation properties and the running performance and can be easily applied to an actual motorcycle.

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A few tests and studies had been carried on in order to clarify the appraising method of elastic rotative rigidity and ultimate resistance moment of an uncovered column base in a posttension system with a cast steel base plate. The test method is to measure elastic rotative rigidity and ultimate resistance moment when the column, which is welded with a cast steel base plate connected with anchor bolts on a foundation of reinforced concrete and expanded mortar, is horizontally and axially loaded at the top. As a result, an appraising formula for elastic rotative rigidity and ultimate resistance moment of the column base in this system was derived.

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In order to estimate the frictional contact conditions between a tool and a workpiece, we have proposed the newly developed method wherein the relative intensity of a reflected ultrasonic wave at the interface provides the measure of the contact ratio. As a fundamental experiment, we carried out the test of upsetting an aluminum cylinder. Turned surfaces of different roughness were tested under dry conditions, and partly tested under the condition of lubrication with mineral oil. In the experiment, the measured relative intensity was plotted against the contact ratio estimated from the surface profiles. It has been clarified that this method can accurately detect the transition of the contact ratio during the process of deformation, the distribution of the contact ratio over the interface, and the trapping behavior of lubricants affected by the viscosity. It has also been found that the method may be very useful for estimating the contact thermal resistance.

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The machining accuracy and the productivity strongly depend on the performances of the guideways of the machine tools. Sliding guideways have been conventionally applied to machine tool tables because of their high damping abilities. However, there are some demerits such as stick-slip motion at low sliding velocities and temperature rise during high-speed operation due to their high friction resistance. In this paper, the application of advanced ceramics to the sliding guideways of machine tools is proposed. The friction characteristics of ceramics slideways is investigated under water lubrication. The friction characteristics depends on the surface roughness of the ceramics sliders. Grinding fluid is also applied as a lubricant, and it gives quite low frictional coefficient. The stickslip motion occurs under water lubrication, but it can be suppres sed by improving the surface roughness of the sliding elements. No stick-slip motion occurs under grinding fluid lubrication.

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The realization of a minute grain depth of cut is an important feature for obtaining a supersmooth surface by grinding. It is desirable to apply a grinding wheel composed of ultrafine abrasives which the diameters areφ10 to 20 nm. but it is difficult to mold homogeneous one due to cohesion of the grains. We have already reported that homogeneous ultrafine abrasive pellets could be manufactured applying electrophoretic deposition and that grinding using the pellets accomplished supersmooth surface less than 10 nmR_max for hard and brittle materiales. However, the bonding agent was sodium alginate which was not familier to grinding wheel makers. Thus the manufacture of ultrafine abrasive pellets using conventional bonding agent was examined in this paper in order to apply their knowledge to production of the pellets, As a result, homogeneous ultrafine abrasive pellets using PVA bonding agents could be developed and accomplished nanometer grinding of silicon wafers.

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