This paper reviews some of the work that has been carried out on golf ball and tennis ball impacts. The emphasis is on the motion of the ball rather than equipment and an attempt is made to focus on ball impacts with turf. It was found that the majority of work has looked at golf ball impacts with the club and that viscoelastic models of impact are used by many authors to simulate the ball/surface collision, although the identification of the viscoelastic parameters has remained a problem for most researchers. Two studies of ball impacts on turf were outlined; golf ball impacts on golf greens and tennis ball impacts on synthetic turf. For golf ball impacts, it was found that the hardness of the turf was an important parameter while for tennis ball impacts the hardness of the ball was important. The harder surface, or ball, causes the ball to slip throughout impact causing less topspin on the ball after impact and allowing the ball to rebound fast at a shallow angle. It was concluded that more work needs to be carried out on the material parameters of balls and turf if suitable models are to be formulated.

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A golf swing-robot is generally used for the evaluation of the performance of a golf club and a ball. A conventional golf swing-robot has two or three joints, and the motions of these joints are completely interrelated. Therefore, the user of this robot can specify only the initial posture and swing velocity. Thus this type of robot can not adjust the swing motion subtly to the characteristics of golf clubs. Consequently the golf swing-robot differs from a professional golfer and it causes serious problems for the evaluation of the performance of golf clubs. In this paper, we investigate analytically the golf swing-robot which can adjust it's motion to the specified value of the swing velocity and the characteristics of golf clubs such as the moment of inertia around the grip and the flexural rigidity of the shaft.

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Understanding the spinning mechanism of an impacted golfball is an important factor in golf science and engineering. The rigid sphere model which considers the Coulomb-type slip friction presented independently by Daish and Kawamura (referred to here as the Daish-Kawamura model) seems to well explain the experimental results of golfball spinning. For a more general interpretation of the spin phenomenon, we attempted to modify this model by introducing a physical quantity called the "s parameter", which is defined as the ratio of the circumferential velocity of the ball to its centroid velocity. An experiment performed to verify the appropriateness of the new parameter introduction led to the following conclusions: The spin phenomenon in golf impact can be divided into two phases, in both of which the Daish-Kawamura model is effective. A method is described to evaluate the coefficient of slip friction under high sliding velocities, and the value is estimated as 0.07 for a slippery surface condition.

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In this study, the influences of the characteristics of golf dub, such as the rigidity of shaft and spring constant of head, are examined on the impact phenomenon such as the dynamic deformation of shaft and the release velocity of ball by the analysis on the ball-head hitting line. As the results of numerical analysis, it is seen that the optimum spring constant of head is as same as the one obtained by impedance matching condition even if the dynamic deformation of shaft is considered. It is also seen that the release velocity of ball isn't influenced by the dynamic characteristic of shaft when the impact phenomenon is only considered.

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We analyse the mechanism of the Alpineski robot which can make only the rotation of hip joints around the femur axes but can execute repeated turns such as Pfiug Bogen, Stemm Turn and Parallel Turn. We take this Alpineski robot as a model of human skier, in order to clarify the relation between the motion of skier and the direction of skis. Assuming that the Alpineski robot is made of rigid wire-frame, we derive the equations which connect the angle of rotation of hip joints around femur axes with the edging angle of skis and the direction of skis relative to skier. We also derive the equations of motion for this model and solve them under realistic conditions to try the computer simulation of the turning behavior of the Alpineski robot on the computer display.

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Acting forces from the snow surface to the skiing robot have been measured in a ski turn using force sensors embedded in the legs of the skiing robot. The robot makes a turn onto the side curve line by the rotation of the hip joints into side direction. Acting force from the snow surface corresponds to the ski motion. In the right turn, force acts to the right direction and in the left turn, force acts to the left direction. If it is assumed that the turning force is caused by the centripetal force and the force is in proportion to the edge angle, the elemental simulation result agrees well with the experimental result.

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Dynamics of Parallel-Turn of Alpineski robot which can rotate hip joints around the femur axes is analyzed. The Alpineski robot is taken as a model of human skier in order to clarify the relation between the motion of skier and the direction of skis. Assuming that the Alpineski robot is made of rigid body, equations of motion which connect the angle of rotation of hip joints with the edging angle of skis and the direction of skis are derived. Both carving-turn and skidding-turn are dealt with, and numerical examples are shown.

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The term sweet area is used in describing that region of a tennis racket where the ball should be hit for optimum results. There are several definitions of this term, each one based on different physical phenomenon, and also a number of unclarified points with the confusion. This paper predicts the racket performance in tennis in terms of the region on the racket face where the ball post impact velocity is above some arbitrary value, when a ball is struck by a player. It is based on the experimental identification and impact analysis of the ball-racket system, clarifying the mechanism of the ball post impact velocity in relation to restitution coefficient, rebound power coefficient, and racket head velocity.

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Two kinds of road racer bicycles are employed to research vibration characteristics of driving bicycles. After obtaing the natural frequencies and modes by vibration test in the non-driving state, practical driving tests are carried out. The acceleration of vibration in the middle of the handles and under the saddles are measured and the corresponding spectral density functions are calculated based on FFT method. The results show that in the driving bicycles, the dominant frequencies exist between 10 Hz and 50 Hz and the lower two modes in the non-driving state are excited.

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Running shoe sole has an important role to absorb the external impact forces that transmitted from the running surface. Especially, tile impact force occurred on the runner's heel is about 3 times of the runner's weight. Therefore, the purpose of this paper is to show the method of measurement and evaluation for the mechanical characteristics of shoe sole. The impact device used in the trials, is made by considering the collision conditions between human heel and the running surface. It means the maximum impact force is about 2 kN, the impact velocity is 1 m/s and the duration time of load is about 20 to 40 ms. To satisfy all the conditions, we proposed a drop-weight type testing system with an accurate measuring devices. A variety of commercial running shoes were chosen randomly for the trials, to check up the validity of the testing system. From the measurements, the mechanical properties of each shoe, including the maximum impact force, maximum deformation, rate of energy absorption, average Young's modulus, etc, are extracted to evaluate the individual cushioning characteristics. At the same time, the human sensory evaluation of each shoe was done to compare with the mechanical measurements. As the result, by observing the similar tendencies of these two evaluations that we have obtained, it is obviously that the mechanical measurements have definite correlations with human senses.

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The record of pole vaulting has progressed rapidly by the appearance of flexible fiberglass pole. In analysis of the dynamics of the pole vaulting, it is necessary to consider a high flexibility of pole. This report deals with a large deformation problem of pole subjected to concentrated loads at two supporting points. It is introduced a simple combination system consisted of a mass (vaulter) and a pole. Several formulae are derived for vertical and horizontal displacements of the vaulter and so on in terms of elliptic integrals. Moreover, time histories of pole deformation are presented. From the results, it is clarified that the initial conditions (e.g., vertical and horizontal velocities of the vaulter) and the applied bending moment during the vault play important roles.

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The purpose of this study was to clarify the influence of different strings on the dynamics of Japanese Bow, and to investigate the relationship between the measured mechanical data and the feeling of shooter. Four strings, aramid fiber "Kevlar", "Technora", polyester fiber "Vectran", and hemp string were used for the shooting experiment by nine subjects. At that time, feeling data through questionnaires were collected. The results were summarized as follows: (1) in the logarithmic decrement of bending and torsional oscillation after release, hemp string was highest in this four strings, (2) the difference of fibers didn't have influence on frequency of the oscillation, (3) in the energy transmission efficiency, Kevlar, Technora and Vectran were about 69%, hemp was 67.7%, (4) it is also found that the feeling of shooter was related to the measured mechanical data significantly.

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The present study is concerned with the estimation of power in Karate-doh. The measuring method and numerical estimation for impact forces produced by Karate-doh hand techniques such as Syutoh-uchi, Tettsui-uchi and so on, are discussed by experiments (by means of Tameshi-wari) and numerical simulations. In the beginning, an impact experiment of simply supported concrete beams was conducted to examine the impact response and the impact breaking of the concrete beam. And then Tameshi-wari of simply supported concrete beams was performed. In order to understand the mechanism of impact breaking of concrete beams by Karate-doh hand techniques, a numerical simulation was also carried using a dynamic finite element method with a Newmark-β method. The impact force generated between the hand and the concrete beam was estimated to be beyond 4.5 kN. It was also found that a reaction at both ends of the beam was almost never generated by virtue of the dominant modes of bending deformation of the beam. This indicates that, by means of Tameshi-wari, the impact breaking of the concrete beam floating in air is quite within the bounds of possibility. Therefore Tameshi-wari for concrete beams suspended in air was also tried and achieved the predicted results.

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Although a ball's rebound height decreases for every fall, a man's rebound height in running is kept constant by supplying the actuating force in a certain amount through the ground reaction force of landing. Purpose of this study is to propose an estimation method of the actuating force from the ground reaction force. In this paper, the mechanical model of running is represented by the mass-nonlinear Voigt model which is composed of the nonlinear spring element whose stiffness decreases with time because of the biomechanical properties of passive tension of muscle and the nonlinear damping element which is expressed by polynomial of viscous element and some elastic-viscous interactive elements. In this model, when the resultant reaction force of the viscous and interactive elements agrees with the velocity of mass center in direction, the force is estimated as the actuating force.

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The purpose of this study is to derive the reasonable lifting movement from analysis of biomechanical characteristics of the snatch, back lift (BL) and leg lift (LL) in a skilled weightlifter. During the snatch lift, the differences between skilled and unskilled lifter appear in EMG and joint torque patterns. The skilled lifter utilizes the double knee bend technique and motor unit recruitment patterns in agonist and antagonist about joint might be reasonable to lift heavy weight. The present data suggest that skilled weightlifter has acquired the higher neuromuscular performance, which is required the control among the recruited muscles with regard to the tension and the timing of the coactivation and the contraction-relaxation. From comparison of BL and LL, it is suggested that BL has higher EMG activity and produces a much higher shear force about L 5/Sl joint which induces a low back injury. In case of LL, the shear force about L 5-Sl joint depends on the lifting posture. Moreover, it is revealed that the skilled weightlifter might have a lower shear force than unskilled person. From the experimental results, it is shown that the detailed instruction about lifting posture is needed to reduce the incidence of low back injury.

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This paper presents an analytical model for the fluid-elastic instability as observed in Super-Phenix-1 LMFBR. This fluid-structure system is constituted by the flexible cylindrical weir and adjoining annular fluid plenums, and the fluid is discharged from the upstream plenum to the downstream plenum over the flexible weir. In this report, to clarify the mechanism for instability, we analyzed the case in which the rectangular reservior was divided into the upstream and the down-stream plenums by a flexible plate weir. The characteristic equation of the system is derived. The effects of the discharged fluid on the downstream plenum sloshing and the effects of the fluid level difference between the upstream and the downstream plenums are examined, and the mechanism for instability is discussed.

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This paper presents an analytical model for the fluid elastic instability as observed in Super Phenix-1 LMFBR. This fluid-structure system is constituted by the flexible cylindrical weir and adjoining annular fluid plenums, and the fluid is discharged from the upstream plenum to the downstream plenum over the flexible weir. In this report, we analyzed the case in which the annular reservior was divided into the upstream and the downstream plenums by a flexible cylindrical weir. The characteristic equation of the system is derived. The effects of the discharged fluid on the downstream plenum sloshing and the effects of the fluid level difference between the upstream and the downstream plenum are examined, and the mechanism for instability is discussed.

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The theory of squeeze film pressure and the theory of acoustic radiation pressure have been generalized to a new theory in this study. When the two flat faces are separated by a compressible fluid film, a dynamic pressure is generated in their normal direction by the oscillation of the faces. In this paper, an analytical solution to the differential equation for the phenomenon considering both the inertia and the viscosity of the fluid is presented. The relationship between the squeeze film pressure and Langevin radiation pressure is also investigated theoretically. The results show that the inertia efects of the fluid on the pressure reveal when a Reynolds number is larger then 1. If a Reynolds number is small enough to neglect the inertia effects, the conventional lubrication theory can be applied to the phenomenon. The time average value of the pressure generated by the inertia of the fluid can be considered to be Langevin radiation pressure.

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An exact solution is presented for solving free vibrations of laminated composite thick shells of revolution having meridionally varying curvature. Based on the thick lamination theory considering the shear deformation and rotary inertia, equations of motion and boundary conditions are obtained from the stationary conditions of the Lagrangian. The equations of motion are solved exactly by using a power series expansion for symmetrically laminated cross-ply shellS. Frequencies and mode shapes of shells of revolution having elliptical and parabolical meridians are presented for both ends clamped, and the effects of shear deformation and rotary inertia are discussed bd comparing the results from the present theory with those from the thin lamination theory.

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Free vibration of a cantilever beam with time varying length is analyzed. An equation of motion described by a partial differential equation cannot be solved by the method of separation of the variables. In the present paper an equation of motion of a beam with a constant length is described by a partial integro differential equation and then the vibration of the beam with a moving support where unknown load and bending moment act is analyzed. From the condition that the displacement and its derivative of the beam at the support should be zero, two integral equations of Volterra type of first kind with respect to unknown load and moment are obtained. These integral equations are solved approximately and numerical examples of free vibration are shown.

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This paper deals with fluid dynamics caused in Kyser type ink jet head. The system of the ink jet head fundamentally consists of an ink-reservoir, pipe line elements, a ink-chamber and a nozzle. In order to execute a simulation analysis of dynamic performance of the system, we construct a mathematical model of the system. As a mathematical model for the pipe line elements, we adopt a modal model which was proposed by the authors for simulating transient response of hydraulic transmission lines in high accuracy. A main interest of this study is, therefore, to investigate applicability of the modal model into a miniature pipe lines such as used in ink-jet head. In the simulation, pressure responses caused in the ink chamber are calculated. The results are compared with the measured responses to confirm the validity of the simulation analysis.

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In this paper, we propose a dynamic vibration absorber (DVA) with an air damper consisting of a piston and a cylinder. The dynamic behavior of the air damper can conveniently be represented by the Maxwell model where a spring element and a dashpot are connected in series. The air damper has no ability to return the piston to its original position. For this reason, it is necessary for the piston to be supported by a spring which is placed in parallel with the damper. The air damped DVA can then be modeled by the three element model. Many studies have been done on the Voigt type of DVA, and the accurate expressions of optimum tuning and damping parameters have already been derived by Hahnkamm and Brock et al. However, only a few papers have been published on the three element type of DVA, and reliable expressions for it have not been derived until now. Therefore, we began our work by trying to derive expressions for optimum parameters of the three-element type of DVA. It was clear that the optimized three element type of DVA is superior to the conventional Voigt type of DVA. The optimum parameters which we obtained from our expressions were tested on a vibratory model. The experiments showed that the our expression is very useful for designing the air damped DVA.

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In this paper, we attempt to identify parameters of the system by using an image processing method. The parameter identification is one of the inverse problems and sensibly on noise. High accuracy of parameter identification needs high accuracy of measurement. Though the image processing method has good features, i.e., non-contact method, high flexibility of setting and so on, many researchers paid little attention on this method because of its low accuracy. In this paper, we examined the approach that made up for defect of image sensing to carry out identification of parameters in case of a non uniform beam.

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In this paper, a new identification method is proposed which is efficient to the identification of nonlinear time lag system on the basis of combination of both genetic algorithm (GA) and sequence method. First, the identified system is described as a discrete model of a polynomial type with unknown parameters using Kolmogorov·Gabor's method, in which the problem of system identification is to determine these parameters. Though the parameters of the identified system can be obtained through the search of GA, there is a potential risk in using a simple GA that a solution is usually stuck at a local minimum. Second, to solve this problem, the new GA search method using a sequence search is proposed which is carried out nearby the value of each estimated parameter by GA. By which individuals whose fitness are larger are found. As a result, the solution escapes from the local minimum and converges to the opthnum one. Finally, through simulations, some examples are given to demonstrate the validity of the proposed identification method.

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There is the more needs for the improvement of the damper ability to control the crankshaft torsional vibration, because of the excited power increase of engine with the higher effective mean pressure. Here is the study about high viscosity type viscous damper. It has the complex damping property with damping and stiffening functions. The new method to decide these functions is proposed by using the map of resonant peak points distribution with the technique of the temperature compensation. The optimization study of viscous damper design can be done visually on this map.

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A large capacity turbine generator has tertiary mode of rotor vibration. Then the thermal unbalance of rotor has a large effect on increasing its vibration. This study presents a method for prediction and diagnosis in order to distinguish the thermal unbalance causes by using rotor condition supervision equipment and rotor thermal vibration measuring equipment. Furthermore this paper deals a method for actual adjustment in order to decrease the thermal vibration stroke by using thermal vibration operator. By this method, a satisfactory vibration was achieved for a large capacity turbine generator.

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The present article discusses a modeling and control of high-T_c superconducting levitation system. The paper first clarifies analytical expressions for obtaining nonlinear levitation force given by the present author, then presents at vibration control method in which feedback currents involving frequency weights. In the method, an addition of a square of the displacement and currents in a frequency domain is taken as a cost function. Optimal coefficients of the transfer function of the controller are obtained by minimizing the cost function. Hence, the spillover instability due to the nonlinear vibration will be redriced. Numerical calculations have been carried out for some typical problems. To validate the present method, experimental tests also have been carried out.

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This paper is concerned with the problem of reducing a high-order controller to a reduced-order one for flexible structures which have transverse-torsional coupled vibration mode without significant errors. Firstly, the controller is designed for the structure by using H_∝ control theory. Due to using the frequency weighting filter for compensating the unstructured uncertainty, the order of that controller leads to the high order, meanwhile, the high-order controller is not practical in implementation. Secondly, the order of the controller is reduced by using the modal truncation. This method is verified by comparing to the model reduction which has been widely used to find a reduced order controller. From the simulation and experiment results, it is confirmed that the reduced order controller obtained by the controller reduction is better than the reduced-order controller obtained by the model reduction.

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This paper deals with a sensor/actuator placement problem in design of active vibration control system for flexible structures. This problem is formulated as a minimization problem of the total energy which is defined as a sum of a kinetic and strain energy in a colatrolled structure with a constraint of control effort. The inequality constraint on the variance of the closed loop control effort is adopted to represent the capacity of the actuator. Using a design algorithm which iteratively tunes the weighting matrix of the quadratic performance index in LQG problem, the controller which meets these specifications can be synthesized. The optimal location of the sensor/actuator is determined by calculating the total energy for each candidate of them under several energy constraints of the control effort. It is found that the optimal placement of the sensor/actuator depends on the input energy constraint. The simulation and a experiment for a cantilevered beam as a typical example of flexible structures are conducted. It is shown that these results of the optimization can be used as a guide to the design of active vibration control systems.

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This paper presents an actuator with a sensor for controlling vibrations of machines. It consists of a voice coil type electromagnetic actuator connected to piezoelectric sensor and a coil spring. The actuator is used for controlling a motor laid on the beam. The disturbance force due to the centrifugal force of the motor is detected by the sensor, and the force which is equivalent to the disturbance force is applied to the motor and the beam by the actuator. This implies that the disturbance force is canceled. The control technique as just mentioned has advantages because it reduces the vibration in the low frequency region, in addition, the actuator becomes compact, and the control force becomes small. But the control is insufficient for controlling the resonance peak. The PD control is available for reducing the resonance peak, but the displacement and velocity sensors are required. In the present article, a method of vibration control of disturbance cancellation combining the PD control is presented in which both the displacement and velocity sensors are not required. The analytical results for obtaining the control current and the response of both the motor and beam have been obtained. To validate the present actuator sensor system and the control method, experimental tests are carried out.

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Recently, the sliding mode control (SMC) is frequently applied to various kinds of systems due to its simple algorithm, adaptability or robustness to complex and nonlinear systems and so on. The disturbance observer is very robust servo system against a disturbance and a fluctuation of plant parameters. In this study, we proposed such a robust servo system based on a combination of disturbance observer and sliding mode control. And also to eliminate the chattering phenomena, we use a sliding mode control with accelerative reaching rule. From the view point of the disturbance reduction, a sliding mode control witin disturbance observer is employed to control the positioning of an oil hydraulic cylinder. The experiments are carried out for several conditions, and the obtained results are compared with those of the slidling mode control without disturbance observer. As a result, it is verified that the introduction of the disturbance observer improves the robustness of conventional sliding mode control.

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Loangevin-type ultrasonic vibrator works as an ultrasonic motor when it is pressed slantwise against the surface of an object. This paper describes a robot hand with three fingers that each works as an ultrasonic motor. This robot hand can simultaneously grasp a cylindrical body and rotate the body about its axis. We propose a PWM (pulse width modulation) Inethod for controlling the speed of ultrasonic motors by changing the duty ratio of the high frequency voltage applied to motors. The vibration of the ultrasonic motor and the driving characteristics of a robot hand were examined experimentally. It was confirmed that the vibration speed on the tip of the ultrasonic motor was approximately proportional to the duty ratio of the applied voltage. The velocity of the motor increases with an increase in duty ratio, except for at the offset region. The torque characteristic curves approach the origin, moving parallel as the duty ratio decreases.

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This paper proposes a localization method among indoor mobile robots (known as AGVs in factory) by using camera and color signboard. The signboard consisting of highlighted area for detection and localization and color identification pattern is attached to each robot. When the onboard camera views a signboard attached to the target robot, the robot verifies the position and velocity of the target robot based on the Interachting Multiple Model (IMM) method. The plant model is derived from the kinematics of the mobile robot. The motion of the target robot is modeled as a switching of three plant models, where they are driven by process noises of different intensities. The measurement model is built based on the geometry of the signboard observation by the camera. The simulation result illustrates the feasibility of the proposed method.

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Being buried to death under eollasped houses without being found became a big issue during a major calamity. The developnaent of a robot which finds life in the suffering district is needed as soon as possible. In this research, the method of lnoving the inchworm-type robot is being developed for the purpose of the rescue. This robot has the ability to traverse obstacles such as the stairs with fewer joints than the wheel type and the legged type. The selfstanding inchworm robot which has five links and four joints is made for trial purposes. In order to achieve climbing stairs for this robot, the kinematical analysis and the development of the program was researched. As a result, the effectiveness of this robot is confirmed by the experiment.

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Recently, the robot assembly industry requires research that deals with flexible parts using human like skills. We discuss cylinder insertion into a hole of a flexible rubber plate. We reported that the magnitude of the insertion force expresses a parabolic field in the three-dimensional space that is composed of position and posture of the cylinder. The parabolic field has a tunneling path from which we can obtain the local minimum insertion force. The tunneling path seems to correspond to the rationality of human skill. This paper proposes a new regression method for searching the tunneling path, using the insertion force of examination points without excessing the minimax force of parabolic center. The method gives us a flexibility for many kinds of size of parts, and the consistency of the insertion task. An experimental results show that the regression method is a possible search method for the tunneling path.

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This paper discusses design and control issues for a robot with integrated locomotion and manipulation which can take various postures. This work is motivated by the fact that persons can take various postures and can work while being in those postures. We show a prototype of four legged twelve joint robot employing timing-belt mechanism. Each leg can be used as a manipulator when it is free from providing the support to the body of the robot. At most two legs are free when the robot stands on its knees. This paper formulates feasible motions of the robot maintaining contact with a supporting plane or the floor. This kinematic analysis is useful to determine whether the robot needs to lift its legs in order to change its postures or not.

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In this paper, we propose a new method to calibrate the orientation error between the leader's coordinate system and each follower's for the leader-follower type of a decentralized coordinated motion control system of multiple robots using motion estimators⁽⁹⁾. This method uses the relation between the leader's velocity vector in the leader's coordinate system and each follower's velocity vector in the follower's coordinate system. The orientation error is estimated recursively by using the extended Kalman filter. Experimental results illustrate the effectiveness of the proposed method.

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This paper deals with a control technique for eliminating the transient vibration of a geared mechanical system. This technique is based oil a model based control in order to establish a damping effect without a response time lag. The control model is composed of reduced-order electrical and mechanical parts. This model estimates a load's speed which is converted to the motor shaft. The difference between the estimated load speed and the motor speed is calculated dynamically and is added to the velocity command to suppress the transient vibration of the load. This control model is easily obtained from design or experimental data and can be easily integrated into a DSP. This control technique is applied to a harmonic drive geared system. Simulations and experiments show satisfactory control results in reducing the transient vibration.

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Wavelet transform, WT, is a representative method of time-frequency analysis of a non-stationary signal. The original time series is obtained from the two-dimensional distribution by applying an inverse wavelet transform, IWT. However, fast Fourier transform, FFT, algorithm can not be applied to fast WT/IWT calculations because the base function of a WT is nonsinusoidal, while the algorithm can be used for fast computation of a short-time Fourier transform, STFT. For fast computation of a WT/IWT, a particular algorithm has been used in a time-domain calculation. In this study, a new fast WT/IWT algorithm, which is applied in the frequency domain, is proposed. Since the amount of data needed to represent a time frequency two-dimensional distribution is very large, a data reduction technique is required to enable fast computation of an IWT. An algorithm which can be used for redundancy elimination of WT data is introduced into the fast IWT analysis. Calculation times of this new fast WT/IWT algorithm are compared with those of traditional ones, for the analysis of both simulated signals and measured voices. From the comparisons, it is clear that the new method markedly speeds up the computation.

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Chirp pulse compression technique can improve signal-to noise ratio of ultrasonic flaw signals. But its disadvantage is the presence of sidelobes which might mask nearby small flaws and make it difficult to separate multiple flaws. In this paper, time-frequency analysis (t-f analysis) is applied to ultrasonic chirp pulse compression signals for range resolution improvement. Short Time Fourier Transform (STFT) is adopted for t-f analysis, followed by the application of Minimization and Polarity Thresholding Algorithm to suppress the sidelobe. In order to achieve the low sidelobe level without suppressing the mainlobe, the STFT is calculated by varying the window length with frequency and both pseudo-twofold and pseudo fourfold frequency cos components obtained from the STFT are utilized. The method is applied to both simulated and measured ultrasonic flaw signals of chirp. The results show a good suppression of sidelobes and a further compression of pulse width with preserving both the polarity and the amplitude of signals.

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The purpose of this paper is to present a numerical method for shape optimization problems related to frequency response problems of linear elastic continuum. Following the previous report in which no danaping was assumed, proportional viscous damping is considered in this paper. Minimization problems of strain energy, kinetic energy and absolute value of mean compliance are treated. A variational form of an equation of motion is obtained with complex number of displacement amplitude. Sensitivity function, that is called shape gradiant function, is derived using the Lagrange multiplier method. A technique using modal parameters for calculation of Lagrange multiplier function, that is called adjoint function, is shown. The traction method is applied for numerical analysis. Beamlike plate problems are analyzed to show the validity of this approach.

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We successfully reached the formation mechanism of corrugation by full scale stand tests, commercial line experiments and theoretical simulation. From these works, we conclude that main causes of corrugation formation are the large creepage between wheel and rail, and periodical change of vertical force on wheel/rail contact surface. That is, the corrugation is caused by: 1) excessively large creepage between wheel and rail, which is caused by insufficient rolling radius difference between inner-outer wheels or large attack angle between wheel and rail; 2) oscillation of vertical contact force between wheel and rail, which is caused by the vertical vibration including Hertian contact stiffness or the rail tilting vibration; 3) stick-slip between wheel and rail accompanying with the vertical contact force oscillating. The frequency of corrugation is decided by vertical contact force oscillation.

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By making use of the contour representation of the damping ratio, the influence of the wheelset misalignment on the stability of the wheelset hunting motion can be shown much more clearly, and it is found that the wheelset misalignnmnt diminishes the stability margin in the high speed range, and that, in the (k_x k_y) plane, k_x and k_y, are better to be chosen in the region apart from a straight line, k_y=1.5k_x. Limit cycle analyses by means of numerical integration of the original nonlinear equations of motion show that, as no unstable limit cycle can be found in the stable region of the (k_x, k_y) plane, it can be said that, in order to analyze the stability of misaligned wheelset motion, it is sufficient to examine the stability of the linearised system.

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For the efficient operation of flexible manufacturing system, it is important to assign the jobs and tools to machining centers taking into account of their interrelations. In this study, we propose an algorithm to assign jobs and tools to machining centers using' an auction method, where each machining center makes a decision autonomously. We realize the load balancing among the machining centers and decrease the job transportation and the number of assigned tools.

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In the present study, shear modulus, refractive index, and dynamic density of the order of GHz frequency were evaluated by measuring Brillouin scattering light under high pressure, employing a diamond-anvil high-pressure cell and a laser light scattering optical system improved on the previous one. The sound velocity on transverse mode and shear modulus were obtained for polyphenylether up to 4 GPa. The slope change in pressure-sound velocity diagram was confirmed at about 0.3 GPa. The change of refractive index became small with pressure and reached to a constant value at 3 GPa for both polyalphaorefine and tar naphthenic oil. The dynamic density was obtained from Brillouin scattering for several synthetic oils. The density change by pressure for naphthenic oils and polyphenylether was a half smaller than static one and its difference decreased with raising temperature. Application of a viscoelastic model with a bulk viscosity for these features was attempted.

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A new method has been investigated for the simultaneous measurement of oil film thickness and temperature by using fluorescence technique, which was proposed by Azetsu et. al.⁽⁴⁾. The capability of oil film temperature measurement was confirmed by the precise calibration in the range from room temperature to 180°C with Coumarin 6 and Rhodamine B, which were dyes of different wavelength and of different dependence of intensity with temperature. The absorption by Rhodamine B was found out to influence the dependence of fluorescence intensity of Coumarin 6 with temperature. Consequently, the concentration ratio of dyes can be determined in which the fluorescence intensity was least affected by temperature. Based on the investigation, Laser Induced Fluorescence system was extended to measure the oil film thickness and temperature simultaneously with dual equipments for measuring fluorescence intensity of different wavelength range. The system was applied to the measurement of piston oil film in real operating conditions, which provided reasonable results for the oil film temperature on the piston top land.

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The limiting ability of oils to build up hydrodynamic lubrication film was investigated using a plate-on cylinder testing apparatus on sliding condition. The oil viscosity entrained into the conjunction zone was estimated by comparing the values of the film thickness and coefficient of friction measured during testing and theoretical ones under oil starvation conditions. There was a critical sliding velocity above which the oil thickness and friction force inversely decreased with increasing the sliding velocity. Below the critical sliding velocity, the oil film thickness and coefficient of friction measured were nearly equal to the theoretical ones. The reduction in oil thickness and friction compared with theoretical ones of the supplied oil resulted from preferentially entraining the lower viscosity components of the supplied oil into the conjunction region.

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