The response of a tilted dynamic vibration absorber system with a parametrically excited pendulum or with a dynamically resonated pendulum is numerically investigated. It is found that each dynamic vibration absorber is useful for suppressing vibration of the main system under some tilted angle, but not under all the tilted angle from 0 to 90 degree. And their vibration absorbing characteristics are dependent on the parameters of pendulum such as ratio of mass and damping ratio. In this paper, the vibration absorbing characteristic of the system is clarified, and the optimum parameters of each dynamic vibration absorber, which make the response of the main system minimum in some range close to the resonance frequency under tilted angles, are obtained. It is shown that the better results of suppressing vibration can be attained using optimum parameters.

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A stabilizing control technique for an inverted-double pendulum system consisting of elastic links connected in series is investigated using a reduced-order model considering only the first strain vibration mode of the upper elastic beam, and applying the H-infinity controller design method for the mixed sensitivity problem which has multiplicative perturbation at the output port and is characterized with a settling function. It is found that although the coupling effect of the different natural frequencies between two flexible beams make the stabilization problem more difficult, even a feedback control using only the output signal based on the strain vibration on the upper elastic beam is possible in stabilizing the system. Furthermore, it is concluded that the more different the lowest natural frequency of each elastic beam is, the more easily the controllability is realized.

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This study aims at establishing a robust and effective intelligent control method for nonlinear and complicated systems by extending the integrated Cubic Neural Network (CNN). In the method, an integrator neural network acquires optimum switching and integration of several controllers for a different local purpose by calculating the fitness based on the system object using the genetic algorithm. The proposed method is applied to an equilibrium point transfer and stabilization control of a double pendulum that possesses four equilibrium points, namely Down-Down, Down-Up, Up-Down and Up-Up points. In order to verify the effectiveness of the proposed method, simulations and experiments were carried out. As a result, it was demonstrated that the integrated intelligent controllers can transfer and stabilize the double pendulum from the arbitrary equilibrium points to arbitrary one without touching the cart position limit. In addition, by taking account of energy variation, the double pendulum was transferred from Up-Down to Up-Up and was stabilized without falling down.

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The container crane of the harbor received the enormous damage in the Hyogo-ken Nanbu earthquake disaster. After that, the container crane with seismic vibration isolation system has been developed and operated in practical use. In this study, a rocking type of vibration isolation system (RVIS) was proposed for the container crane. And the experiment of the scale model was performed to verify the analytical model. From the results of the experiment and the analysis for the scale model, the validity of the model was demonstrated. The influence on the quay structure which is excited by the load of the container crane was made clear. The results of the RVIS showed better performance to reduce the load to the quay structure than the conventional container crane.

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This paper deals experimentally with the squeal and chatter phenomena generated in mountain bike disk brakes. First, the authors performed the traveling test using actual bicycle on downhill road in a mountain. As the results, there are two kinds of frictional self-excited vibrations in the bicycle disk brakes called by squeal with frequency of 1 kHz and by chatter with frequency of 500 Hz. In order to regenerate the squeal and the chatter, a bench test apparatus by actual bicycle was set up and their characteristics were experimentally examined. By using the bench test apparatus, it was made clear that their frequencies were independent of temperature of pad and rotating speed of rotor, and the chatter was generated in a certain limited region of high temperature though the squeal occurred in arbitrary temperature region of pad.

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This paper deals with the occurrence mechanism of the squeal and chatter phenomena generated in a bicycle disk brake and their countermeasures. From the results by bench test apparatus, it was made clear that the squeal is in-plane vibration in the direction of rotor surface with frequency 1kHz caused by the frictional characteristics with negative slope with respect to the relative velocity generated in the vibration system including brake components and spokes, and the chatter is another frictional vibration with frequency 500Hz in which the squeal occurring in the in-plane direction of rotor and the out-of-plane vibration of rotor due to Coulomb friction are superimposed through the internal resonance relation caused by temperature increase of rotor during braking. The measures for squeal and chatter were taken on spokes and hub, and the validity was confirmed by using bench test apparatus.

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This paper deals with the active wave control of a flexible beam using wave filter which enables the direct sensing of a designated wave amplitude. It is the purpose of this paper to present the basic properties of active wave feedback control system based upon wave amplitude signal. First, the state equation of a flexible beam with arbitrary boundary condition is described by using a transfer matrix method. Then, two kinds of control laws are derived; one is for absorbing reflected wave and the other is for eliminating transmitted wave. Next, from a viewpoint of numerical analysis, the basic properties of control laws and its control effects are investigated. Finally, an active wave control system is found to be stable regardless of whether collocation holds or not, demonstrating the relation of stability between control and measurement point placement.

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The Engine Mounting Layout is very important to provide the performance of NVH (Noise, Vibration, Harshness). In the conventional studies, the only un-coupling engine with the vehicle body is optimized. But we sometimes can't secure the performance of NVH when this engine is coupled with the body. So we need to use the analysis model made of the engine and the vehicle body. Usually these models need a long time for analysis. So we use CMS (Component Mode Synthesis) for the efficiency of the calculation. We use the MPOD (Most Probable Optimum Design) method using HNN (Holographic Neural Network) as the basic functions for this optimization problem of Engine Mounting Layout. Since this problem has as many design variables as 15, it is needed many sampling data to get the global optimum design using any optimizing method. So we improve the MPOD to get the local optimum design with the fewer sampling data for reducing the cost of the calculation. We also improve HNN, because its theory has problem when we use higher order system of the basic functions.

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In this paper, we propose the fast calculating method for eliminating the impulsive noise by using the non-linear digital filter, ESDS. In our research, we have proposed a new technique to estimate the smothed value and the differential value by using sliding mode system (ESDS). It works effectively to eliminate the impulsive noise. The system of it is represented by differential equations, and we have used Runge-Kutta (RK) methods in order to solve them. RK methods require heavy calculation, and it requires high-performance processor in order to calculate rapidly. Consequentially, by using the knowledge of the phase plain, it becomes possible to reduce the calculated amount of our proposed method. The experimental results show the our filter with RK method needs plenty of time for calculation, but that with the fast calculating method needs little time.

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This paper presents a novel control strategy for a human-robot cooperative task. There is a problem that a cooperative fitting task, i.e. peg-in-hole task, could not be performed precisely using a conventional impedance control because of instability of a system. A proposed controller changes a control mode according as a task. A variable impedance control based on a position control is used in a carrying task and a torque control with compensation for its dead weight and friction is used in the fitting task. In order to confirm the usefulness of the proposed control, a human-robot cooperative carrying and peg-in-hole task is performed. Experimental results illustrate that the proposed control is effective for the human-robot cooperative task in spite of possibility of the system's instability.

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Recently, robots have been expected to be used in various fields such as not only usual manufacturing industry but also medical welfare, agriculture, security system and so on. Especially, in the coming advanced aged society, the demand of robot will be more increased in medical welfare and human life assist technology. In such a field, sice robots must work together with human or contact with a human body directly, they require safety and flexibility. In this study, in order to realize a flexible mechanims satisfying the above requirements, a soft-mechanism has been developed. It is composed of a body made of silicone rubber and driven with a pneumatic power. Both the elasticity of rubber material and the air compressibility are effective to realize such a soft-mechanism. A developed tactile soft sensor is composed of cylindrical silicone rubber. When the force is applied to it, by detecting the inner pressure change with built-in pressure sensor, a tactile information can be detected. In this paper, firstly, we discuss the structure and the fundamental characeristics of this sensor. And then, applications of this sensor are experimentally discussed. The effectiveness of this sensor is shown from the results.

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A two axial finger-shaped sensor is developed for controlling grasping force so that an object is lifted with appropriate grasping force at any grasping direction. It consists of silicone rubber having spherical surface and strain gauges arranged in two perpendicular axes. First, the relationship between stick area and the internal strain distribution of the sensor are calculated using FE (finite element) analysis when the sensor is in contact with an object. It is necessary to detect the shear strain distributed in the sensor in order to grasp the object with appropriate force. Then, the method for estimating stick area of the sensor is proposed using FE analysis. Finally, the grasping force control is achieved using the constructed system. It is shown that arbitrary objects with various weight and friction coefficients are lifted using the developped sensor and control method.

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There are many references on “Information Theory” that treat information amount and entropy, but no study has been reported on the practical usage of this theory. In this study, this theory was tried on the recognition time of station selecting button number for automobile radio. Process to seek button number is considered to depend on button arrangement, and recognition time to depend on the information amount and entropy possessed by the button arrangement. So information amount and entropy were calculated and recognition time was measured, for three types of button arrangement : one set of six buttons (1×6), two sets of three buttons (2×3) and three sets of two buttons (3×2). It was found that there is a strong correlation between entropy (average information amount of each button arrangement) and average recognition time of six buttons, for three types of button arrangement. To seek by smaller entropy, average recognition time was found to be shorter. Recognition time, especially for the inner ones of six buttons was found to become shorter by dividing six to two or three sets.

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Function test results of an adaptive attitude control system of the Data Relay Test Satellite (DRTS) that was launched on September 10, 2002 are summarized in this paper. The purpose of the adaptive attitude control system is to compensate for attitude disturbances caused by motion of an inter-satellite communication antenna. The control system estimates mass property parameters and improves attitude accuracy when the antenna motion effects are mainly cancelled by feedforward control. The estimation accuracy of the mass property parameters is improved with the antenna motion even when the initial estimation accuracy is not enough. The function tests confirmed that the attitude control system realizes almost the same performance as predicted on the ground. Since the accuracy of the feedforward control is easily improved by adopting the adaptive attitude control system, this system is effective for attitude control of spacecraft with mobile bodies like antennas.

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In this paper, we discuss the dynamic response of a system consisting of a very flexible body and rigid bodies at its end under attitude control to the end body. A tethered subsatellite in space is known as an example of this system. Two mathematical models for a planer motion of a flexible body are considered using FEM and Absolute Nodal Coordinate Formulation. In A.N.C Formulation, it is easy to describe the motion of the flexible body with large deformation, rotation and translation displacement. We attempt to control the attitude of the end body using a reaction wheel. The control technique consists of an attitude control by the reaction wheel and a control by the reaction wheel with the joint torque control to cancel accumulation of angular momentum. First, eigenvalue analysis is carried out where control gain changes. Second, the motion under controlled system is discussed its free vibration, comparing the motions of FEM model and A.N.C one. It is pointed out that the axial stress in the tether plays an important role as constraint force at the joint between the tether and the rigid body. Furthermore we treat large deformation, large displacement problem, where the end of the flexible body moves horizontally. We confirm the interaction between flexible body with large deformation and rigid body under the attitude control and clarify its mechanism.

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One of the fundamental problems of the mobile robots is self-localization, i.e. to estimate the self-position by comparing sensor data and a map. In non-stationary enviroments, a robot should avoid to use changed objects as landmarks in the localization. In this paper, we propose a self-localization method that is robust against changes in environments. The method identifies changes from noisy and ambiguous sensor data. Since an object with a random shape may be added at a random position, it genetates and utilizes multiple hypotheses about the changes. A number of simulation experiments have been performed in various environments, to demonstrate the effectiveness of the method.

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In this paper, we propose a new control method for two-wheeled non-holonomic mobile robots. Since the non-holonomic mobile robots has non-integrable constraint conditions, it is difficult to derive a control law so that the robots are convergent to the target state. The proposed method designs a nonlinear regulator carrying out asymptotic convergence of non-holonomic mobile robots to a given trajectory family. The trajectory family is chosen so that it passes through the origin and its gradient at the origin is equal to zero. As the result, the mobile robots are convergent to the origin as the target state while generating their path. We name this method Path-generating Regulator. Neither the coordinate transformation nor the input transformation is needed in this method unlike other methods. Global asymptotic regulation property of this method is proven by a Lyapunov-based stability analysis. By numerical simulations and experiments, we show the validity of the proposed method.

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Power-assist system technology and its applications to manufacturing systems, rehabilitation and welfare services have attracted special interest recently. In the field of manufacturing systems, automobile assembly processes utilizing power-assist systems exist. Many power-assist systems for industrial uses possess simple power-assisting function only. Conveyance of controlled objects is generally processed by another system. However, it seems that the progress of such actuators as linear motors produces single actuator which realizes both the functions. Taking the above expectation into account, this fundamental study proposes a positioning method of a cart with motor by means of a smooth switching from the servo access control for the conveyance function to the impedance control for the power-assisting function. We apply the idea of the nonstationary optimal control method to obtaining the smooth switching. The controller is formulated as a state feedback style utilizing time-varying feedback gains. The effectiveness of the method is verified by experiments.

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Wheel slide protection devices have been installed on Shinkansen braking systems to prevent wheel flats. However, braking distance considerably increased when wheel slips frequently happened under wet conditions. This problem was caused by that braking force was excessively decreased due to slow wheel slip detection. We proposed the slip rate wheel slide control system supported by synchronized pulse processing method in order to calculate wheel speed/deceleration more accurate and to detect wheel slips more rapidly. Accuracy of speed/deceleration calculation is discussed. Those were reduced to about one-third of a conventional method. We obtained good results at running test of series E 3 Shinkansen that increase of emergency braking distance was less than only4.5% when compared with about 20% that is obtained with the conventional systems. This system is made for practical use on series E2, E3 and E4 Shinkansen vehicles.

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Adhesion under wheel slipping affects essentially the performance of traction and brake in railway vehicles. However, most of experiments have been made in laboratory rooms. In order to analyze the variation of adhesion, precise measurements of wheel slip speed and braking forces are needed. For the purpose, we have newly developed an adhesion test device using a continuous measurement system including speed and torque detection devices. The experimental results using the test vehicle show that the adhesion force varies nearly according to the wheel slip rate. By means of this method, adhesion coefficient has come to be evaluated in a wide range of wheel slip rates. Authors discussed the state of adhesion and made clear that though the adhesion coefficient generally decreased with an increase of the slip rate, the maximum value of adhesion coefficient could come under about 5% slip rate. We proposed a wheel slip protection concept for high availability of braking force during wheel slipping based on results of these experiments.

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To clarify the mechanism of a wheel flat formation, it is necessary to precisely identify the site, where the wheel skidding occurs. However, it is so difficult to identify the skidding occurrence sites that many studies on the wheel skidding have not refer the site where the skidding occurs. As a result, only a few development is found on the studies to specify the factors which cause the wheel skidding. The authors developed an event recorder which can record not only the behavior of the train when the skidding occurs, but also precisely identify the site where the wheel skidding occurs. The recorder was installed on a JR limited express EMU operated on a conventional line. To specify factors which cause skiddings, they analyzed the date piled up in the event recorder. At the same time, they attempted to classify, those factors systematically.

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In recent years, speech-recognition technology progresses dramatically, and it has already been used for word processors etc. If this speech-recognition technology is used for operation of an electric wheelchair, an electric wheelchair is thought to be a useful vehicle for a physically handicapped person who has a trouble especially in hand. However, continuous operation cannot easily be performed by voice instructions, so operativity is not good. In this research, in order to solve this problem, automatic operation by visual feed back control was proposed, and we improved operativity of voice controlled vehicles.

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The research and development to use wood ceramics (WCM) as a new type gas sensor is being carried out. In the experiment, the temperature of WCM must be controlled on the desired value in order to measure a change of the electric resistance of WCM to gas. However, it is very difficult to control from the several reasons; the temperature falls sharply because the temperature of gas is low, the size of WCM isn't always the same, and the physical constants of the thermal conductivity, density and specific heat cannot be obtained correctly, these values depend on the temperature when WCM is made. Therefore, a robust control law is necessary to overcome these disturbances and uncertainties. This author showed that sliding mode controller was effective in the past to control the temperature of processes with uncertainties. This paper applies a sliding mode controller for the temperature control of WCM. Cascade control, the algorithm of fictitious set point, and the new estimation of disturbances are added to the usual technique. The experimental results show that fixed temperature rise can be realized and that overshooting from the desired value can't occur.

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Electroaerodynamic investigation has been carried out in a pin-to-plate gas discharge system to clarify the mechanism of repulsive force generation between the pin and the plate electrode at corona discharge. Numerical calculation has been conducted by two steps. At the first place, corona discharge field was calculated with the finite element method to deduce volumetric force ρE, where ρ is the charge density and E is the electric field, applied to the air, and then induced ionic wind was calculated with the finite differential method. Calculated pressure distribution on the plate electrode was in the order of 10 Pa that was in good agreement with the measured pressure distribution. Calculated velocity at the center was several m/s that is confirmed by a time-of-flight experiment and the velocity distribution near the pin electrode also agreed with the measured with a laser Doppler velocimeter. Pressure and wind velocity were increased at high applied voltage. These results confirm that the ionic wind is the cause of the repulsive force to the pin electrode at the corona discharge.

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We have already proposed a Complex Multi Resolution Analysis (CMRA), which can provide shift invariance approximately. And in this study, we propose a 2-Dimentional Complex Multi Resolution Analysis (2-D CMRA), which can provide 2-dimensional shift invariance approximately, and applied it to image denoising. The main results obtained can be summarized as follows : 1) Poor 2-dimensional shift invariance in which occurred by the discrete wavelet transform in the case of using real mother wavelet has been improved by using 2-D CMRA. 2) The discrete wavelet transform corresponding to 2-D CMRA has been applied to image denoising, and obtained very encouraging results.

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Wavelet transform is effective in the processing of an unsteady signal like the tapping tone of the wood. In this study, we try to develop a method for evaluating wood quality using wavelet transform and the main results obtained can be shown as follows : 1) The Young's modulus calculated using the resonance frequency which is obtained from wavelet transform, is compared with the Young's modulus whose dead load is put on the sample. As for both the clear sample and the sample which includes a knot, Young's modulus of the wood can be estimated by finding resonance frequency in wavelet Transform. 2) Relation between the degradation of resonance frequency caused by the existence of a knot and the ratio of the knot and the diameter R_K can be approximated in the 1st polynomial in the region of R_k>50%.Therefore, the analysis of the resonance frequencys of clear wood and the wood which includes a knot leads to estimate the amount of knots of the wood.

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This paper describes a method of giving impression words for images based on colors. 160 impression words are prepared, and colors which are strongly related to each of the 160 impression words are registered into the system in advance. In this system, we adopt Lab color space which is a color coordinate system and can obtain exact color difference between pixels and extract main colors of images based on the results of clustering in Lab color space. The number of main colors of an image is determined when the sum of pixels of the main colors is larger than 85% of all the pixels in the image, and the colors with the larger number of pixels are determined in ascending order. We propose a distance between the main colors and the registered colors. In this system _mC_n combinations of distances between m colors registered in an impression words and n main colors are obtained. Using the _mC_n distances, we calculate a minimum distance and an average distance every 160 impression words. By the comparison of the minimum distance and the average distance of each impression word, the system determines suitable impression words for the image. Experimental results show the proposed method to be effective.

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This paper describes the on-line estimation method of Mental Work Load (MWL) during machine operation. The time-dependent changes of MWL may be estimated from the amplitude of Respiratory Sinus Arrhythmia (RSA), which is variation of heart rate mediated by parasympathetic nerves. However, the RSA amplitude is also accompanied with respiration, such as tidal volume and breathing frequency. Therefore, we used Kalman filter to eliminate respiration-correlated fluctuation, and to estimate the trend of RSA amplitude. Finally, we developed an on-line estimation method of the trend of RSA amplitude. This method was verified with mental arithmetic testing. The results showed the method could detect the change of mental states in real-time and track the trend smoothly.

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Recently, the user of electric powered wheelchair increases, and they are requiring the improvement on the riding quality. Various factors are related on the riding quality of electric powered wheelchair. The human body tilting by acceleration and deceleration of electric powered wheelchair is one of the factor which is related to the riding quality. In case of the electric powered wheelchair, tends to become rapid acceleration and deceleration in speed control through the joystick especially. Therefore the human body becomes instability, and large effect is given in the riding quality. In this study, the control system which reduce the human body tilting was designed, using the model of human electric powered wheelchair system, and the effectiveness was examined. The optimal regulator was designed which used the two-dimensional model considering the human body tilting only of front-back direction in order to ensure the operatability of electric powered wheelchair and kalman-filter for the estimation of deflection angle of the trunk. This control method was confirmed that the reduction effect of the human body tilting by the simulation. In addition, the controller has been applied to the wheelchair with the auxiliary power unit, then the reduction effect of the human body tilting was examined.

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In this paper, the role of the toe of the human being is investigated. The change of the sole pressure distribution using a sole pressure distribution measurement system and that of the toe pressure using a toe pressure measurement system at walk by the existence of a toe are investigated. In order to investigate the change of the whole walking, the affection of a walk posture using a 3D motion capture system by the existence of a toe is also measured. Furthermore, the change of the amount of energy consumption at walk by the existence of a toe is measured by a spirometry system. At last, we investigate the roles of the toe, such as, the effectivity of the 1st and 2nd finger, and the stabilization of the posture, by the synthesis of these results.

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The authors have proposed a numerical approach for estimating a snowboard turn. Also, they have proposed an identification method for equivalent elastic parameters of a snowboard. In this study, to clarify the effect of the mechanical property (elastic parameter) of snowboard on the snowboard turn, the numerical approach and the identification method are used. First, by using vibrational properties of the snowboard, the mechanical property that is one of important factors for simulating the snowboard turn is identified. Next, by using the identified mechanical property, the snowboard turn is simulated. Consequently, it is shown that the snowboard turn is influenced by the snowboard model. Furthermore, it is presented that the snowboard turn changes extremely even if the mechanical property of the snowboard are changed partially.

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The difference between forward and backward swimming speeds has been observed for Vibrio alginolyticus by use of high-intensity dark-field microscopy. The reason that causes the difference is not clear at present. There are some possible reasons we may take into account ; the deformation of a flagellum which is caused by the fluid force exerting on the flagellum, the hydrodynamic interaction between a cell and a slide and the changes in rotational speed of a flagellar motor. In order to investigate the reason for the difference, we measure cell body rotation rates simultaneously with swimming speeds of a cell swimming forwards and backwards. The results show that the difference is mainly caused by the variation in the rotation rates of the cell body at least when the cell moves straightly.

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As CAE (Computer Aided Engineering) applications become increasingly precise, the knowledge and technical skill required to operate such application has become more highly specialized. Such tools have not been utilized in the initial design process of mechanical products, where designers cannot construct detailed analytical models. This paper proposes a cross-sectional shape design optimization system that supports the initial design process for automotive frame structures. The cross-sectional design problem is formulated as a multiobjective optimization problem that can be solved using genetic algorithms. A method for generating cross-sectional shapes satisfying designer-required characteristics is also proposed. These methods, which reduce the number of trial and error process and product design failures, are expected to enable shortened product development leadtimes.

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Recently, the concept of Mizen Boushi (reliability problem prevention) has been applied in automotive development as a tool to refine drawings to the greatest completion possible by the prototype stage. In this point of view, we are promoting a quality innovation process, “GD³” that means “Good Design”, “Good Discussion” and “Good Design Review”. The process utilizes creative FMEA, FTA and a System Design Review. These tools focus attention on the many potential problems that could occur due to a change in design or environment. The System Design Review is especially useful to examine potential failure modes, root causes, part drawings and prototype part designs. This is followed by a Design Review Based on Failure Mode (DRBFM method for short), as a tool to guide discussion. In this way, it is possible to generate the best approach to handling design, evaluation, and production concerns. This paper will introduce some of the specific ways that this creative process is currently used in development as a tool to prevent reliability problems.

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The aim of the present paper is to develop compact folding/wrapping method of circular and conical shaped membranes facilely deployable. By using folding condition at nodes and generalized continuous condition of fold lines in the membranes, various kinds of folding methods have been newly devised by prescribing two groups of equiangular spirals, e.g., stowing method of circular membrane wrapped downwards round its central axis. Subsequently, modified fold patterns consisting of arbitrary type spirals are newly developed, which are available when the thickness of the membrane is taken into account. Finally, fold pattern of conical shaped mambranes has been newly developed. The availability of prescribed models has been checked by making origami samples.

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One of the most important performances which a pair of tooth surfaces of gears for power transmission must have is smooth and quiet transmission of the torque. However, the present designing methods of gears cannot choose the tooth surfaces to satisfy the performances, because they have no designing criteria in choosing the tooth surfaces from the view point of the dynamic requirements like “no variation of bearing loads”. Therefore, according to the present methods, any pair of conjugate surfaces has no difference as that of gears for power transmission so that the easiness of production is the only criterion in choosing the tooth surfaces. In this series of papers, a unified designing method for all kinds of gears is presented, in which the designing conditions of gears for power transmission are clarified and the tooth surfaces are determined directly by them in the unified coordinate systems which are determined by the disposition of two axes and the axis of relative rotation. The first paper discusses basic characteristics of a path of contact, such as, its surface of action and tooth surfaces in the vicinity of a point of contact, radii of curvature, limits of action and velocities (pheripheral, normal and relative) which are basic parameters necessary to design tooth surfaces, when the equations of a path of contact and its contact normals are given in the unified coordinate systems.

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Based on the recent demands for higher sliding velocity of components, the excessive wear of the slider due to it has been discussed. However, since R. S. Montgomery reported his experimental work on the wear at high sliding speeds, no one has reported theoretical analysis of the slider wear. In this study, the frictional resistance was examined with static intrusion and dynamic acceleration tests. In the static intrusion test, the static frictional resistance increases linearly as the slider travel increase until the slider come to fully contact the cylinder. Meanwhile, the dynamic acceleration test revealed that the dynamic frictional resistance is about 30-40% of the static one with the slider travel up to approximately 50 mm, and that it then falls to the level of about 10% as the slider travel further increases. Such the sudden change corresponds to the estimated values of the friction coefficient : the friction coefficient estimated from the dynamic acceleration test results is about 0.1 in the earlier stage and falls to about 0.03 in the later stage, while the static intrusion test results only show a constant coefficient value of about 0.3. This drastic reduction of the friction coefficient in the dynamic test is considered to be attributable to the surface liquefaction of the slider material, where a melting lubrication may occur. The transitional condition to such a melting lubrication can be quantitatively expressed and evaluated by means of the melting lubridcation index, BLI.

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A new melting wear analyzing method of the slider is proposed based on the non-steady heat conduction equation. The friction coefficients calculated with the theory agreed well with those reported by previous workers. The estimated values of the slider wear also agree well with those obtained experimentally. The melting wear analyzing method is confirmed to estimate the melting wear quantitatively from thermal properties of sliders. Based on the method, a practical selection method of slider material has been established.

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An analyzing method to estimate sliding resistance is proposed. In this method, variation of contact pressure caused by plastic deformation of the slider in intrusion process and variation of friction coefficient caused by surface melting are considered. The sliding resistances calculated with this method are agree well with those reported previously. The surface melting phenomena appears in the calculated result too. Based on this method, it allows us to estimate sliding resistance in high sliding speed and high contact pressure conditions without large-scale experiments.

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In the friction characteristics of the polyamideimide (PAI) resin bonded PTFE films, the friction coefficient (μ) kept approximate constant low value, and then rose, finally turned out to be the value of final use life. Moreover, μ decreased with the content of PTFE. On the other band, the following interesting characteristics were shown in the PAI resin bonded MoS₂. That is, μ initially increased with the sliding distance. After showing the maximum value, μ began to decrease, indicating a low level value for a long distance. And then, μ rose again and reached the value of final use life. In the wear characteristic, the PTFE films showed “initial wear” and “steady-state wear”, and the wear rate was different at various content rates. For the PAI resin bonded MoS₂ almost the same thickness as the film thickness was worn out at early states. From the viewpoint of the relative relationship of the hardness between the lubricant particle and the PAI resin binder, it was discussed that PTFE functioned from the first stage as a lubricant, while MoS₂ functioned as a lubricant after the film almost disappeared and MoS₂ particles were extended to the thin film on the friction surface.

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The relationship between the abnormal vibration and the noise incidental to abnormal vibration was studied. The test bearings were type 6303 CM deep groove ball bearings which were lubricated with three types of grease : Li soap/silicone oil grease, Na soap/mineral oil grease and Li soap/ mineral oil grease. In the experiments, the room temperature was kept constant, the axial-loaded ball bearings were operated at a constant rotational speed, and the vibration and noise of the test bearings were measured. On the basis of the experimental results, the relationship between the abnormal vibration and the noise incidental to abnormal vibration was discussed. From the experimental results and discussions, the conclusions were obtained as follows : (1) There are two types of the noise incidental to abnormal vibration : the whirring noise and the rattle. The whirring noise and the rattle occur on the test bearings lubricated with all types of grease used in the experiments. (2) The whirring noise occurs only when the abnormal vibration occurs. The occurrence and disappearance of the whirring noise and abnormal vibration change according to the type of the grease. (3) The abnormal vibration is the likely causes of the whirring noise. For example, in the case of the test bearing lubricated with Li soap/silicone oil grease or Na soap/mineral oil grease, the abnormal vibration and whirring noise were generated by the negative damping moment due to the grease characteristic. In the case of the test bearing lubricated with Li soap/mineral oil grease, the abnormal vibration and whirring noise were generated by decreasing the positive damping moment of grease due to the rise in temperature. (4) The rattle occurs during both normal and abnormal vibration. The sound pressure of the rattle increases during abnormal vibration. Time envelopes of the sound pressure of the rattle vary repeatedly at 1/f_c (f_c : rotational frequency of the cage). The rattle does not occur on the test bearings without a cage. (5) The outer ring is excited angularly due to the balls colliding radially with the cage repeatedly at f_c. This results in the rattle.

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For the optimal design of ball bearings, measurement and its elucidation of complex three-dimensional ball motion are very essential. Only the way to detect ball motion in a ball bearing is the magnetic measuring method, developed by Kawakita et al.. However, due to the considerable effect of errors in the measurement, the angular velocity components of ball rotation analyzed by their method lead to problems on the accuracy in analyzing the contact angle and spin moment of the ball. In this report, by applying the magnetic measuring method to the ball bearing under the axial load, the main causes of error affecting the detection output were clarified. Also, using frequency analysis, a simplified method was proposed to analyze the angular velocity components of the ball rotation. Finally, evaluation and examination were carried out about the practicality of our method.

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The strategic importance of global competitiveness of machine tools manufacturing industry in Japan is steadily increasing and machine tools manufacturers require effective corporate strategy to achieve sustainable competitive advantages. SWOT (Strengths, Weaknesses, Opportunities and Threats) analysis is one of the most effective approaches used for analyzing strategic management policy of an organizations. However, the use of conventional SWOT analysis is based on the qualitative analysis and has no means of determining the importance of each SWOT factor. In this study, a newly structured SWOT analysis has been proposed for weighting and rating individual SWOT factors using the pairwise comparison matrices. By the proposed method, the industrial strategy planning for the machine tools manufacturing industry can be carried out using both qualitative and quantitative analyses of the SWOT factors.

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A concave conical gear is a new type of a conical gear. The concave conical gear has higher tooth durability than the conventional conical gear. So the concave conical gear has the possibility to be used instead of the bevel gear. However, the cutting method of this gear has not been developed so far. This research presents a new hobbing method to cut the concave conical gear correctly. Test gears are cut and measured, and it is proven that the new hobbing method has practical utility in producing the concave conical gear.

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