Characteristics of vibration and damping are investigated for a parabolic curved bar having two layers, one of which is elastic and the other viscoelastic. Equations of motion are obtained from the stationary condition of the Lagrangian, and they are solved exactly in the case of two elastic layers by means of the series expansion method. Composite loss factors are calculated by the strain energy method. It is found that the composite loss factors in the case of out-plane vibration depend on the Young's modulus ratio, loss factor ratio and diameter ratio of the two layers, but in the case of inplane vibration, they change complicatedly, especially in the symmetric mode vibration. Experiments are carried out on a parabolic curved pipe of aluminium alloy which is filled with acrylic acid resin. The natural frequencies and composite loss factors calculated theoretically are compared with the experimental results and found to be in good agreement with them.

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A method to estimate the stochastic response of hysteretic structures under combined random loads regarded as Gaussian white noise is investigated. The response statistical moments of structures, with hysteretic characteristics approximated by Wen's mathematical model, are obtained by using the Fokker-Planck equation method with a cumulant truncation technique. This paper deals with the formulation for the multi-degree-of-freedom system, and demonstrates that resulting variances of the response for a three-degree-of-freedom structure, as a numerical example, agree well with a Monte Carlo simulation.

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A simulation method was studied to calculate vibration response of a bar group installed between restraints in a single row under seismic excitation. Because impact phenomena take place between adjacent bars or a bar and a restraint, nonlinear force caused by the impact should be considered in the response calculation. In this study, a new method for determining the nonlinear force without convergence iteration was proposed. The simulation method is basically a combination of the mode superposition method and the pseudo external force method. The method proposed by Nigam is applied for time integration. An impact point is modeled as a set of a gap, a linear spring and a linear damper. The nonlinear forces at the next time step can be determined with matrix calculation by introducing influence coefficient matrices, which express the influence of impact forces on intersections at impact points. In order to verify the above method, the calculation results were compared with experimental ones, which showed that the method can simulate the experimental results well.

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Chatter vibration is sometimes observed in an automotive wiper. The objective of this paper is to explain the mechanism of the occurrence of chatter vibration. For this purpose, first, experimental analysis is conducted using a currently employed wiper. It is found that the chatter vibration is a kind of stick-slip motion, and it occurs in the second mode with two blades of the wiper deflecting in opposite directions. Next, by assuming that the wiper is modelled by a two-degree-of-freedom system, the equations of motion are proposed. By integrating them numerically, it is found that they well explain features of the chatter vibration observed in the experiment.

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Self-excited forced vibrations with solid friction of a block lying on a moving surface of nonconstant speed stated already in the previous report are treated theoretically, using a piecewise linear approximation method in case of cubic friction-velocity characteristics. The motions of a block in the system are studied for two cases. Namely, the first is the case in which the maximum static friction is equal to the kinetic friction without slipping and the second is the case in which it differ from it. The steady-state vibrations are obtained with regard to the stick and the slip motions of the block. The distributions of various types of these vibrations occurring in the system are shown in several figures and the amplitude curves of the displacement waves are described against the frequency ratio Ω and the speed of moving surface Y₀/Y.

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Recently, in order to improve power plant thermal efficiency, the turbine blade, which is the most important element of the power plant, has been used under severe conditions of high loading. Therefore, for the purpose of increasing plant reliability, the blade with friction dampers has been used. This paper presents the analysis method to predict damping characteristics of the dampered blades by applying the harmonic balance method to the bladed disk. The numerical results show that a large damping effect can be obtained by using the damper elements. It is found that the peak frequencies of the dampered blades can be estimated by the linear finite-element method, if we choose the appropriate ratio of the friction force and the excitation force. Also, the validity of the method used in this paper is examined by comparing the calculated results with the experimental data.

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In this paper, the optimum design of the seismic base-isolated table with a rotational inertia mass (R.I.M.) is executed from the point of view of minimizing the rotational moment caused by restoring forces applied to the table and of linearizing the restoring force of nonliear hardening-type which causes the keen spikes in acceleration response of the table. For the first time, a planar optimum arrangement of pulleys is obtained under the above condition. Although this planar optimum arrangement of pulleys succeeds in making the rotational moment of the table zero and linearizes the nonlinear restoring force as well as possible, the weak nonlinear hardening-type characteristics of the restoring force still remain. Then, the optimization of inertia moment of the R.I.M. exists and can be obtained, because the R.I.M. rotates according to the movement of the rope installed between pulleys and produces the spikes in acceleration if too large an inertia moment is selected. Finally, the table with this optimum arrangement of pulleys and inertia moment of the R.I.M. is confirmed to give the desirable response through simulation and experiment.

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In this paper, it is examined the lateral oscillation of the moving elevator rope and cab, using the method of characteristics. We consider forced oscillation of the system composed of a rope with time-varying length and a mass-spring system at a lower end. When the upper end of the rope is excited sinusoidally, the elevator in a high-rise building passses through plural resonance points. First, we show that the rate of the cab's guide spring influences the resonance amplitude. When the natural frequency of the lateral oscillation of a cab is equal to the frequency of excitation, the amplitude of the cab has a maximum value. Next, it is examined whether the sign of the moving velocity influences the amplitude of the lateral oscillation of the cab at a resonance point. Furthermore, it is examined its oscillation mode jumps many times in the going up or down process, because the natural frequency changes in a wide range. These are closely related to the transition of the natural frequency of the system.

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This paper presents a poly-reference modal identification method which is based on multivariate ARMA (autoregressive moving average process) model fitting. The mono-reference method as a scalar approach based on single variate ARMA model fitting was proposed in the first report. This report presents a poly-reference method as a vector approach which develops the scalar method by state-space formulation and the numerical solution of an algebraic equation is replaced by the numerical solution of an eigen problem. As a fundamental example, a three-degrees-of-freedom lumped-mass system is identified by the two methods with the aid of numerical simulation. From the comparison of the results obtained through the scalar method with those obtained through the vector method, it was confirmed that the vector method has the advantage over the scalar method particularly in obtaining accurately identified modal parameters.

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Feedforward control of sound and vibration using a neural network-based control system is considered. By using a back propagation method, an adaptive algorithm is derived which enables stable adaption of the neural controller for this purpose, while providing the capacity to maintain causality within the control scheme. The neural network controller is shown to be able to compensate for the introduction of harmonics by the control actuator by producing a control signal, derived from a pure tone reference signal, which contains some level of harmonics. Also, the neural network controller is seen to be able to compensate for a distorted reference signal in a manner superior to that of a linear controller. Furthermore, experiments are undertaken which demonstrate the utility of the proposed arrangement, showing it to be the equal of a linear control system in performance for a linear control problem, and superior for a nonlinear control problem.

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Recently many kinds of four-wheel-steering (4WS) systems have been studied and proposed. 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 condition. Hence, it is difficult to express the vehicle motion accurately by the two-degrees-of-freedom model. In this paper, a method of 4WS control system is presented by applying a neural network. First we identify the vehicle motion as a system neural network. Next we construct a neural network controller by using this system neural network. The effectiveness of the proposed method is demonstrated by a computer simulation.

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This study realizes robust vibration control for a multi-degree-of-freedom structure with a hybrid dynamic vibration absorber by applying H^∞ control. The controller for the hybrid DVA is shaped in frequency domain for a four-degree-of-freedom structure in order to control the vibration of the first and second modes as the reduced order model and to stabilize the third and forth modes as the residual model. The stroke of the hybrid DVA is taken into account as a constrained function in criteria. The active DVA is also designed by using just the same frequency weighting functions as used in the design of the hybrid DVA. The vibration control performance is clarified by carrying out numerical calculations and experiments. In experiments, the H^∞ controller designed in a continuous system is digitized, and is realized in a digital signal processor. It has been made clear that even the hybrid DVA and the active DVA have the same vibration control performance for both stationary and nonstationary random excitations, while the active DVA exhibits undershoot phenomena. Also, we have confirmed that the hybrid DVA has strong robustness against parameter variations of both the mass of the primary structure and the spring and damping constants of the hybrid DVA.

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In order to control the vibration of tower structures, this paper proposes a two-dimesional hybrid dynamic absorber that combines an electromagnetic actuator with a magnetic-damping-type dynamic absorber, and also shows a new method for making a reduced-order model. To control the vibration of a flexible structure like a tower using LQ control theory, it is ncessary to make a reduced-order model of the structure. However, the order reduction may cause a spillover instability problem, the effect of which can be ignored higher-order modes in a full-order structure. In this method, nodes of the higher-order mode are selected as set points for the model sensors. It is shown that the two-dimensional hybrid dynamic absorber can control two-dimensional vibrations, and spillover instability can be prevented easily using this method.

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This paper discusses vibrationless access control of a vibratory positioning mechanism with robustness to high-order natural modes of vibration. From the ceaseless requirement for high-precision positioning, it is desirable to eliminate residual vibration of higher-order natural modes of vibration at a target position. To obtain a feedforward access control force which does not excite high-order natural modes of vibration, a frequency-shaped cost functional whose weighting function is represented by a second-order high-pass filter is used in the optimal control theory. The control force has smaller frequency components in high frequency region as compared with the conventional feedforward control forces. The performance of the proposed vibrationless access control is demonstrated with experimental results using a flexible swing arm positioning mechanism.

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Microvibration control technology has been rapidly becoming important in a number of fields in cluding superfine technology in semiconductor manufacturing and microgravity research experiments in space. A piezoelectric actuator has recently attracted much interest in active vibration control because it has high displacement resolution, wide band characteristics, and leaks no magnetic flux. In the presented study, an active 6 DOF microvibration control system using a piezoelectric actuator was developed. A control law is adopted to provide almost the same performance as sky-hook systems by using only absolute acceleration, instead of achieving feedback of absolute displacement and velocity. Vibration control experiments were conducted, with satisfactory results in isolation performance against micro-ground motion, damping performance against direct disturbance, and control system robustness.

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In order to reduce low-frequency vehicle vibration, the development of semi-active control theory on hydraulic engine mounts has long been anticipated. However, because the changes in mount vibration characteristics introduce nonlinearity to the mathematical treatment, no successful study has been achieved. In this study, the variable orifice damping in a semi-active engine mount was approximated as a linear forcing device. This approach enabled us to use optimum regulator theory in obtaining the optimum control of orifice damping. This method was proved to be effective by a shaker test on an engine mass-mount model setup.

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In the preceding related paper, the authors discussed a plate-type magnetic damper with alternative magnetic poles. The paper presented the analytical expressions of eddy currents in the conductor and the damping coefficients for the single row of alternative poles. The damping effects of the damper having alternative poles of a number of rows and columns are different from those of the previous model. The present article discusses the damping increasing mechanisms for the plate-type damper with alternative magnetic poles of a number of rows and columns. The analytical expression for finding the eddy current patterns and the damping coefficient are obtained. Numerical calculations are carried out for some important examples. Since the present article gives the analytical expression and the numerical data of dimensionless damping coefficients, the results may be used directly in the practical design of such devices as vibration absorbers.

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This paper deals with the identification of a uniform beam. Two-degree-of-freedom characteristic matrices are introduced theoretically. Time domain data of displacement are obtained at two points of a uniform beam, and characteristic matrices are calculated from the natural frequency and the modal decay rate using a complex modal method. The experimental results are in good agreement with theoretical results of mass and stiffness matrices. Three models were considered for the damping matrix. The first is the model where the matrix has a diagonal element. The second is the model where a damper exists between two masses. The third is the model where the matrix is symmetric. The identification by the second model agrees well with that by third model.

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Solid friction in mechanical control systems causes undesirable effects such as a jerking motion. To avoid such effects, identification of the velocity characteristics of solid friction is indispensable. It has already been reported that on-line estimation of the solid friction is possible by using standard Kalman filtering techniques. In this paper we discuss an application of a fixed-lag smoother to the solid friction estimation. Although this technique cannot be used on-line, the resulting estimate is more accurate than that which can be obtained by a standard Kalman filter. It is shown that there exists an appropriate number for the lag in the smoother to achieve efficient estimation. Simulation and experimental results are presented to show the effectiveness of the proposed technique.

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This paper discusses the kinematics of a multifingered hand and object with roll-sliding contact. Manipulations of the multifingered hand have been studied in joint contact or rolling contact with the object, under the condition that both finger and object surfaces have arbitrary shapes. This paper clarifies the relations of prismatic velocity and angular velocity of finger surface to those of the object surface with roll-sliding contact in three-dimensional space. An example shows that the moving direction of the spherical finger surface is different from that of a contact point on the cylindrical object surface, and that the integrations of velocities of the contact point give a curved trace of the contact point.

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A theoretical and simulation study on the vertical dynamic characteristics of a Maglev transport vehicle that has a permanent magnet suspension with mechanical levitation control is described in this paper. The vertical dynamics of the vehicle, including pitching motion, is formulated first. We examine the influence of the pitching motion of the undercarriage on the guide wheel load, which is one of the performance measures of the vehicle, theoretically. The running simulation is carried out to confirm theoretical results. The results show that the pitching motion of the undercarriage has a great influence on the guide wheel load, and the suitable relation between magnet length and wheelbase length is discussed from the viewpoint of reducing the guide wheel load. We point out that a small control lever ratio causes a lack of pitch stiffness and damping of the undercarriage and that small size of the undercarriage is effective in reduction of the guide wheel load.

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By means of creep force test equipment which contains full-scale rail and wheelset, we have successfully carried out creep tests under controlled test conditions. Differences in the creep parameter between test results and theoretical calculation results with DePater's equation summarized by Kalker are found. By modifying Kalker's linear crrep theory based on the test results, we delivered a new experimental formula.

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An analysis is presented for the dynamic stress concentration problem of an infinite inhomogeneous rod having a discontinuity of the curved portion in which the radius of cross sections varies continuously. The rod treated in this study consists of two infinitely straight portions and one finite curved portion of arbitrary curvature. The curved portion lies between the two straight portions. The twisting wave propagates from one of the infinite straight portions to the other, passing through the curved portion. The exact solution for the equilibrium equations for a curved rod has been obtained. The transfer matrix has been derived based on the exact solution and upon considering the internal forces and moments. At discontinuous sections, solutions of curved and straight rods have been connected by adjusting the boundary conditions. As examples, stress concentration factors in circular, elliptical and parabolic arc rods have been obtained.

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Discrete, deterministic and reproducible conversion can provide a drastically varied difference emerging from a slight difference. In this paper, applying the conversion, an assembly method is developed for block structures with qualitatively diversified shapes. For each growing end, a rule (sign) assigned by a term of a simple input numeric series is converted to a growth direction (physical dimension) through interpretation. Utilizing a degree of freedom remaining for selection of contexts to be referred for the interpretation, information processing is simplified by sharing the load with the structure being assembled. For the context, information on the figure is adopted, which is locally extracted from information accumulated along the structure as it grows, expressed as orientation vectors. An example of cubic block structures shows that the conformations can be qualitatively varied by replacing a term in the series. The present method may be applicable to mechanical systems such as microrobots and models for research on system characteristics.

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This paper introduces a new structure of an optical microgripper in which the bimorph PLZT-type actuator is applied. Based on this new structure, the photoresponse characteristics of the optical microgripper is also addressed. This microgripper consists of two-group bimorph-type PLZT. These two-group bimorphs are designed in a parallel geometric structure, and both of them have extensions which can turn from one side to its another side. Therefore, when a U.V. beam is irradiated, the extended parts of the PLZT can absorb the U.V. beam directly, then close the gripper. Utilizing U.V. beam irradiation, we can characterize the photoresponse of the microgripper. The experiments show that the photoresponse is rather complicated, as it involves the photostrictive effect, pyroelectric effect, and the thermal deformation phenomenon. All of these have a great impact on the photoresponse. The photostrictive effect, pyroelectric effect and thermal deformation phenomenon are influenced by the characteristics of the input light beam.

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Dynamic characteristics of a gas engine cogeneration system are analyzed using a simulation model. DYNAMO(dynamic model) is adopted as a simulation language because it enables an easy and flexible change of model structure and parameters. Dynamic characteristics of each piece of constituent equipment are expressed by using dead time and first-order lag elements. Their parameters are determined so that the simulation results match the measured ones accurately enough. The simulation model of the whole system is created by linking each submodel of constituent equipment. The simulation and measurement results show that the proposed modelling method is a useful tool. As an example of dynamic simulations, it is investigated how the location of measurement points influences the temperature of jacket water for cooling the gas engine.

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In the development of a strictly dynamic computer simulation for cranes with a spherical pendulum such as a rotary crane, it is necessary to derive the complex equations of motion. This paper presents a new approach of the mathematical model that is expressed using the open-loop linkage model. To simulate the crane's load swing efficiently, a new simulation method based on both this model and the recursive Newton-Euler formulation developed for the robots is also proposed. This method is applied to the reduced scale truck crane which can carry out four kinds of motion (i.e., rotation, boom hoisting, boom extending-shrinking and load hoisting) simultaneously. A further advantage of using this model is that many results developed for robots can be applied to developing the intelligent crane.

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This paper deals with the development of a new detecting method of a number of sheets without contact. For example, in a cash dispenser paper sheets are transferred one by one and counted synchronously. So it is necessary to detect one or a plural number of sheets to avoid mistransferring. Hitherto, the contact measuring method has been used for detecting the transference of sheets. This noncontact sensor utilizes the variations of frequency response of the whole acoustic system of the sensor with sheets which are set near the sensor. The impedance of sheets varies with its number. The number of sheets has shown good correspondence with the resonant frequency and frequency response of the acoustic system. An electrical analogy is adopted for theoretical analysis of the acoustic system. The results of the calculation and experiments coincide significantly. It is possible to detect the number of sheets within a very short time period by means of variations of the frequency response.

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This paper presents damping control with consideration of the dynamics of objects based on predictive control in a 1-D.O.F. manipulator system. As one of the problems in force control of robotic manipulators, the collision between the endpoint of a manipulator and the object is given. As the force control scheme in the case involving such collision, damping control is the most suitable. Because such control does not require switching of control rules in the transition from free space to constrained space, and since, in general, the position of objects cannot be measured, the method, based on the velocity, is effective. However, in conventional damping control, the dynamics of objects is not considered. Therefore, in the case of soft objects, this control scheme cannot be applied. We propose damping control with consideration of the dynamics of objects based on predictive control, and simulation and experimental results illustrate the effectiveness of the proposed method.

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In grasping motion of a serial-link hand, contact forces at a proximal link are interfered with by distal forces, and are independent only on both ends of the hand. If each joint torque can be regulated to match the distribution of contact forces with that of the reference ones, a more adaptable grasping operation will be achieved. In this research, we consider the property of the serial-link mechanism and discuss the grasping control method with its mechanism. The control method proposed is based on the information from tactile sensors. The whole grasping operation can be achieved by the parallel process of feedback control on the local parts of the serial-link system. Feedback control of each local part consists of two basic actions : pinching and folding. For softer grasping operations, additional position feedback of the grasping shape is effective. The compliance of grasping operation is controllable to regulate the ratio of force and position feedback. This method is estimated by the numerical simulation and the experiments with the 7-serial-link hand mechanism.

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This paper proposes a method to calculate manipulator inverse dynamics using a neural network. In this method, two sets of neural networks are prepared. One is for the elements of inertia moment matrix, and the other is for gravitational force. Each input for the network is only a joint position. Teacher signals of each network are also calculated using only a joint position, and therefore learning of each network is fast. The neural network, which acquires a model of inertia moment matrix, is used to calculate inertial force, centrifugal force and Coriolis force. In particular, the terms of centrifugal force and Coriolis force are calculated using a characteristic of manipulator dynamics and structure of the neural network. This method can be applied to the wide area data of joint positions, joint velocities and joint accelerations to calculate manipulator inverse dynamics. To show the validity of this method, the inverse dynamics of a two-dimensional manipulator are calculated.

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A motion control system which can make a rate-input-type manipulator operate in position, force and/or compliance control mode, has been realized and each mode can be alternated on-line. In this case, since transformation from orthonogal coordinates to articulated coordinates is carried out by only a Jacobian pseudo-inverse matrix, force and/or compliance control and redundancy control are realized simultaneously. We noticed a mechanical mobile range on each joint of the manipulator, and each joint was positioned as far from its mechanical limits as possible, while the manipulator hand was kept at a reference position. This made the mobile range of the manipulator's hand wide. We confirmed the property of the control law through analyses and experiments.

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In this study, the authors elaborated a robot composed of three serial links with curved contours. The outer contour of each link is made of a combination of large and small curvatures, and the links are connected serially. The outer two links of the robot have the same configuration although the middle one is different. A DC servomotor is installed in each of the outer two links, which can rotate freely round the connected joint. Then the three serial links can constitute a part of a large arc at a certain angle by controlling the motion of the outer two links. This robot could perform several actions using dynamic interference forces between the links. In the previous study, the robot succeeded in standing up from a prone position on the floor by inducing large vibration on all links by swinging the outer links. This study describes three types of motion performed by the robot. The first motion is a falling down and standing up action. Simulation and experimental results concerning this motion are given. The robot could fall down without shock by forming a part of a large arc and stand up by virtue of dynamic interference force. The second motion is locomotion by peristaltic motion, in which the robot accomplished a locomotion velocity of 220 mm/min. The third one is ascending a step. A step of 120 mm height was climbed over by this robot, using initial potential energy when it fell down from an upright position.

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Studies on space robots have assumed a relatively small object as a manipulated target. But in space, a target object can be relatively huge, for example, a spacecraft, a space station, or a solar power satellite. In these cases, manipulation by several vehicles which have thrust engines is superior to that by arms mounted on spacecraft. In the manipulation by vehicles, the fuel consumption in a thrust engine is related to the size of force generated by a vehicle. The size of the force depends on the positions of contacting points. Therefore, contacting points of the vehicles are important in view of the fuel consumption. In this paper, we discuss how to find the optimal contacting points. The optimal contacting points are defined as the points which minimize the norm of force needed for the specified acceleration of the target object or maximize DMM (dynamic manipulability margin) according to the characteristic of the task. The results of calculations are shown in this paper. The results of experiments are shown in the 2nd paper.

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The previous studies on space robots have assumed a relatively small object as a manipulated target. But in space, a target object can be huge, for example, a space station or solar power satellite. In these cases, manipulation by several vehicles which have the thrust engines is superior to that by arms mounted on the spacecraft. The thrust engines fixed on a vehicle and a 3 DOF Control Moment Gyro are necessary for controlling the direction of the contacting force. In this paper, we discuss on experimental system using multiple vehicle-type robots to simulate huge object manipulation in space. We also discuss experiments to verify the validity of the optimal contacting points selection method proposed in the 1st paper.

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In the first report, a laser light scattering apparatus and a diamond-anvil cell were designed and set up for the evaluation of mechanical properties of lubricating oils under high-pressure EHL conditions. Employing these appratuses, Brillouin scatterings were measured for several alcohols, hydrocarbons and synthetic lubricating oils at high pressure. Pressure dependency of sound velocity and density for these liquids was obtained and was discussed considering the molecular structure of paraffinic oils and naphthenic oils.

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In the design of machine elements, in general, the approximate expression of Dowson is used to obtain a minimum film thickness of the elastohydrodynamic line contact. The approximate expression of Dowson is a calculation result of the elastohydrodynamic lubrication in the steady state. Therefore, there is possibility that error will arise if it is applied to nonsteady elastohydrodynamic lubrication. In this research, a numerical calculation was performed for nonsteady elastohydrodynamic lubrication caused by the change of the cylinder rotating speed. Then, the error caused by the application of the approximate expression of Dowson was examined. As a result, a maximum difference of about 15% was found in the range of calculation adopted by this research between the calculated value of the minimum film thickness obtained as a steady state and the calculated value obtained as a nonsteady state.

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The results of static and dynamic characteristics of a large circular superconducting magnetic bearing using MPMG-YBaCuO are presented. In the static experiments, the attractive force performed more effectively in both axial and radial directions than the repulsive force exerted by the pinning effect. The levitation performance in thrust and radial bearing were analyzed qualitatively by magnetic field distribution model. In run tests, a shaft of 2.4 kg weight rotated safely up to 33000 rpm. At speeds higher than 25000 rpm, the amplitude of the shaft vibration was almost constant, 120 μm peak to peak, in long-period whirling motion compared with rotational speed.

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The shrink-fitted assemblies between a ceramic shaft and a metal ring with a hybrid shrink fitter which contains liquid have been analyzed as a two-dimensional elastic problem. Water was used as the liquid contained in the hybrid shrink fitters because its thermal expansion at elevated temperature has already been investigated in detail. Calculations were performed for the temperature range 20°C up to 600°C. Materials were Al₂O₃ and Si₃N₄ for the shafts, SUS403 for the metal ring and SUS304 for the casing of the hybrid shrink fitters. Three different shapes of hybrid shrink fitters were used for the distribution of the contact pressures. The mean contact pressures of the assemblies depended greatly upon the internal pressures of the shrink fitters. The mean contact pressures decreased with temperature from 20°C up to a certain degree of temperature, and at higher temperatures, the mean contact pressures increased with temperature. These calculated results were quantitatively in agreement with the experimental results in a previous paper, although the contained liquids were different from each other. The equivalent stresses of the casing were high when the casing contained only water. Then, an amount of Si₃N₄ powder was mixed with the contained water to decrease the equivalent stresses of the casing. Longevities of the assemblies with the hybrid shrink fitters were discussed.

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The authors tryed to develope the small size Involute worm gearing of non-right axial angle. In case of the small size worm gearing, the manufacturing of the wheel becomes difficult. For, the small size hob can hardly have the rigidity and the high cutting speed. To improve this weak point, the authors derived the equation to decide the dimensions of the large size hob to generate the small size wheel and manufactured a pair of the small size Involute worm gearing of non-right axial angle. This worm space gearing does the point contact theoretically. And the authors searched the design of the gearing with higher performance by using the tooth contact analysis.

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In hobbing, cemented carbide hobs and cermet hobs are used because of their high productivity and high precision of grears. It is a problem, however, that chipping occurs at the cutting edges of these materials. In order to develop a hob material which decreases wear and chipping, the influence of composition, hardness, and transverse rupture strength (TRS) of the hob on flank wear, crater wear and surface roughness was investigated in this paper. Experiments were carried out with a single fly tool. A cemented carbide tool containing 72%WC and 18% (TiC+TaC), and having 91 HR_A in hardness and 2300 N/mm² in TRS performed best with respect to flank wear and crater wear. A cermet tool containing 43%TiC, and 91 HR_A hardness and 1700 N/mm² TRS is effective in decreasing flank wear and finished surface roughness.

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This paper describes the cause of the increase in ceramic and CBN tool wear with the decrease in work hardness in the cutting of high-carbon steel. The following results were obtained. 1) Tool flank wear increases with increases in abrasive wear in the cutting of high-carbon steel. 2) The size of the true contact area between the tool flank and the cut surface increases with the decrease in work hardness. 3) Increase in flank wear with the decrease in work hardness is due to reinforcement of abrasive action of cementite in the work material.

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Recently, the reduction of tool cost in mechanical industry has become a serious consideration. Therefore, it is one of the most important subjects in machine shops to develop a tool having a long tool life. Boride-cermet tools are one of the prospective tools which meets such a requirement. However, there are few studies hitherto which deal with the cutting characteristics (wear mechanism) of boride-cermet tools. In the present-day situation, taking up the wear mechanism in rough cutting of S 45 C by the new boride-cermet tool as a subject of this paper, the authors examined such factors as cutting temperature, crater wear at rake face, and diffusion condition at interface between tool and chip. The formula for diffusion at the interface of tool and chip was introduced and diffusion density was also computed by the finite element method.

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Recent manual transmissions are equipped with asbestos-free clutch facing. The authors have been developing organic-type facing materials for the past 10 years. Rubber with glass-fiber composite material has the features of long life, high-temperature durability, and mild friction characteristics in low-speed sliding contact, but is aggressive to the countersurface under some working conditions. This paper presents wear models of cast iron against glass-fiber material and shows the effect of porosity and chemical treatment of fibers on countersurface wear.

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The generation of three dimensionally formed cutting edges such as drills and endmills, has been quite a difficult problem for tool makers, because those cutting tools have been manufactured on specially designed tool grinders, and conventionally, cutting edges have been generated with formed grinding wheels, profiles of which were obtained empirically by trial and error. Recently, with the development and widespread use of the multiaxis NC tool grinder, the theoretical analysis of the relationship between the cutting edge and the profile of a grinding wheel used is earnestly required. This paper aims to estimate the profile of a formed grinding wheel and the wheel-work relative movements in the NC programming necessary for realizing the desired flute configurations and cutting edges of drills. It was clarified that the results theoretically obtained here by computer simulation agree quite well with experimental ones.

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This paper compared and evaluated several kinds of representative robotic mechanisms based on static characteristics. In particular, open-loop mechanisms and two kinds of closed-loop mechanisms, that is, parallel crank mechanisms, were adopted as the representative robotic mechanisms. On the characteristic comparisons of the robotic mechanisms, former research had been carried out on the condition that the configurations of the mechanisms were limited to a certain form. However, static characteristics of the robots are greatly changed by the mechanism configurations. Therefore, this paper paid special attention to the changes of each mechanism characterized by those configurations. Geometrical characteristics, strength characteristics and characteristics based on input/output displacement of these robotic mechanisms were compared and evaluated. As a result, the superior and inferior characteristics of each robotic mechanism were revealed.

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In this paper, a systematic synthesis of the optimum arrangements of links and pairs in spatial mechanisms with multiple moving closed circuits is studied with consideration of the degrees of freedom of the mechanisms. Namely, the conditions required to construct the mechanisms with multiple moving closed circuits are formulated. Moreover, mechanisms with multiple moving closed circuits are constructed with some basic links and open chains, obtaining the optimum arrangement of links and pairs. Based on the above analytical results, a type synthesis system is proposed which determines the optimum arrangements of links and pairs. Finally, the types of spatial seven-link mechanisms which satisfy requirements of the above-mentioned basic links and open chains are synthesized to illustrate the method.

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The macrofunction in Computer Aided Manufacturing (CAM) systems is executed based on the macrocode which is transformed by a series of operations input by the user. By the use of this function, operations which should be performed by the user can be simplified. Therefore, if the transformation from mechanical drawings to NC code can be changed directly into macrocode, NC machining can be achieved easily. In our study, a function for transforming macrocode from data of a CAD drawing to CAM data is developed. However, drawing data of a CAD system (CAD drawing) does not always coincide with drawing data of a CAM system (CAM drawing), because in a CAM system, restricted conditions, such as machining conditions, must be considered. Consequently, drawing data must be represented by a structure and function which include information about restricted conditions. Thus, the concept of the relationship between "master and servant" for expressing structure and function in an object model definitely is specifically incorporated. As a result, even in the case where structure and function are changed, the knowledge base can be consistently maintained. This paper describes representation of knowledge in the knowledge base and a method for generating a macro code using this knowledge base.

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This paper proposes methodologies for the integrated optimization of motion planning and structural design for increasing product performance of articulated robots. First, the following three types of optimization procedures are constructed : (1) cross-sectional dimensions of arms are determined so that the summation of the moment of inertia of each arm around the driving axis is minimized under the constraint of the static compliance at the end-effector point of a robot, (2) arm lengths and the positional relationship between the path of the end-effector point and the representative point of a robot are determined so that the operational time is minimized within the constraints of the upper limits of the driving torques and the upper limits of the ratios of the torque changes, and (3) motion planning concerning the velocity at the end-effector point is determined so that the operational time is minimized within the constraints of the upper limits of the driving torques and the upper limits of the ratios of the torque changes. Then, the integrated optimization procedures of motion planning and structural design of articulated robots are constructed by integrating the three foregoing kinds of optimization problems. Finally, the proposed procedures are demonstrated on an articulated robot.

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