The effect is discussed of the rigidity of a scale-pan and the location of load on the natural frequency of a beam-type loadcell scale. First, the modeling procedure is described. The dynamic model can be constructed by combining two vibration models : one is a five-degrees-of-freedom model concerning a part of the scale without the scale-pan, and the other a model concerning the scale-pan itself which is described by applying the equation of bending vibration of an elastic plate. Second, the natural frequencies, f₁, f₂, f₃, which are calculated using the proposed dynamic model are compared with those obtained by experiment. Through this comparison, the adequacy of the proposed model is verified. Consequently, the dependence of f₁, f₂, f₃ on the rigidity of the scale-pan and the location of load is made clear.

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This investigation deals with seismic response analysis considering the nonlinear support-gap characteristics. The dynamic restoring force-deformation relation for a pipe-support system is assumed to be a simplified bi-linear model. This paper highlights particularly the effect of support stiffness and gap size upon the maximum response of the piping system subjected to random excitations including seismic motions as follows : (1) Displacement and velocity are suppressed by the growth of support stiffness, however, acceleration response frequently provides higher pulsive peaks. (2) The effects of support stiffness and gap size upon piping response are summarized by the "f^*-z^* diagram" proposed in this study. This diagram can be drawn only through the ratio of the natural period of piping and that of supporting structure system. (3) The "F^*-Z^* diagram" proposed in this study can be obtained only through the response for the least feasible condition where the natural period of piping coincides with that of supporting system.

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The rubber bearings to be used for an isolation floor which is effective not only for strong earthquakes but also for weak earthquakes and even ambient micro-vibration, must be able to provide the rated masses of 1 5003 000 kg per bearing with horizontal stiffnesses corresponding to natural frequencies of 0.40.5 Hz and to undergo a horizontal displacement of 20 cm or so. Such performance cannot be achieved by rubber bearings of normal structure because the rated masses are too small. As a solution to this problem, multi-stage rubber bearings were developed, which consisted of 8 stages (each stage comprising 4 rubber bearing elements) piled up with 7 stabilizing plates between the stages. Through static and dynamic tests, it was confirmed that the multi-stage rubber bearings satisfied the requirements and were effective even for micro-vibration.

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Random response of a material particle pressed on the outer radius of a rotating ring with surface roughness is investigated theoretically and experimentally. The stiffness characteristic of the Hertzian contact between a material particle and a ring is nonlinear, and the theory involves replacing the nonlinear contact spring by an equivalent linear spring with precompression, the stiffness and precompression being determined so as to minimize the error in linearization. In giving the input waviness of the surface of a ring, the power spectral density at each frequency is attenuated by some factor by the fact that the two bodies don't contact at a point but at a finite area, so in the direction of relative movement the height of each harmonic component must be averaged. The response of the contacting bodies is then determined from their point impedance. Acceleration spectra for the material particle have been measured and found to compare very favourably with the calculated spectra.

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Most research into transient vibration during acceleration through a major critical speed has treated a symmetrical system constituted of a disk and a shaft with a circular cross section. In this paper, we discuss experimentally a transient phenomenon in an unsymmetrical rotating shaft system when it passes a major critical speed with a constant angular acceleration. It is elarified that the maximum amplitude is larger than that of a symmetrical system, and the difference depends on the magnitude of the unsymmetry and the angular position of the unbalance. It is also pointed out that the wave form of the amplitude changes extremely depending on the angular position of the unbalance. Experimental and theoretical results are compared.

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Behavior of a dynamic vibration absorber system with combined viscous and Coulomb friction both in the main system and in the absorber is investigated. In this case, the main mass is excited by a rotating imbalance and the amplitude of the disturbing force varies as the square of its frequency. The solution of non-stop steady motion is deduced by means of the same boundary condition method as in the previous report. The numerical results of analytical solution coincide very well with those of digital simulation. A set of empirical formulae for calculating the oputimum tuning and damping of the absorber, constructed by composing the formulae given in the previous reports and adding some correction terms, are presented.

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In order to improve their performance, rotating machines must often be operated in a high speed region beyond the first critical speed. Above the first critical speed, self-excited vibrations may be caused by internal friction which includes both internal damping of the shaft material and structural damping due to dry friction between the shaft surface and rotor-hub. In this paper, structural damping due to dry friction at a sleeve fixed to an arbitrary position of a shaft was studied. The mechanism of the whirling force generated by sleeve friction is clarified. The experimental results of two kinds of over-hung vertical shafts, supported by two ball bearings at their upper end can be explained well by t-heory.

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The present paper deals with the problems of the steady-state radiated acoustic field generated by vibrating plates with narrow slits in an infinite fluid medium, and analytically and experimentaly investigates the effects of slit geometry on the characteristics of the acoustic field. The numerical analysis based on the Boundary Element Method, which can be applied to the Helmholtz integral equation, has been used to predict the acoustic radiation. The nodal displacements of the slit plates in the vibration problems calculated by the Finite Element Method have been transformed to the vibration velocity, which is utilized as boundary conditions in the B. E. analysis. Comparison with experimental results indicate that the numerical schemes employed are effective in correctly predicting the characteristics of acoustic radiation from vibrating arbitrarily shaped surfaces with slits.

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Three kinds of calculation methods to estimate easily the sound directivity in the plane perpendicular to the principal axis of a cylindrical housing, which represents a vibrating housing of planetary gearing, are provided and experimentally verified. One method is to apply the theoretical solution of the sound field produced by a point source placed on a sphere which replaces the housing of the same radius. The other two methods are based on an approximation in which point sources are placed on several infinite baffles attached to the cylinder surface. The former one gives very good estimation for the radiation. The latter two methods, causing irregular deviations in the resultant directivity, can be used sufficiently as the simplest way of calculation.

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In this study an adaptive observer is applied to an analysis of a distributed parameter system. The system considered is an unsteadily and uniformly heated circular cylinder, whose heat transfer coefficient is unknown. A set of equations for the lumped parameter system is obtained using the first four terms of eigenfunction expansion of the temperature field. The radial temperature distribution in the cylinder and the Biot number on its surface are estimated in a computer simulation using the input data of heating rate variation and the output data of temperature variation on the axis of the cylinder. The results reveal that the adaptive observer is useful for analysis of a certain type of heat conduction problems.

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One analytical method of three-dimensional measurement with monocular vision, where the size of the object is known, was reveald. There is a possibility that the number of solution sets amounts to four. Thus, the process which discriminates the efficient set with a computer was given. Further, in order to apply this theory to measuring the three-dimensional displacement of the vehicle, the procedure, which transforms the vehicle coordinate system to the absolute coordinate system, was also shown. In addition, the three-dimensional measuring system of the vehicle displacement, where the 35 mm camera was placed in the vehicle, was organized, and some running experiments were made. Since we execute the measurement with one camera and obtain the solutions analytically, the process of the computation is simple and requires a short time.

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A simple new model is developed to analyze the dynamics of active magnetic bearings. In the model, the time lag of the flux due to eddy current is considered, but the gyroscopic effect is neglected. Magnetic force is described by the flux instead of the coil current. This description converts the equations of rotor dynamics into a simple form, although the time lag of the flux should be assumed when the dynamics of the flux are unknown. In the frequency and impulse responses, the numerical analysis is compared with the experimental results of a radial bearing whose control system is constructed by a PID compensator with a single loop. The results show that the numerical analysis fits the experimental results well by assuming an appropriate time lag for the flux.

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This research is concerned with a device for measuring the differences of pressures between two points, used for investigating ventilation in tunnels. This device is composed of a double-walled container in which the air pressure is kept constant as the reference pressure. In order to obtain the exact constant pressure, the temperature in the container must be controlled to a high accuracy within 10^-3°C. In this paper, analytical and experimental studies are developed for the estimate and control of the temperature in the container. First, the parameters of a bilinear control system can be estimated using the least-squares and the correlation-regression algorithms from input-output measurements. Using these parameters, the temperature in the container can be estimated. Nextly, the ambient air temperature influences the accuracy of the temperature in the container. In order to estimate this effect, a feedforward controller can be added to regulate the output of the heater according to atmospheric temperature. The experimental results show the good regulation.

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The objective of this study is to develop a personal CAD system which is aimed at calculating the time response characteristics of hydraulic control systems. In the previous paper, a simulation method for fluid line systems was investigated, based upon their block diagram representations for four terminal networks. An important limitation in the method, however, was that the response could be calculated only at the up- or down-stream end of fluid lines. In the present paper, therefore, the block diagram representations of a fluid line are obtained as expanded ones for arbitary pipe positions, in order to develop the calculation method at these positions. To see the applicability of the diagram to the simulation, time responses at arbitary pipe positions are calculated under various fluid line conditions. Their results are compared with the measured responses to show the validity of the method.

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In the previous papers, a simulation method for fluid line systems was investigated based upon their block diagram representation for four terminal networks. In the application of this type of simulation, severe numerical instability problem often results. This problem is due to an algebraic loop in the block diagram. The loop is observed when the up- and down-stream end of the pipe-line is connected with, for example, a control valve and load, respectively. In this study, a method to avoid such an instability, without losing accuracy in calculation, is developed. A simulation is made by adopting the developed method. The calculated response curves are compared with the measured ones to show the validity of the method.

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New driving techniques of a five-phases pulse motor for precise angular control are proposed. At first, available magnetizing conditions for all coils (combination of magnetized phases) are searched and their angle-to-torque properties are measured. Then, elaborate sequences for magnetizing coils are made from these combinations. These sequences are useful as new driving techniques with high angular resolvability for a five-pahses pulse motor. Advantageously, they are easy to use by improving only the software without changing the hardware. Finally, their frequency-to-torque properties are tested and advantages of these techniques are discussed.

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A 16-bit parallel data controlled robot is made which can easily be controlled by a personal computer. Fist, the trajectory is planned to calculate the driving torque which compensates for the dynamic reflection of the robot. The trajectory and the driving torque are fed through the parallel port to produce the fast motion of the robot. However, the dynamic property of the robot will change according to the arm position. The computer monitors both actuating signals and controlled position. After one cycle of robot motion. the auto regressive method is applied to identify the robot dynamics. These data are used to calculate a more accurate driving force which is fed to the robot controller on the next motion. The results obtained clarify the ability to identify inertia and damping factors.

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High tin and aluminum alloy bearings can seize easily when used with nodular cast iron shafts. The process of seizure is studied and it is found that the burrs left around the graphite on the surface of the nodular cast iron shafts abrade the aluminum alloy and that embeded debris causes further transfer of the aluminum alloy, which leads to eventual seizure. In an attempt to remove the burrs and transferred aluminum alloy during operation, hard particles of Si are dispersed in the alloy bearings. This arrangement provides much higher seizure resistance than the conventional aluminum alloy bearings in sliding against nodular cast iron shafts.

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Hard particulate inclusions can improve the seizure resistance of aluminum alloy bearings through a mild lapping action, when used with nodular cast iron shafts. In the present paper, the effects of hardness of the particulate inclusions are studied. A mixed lubrication tester is used to evaluate friction and wear properties of four alloys with inclusions of varying hardness. The wear amount is least and low friction appears at the earliest stage with hard Si particles. while softer inclusions show larger amounts of wear as well as prolonged periods of initially higher friction.

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High tin aluminum alloy bearings can seize when used with nodular cast iron shafts in automotive engines. In an attempt to remove burrs and transferred aluminum debris which cause the seizure from the surfaces of the shafts, hard Si particles are dispersed in the alloy bearing, which provides much higher seizure resistance than in the conventional aluminum alloy bearings. The hard Si particles show mild lapping action to the shaft surfaces, as well as removal of transferred aluminum debris on them. To maximize the action of hard Si particles, the effects of amount and shape of the Si particles are studied. The effects of shape is critical and it is found that the seizure resistance becomes far higher when the particles are lumpy. The flaky Si particles are broken during the test and the removing action is minimized leading to a lower seizure resistance.

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The relation between the contact ration and the vibration level has been investigated for decreasing the vibration of a gear unit having errors. In this report, the analytical method has been investigated. The rotational motion of the gear pair has been treated as a single degree of freedom vibration system. The stiffness of the pair of teeth has been obtained by solving the equilibrium equation numerically, and substituted into the vibration equation. Then the equation has been numerically solved and the acceleration has been obtained. Furthermore, the proposed analytical method has been experimentally confirmed by measuring the rotational acceleration of the gear pair having errors under loading. It is found that the calculated results agree with the experimental results, and that the proposed analytical method is applicable to evaluate the vibration level.

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The present paper reports the effect of the slight eccentricity in the rotational axis on the ball motion of a thrust ball bearing. The measurement of the ball motion has been done three-dimensionally through the Hall element device under the condition that the rotational axis has a small restriction in radial direction due to a slight discrepancy between the upper and lower race. As a result it has become clear that the motion of a ball can remain stable even under a lubricated condition just like the phenomena of the case of a four point contact ball bearing, if freedom of the ball motion is prevented radially by its eccentricity.

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Surface roughening of sheet metals with plastic strain is one removed at a given strain during the forming process and its effect on the improvement of the forming limit is investigated. As a preliminary examination to estimate how the onset of localized necking is delayed by the removal of surface roughness, a rigid-plastic FEM simulation is first made. Experiments for soft aluminium and copper sheets are also carried out and the increase in forming limit strain is examined for a few strain paths. It is shown that the improvement of the forming limit is considerable in the stretch forming region where the major and minor strains in the plane of a sheet are positive. For balanced biaxial stretching, for example, the forming limit strain can be increased up to about one and a half times as large as that for ordinary in-plane stretching.

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In the free expansion of a tube end by electromagnetic force, the effects of forming conditions on the deformed shape are experimentally investigated. The charged energy of condenser bank, the electrical properties of the coil protecter and geometries such as the relative position of a tube end to the coil, and the tube length, are taken as experimental parameters. In most cases, forming operation results in a type of flaring, and in the case of a combination of short tube and high charged energy it results in flanging. Results for flaring are summarized as follows : (1) The radial expansion rate, defined as conventional hoop strain varies in proportion to the charged energy. (2) The end effect of the solenoidal coil vanishes around a point distant from the coil end by a half of the tube radius. (3) Local expansion rate at the tube end increases with lower electrical conductivity of the coil protecter. (4) Deformed shapes near the fixed end and central part, like a plateau, do not depend on any parameter except for the charged energy. A longer tube merely increases the width of the central plateau.

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The present study is an attempt to build a consulting system for decision-making about turning conditions. Our primary concern was with building a system which attached a great importance to the subjective knowledge of the human experts rather than placing emphasis on objectiveness based on numerical information. The procedures used are as follows. (1) Because the memories of the experts deeply versed in the question of machinability are perfectly possible to be systematized by the threshold logic, the reasonable turning conditions can be derived from the logic. (2) The experience rules of the experts for dissolving the poor machinability can be expressed by the fuzzy relation. Therefore, the cause can be inferred by using an inverse operation of the composition of the fuzzy relation, and some pertinent suggestions can be made.

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Fatigue tests of spot welded joints were carried out in order to evaluate the effect of the difference between two nugget sizes on fatigue strength. It appears from the obtained results that the smaller the difference between both nugget diameters or areas, the longer the fatigue life of the joints, because of the decreasing stress concentration within the joints. Consequently, it is clear that this difference is a very important factor in the development of the fatigue strength of multi-spot welded joints.

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The objective of our study is to realize a computerized method of design diagnosis, that is, a process of detecting questionable portions of a design result and presenting plans for corrections. Computerizing design diagnosis makes it possible to actualize a CAD/CAE system which can remove designer's errors. This paper shows a computerized method of inferring functions of a designed machine, which is inevitable for design diagnosis. As an actual example, a process of the dynamic analysis of a rhombic mechanism is presented. Our system, which treats a specific case where a designed machine is a planar link mechanism with pin joints at present, transforms the structure of a rhombic mechanism described concisely in the feature description method into a frame representation. Then the system automatically generates dynamic equations, which represents the link mechanism as rigid bodies coupled with springs and dampers, in S-expression of LISP as a function representation. The results of numerical analysis of the equations are shown as the inferred functions of the rhombic mechanism.

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A measurement method of force and moment for robot applications is presented in this paper as a force sensor with evaluation results of grasping experiments. The sensor for measuring force and moment consists of quadrangularly located electro-conducting rubbers, where the rubber is selected to have less hysterisis in the range of linearity. The rubber is so thin that it can be installed in a jaw-type robot hand. The force and moment can be measured by using the characteristics such that the electic resistance of the rubber changes according to the pressure applied on the surface of the rubber and moments can be calculated from the quadrant outputs due to the changes in resistances, when the hand grasps an object. Therefore, from the sensor outputs, it can be recognized where an object is held in the hand. Some experimental results are shown by grasping objects.

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The finish of a painted car body surface is one of the important values by which many customers select the car. It requires both excellent skill and susfained eye consentration to find small defects on the painted surface. It has become an urgent need to develop automatic inspection equipment solving the above-mentioned problems.

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In the process of sawing a timber into a square bar, knots directly influence the quality of the square bar. The recognition of knots depends on the operator and he determines the cutting position based on many years of experience. As skilled workers become few and old, and the cost of imported square bars decreases, it is necessary to develop a computer aided design (CAD) for the sawing of timber. In this paper, we propose a method for recognizing knots on the surface of timber (Japanese cypress) using the image processing technique. The wave lengths 625 to 770nm (red) or 900 to 1 000 nm (an infrared) are useful for distinguishing clearly between knots and other parts on the timber surface. The knot can be recognized in the process of thresholding the input image, calculating the marginal distribution, approximating an ellipse, and judging the knot.

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