This paper deals with the estimation of hydrodynamic forces acting on tube bundles in a circular tank by sloshing. The sloshing phenomena are calculated by the Boundary Element Method (BEM). The hydrodynamic forces acting on the tubes are integrated dynamic fluid pressures around the tubes. When there is one and four tubes in the tank, the displacements of the fluid surface by this analysis agree with the experimental results. This analysis is a vary effective method. By analysis, as the tubes increase, the hydrodynamic force acting on the tubes derease. The hydrodynamic force is the greatest on the fluid surface and decreases suddenly at the bottom of the tank.

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This paper presents an analytical method of solving the free vibration problem of cantilever plates made of laminated composite materials. The analytical approach is based on the well-known Ritz method, with displacement functions in complete power series, and is applied to laminated plates of various shapes with straight-line boundaries. A computer program code was developed to accommodate a wide range of material constants for FRP (fiber reinforced plastic) and a variety of plate planforms. Numerical examples include cantilever plates of triangular, L-shaped and parallelogram planforms.

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As a step toward explaining analytically the mechanism of limit cycle evolution, the present work derives a linearly approximated equation of a single degree of freedom of the closed-engine-governor loop, noting the phenomenon of very slow frequency while considering the results of the previous work. Further it gives a simple physical reasoning to the mechanism of the negative damping force which causes an instability, resulting from a concept of the dynamic feedback torque gain composing a static feedback torque gain and a virtual time constant depending on the phase relations between the feedback torque and the engine speed. Results show that there is energy input during a cycle when the dynamic feedback torque is larger than the inertial torque. This increases the amplitude, and the virtual time constant increases with increasing damping of the governing system due to the presence of a response lag of the speed-sensitive part in the governing system.

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A new simulation method to treat the fluid-structure interacted problem is presented. The insulation oil is regarded as the two-dimensional uncompressible fluid flow in the gap between two structural plates. Sufficient correspondence in resonant frequency has been achieved using computer simulation compared with the conventional method. A good agreement also can be obtained between experimental and simulation results in the verification using a model shunt reactor.

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This paper deals with an equivalent damping ratio of a nonlinearly vibrating beam due to a collision between the beam and a plate. The vibration model is a cantilever beam with a gap. The input force, generated by an electromagnet shaker, is stationary white noise. Acceleration of the spherical top of the cantilever beam is measured and used to experimentally evaluate the transfer function. An analytical transfer function for a vibration model without a gap is obtained and employing the parameters η, ω_e, and ξ_e for expressing the magnitude of the transfer function, dominant angular frequency and equivalent damping ratio for the nonlinear beam system respectively, we compare the equivalent transfer function with those obtained experimentally. The equivalent damping ratios from experiments are constant at about 20% within 0.4 to 0.8 of the collision rate. Reduction of energy by collision is evaluated to produce only 3% to 4% damping under the experimental conditions. If the plates have the characteristic of the nonlinear spring after the collision, it is shown by calculations that the equivalent damping ratios become a large constant value. We think that the equivalent damping ratios ξ_e from experiments are composed of the reduction of energy by collision and characteristic of the nonlinear spring.

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In this paper, the growth mechanism of corrugations on rolling surfaces has been analyzed by computer simulation. Whether the corrugations grow or diminish has been calculated using the models of plastic deformation with vertical contact vibrations, which were determined in former experiments. The effects of the vibration system on the stability conditions have been examined. In the case of a system with two degrees of freedom, considering elastic support of the roller rig and contact stiffness between the wheel and the roller rig, the growth conditions depend on the natural frequency of the system as in the case of a single degree of freedom. Rigid support of the roller rig leads to more sever growth of corrugation due to the first coupled natural frequency compared to soft support. By appropriate selection of the natural frequencies, it is possible to develop the corrugation with two wavelengths and to decrease it without the growth of another corrugation.

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For manufacturing equipment of VLSI chips, etc., it is desirable to have isolation floors which are effective for not only ambient micro-vibration but also weak earthquakes and even strong earthquakes. Though the isolation floor mentioned in the 1st report could meet such requirements, its applicability was limited because its structure needed a height of 1.8 m or so, Which was too heigh for wide application. A new device for vertical isolation was developed to make the isolation floor having a lower heigh. The device integrated a coil spring and viscous dampers for micro-vibration and for earthquakes. By using the device for vertical isolation, the isolation floor with a heigh of 0.6 m was achieved. For horizontal isolation, the floor used multi-stage rubber bearings and viscous shear dampers which were already used in the former structure. Seismic excitation tests and micro-vibration tests were carried out for a test model on which a equipment model was mounted. The tests verified that the newly developed isolation floor performed satisfactorily for implementation.

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Air suspension truck has been used for transport many precision machinary. However, the air suspension is not so effective in horizontal direction as in vertical direction. For the seismic vibration, some isolation systems have been developed. But, the effect of these seismic isolation systems is depend on the weight of the load. In this paper, we present a new vibration isolation system making use of a table supported by wire ropes. Foundamental excitation tests and vihicle running tests on an actual road are performed to verify the advantage of this system. The maximum horizontal acceralation of the table is reduced to 0.5G from 1.7G.

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The splashes Which are formed by a car running in a puddle are given little attention despite their habitual damage to pedestrians. A simple physical model is constructed on the basis of knowledge from experimental studies which were conducted to explore the phenomenon. Although the phenome-non is highly nonlinear, the main feature can be described in terms of elementary dynamics because of its dominant conservative nature. The maximum flight distance of the splashes is independent of the depth of the water layer, while it increases with car speed.

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Solid friction in mechanical control systems causes undesirable effects such as a jerking motion. Taking account of negative gradient characteristics from a static friction to a kinetic one, we propose an extended Kalman filter algorithm for solid friction estimation. An application of this estimation technique to a servo system is proposed in this paper. The proposed controller consists of a conventional linear controller and the extended Kalman filter. The real-time estimate given by the extended Kalman filter is fed back so as to cancel the solid friction. Using hybrid simulation where a plant with a solid friction is simulated by an analogue computer and the controller is simulated by a digital computer, we compare the performance of the proposed controller with that of a controller which neglects the negative gradient characteristics of the friction. The result shows that the proposed controller provides better performance.

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The aim of this investigation was to study a manufacturing system by the method of a centrifugal casting technique for a ceramics/metal functionally gradient material. The centrifugal force enables the ceramics powder in a metal to Create a gradient distribution. The mixtures consisting of plaster and corundum was chosen as a experimental model. The mixed materials were cast into rings under the combined conditions of four different volume fractions and three different No. times of gravity. The corundum profile was measured and analysed cubic order porinomial equation. A mathematical model based on the expression was proposed to consider the effects of the volume fraction of the powder and the centrifugal force on the distribution. The model can express the observed distribution fields in a unified manner. A manufacturing system using the model was discussed wether it satisfies the designed distribution of the powder.

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When compared with active suspensions, semiactive suspensions have the advantages of simple hardware requirement, lower capital and operational cost, and the desirabl stability and reliability behavior that characterizes passive devices. They can achieve performances close to those of active devices. Generally, semiactive devices use a damper in which the damper coefficient is variable. This paper proposes a new semiactive suspension in which both damper coefficient and spring constant can be modulated at high bandwidth. The control strategy for this device uses only a directly measurable relation position in vehicle applications. Simulations and experimental studies show that the proposed system is compared to passive and ordinary semiactive suspensions.

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In this parer, we deal With the process control system(SISO) and model prediction control(MPC) algorithm. The control results of MPC for a standard performance index do not behave as one expect. We study the MPC algorithm on a performance index with the control energy constraint. Furthermore, we propose an adaptive MPC algorithm with an estimation of the impulse response function by means of least squares. The steady state error is improved by the proposed method. The method is examined by simulation and experimental studies on the air pressure control plant.

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This paper describes a new method of position control of a pneumatic cylinder of which motions are simply repeated. A concept of time-optimal control and learning is introduced in the control method to realize high speed and a good transient response. The pneumatic system is basically composed of a pneumatic cylinder with a brake, a three-position solenoid-operated valve, a relay, a position sensor and a personal computer. Switching time of the valve is updated by learning after every repeated motion of the cylinder so that the piston rod has zero velocity at a desired position. Newton-Raphson's method and/or fuzzy reasoning are used as the learning methods. Experiments show that the learning is effective to make the cylinder motions converge to the desired steady ones and that the positioning accuracy of about 0.3 mm can be attained at the average velocity of the piston rod below about 1 m/s.

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It is widely recognized that the industrial robots used in the production lines or in other engineering fields are installed comparatively higher rated actuators and have higher rigidity than those required, whereas they have too small payload capacity. To achieve high speed drive and accurate positioning under a high payload is indispensable for an advanced industrial robot. In order to increase payload/deadweight ratio without losing high speed driving and accurate control of robots, the nonlinear terms in the equations of motion relating to their load and attitude must be well compensated. The authors have developed and examined two kinds of the load estimation and compensation control method for a vertical-type manipulating robot, which are based on the gravity estimation-compensation and the Fuzzy-set theory. It is confirmed experimentally that although both compensating methods are useful, the Fuzzy theory is much better than the gravity compensation method.

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This paper deals with a thumb and finger model of human type which has almost same motions and same sizes as those of human hand. The object which is handled by the fingers is modeled as a point or a line. Evaluations of workabilities which depend on the work space of the fingers are essentially indispensable to the elementary motion patterns which may possibly control a robot hand mechanism. The spatial points where both finger tips can encounter with each other are analyzed. A finger has an elementary linkage that is a directly chained three links finger mechanism. The postures of the finger element are searched on a relation of the direction of force that is loaded on the tip of the link. The spatial points of the two-fingers model which pinches a pen are evaluated by the torques which act on the finger hinges.

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This paper discusses the evaluations of work space of a thumb-finger model of human type. The evaluations are indispensable for design the motion patterns which may possibly control the finger mechanism. The direction of the end link of thumb is numerically analyzed from that of the finger. And the angular mobility of the direction of two fingers is cleared to have a great magnitude at the middle zone of the work space where both finger tips can encounter with each other. The shape of the finger tip is assumed as a half cut ball. And the Work space is evaluated by the size of particle which can be pinched by the two finger tip surfaces. The spatial position suitable for the pinch motion and the posture of the finger links are cleared to be almost given uniquely.

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This paper deals with inspection path planning for in-pipe inspection mobile robots which have the capability of moving through complicated pipeline networks. It is imperative that the robot systems have an inspection path planning system for such networks for their reasonable and rational operation, controlled by themselves or by the operators. The planning mainly requires two projects: the selection of the place to put the robot in or out, and the generation of the paths in the networks. This system provides the for complicated problems with plural inspection points using a basic strategy of systematic ally producing patterns and dividing partial problems of simple searches based on rules.

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A model-based image measurement system which defines a model with variables. measures data, defines measurement equations, solves these equations and estimates values of the variables is proposed. The feasibility of the system is verified by an experimental system that estimates the position, attitude, and inner parameters of an object from its image. Using the numerical method, this system can use measures not expressed by mathematical equations.

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In this paper, a new type of aerostatic floating-bush bearing is proposed to establish relatively high stiffness, low power consumption and excellent stability in the high-speed region. The proposed floating-bush bearing employs slot restrictor and is operated in a relatively small bearing clearance to obtain high stiffness. Furthermore, the floating bush is flexibly supported by an aerostatic bearing Which enables the floating bush to rotate with a rotor. This makes the power consumption of the proposed bearing low even in a high-speed region. Here, the stability of the proposed bearing is discussed theoretically and experimentally. Consequently, it is found that the proposed bearing shows an excellent stability and can have relatively high stiffness and low power consumption.

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Recently due to increased usage, there are many instances where plastic gears are used in combination with aluminum alloy gears. In these cases, since aluminum alloy gears are considerably softer than steel gears, the tooth surfaces become extremely worn and rough, and it is feared that the phenomenon of multiplied effect promoting the wear of plastic gears by such rough tooth surfaces may occur. Thus, in this study, an operating test was carried out by combining an MC nylon gear and an aluminum alloy gear, and the actual conditions of the wear of teeth, the roughness of tooth surfaces, the temperature of teeth, the change of tooth profile and so on were investigated.

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In the first report, the .method of calculating the fatigue strength of plastic gears using strain energy was proposed; however, the conditions only extended to gear life in the normal temperature environment. Recently, the use of plastic gears has expanded, so that they are used frequently in elevated temperature environments. For example, the plastic gears used to drive the drying drum of a paper-making machine perform at the ambient temperature of about 90°C. Owing to these facts, the method of estimating the operation life of plastic gears is proposed in this report. Here, the change of the properties of teeth due to temperature difference was taken into account using the calculation method from the previous report in order to determine the type of teeth which can cope with the plastic gears in the environment of both elevated temperature and normal temperature.

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This paper describes the manufacture of injection-molded plastic magnetic gears. The polarity of the right tooth face is different from that of the left tooth face in all teeth. Such gears mesh with either nonbacklash or noncontact gears. This paper describes the former. If practical the nonbacklash gears should be used in such applications as measurement meters and the joints of robots due to their accurate rotary transmission. This first paper was written primarily on the principle of plastic magnetic gears regarding the method of injection, molding-method of magnetization and measurement of flux density. It was possible to put the injection-molded plastic magnetic gears to practical use in this experiment.

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The Purpose of this paper is to estimate the root bending stress of a helical gear tooth. and to present factors and formula which can be used practically to appraise the stress accurately. Most methods for estimating the stress have been mainly based on analysis and test results for spur gears, and have not been sufficiently accurate. In order to estimate the stress more accurately, the finite element method, in which the calculated load distribution is applied to the 3-dimensional finite-element model, was introduced. After verifying the method through several tests with strain gages, factors and formula were derived using the method to estimate the stress in the range of automotive transmission gear dimensions. The accuracy of the methods were then confirmed through several examples.

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The rotational transmission errors of several assembled harmonic drive devices are precisely measured over one revolution of an output shaft by using three test pieces of each element, a ring gear, a cup gear and an oval cam. Further, angular pitch errors of the tooth spaces of the tested rigid and cup gears with a small module (0.5mm) are also precisely measured by a newly designed measuring device with a resolution of 1/1000 deg. It is found that the rotational transmission error is composed of two components. One is caused by the angular pitch error of the ring gear and varies periodically with a period of half a revolution of the input shaft. The other is caused by that of the cup gear and varies with a shorter period.

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Thermal expansion of the ball screw in semi-closed loop type machining centers directly introduces positioning errors along the travel axis. The purpose of this study is to develop an automatic compensation method for the expansion of the ball screw using the thermal expansion detector installed near the NC zero point. The thermal behaviour of the ball screw of the horizontal machining center under the various driving conditions was measured to examine the effectiveness of this compensating method. From these results, the thermal expansions of the ball screw along the travel axis were approximated by a linear function of the distance from the ball screw support, and thereby the positioning accuracy could be maintained to better than ±3μm while using this compensation.

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This paper is concerned with the rupture configurations in a full circular journal bearing. The rupture extent has large influences on the characteristics of a journal bearing, especially on its damping coefficients. It is necessary to estimate the rupture inception point more accurately. A numerical technique using the finite element method is proposed for two-dimensional analysis in the plane normal to the journal surface along its rotating direction. Oil cavity interface is treated as a free boundary, and the rupture configurations and the flow in the lubricating oil film are shown in the present paper.

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In order to examine the brake noise occurring at very low speeds, disc brake pads were connected with coil springs, and the stick-slip motion at a low friction speed was measured. The stick-slip motion was relatively prompted with steel fibers contained in the pad material. The addition of graphite to the pads and the lubrication of the frictional surface with water or castor oil increased the amplitude of the stick-slip motion. On the other hand, the formation of the transferred films on the opposite surfaces and the addition of cashew nut resin to the pads decreased the amplitude of the stick-slip motion. These results were explained by using the friction model of the disc brake pad. Moreover, the amplitude of the stick-slip motion and the brake noise level were compared.

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The ironing process of thin-wall aluminum cups has been analyzed by using the rigid viscoplastic finite element method. A simple and reliable approximation procedure has been developed for integrating the effective strain that can arise in finite element analyses associated with Eulerian formulation or arbitary Eulerian-Lagrangian formulation. As an inverse solution of the analysis, the mean frictional coefficient μ_d, on the die surface, and μ_p, on the punch surface, were also obtained with the ironing punch load and the frictional force acting on the punch which were measured in the corresponding experiments. It is found that the friction values estimated by the slab method agree well with those calculated by the present approach in this case.

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Regarding the thermal behavior of the main spindle driving system with the electromagnetic disk clutch, experimental investigations have been carried out in both the rotational and nonrotational conditions, in which the visualization of the temperature distribution has also been employed. This paper presents some interesting observations obtained from such experiments, and gives very useful guidelines to reduce the thermal behavior in designing such a driving system. For instance, the results show that the frictional heat of the clutch bearing strongly affects the thermal behavior of the friction disk, driven shaft, magnetic body and that the slip characteristic of the clutch has considerable effects on the thermal behavior of the system. In addition, this paper suggests that the self-ventilation using the rotational friction disk is the most effective in reducing the thermal influence on the system.

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An attempt was made to cutting by rising gradient cutting, falling gradient cutting in a inclined plane with ball end mill. It was observed that there was optimized feed in each inclined plane. So, an attempt was made to cutting by gradient optimized feed and continuous feed. As a result, it was found that the gradient optimized feed was successful not only in improving tool life, but also in achieving better finished surface roughness.

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Experimental research to clarify the relation between cutting edge geometry and plastic sliding on a four-fluted end mill is performed. Also, an edge, which can reduce dimensional inaccuracy and surface profile error in the finishing process of end milling, is presented. The performance of a newly performed cutting edge is verified through the measurement of chip geometry and cutting force variation in the face milling. It is shown that the sum of the rubbing and ploughing forces can be reduced by making the edge sharp as well as the margin width small. Both surface profile error and surface roughness can be improved in the case where the margin face is polished and protected from the flank wear by TiN coating. It is expected that a finer finished work surface can be derived by polishing the rake face along with the margin face.

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The magnitude of the ploughing force on a cutter edge can be reduced by decreasing the contact area between work surface and edge. In this paper, a fine nick is performed to the cutter edge on a four-fluted end mill in view of the decreasing surface profile error produced by the tool deflection. The performance of the end mill with the fine nick is verified through the measurement of ploughing force and chip geometry in the face milling. It is shown that the magnitude of force drop exceeds the expected value that was calculated from the geometrical change of the contact area since the plastic sliding region decreased near the wedge that was created by the nick. The cutter has the capacity to reduce the surface profile error as well as to maintain the surface roughness by improving the wear resistance, while a deterioration of surface roughness produced by the groove wear is unavoidable under normal conditions.

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A CAD/CAM system of cone-shaped tools for high-speed groove cutting on which many cemented carbide disposable tips are mounted is developed by applying the coordinate transformation method to a three-dimensional layout of the tip on the tool. The points considered in designing the tool are the selection of the cutting tool edge location on the cutter body to maintain the machining error within an allowable limit and the position of the tip posture to avoid interference of the flank with the machined surface. Following the tool design, the NC machining data of the cutter body for a five-axes controlled machine is generated automatically. Through the actual design and machining, the reliability of this CAD/CAM system is confirmed.

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Diamond blade are widely used for cut off grinding of hard and brittle materials. However, there are some problems to be solved in order to improve the cutting accuracy and the productivity. They are the occurrence of chipping, which results in the increase of the kerf width, and the deterioration of the cutting groove straightness. In this study, a series of cutting tests are carried out to clarify the influence of the cutting conditions on these technological problems. Practical cutting conditions, which can reduce the occurrence of chipping and improve the groove straightness are presented.

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Superabrasive grinding wheels have an excellent grinding performance. It is, however, not easy to prepare (truing and dressing) superabrasive grinding wheels because of their high degree of hardness. In this study, an efficient new preparation method for CBN wheels is proposed. The resinoid-bonded CBN wheel is trued and dressed with a metal-bonded diamond wheel and steel wire brush, respectively, which are integrated in the preparation equipment. An optimum preparation condition is found.

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In order to clarify the formation mechanism of liquid phase degradation products that cause the fade phenomenon, we carried out the solvent extraction of cured phenolic resin, and then the molecular weight distribution of the extracts was measured. In the case of the extracts of cured phenolic resin powder to which a shearing force was applied in a steel mill, a peak appeared on the high molecular weight side of the molucular weight distribution curve, and the average molecular weight increased. On the other hand, the average molecular weight of the extracts of cured phenolic resin powder, to which heating with an electric furnace was applied, was the same as before heating or decreased. From the above results it was found that the products of degradation due to heat alone are of the gas phase, but those formed by the simultaneous action of heat and shearing force have large molecular weight and are apt to be of the liquid phase.

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Surface roughening phenomena in the upsetting of sintered aluminium powder preforms have been investigated experimentally. The effects of the initial density and crystal grain size of sintered preforms on surface roughness development are mainly examined. An empirical expression of the surface roughness development with equivalent strain is derived. In the expression, the variation of density during the upsetting process is taken into consideration in addition to the grain size of sintered preforms. The roughness on the free surface of sintered preforms increases as the plastic strain and grain size increase. This tendency is similar to the case of conventional pore-free metals. However, unlike the pore-free metals, the rate of increase in surface roughness of the sintered preform varies from strain to strain depending on the density during upsetting. When the relative density of sintered preform increases up to about 0.95, the rate of increase in surface roughness is almost reduced to that of pore-free metals.

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This paper describes a new method for solving the facility layout problem. In this floor-plan placement problem, a placement unit consists of a block which has various rectangular shapes. There are two phases in the algorithm. In the first phase, the initial block placement is obtained by an attractive and repulsive force method. In. the second phase, a preliminary block-packing process is performed by using a placement-ordered tree which keeps information about distances and directions between blocks contained in the initial solution given by the first phase. Finally, a subsequent block-packing process is performed by gradually moving and reshaping the blocks. The methodology is presented and demonstrated via an example problem.

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In a manufacturing system, efficient production is often disturbed by unexpected events such as interruption of urgent jobs and failures of machines, which cause some delay in the production process. In such cases, execution of rescheduling could partially or completely recover the delay. POP (point of production) systems, which can detect any delay occurring in the production process in real time are becoming popular. On the basis of the information obtained using a POP system, the present study proposes a policy for the rescheduling of planning and provides a formulation for optimal planning. The policy proposed in this study is to conduct rescheduling when the number of problems causing delay in the production process beaches a prespecified value. The conditions under which an optimal solution exists are also clarified. Numerical examples are presented to indicate the characteristics of the proposed method.

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In this paper we consider a critical production scheduling problem, the part selection problem, for the effective utilization of a flexible manufacturing system (FMS). The problem is to determine how to split up the production requirement given for a certain period into a number of subsets in order to minimize the number of tool changeovers and the sum of maximum workloads. First, we describe the part selection problem and show that, although the problem can be formulated as an integer programming problem, the number of integer variables is too large to obtain optimal solutions for realistic problems. Then, we develop a heuristic method and carry out the computational experiments to test its efficiency and validity. The computational results show that our heuristic method is efficient and can be used to solve large-scale problems.

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It is very difficult for a designer to design an aircraft, because many design variables with complicated relationships are involved in the aircraft design process. This is one of the reasons why progress is slow in computerizing this process. In this paper, an expert system for preliminary aircraft design is studied with emphasis upon the design knowledge. The design knowledge is constructed by using the design-object knowledge and the designer's knowledge as the object-oriented representation. The design-object knowledge consists of design variables and relationships among design variables. The designer's knowledge consists of the designer's strategy for aircraft design. This system enables one to develop a flexible and dynamic design process according to a design condition.

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