This paper deals with the quenching of self-excited vibrations of a rotating circular plate subjected to a concentrated frictional force as a function of relative slip velocity exerted on its outer circumference by dynamic absorbers. Results obtained with the method of multiple scales and the shooting method showed that (1) dynamic absorbers tuned to the natural frequency of the vibration mode to be controlled and arranged at a certain angle relating to the vibration mode are the most effective, (2) such mountings of not one but several dynamic absorbers for every possible occurring mode, enable us to quench self-excited vibrations perfectly, and (3) thus, the effective masses of the dynamic absorbers are 10^-3 in the order of mass of the circular plate. The analytical results are confirmed by the experiment concentrating on the perfect quenching of frictional vibrations of the rotating disk.

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A general purpose analysis system for the free vibration of rotating general axisymmetric shells is developed. The basic equations, including that of the effect of the initial stresses due to the rotation are formulated based on the finite element method. A general axisymmetric shell is treated as a set of conical frusta and the characteristic equations for each element are derived by applying the energy principle to the strain, including the secondary strain and kinetic energies. The basic equations for the total system are obtained by summing those for all elements. These equations can be separated into quasi-static and dynamic ones, i.e., the equations in the steady rotating state and those in the vibrating state. The frequency analysis is carried out for rotating cylindrical, truncated conical and partical spherical shells. The validity of these analytical results is verified by comparison with previous work.

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This paper discusses a new method of analysis of two-dimensional eigenvalue problems de-scribed by Helmholtz's equation. A general solution is assumed as a linear combination of plane waves which have the same wave number and travel in different directions. Nodal points are located only on the boundary of a convex domain which has an arbitrary shape. A set of equations similar to finite element equations can be derived from the general solutions. Eigenvalues obtained by this method are very close to the exact values. This method is effective in simplification of programming and in shortening of computational time.

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The dynamic instability of a free-free column subjected to a tangential follower force has been investigated. A suspended column, in which one end is supported by a rotational spring and the other end is free and thrusted, is proposed to simulate the dynamic instability phenomena of a portion from the nodal point to the trailing end of an accelerated free-free column in space. These two systems are formulated using FEM, and the vibration modes are compared to discuss the equivalency of the two systems. The rotational spring constants satisfying the equivalency are obtained for the cases with and without structural damping.

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This paper considers the active control of a vibrating thin plate from the viewpoint of a power flow control methodology. It is the purpose of this paper to elucidate the generation mechanism of power flow patterns induced in an actively controlled thin plate. Particular emphasis is placed upon the vortex-type response pattern, which has the potential for realizing energy confinement into a specific area of the plate. Firstly, it is shown that two vibration modes dominate the plate response in the case of vortex-type power flow near the optimum condition for suppressing the plate vibration. Vibration intensity is derived for these two vibration modes. An energy stream function for the vibration intensity field is then introduced, to whose contour the vibration intensity vector proves to be tangential. From the characterintics of the stream function, the number and direction of the vortices are predicted. Finally, it is shown that the period of the vortex is not always the same as the exciting period, but rather equal to some integer times the exciting period.

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In the previous report, a self-induced manometer oscillation in a How channel connecting two large tanks was observed, which was caused by the circulating How in the upstream tank. In this study, the geometrical effects on manometer oscillation are experimentally investigated. As geometrical parameters, the inlet position, the outlet position, and-the width of the upstream tank are systematically changed. Manometer oscillation occurs in the case where the inlet How incident angle to the outlet is small, or when the length between the inlet and the outlet is short. These results show that manometer oscillation can occur when most of the dynamic pressure of the inletflow directly flows out through the outlet with little dissipation in the upstream tank.

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Nonlinear liquid motion in an elastic circular cylindrical tank partially filled with liquid, in response to pitching excitation, is investigated. The nonlinearity of liquid surface oscillation and the elastic wall deformation caused by the liquid pressure are considered in the response analysis of sloshing motion. Basic equations are derived by employing the variational principle. Free vibration analysis of the linearized system confirms that the influence of wall deformation on sloshing motion is negligible. The time histories of the liquid surface displacement and the deformation of the tank are calculated to the harmonic pitching excitations. An experiment was conducted using a model tank. A fairly good agreement was found between the theoretical and experimental results. It is shown that the nonlinear analysis is important for estimating sloshing responses.

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The authors have been conducting research on the evaluation of errors caused by time integration methods. They proposed, in the previous paper, a method of evaluating errors in the solution of time integration methods when the harmonic input is applied to the first-or second-order system. The method is extended, in this paper, to the case where an arbitrary forcing function is applied to the system. Based on this method, a conventional method to evaluate the error in the numerical solution of forced vibration is also proposed in this paper.

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This study is concerned with several aspects of the nonlinear vibration of a body levitated by an electromagnetic force. Firstly, from the viewpoint of analyzing the qualitative properties of the vibrations, the fundamental characteristics of the electromagnetic levitation system are investigated using phase plane portraits and Poincare maps. Secondly, aperiodic motions are identified as chaotic vibrations by their quantitative properties, such as Lyapunov exponents, fractal dimension and power spectra. Finally, on the basis of the above-mentioned study, the control of chaotic vibration using neural networks containing recurrent paths is investigated. Two architectures of the neural networks, Jordan-type and Elman-type networks, are shown to work as adaptive nonlinear feedback controllers. It is further shown that the neural networks controller can suppress the chaotic vibration more effectively than a PD feedback controller can.

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This paper describes an optimal tuning method for swing reduction of a gondola lift by a pendulum type dynamic absorber. The fixed point theory used for the design of the conventional dynamic absorber modeled as a mass connected with a main rectilinear vibration system by a spring and a damper are first examined in detail. Behavior of two fixed points of the pendulum type dynamic absorber attached to a pendulum type main system is next investigated. As a result it is found that behaviors of these fixed points are different from that of the conventional dynamic absorber and that the optimal tuning can be obtained by choosing a cerain value of inertia ratio of the dynamic absorber to the main system. It is also found that the maximum value of the amplification factor can be decreased without limit as the natural frequency of the dynamic absorber is decreased. Theoretical results are confirmed by experiment.

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In this paper, a new type of semiactive seismic isolation device for machines is proposed. This isolation device is composed of rubber bearings and semiactive dampers consisting of a ball screw, a brake disk, a brake shoe, a flexure hinge and a piezoelectric actuator. The seismic responses of a machine supported with the isolation device, which is installed on the 5th floor in a 7-story building, are calculated using a continuous system simulation language (FACOM SLCS4), and the effective control condition of the semiactive damper is discussed. An experimental semiactive damper and a model of a machine-isolation device system are made, and the resisting force characteristics of the damper and the seismic response of the machine are measured using an electrohydraulic-type shaking table. The experimental results are compared with the calculated ones, and the effect of vibration isolation of the isolation device is confirmed.

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The design method for a gyroscopic mechanism for stabilizing torsional vibration is discussed. The passive gyroscopic damper (PGD) has a rotor in the gimbal rotating at a constant angular velocity. The gimbal is driven by a gyroscopic moment induced by the rotation of the main system, and is passively controlled by the rotational spring and the viscous damper around the gimbal axis. The gimbal rotation induces the resisting gyroscopic moment against excitation. The mechanism enables effective vibration control compared with conventional dynamic vibration absorbers, while it has a fairly simple structure and requires no actuators except for that of the rotor rotation. In the paper, the Galerkin method is applied to analyze the stationary response of the PGD subjected to ergodic Gaussian white noise excitation. The PGD shows considerable nonlinearity under strong excitation which causes large amplitude of the gimbal angle. Numerical optimization techiniques are employed to minimize the rms value of the main system angle. The simulation results are compared with those obtained using the linear design ; thus, the optimization effect is demonstrated.

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To reduce unbalance response of a flexible rotor suspended by electromagnetic bearings, two methods have mainly been investigated. One is the method to increase damping of the mechanical system ; the other is the method to cancel out unbalances. For the former method, PID control is generally used. Although PID control is very effective for reducing resonance vibration, in other ranges of rotational speed it yields little effect. On the other hand, with the latter method of feedforward control, it is expected that unbalance response is greatly attenuated in all ranges of rotational speed. In this paper, we used both PID control and feedforward control with variable gains against rotational speed. PID control needs to stabilize the rotor system and feedforward control is used to reduce unbalance response. From calculated and experimental results, we find that the above method has greater capability of suppressing vibration of a flexible rotor than does ordinary PID control.

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The direct numerical integral method (D.N.I.) which is a kind of shooting method, is presented for determining the periodic solutions of nonlinear systems with discontinuous characteristics. The present method is applied to a system with Coulomb's frictions, a system with bilinear stiffness and damping, and a system with preloaded compliance. By comparing the results of this method and the analytical method, it is found that this method yields very accurate results. In the system with Coulomb's frictions, many kinds of periodic solutions, i.e., slip, stick-slip and lockup solutions are obtained. In the other two systems, superharmonic vibrations, subharmonic vibrations and ultra-subharmonic vibrations are obtained by the D.N.I. Moreover, Liapunov numbers are calculated by applying the algorithm to integrate the corresponding variational equation in the D.N.I.

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A theoretical formulation of a new fast learning method based on back propagation is presented in this paper. In contrast to the existing back propagation algorithm which is based solely on the modification of connecting weights in between the units of different layers of the neural network, the present method involves calculation of the optimum slope of the sigmoid function in each unit together with the variation in the connecting weights. The effectiveness and versatility of the present method are verified by the system identification of (a) linear and (b) non-linear (Duffing and fluid-type) single degree of freedom mass-spring dynamic models. In all the three cases, the present method excels in speed and accuracy compared to that of the existing method of fixed slope. Physical significance of the faster convergence rate and better accuracy of the proposed variable slope method is illustrated in terms of the effect of the slope of the sigmoid function on its output level. It is observed that compared to the fixed-slope neural network model the variable-slope neural network model brings flexibility to the output level of each neuron and hence enhances the dynamic system identification capability.

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Many container cranes have sway-control mechanisms, but most of them consist of a mechanical damper with a hydraulic cylinder, which is very heavy. We have developed a new computerized sway-control System which solves the above problems. This system is based on two theories. One is time-based optimal control, and the other is advanced feedback control. These two theories have been merged into one control method by a software program. Two experiments were carried out using a 1/10-scaled test rig and an actual container crane at the yard. From these experiments, it was confirmed that this system gives excellent performance and sufficient practicality in such areas as ease of operation and comfort of cabin ride.

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In this study, the temperature control system of an incandescent lamp is used. This system consists of a thermistor, multimeter, microcomputer, D/A converter, variable AC power supply and incandescent lamp. This system is a nonlinear and a first-order lagsystem. Therefore, it is very difficult to control smoothly the system. To cope with this problem, a newly developed fuzzy control is applied. This controller consists of the modules of the fuzzy calculator, the scale's optimizer and the scale's selector. The effectiveness of this method is confirmed and influence on the tuning of the scale of the fuzzy's membership functions according to the environment adaptable-type fuzzy control is examined.

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This system for controlling the temperature of a climate camber consists of a small electric heater and a variable capacity refrigerator that uses waste heat from a refrigeration cycle condenser. Interactive control of the use of waste heat and the use of the heater enables temperature to be controlled to within 0.1°C with a power consumption about 50% lower than that of conventional room temperature control systems with constant-capacity refrigerators. A simualation model for the proposed system is developed, and its validity is demonstrated by comparing simulation results with measured data.

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An attitude control algorithm of a free-flying space robot with thrusters is proposed. It is known that the motion of the manipulator attached to the main body of a space robot causes the attitude deviation of the main body because of dynamic interaction, and an effective attitude control algorithm is desired. An equation of motion for the attitude of the space robot is derived using the Lagrange equation. The proposed disturved-torque compensation algorithm, which is a kind of feedfoward control, is as follows. The inertia force, which is calculated from the equation of motion, is considered as the disturbance torque for the main body. Thrusters act to compensate the impulse of the disturbance torque. The proposed algorithm is compared with the time optimal control and time-fuel optimal control algorithms. Simulation results of attitude deviations and input energy are discussed.

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In order to stabilize the unstable vibration of a flexible disk coupled with a head-suspension system, the effects of damping factors on instabilities due to the dynamic frictional force between head sliders and disk are analyzed using a disk-heads coupling model. From parameter studies, the following results are obtained. First, it is found that the internal and external damping acting on the entire disk make all real parts of natural modes of vibration of the head-disk coupling system shift in the negative direction. Second, the transverse or pitch damping of the head-suspension systems can stabilize an unstable component near the transverse or pitch resonance of the upper and lower head-suspension system, respectively. When the transverse and pitch resonances are close to each other, there are two types of strongly destabilized components in the vicinity of those frequencies. Third, the instabilities due to frictional forces are hardly affected by transverse or pitch contact damping factors.

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The study analyzes the recognition process in the examination of the texture of fine particles through tactile sensing with human fingers, and aims at establishing the structure of texture recognition. It investigates the effects of the physical attributes of the particles on the recognition and prepares the foundation for developing sensor devices which implement human tactile sensing. The authors found 1) that there is a clear relationship between the physical attributes and subjects' verbal response, and 2) that there is a threshold at which the subjects switch from feeling particles as separate, individual bodies over to associating them with a fluidlike character. The authors also established 3) correspondences between the diameters of the particles and the terms expressed by the subjects.

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When two-tone stimulation with different frequencies (f₁<f₂) is delivered to the ear canal, a response including new frequencies related to the frequencies of the two primary stimuli by a simple algebraic expression is generated. This response is called "Distortion-Product Otoacoustic Emissions (DPOAE)". In this study, for the purpose of understanding the general tendency of DPOAE and the middle ear effect on DPOAE, the DPOAE level of the 2f₁-f₂ frequency component and middle ear dynamic characteristics of normal human subjects were measured. The results revealed that the DPOAE level was largely dependent on the condition of primary stimuli, and was large in the region of middle ear resonance frequency.

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This paper deals with an expert system for the recognition and counting of a mammalian cell, which is the fibroblast, by image processing and a neural network. These cells are cultured on the surface of a microcarrier which is 150-200 micrometers in diameter. This culture method using microcarrier is one of the high efficient productions. To monitor the culture conditions, expert operators must count the number of cells on the microcarrier. We have proposed the counting algorithms, and we have room for improvement with respect to the recognition rate using the neural network. The purpose of this paper is to study the optimization of initial values for a multilayered feed-forward neural network using a genetic algorithm. The genetic algorithm is available for optimization problems. We apply the genetic algorithm to neural network problems, such as the exclusive-or problem, the function approximation problem and the cell recognition problem. We show the validity of this method using the genetic algorithm.

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This paper describes a continuous recognition method of sign language (numerals 0∼9 and a word [bad]) on hand motion by image processing technique. Finger Language communicates by means of state of the fingers and motion of the hand. Therefore, judgment rules are made clear from the state of fingers (bent, stretched, direction, angle of the interdigital web) for discriminating numerals. Each input hand image at 0.2(sec)is discriminated by using the judgment rules from the hand contour feature. Finger language can be recognized based on the continuous discrimination rule and above-mentioned judgment rules in real time.

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The behavior of elastohydrodynamic lubrication (EHL) films formed between a steel ball and a normally vibrating optical flat is examined by means of the duochromatic optical interferometry technique. The shape of the film entrapped between the ball and Hat plate forms an envelope at the end of the load applying process. The maximum height of the film, which depends on the non-Newtonian response of oils and the squeeze number, stays at a constant value during the cycle. Under conditions of short strokes and high frequency, air bubbles produced in the load removing process result in the collapse of the entrapped EHL film.

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The lubrication problems of wear, friction, oil consumption and scuffing in internal combustion engines are closely related with the oil-film thickness between piston rings and cylinder liners. The piston rings usually operate under the condition of starved lubrication for the pack slide. We analyze on the oil-film characteristics of a piston ring pack, taking account of the interaction between rings. The experiments to examine the oil-film behaviour of ring specimens sliding under oil starvation are conducted using reciprocating test equipment. The oil-film characteristics of starved lubrication are clarified from the results of calculations and experiments.

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It has become very important to improve hydraulic motor efficiency, especially in the low speed ranges, for finer operation. From this point of view, this report aims to provide technical data to help improve swashplate-type axial piston motor performance, particularly concerning the leakage and oil film thickness fluctuation between the valve plate and cylinder. The factors on their fluctuation were analytically examined. In the analysis, the friction loss between piston and cylinder, the accuracy of the motor shaft and rigidness of the motor shaft were regarded. The analytical results were in qualitative agreement with the experimental results.

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A method for exactly solving the condition of contact of the cam and roller follower and analyzing the output displacement of plate cam mechanisms is presented, which have a certain error of the cam profile or a devitation of any kinematic constant from the theoretical value. By using this method, the sensitivities of the output displacement, velocity and acceleration can be evaluated as the ratios of the differences between their actual and ideal values to the deviations of the kinematic constants. Moreover, the relationship between the input angle and the output displacement of the plate cam mechanism with the translating roller follower is precisely measured and the cause for the error of the output displacement is investigated by means of sensitivity curves.

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Using axially ground steel rollers with a hardness of about 320 Hv or 440 Hv, the authors examined the effect of roughness combination of two mating surfaces on the occurrence of pitting in the case of almost the same hardness combination. As a result, it was shown clearly that pitting is apt to occur on the smoother surface but is restrained on the rougher mating surface when two rollers with a large difference in roughness are combined under pure rolling conditions. Consequently, the pitting life is generally short when the faster roller is rough and the slower roller is smooth, while the life is extremely long when the roughness combination is reversed in rolling with sliding conditions. On the other hand, when two surfaces are equally rough, the roughness has a tendency to diminish on both sides and the pitting life is prolonged in pure rolling conditions. In rolling with sliding conditions, however, pitting occurrs at an earlier stage of operation corresponding to the severity of asperity interactions. This is in contrast with the case of cylindrically ground rollers.

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This paper reports on line contact skew gears, one of which is a spur gear, where the angle of axis of the gears is free. First, the subpitch line of the skew gears, which is newly defined, is investigated. From the results, the characteristics of the subpitch line are obtained. Secondly, the contact condition of the skew gears by the subpitch line is investigated. From the results, characteristics of the contact condition similar to those of spur gears are obtained. Thirdly, the zone of contact of the skew gears by the contact condition is investigated. From the results, a graphical solution and the characteristics of the zone of contact are obtained. Finally, the form of the skew gears is investigated in terms of the characteristics of the zone of contact. From the results, various forms of gears are obtained.

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Surface roughening of metals with plastic deformation is governed not only by the strain but also by the crystal grain size of the materials. Therefore surface roughening may be expected to decrease when a material with smaller crystal grains at the surface layer is produced. In the present investigation, a thin layer with small crystal grain size is coated on the surface of an aluminium alloy and the effects of the crystal grain size, as well as the thickness of the surface layer, on surface roughening are evaluated in an upsetting test. It is shown that surface roughening is dominated only by the crystal grain size on the surface layer and so surface roughening can be suppressed by coating the surface of the material with a thin layer of small crystal grains.

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The strength of BMC using bagasse filler was experimentally investigated in relation to three factors, i. e., the shape, fiber length and amount (weight content) of bagasse. BMC(bulk molding compound) is composed of glass fiber, unsaturated polyester and filler. In this study the tiller used is plant bagasse fiber. Bagasse is the refuse of sugar cane. Of significant interest is that the shape of bagasse fiber is needle like and it resembles glass fiber. This is an advantage to make bagasse tangle easily with glass fiber in kneading process, and is helpful for fixing the glass fiber to matrix during solidification. Therefore the bagasse fiber is effective in increasing the strength. Hence the mixture with bagasse and glass fiber is designed to tangle itself. As the content volume of bagasse fiber reaches 23% weight content, the tension strength shows the highest value. The magnitude of its strength depends essentially on the size of the bagasse fiber. Bagasse is found to be suitable as a filler for BMC.

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This paper deals with the theoretical investigation of the arrangement of slideways for five-axis machining centers. There is a considerable number of combinations with respect to the five-axis slideways. However, a critical assessment of the possible combinations of slideways has not been performed so far. In this paper, therefore, theoretical investigation of slideways arrangements which can accommodate the five-axis machining center is carried out using the coordinate transforation matrices. In addition to those functional analyses, the method to obtain the theoretical length of slideways, which is necessary for machining a particular workpiece size, is proposed by applying the form-shaping function.

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The purpose of this paper is to clarify the surface-flattening mechanism under contact states with a large relative slip. In this case, the outflow behavior of lubricant trapped in the pits is the most important point in the surface-flattening process. It was deduced from ironing experiments that oil flows out, due to the plastic deformation of the metal surface layer, along the direction of the frictional force acting on the oil-tool interface. Contact states were modeled and variations in frictional stress were estimated. Optimum conditions for surface flattening were proposed on the basis of the model. The metal surface should be best flattened under the condition where the minimum frictional stress appears.

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There have been recent reports made on a pattern recognition system using a neural network. However, difficult problems, such as how big a neural network should be adopted and which feature values for input of the neural network should be selected, have existed in the development of the recognition system. In this study, a new optimizing procedure for the neural network recognition system is proposed. Each output value for the nodes of the neural network after learning is used in the optimizing procedure. An optimum recognition system using a neural network for electrical discharge machining is developed as a good example of its application. The effectiveness of the optimum recognition system is proven to be practical in the electrical discharge machining process.

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The study deals with the generation of collision-free control data of a polishing robot with 6 degrees of freedom for workpieces with complicated curved surfaces. The collision between the polishing tool and workpiece is an important problem to be solved in terms of carrying out polishing work automatically. To obtain the collision-free polishing path, the collision is subjected to check, and the collision avoidance tool axis vector is determined on the basis of a solid model of the workpiece and the tool shape representative points. The generated collision-free polishing path is converted into the actual robot control data, taking account of the robot structure. The system is found to be effective from the polishing experiments of workpieces with overhung curved surfaces.

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This paper describes a strategy for foreign direct investment (FDI) of multinational enterprises when manufacturing costs change with time. This FDI planning problem is formulated in order to determine how many manufacturing facilities are needed in each country when they are needed, and how many products should be manufactured to meet the product demand in each country. It is assumed that both product demand and manufacturing costs in each country change with time. Finally, an algorithm for finding an optimal solution of the FDI planning problem is developed and an example is demonstrated.

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For the operation of automated guided vehicles (AGVs) in factories, a rescheduling of AGVs is necessary to recover the delay in arrival time or departure time. This study deals with such a rescheduling problem. First, the problem is formalized as a problem on a network with time constraints which are referred to as time windows. Secondly, a solution algorithm is proposed to obtain two kinds of scheduling information, the earliest arrival time on each node and the latest departure time from each node, to assure the earliest possible arrival of the AGV at a goal node. Lastly, the rescheduling procedure using the algorithm is constructed.

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In the design of mobile cranes, the dynamic load factor is of great importance. However, the dynamic load factor during propelling with a lifted load has never been described in "The Code of Structural Standards for Mobile Crane." In this research, the dynamic behavior of lifted load on a propelling crawler crane is studied. A suitable simulation model capable of accommodating the shape of the road has been proposed. The theoretical results of the tensile force in load-hoisting rope and jib-suspension rope are in good agreement with the results of experiments with an actual crawler crane. The effect of road surface on the dynamic behavior of a lifted load has been explicated.

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