We investigate the characteristics of a forced nonlinear oscillating system corresponding to the van der Pol and Duffing system with retardation. Making use of a numerical analytical scheme, the characteristics in the higher harmonic resonant region of the system have been considered in detail. The system has been found to possess very complex characteristics, e. g., many kinds of subharmonic vibrations, both symmetric and unsymmetric subharmonic solutions, bifurcations and aperiodic motions. Configurations of these subharmonics have been isolated as islandlike response curves. Among these subharmonics, there may exit islandlike response curves which show only imperfect period doubling bifurcation. However, aperiodic motions, i. e., chaotic behaviors, appear in various frequency regions, and a chaotic switching phenomenon has also been observed.

抄録全体を表示

For the free vibration problem of a symmetrically laminated FRP (fiber reinforced plastic)composite plate, the authors proposed a numerical approach using Green's function for a static bending problem. By this approach, one can accurately estimate the natural frequency and mode shape of plates with various shapes and boundary conditions. First, in the present study, this approach is modified for application to an unsymmetrically laminated FRP composite plate. Numerical calculations are carried out for a clamped antisymmetrically laminated rectangular plate which is a kind of unsymmetrically laminated plate. Convergence of natural frequencies of the plate are discussed. Next, by the vibration tests of clamped antisymmetrically laminated rectangular plates, natural frequencies and mode shapes are obtained. From the comparison between experimental and numerical results, it follows that one can accurately estimate the natural frequency and mode shape using the numerical approach proposed by the authors.

抄録全体を表示

The three-dimensional vibration behavior of a rotating crankshaft system under firing conditions can be analyzed either by using (1) a stationary coordinate system attached to the engine body, or (2) a rotating coordinate system attached to the crankshaft body. For the former, since a crankshaft body has anisotropic properties, e. g., each crank-throw has different bending stiffness in the two orthogonal planes, time-variable properties can be introduced in the equations of motion. Therefore, the solution can only be obtained by a numerical method in the time domain. However, for the latter, the equations of motion can be derived as a system of time-invariable properties, and the vibration behavior of the crankshaft system can be calculated directly in the frequacy domain. In this paper, for a rotating coordinate system, (1) we derived the time-invariable characteristic matrices of multidegrees of freedom for the crankshaft system, and (2) the forced vibration behavior of the crankshaft system under firing conditions was calculated in the frequency domain. The validity of the approach was confirmed from the calculated and experimental results.

抄録全体を表示

It is important to clarify characteristics of dynamic problems of structural systems loaded with liquid in the case where the systems are subjected to shock load or engine vibration. The purpose of this investigation is to develop the method by which to analyze the systems' coupled vibration and acoustic problems in order to reduce vibration and sound output of such systems. We developed the method by which to analyze dynamic problems of the coupled solid, liquid and air systems using the finite element method (FEM). The proposed analysis method was applied to vibration and acoustic problems of the twin cabin partially filled with water. We also carried out a series of experiments by using the twin cabin model. The validity of the proposed method and the applicability of the developed FEM programs were demonstrated by comparison with experimental results.

抄録全体を表示

Nonlinear sloshing motion of the liquid in a partially filled circular cylindrical tank is investigated. The tank is subjected to horizontal, vertical and pitching excitations. The nonlinear ordinary differential equations governing the liquid surface oscillation are derived by applying Galerkin's method to the basic equations. The higher order radial modes are considered in the admissible functions which are assumed to be represented by combining the modal functions obtained by the linearization analysis. The effects of these higher order modes on liquid surface oscillation are discussed. The time histories of the liquid surface displacement to the harmonic pitching excitations are calculated. An experiment is carried out using a model tank. The usefulness of the present nonlinear analysis was demonstrated by comparing the theoretical results with the experimental ones. It is shown that the higher order radial modes play an important role in estimating the liquid surface displacement.

抄録全体を表示

The relationship between kinematic energy flow and the effect of the dynamic absorber on suppression of vibration is studied. Energy flow is shown as vibration intensity. It is clarified by simulation that the effect varies according to where the absorber is attached, even if all positions have the same maximum amplitude of vibration.

抄録全体を表示

Energy flows are analyzed in some typical structures undergoing the forced vibration. Energy flows are shown as the vibration intensity vectors. The followings become evident : three types of energy flows exist in the forced vibration of a rectangular plate ; energy flow patterns of multiple resonance peaks of which the resonance frequencies are near each other are apt to be the same because of mutual interference ; an energy vortex appears in the case of two-point excitation ; and energy flows on the box Can be analyzed with the plate theory.

抄録全体を表示

Actively controlled suspensions with pneumatic actuators have been studied to improve the ride quality of railway vehicles. This paper deals with the applicability of oil-hydraulic actuators that may have more effect on the control of vehicle vibrations. A numerical analysis and its fundamental experiments on a test stand with a life-size model were carried out to investigate active vibration control. In the experiment, the employed control law based on LQR can use measured accelerations directly as feedback variables, so that the time derivative of the actuator force acts as the control input. As a result, the vibrations in a lower frequency range under 4 Hz were controlled well by the simple control law. This range includes natural frequencies of the vehicle model. However, it requires some countermeasure for vibrations in a higher frequency range from 5 to 10 Hz.

抄録全体を表示

Active suspensions have been studied to improve the ride quality of railway vehicles. In many cases, pneumatic actuators were employed in those studies. This paper deals with the applicability of oil-hydraulic actuators that are expected to have more control on the running vibration for active suspension. This was examined experimentally with the optimal control theory using a 3 d. o. f. half-car scale model. The results show that the controllable frequency range extends with adequate control. Especially, in a case where the actuator properties were considered in the feedback gains, superior property of the vibration isolation was obtained in the middle frequency range of 3 Hz to 13Hz. Here, the selection of valve equivalent resistance is significant in feedback gains, because the actual valve resistance changes with oil flow passing through the servo valve. Some cases based on output feedback show more effctive results than the full-state feedback in the lower frequency range.

抄録全体を表示

Vibration reduction of a multiple degrees-of-freedom system by controlling one of the spring stiffnesses is developed in this paper. Control is achieved by using the displacement and velocity feedback, and the procedure uses independent modal space control (IMSC) to deduce the spring stiffness according to the feedback of each mode. The stiffness-controllable spring is fabricated from a beam of rectangular cross section, whose setting angle is controlled by the DC servomotor. Impulse response is investigated by numerical simulation and experiment to demonstrate the effectiveness of the control.

抄録全体を表示

As a basis for developing experimental identification techniques for rotating machines, a new one for identifying a rotating shaft system constructed of an elastic shaft with a disk is proposed. The technique is based on the principle of harmonic balance, and enables us to determine the equations of motion of the system. The technique uses data of vibrations caused by unbalances of the system, and hence does not require application of excitation. Two varied forms of the technique are developed. In one form, some parameters which can easily be calculated from the geometry of the system are assumed to be known beforehand. In the other form, data of vibrations produced by known additional unbalances attached to the system are used. Numerical simulation is conducted, and it is shown that the technique in both forms is applicable.

抄録全体を表示

Recent research related to probability-based structural design has become more active, especially in the field of the load and resistance factor design (LRFD) technique. This paper also describes some contributions to the improvement of the LRFD method. In this paper, a rational and analytical method to determine the required code format and load factors, which were determined experimentally in many former LRFD studies, considering the dynamic characteristics of a structure is newly proposed on the basis of the dynamic reliability technique with the load combination theory. The usefulness of this proposed method is described in an application to the selection problem of the required code format and load factors against a typical structure that is flexible and excited due to multiple random loads.

抄録全体を表示

In this paper, a peripheral restraining-type rubber bearing is proposed which has adjustable damping ability. An equation to calculate the damping ratio in a rubber bearing is derived, and the equation is confirmed through the vibration tests. The rubber bearing is composed of a core block made of superhigh damping synthetic rubber and a restraining ring made of high damping rubber surrounding the core block. Thus it is possible to vary the damping ratio of the rubber bearing by adjusting the outside diameter of the core block and the inside diameter of the restraining ring. The rubber bearings used for the tests are 0.3 scale models of actual bearings. The test has been performed, giving horizontal forced displacement to the rubber bearings, under the condition of a given vertical load. The experimental results show that the present equation is feasible for calculating the damping ratio of peripheral restraining-type rubber bearings.

抄録全体を表示

In order to achieve compact size, light weight and cost reduction of machines, critical design considering the well-known load acting on the parts is very important. The simulation of cylinder pressure and crankshaft kinematics of a refrigerating scroll compressor is usually performed, but the accuracy of kinematic analysis of refrigerating compressors is not verified because the compressor is small and the parts are under refrigerant pressure. We have analyticaly and experimentaly studied the bearing load behavior of a scroll compressor for an automotive air conditioner. This paper presents the following results. (1) The statically indeterminate kinematics model of the crankshaft system has been developed to improve the simulation accuracy. (2) Each load acting on ball bearings under compressor operating has been measured. (3) The simulated and measured values of bearing loads agree, and bearing load behavior of the scroll compressor is clarified.

抄録全体を表示

Rolling motion is one cause of sound produced mechanically. Rolling sound may cause serious problems when it exceeds a certain level in machines and structures. A series of studies was carried out in order to obtain basic information for the reduction of the rolling sound. This first report concerns the fundamental characteristics of the rolling sound at one point of the underside of a horizontal square steel plate simply supported at four points when a ball rolls on the plate. Nylon and steel balls with different diameters were rolled at various rolling velocities on the plate, and the rolling sound and the vibration of the plate were simultaneously measured. These signals were analyzed by a FFT analyzer. As a result, the fundamental characteristics of the rolling sound were clarified.

抄録全体を表示

Rolling motion is one cause of mechanical sound. Rolling sound may cause serious problems when it is excessive in machines, structures, and the like. A series of studies have been carried out in order to obtain basic information for the reduction of rolling sound. This second report concerns the effect of the distance of the measuring microphone on the sound and the sound radiation characteristics. A horizontal square steel plate was simply supported at four points. Nylon and steel balls with different diameters were rolled at various rolling velocities on the plate, and the sound and the vibration of the plate were simultaneously measured using a condenser microphone and an accelerometer, respectively. The signals obtained in the measurements were analyzed with a FFT analyzer. From the experiments, analysis and considerations, the effects of the distance of the measuring microphone on the sound and the sound radiation characteristics were clarified.

抄録全体を表示

This paper presents an approach to the integrated structural and control design of the tendon control system for flexible structures. The tendon control system is an active vibration control system using tensile cables and electrodynamic actuators. The proposed method designs the stiffness parameters of the flexible cables so that the dynamics of the tendon system may function as a dynamic compensator for frequency-shaping the feedback control force. Thereby it provides the closed-loop system with improved stability robustness with respect to the mode truncation errors outside the passband. This approach allows the designer to obtain an efficient and stable reduced-order controller for the tendon control of highly flexible structures. The results of the numerical simulations and hardware experiment show the usefulness of the proposed design approach.

抄録全体を表示

This paper describes a variable torque transmission control using a magnetic fluid which is influenced by a magnetic field. A nonmagnetic disk rotates inside a case made of iron and the magnetic field is induced by a magnetic coil. When an electric current is applied to the coil, the magnetic fluid is shifted to the outer area of the rotating disk, and a torque is transmitted via the viscous friction of the magnetic fluid between the disk and the case. The basic characteristics of this magnetic fluid coupling were examined experimentally. It is confirmed that the output torque can be controlled by electric signals. The values of output torque depend on the amount of magnetic fluid when the input signal is turned on or off.

抄録全体を表示

This paper presents a highly accurate trajectory control method and auto-tuning for its mechanical systems based on two-degree-of-freedom control theory. This control method is useful because its controller consists of a conventional PID feedback compensator and a simple feedforward compensator. The proposed auto-tuning method does not require a fixed reference for tuning and determines control parameters in the feedforward and feedback compensators using the identified parameters such as load inertia, a damping coefficient and Coulomb friction. Furthermore, this paper proposes a new algorithm for automatically determining an allowable maximum velocity with which the mechanical system is able to be driven with accuracy. The experimental results of circular motion with a XY table system show that the proposed method is effective in practical use.

抄録全体を表示

Antirepeat is one of basic concepts for safe operation of industrial machines. It is regarded as safety control concerned with start of operating. In this paper, logic of antirepeat control is discussed and the concept of antirepeat is evaluated by using multiple-valued logic based on the degree of safety. It is shown that two different strategies exist for achievement of the antirepeat control and basic construction methods based on fail-safe signal processing are presented. An example of automated restarting confirmation based on antirepeat control, which is superior to manual restarting in safety assurance of multiple workers, is proposed in this paper.

抄録全体を表示

This paper is concerned with the design of a slide mode control system from the view point of practical application. The problem is treated using the asymptotic reaching law method for assuring global stabilization, and the chattering phenomenon is alleviated by the saturated function of the boundary layer The design algorithm is simple and applicable to a nonlinear system including disturbances and uncertainties with high robustness. Its effectiveness is proven by simulation as well as a bench experiment of a brushless motor vehicle.

抄録全体を表示

In teleoperation, bilateral master-slave arms are essential to handle objects effectively, when computer systems support the operators to coordinate both manual and automatic modes. Our previous study has shown that the operator can easily adjust the variable gain by the sensed force of gripping at the handlebar of master arm ; that changes the gain of connection between the manual and automatic modes. In this paper, the method for bilateral control of master-slave teleoperation is studied to realize robustness and smoothness in controlling the slave-arms with the computer supporting systems. The sliding mode control, better for robotics, is applied to the control system with variable gains by force-sensed grips. The parameters of the proposed method are examined through some simulations and some actual trials by using a master arm developed for this purpose. The method, proven by some examples of the master-slave movements in the one-degree freedom arm, realizes efficiencies in master-slave arm control with simplicities of commands and flexibility of skilled human operators.

抄録全体を表示

A traveling wave-type ultrasonic motor is one of the promising actuators for robot manipulators, since it has a simple structure, a high response, and large torque at low speed. The rotational direction of the rotor can be changed easily by reversing the direction of the traveling wave. We propose position control using a fuzzy controller and a rotational speed control method, such as pulse width modulation (PWM), by changing the duty ratio of the reverse-direction duration, which we proposed in a previous paper. The basic characteristics of the ultrasonic motor using this position control are examined experimentally. It is confirmed that exact position control of the manipulator can be achieved through an adjusting motion, such as with a pulse motor, in addition to position control using a fuzzy controller.

抄録全体を表示

Stress is applied to an underwater manipulator driven by a DC motor by fluid forces due to the added mass and the drag. Especially, the stress at the clamped end of manipulator with the motor shaft is very large. To suppress the stress, this study proposes the manipulation of the arm driven by a thruster installed at the tip of the arm, and develops a position control system of the underwater flexible rotating arm with a thruster using the optimal control theory. A model of an underwater flexible rotating arm driven by a thruster is made and control experiments are carried out. Using this model, the performance of the developed control system is evaluated. Using experiments and computer simulations, it is clarified that the maximum stress of the arm driven by a thruster is under 20% compared to that by a DC motor.

抄録全体を表示

This paper describes an optimum motion control method for robot serial manipulators with multiple redundant degrees-of-freedom. The manipulability measure, which is given using the Jacobian matrix for both the position and posture of the endeffector of a serial manipulator, is proposed as the index for evaluating dexterity, and the manipulator is defined most dexterous when the manipulability measure has a maximum value. To drive serial manipulators most dexterously, two new methods, namely the optimum CP control methods with and without consideration of the posture angle of the endeffector, were proposed and experimentally studied for redundant planar 3R, 4 R and 5 R manipulators. Consequently, the optimum CP control method with consideration of the posture angle of the endeffector gave a better result : the manipulators were driven most dexterously over almost the entire driving range and high response was obtained.

抄録全体を表示

We propose a design scheme for robust control which achieves precise trajectory tracking for robot manipulators. In the scheme, the nonlinearity of the manipulator is divided into two types : one is nonlinearity that can be formulated, such as centrifugal force and Coriolis force, and the other is nonlinearity that can't be formulated, such as fluid drag by the surrounding air and magnetic force of the surrounding servomotor. The influence of the unformulated nonlinearity for control precision is considered through the simulation of a 2-link manipulator and from the experimental results of tracking control for a desired trajectory.

抄録全体を表示

Finite-element analysis is now a very important tool for biomechanical studies of bones to estimate the stresses produced by load application. Stress analysis requires an exact mechanical model if we desire valid results. This paper describes a method generating a three-dimensional finite-element model from X-ray CT data. We focused on a human mandible and proposed the modelling method. The method mainly consists of four parts. First, contour images of the shape of the mandible are extracted from the X-ray CT. Second, a surface model covered with polygons was made from the contour images. Third, an approximate model modified from a standard model was provided. Finally, we obtained an individual finite-element model by transforming the modified model so that it fits the shape of the surface model.

抄録全体を表示

Particle image velocimetry (PIV) is a useful tool in the study of transient fluid flow phenomena, The light of a laser sheet scattered by seeding particles generates a moving particle-image pattern. This pattern is recorded using a multiple-exposure photographic technique, where the distance between corresponding particle images in the interrogation region is proportional to the local displacement. To determine the direction of the velocity vector from the multiple-exposure photograph, a velocity bias technique is used. The processing techniques for PIV data have traditionally been tedious and time-consuming. In this paper, a new approach to PIV data processing is presented. The 2-D intensity distribution array in the interrogation region is replaced by two orthogonal 1-D distribution arrays using integration. Each velocity component is extracted by autocorrelation of the 1-D array. This system has been applied to a quantitative measurement of the vortical structure behind a circular cylinder.

抄録全体を表示

Trial manufacture of a tip clearance measurement system with spark discharge has been conducted, through which the structure of this apparatus was clarified. The characteristics of spark gap between the probe and the blade that determines the measurement accuracy of this apparatus and the effect of UV irradiation were investigated. As a result, the measurement value was affected significantly by voltage which is one of the factors of the spark discharge law (Paschen's law) . When supply voltage is more than 900 V, the scatter of measurement value increases. However, this scatter, obtained when ultraviolet irradiation was used, was found to remain in the initial range of the minimum spark discharge voltage, and the spark gap corresponding to supply voltage was also observed to approximate the Paschen curve. The measurement value was affected by the shape of the blade, but the spark gap was observed to approximate the Paschen curve when ultraviolet irradiation was used. The peripheral velocity of the rotor within 140 m/sec did not affect the measurement value.

抄録全体を表示

In order to investigate the behavior of adhesion force from a microslip region to a gross sliding one, we carried out experimental studies mainly under water lubrication with static and dynamic contact loads. Every repeated experiment up to gross sliding showed a decrease in the adhesion coefficient under water lubrication and the traction force in the gross sliding region showed unstable behavior. Furthermore, it was recognized that the measured adhesion force during gross sliding agreed well with the values calculated with sliding acceleration and moment of inertia of rollers. The adhesion force under dynamic load was less than that under static load.

抄録全体を表示

To clarify the frictional characteristics and the seizure resistance of austenitic stainless steel SUS 304 rollers and martensitic stainless steel SUS 440C rollers, of which the surface layer was thermally diffused at a temperature of about 400°C after being Sn-plated, a two-roller test was carried out under forced lubrication and dry friction using an Amusler machine. From the test, the following results were obtained. Under forced lubrication, the seizure resistance of the rollers with the diffused layer was at least six times as large as that without the diffused layer, and the seizure resistance of SUS 440 C rollers was considerably larger than that of SUS 304 rollers. The coefficient of friction of SUS 440 C rollers with the diffused layer was in the range of 0.05 to 0.06 at a normal load of more than 5 kN. The seizure resistance of the rollers under dry friction was less than a third of that under forced lubrication.

抄録全体を表示

This paper describes the float characteristics of a new type of squeeze-film gas bearing which can realize noncontact linear-motion guide systems without externally pressurized air. This bearing uses piezoelectric actuators and elastic hinges in order to vibrate a bearing and generate squeeze-film pressures under the bearing. In the theoretical analysis, a simple dynamic model of the proposed bearing structure is presented. The influences of displacement and vibrational frequency of piezoelectric actuators on the float characteristics are investigated theoretically and experimentally. Furthermore, load capacity at vibrational frequency of 2400 Hz and the float characteristics at resonance frequency of a bearing structure are measured. It was consequently found that the proposed bearing can realize a non-contact linear motion guide and the dynamic model presented in this paper can predict well the float characteristics of the proposed bearing.

抄録全体を表示

This paper describes the development of a finite element analysis program for the nonlinear and time-dependent Reynolds equation based on an incremental formulation. This program can be utilized to predict the dynamic behavior of gas-lubricated grooved journal bearings. The accuracy of the program is clearly demonstrated through some analyses of both non-grooved and grooved journal bearings.

抄録全体を表示

This paper treats the pumping characteristics of a herringbone grooved gas journal bearing when this bearing is used as a viscous vacuum pump in order to reduce the windage power loss of a laser scanner mirror. Furthermore, many parameters affect the pumping characteristics of the proposed viscous vacuum pump but in the experiment, the effects of rotational speed of a rotor and inner volume of a housing are investigated. It is consequently found that the proposed viscous pump is very useful for reducing the windage power loss of laser scanner mirrors.

抄録全体を表示

Tool wear on land edge of shaving cutter has a large effect on shaved tooth form, tool life of cutter, and the optimum modification of cutter tooth form. However, it is very hard to observe the land edge even by an electron microscope or a profilometer, because these apparatuses can be applied only to very small specimens. Hence, one tooth must be removed from the cutter for observation. For this purpose, shaving cutter with a removable tooth has been developed. The removable tooth can be attached and detached repeatedly, easily, and accurately, so that it enables the observation of tool wear on land edge of shaving cutter which increases with an increase in the amount of gears shaved. Such an observation will provide fundamental information for the design of shaving cutter taking into consideration tool life.

抄録全体を表示

In the previous paper, a simultaneous rolling experiment of both the tooth and fillet surfaces of spur gears was performed using several kinds of screw-shaped tools. In this paper, a simulation model which utilizes 3-D elastic-plastic finite-element method is proposed to investigate the deformation of work during rolling and to obtain some information on the optimum design of the tool. The influence coefficient method is employed to evaluate the elastic deformation of the tool during rolling. The analytical results agree well with the experimental ones. The elastic deformation of the tool can never be ignored when evaluating the amount of deformation of the work precisely. The amounts of stock rolled along the tooth surface are nearly constant. On the other hand, the amounts of stock rolled along the fillet are much larger than those of the tooth surface, since the tip corner radius of the tool is very small.

抄録全体を表示

The CBN grinding wheel is now recognized as the preferred choice over Al₂O₃ or SiC grinding wheels for processing difficult-to-grind materials such as hardened steels and alloys. An important and difficult problem in the practical use of the CBN wheel is truing/dressing. In this paper we discuss the characteristics of the cutting edge formed on vitrified CBN wheels as compared the GC Cup Truer with an impregnated diamond dresser. Depending on interference mechanism between the CBN grain and the truing tool, the cutting edge after truing falls into three categories : The diamond tool produced a large wear flat on the particle tip, while the Cup Truer with a coarser GC wheel formed the CBN grain micro fractures, and with comparatively fine grit GC wheel, the CBN grains remained undamaged. The grinding performance of each type was investigated individually to reveal the influence of the truing/dressing operation.

抄録全体を表示

The purpose of the present research is to establish a simple method of forming holes in brittle sheet materials by a conventional punching technique. By utilizing a specially designed round-top punch, a small hole is formed at the center of the sheet specimen at its first stage, and subsequently the hole is enlarged by a continuous punching operation. The present improved technique realizes a very low load for punching operation as well as a considerably low precompression stress for preventing serious radial cracks around the hole. The technique is also successful in forming many holes by a single operation.

抄録全体を表示

It is well known that the vibration cutting process utilizing a pulsating cutting force is suitable for precision machining. Dynamic motion of the work is theoretically analyzed on a linear tool-work forced vibration system. The purpose of this study is to analyze the nonlinear vibration phenomena on vibration cutting. In this report, experiments are carried out using the 2-dimensional vibration cutting device to confirm the nonlinearity of the dynamic motion of work, and the profile of a machined surface in such a case. The trajectory in a 3-dimensional phase space of work displacement, velocity and time, is mapped on the Poincare section of displacement and velocity. On the mapped points, such nonlinear vibration phenomena as subharmonic vibration, quasi-periodic vibration and bifurcation, are shown. And It is suggested that the profile of a machined surface can be analyzed by using the Poincare map.

抄録全体を表示

In the first report, when the mirror superfinishing was performed with water, occurrence of phenomena such as loading or glazing or grain fracture on the surface of abrasive stick, was found to result in suppression of sufficient superfinishing on the surface of abrasive stick and the superfinished work surface. However, it was investigated whether formation of the mirror superfinished work surface with decreased roughness is attainable or not by supplying, at the point of contact between the abrasive stick and the work material at the time of superfinish processing, fluid having better performance characteristics of cooling, penetrating, cleaning and oilness in contrast with water. In this report will deals with the effects of performance characteristics of the fluid that was supplied on the roughness of the superfinished work surface.

抄録全体を表示

In an effort to develop a scanning acoustic microscope (SAM) providing high resolution at room temperature, an acoustic lens with 55 μm radius for use in the 1 GHz frequency range was fabricated by micromachining. Single-crystal silicon was used as the material for the acoustic lens. Suitable etching conditions for obtaining excellent sphericity and the required radius were investigated. When the mask hole diameter is less than 80 μm, there are optimum etching times for obtaining good sphericity. The concave etched profile for a 1 GHz range lens showed a maximum deviation of less than 0.2 μm from a perfect sphere. A silicon acoustic lens designed for use in the 1 GHz frequency range has been achieved with a resolution of 1.1 μm expected at the given wave-length.

抄録全体を表示

A cylindrical lens for quantitative measurement of acoustic properties including anisotropy on various solid surfaces, has been fabricated by micromachining. A silicon single crystal was used as the material for the acoustic lens. The etching conditions suitable for obtaining excellent circularity, less than 0.5 μm, demanded for use in the 400 MHz range, have been investigated. When the ratio of length along the longitudinal axis to length along the transverse axis is more than 10, circularity of the etched cylindrical lens showed a maximum deviation of 0.3 μm from a perfect circle. A silicon line-focus beam lens designed for use in the 400 MHz range has been successfully achieved using the V(z) curve measured for fused quartz.

抄録全体を表示

In order to develop a robust control system to detect a weld line and to track the weld line automatically by means of a welding robot with a visual sensor, a new control system applying the artificial neural network was constructed. Before the image taken was input to the neural network, the LOG filter was applied to the original image to enhance the weld line image, and then a binary image was generated. The binary image was input to the artificial neural network, and the weld line direction was detected. Then seam tracking was performed using the weld line direction. Because the neural network was used for detecting the weld line, a more robust control system was obtained. Moreover, as the result of seam tracking simulation, the applicability of the system to automatic welding was confirmed.

抄録全体を表示

Design is the process of translating an idea or a market need into detailed information from which a product can be made. Each of its stages requires decisions about the materials of which the product is to be made. The number of materials available to a designer is vast under these circumstances, and he must select from this vast menu the material best suited to his task. Thus it requires considerable intellectual effort to choose the material suitable for a certain purpose. In recent years greater cooperation with the designer has been proposed. For example, production systems such as CAD have exceptional information on design. Our aim is to develop a methodology for materials selection in the design process. The present study is an attempt to build a consultation system for the selection of suitable materials. The system consists of a neural network which has learned the pattern sets dealing with the interaction between the function of products and materials. Knowledge from literature and the skilled machinists' knowledge on materials selection are incorporated into the pattern information. The output from the system was examined by comparing it with the technical knowledge from literature and designer, and the validity of the system was confirmed.

抄録全体を表示

The final aim of this study is to realize a human-oriented manufacturing system (HOMS). To provide the design basis for one of the three functional requirements of HOMS, that is, a system with which a person feels pride in his work and pleasure, a survey of the satisfaction of workers in a foundry has been conducted. Results show that there are three motives for work. They are the pleasure of the creating (manufacturing), good human relations and positive attitude toward work. Among them, the first one is the most important. Moreover, it is found that there are seven satisfaction factors for the pleasure of creating : diversity, creativity, subjectivity, feedback effect technical skill, interest and social contribution.

抄録全体を表示

This paper deals with the fundamental research for the development of human-oriented NC machine tools with which workers can feel pride and pleasure making full use of their ability in manufacturing. As a first step toward human-oriented NC machine tools, Machining Phenomenon Visualizing System (MPVS) which allows workers to see and check actual machining process as stationary state has been developed and installed on a NC lathe. Through many practices, it has been proved that the vision by MPVS provides much usefull information on machining for workers. Meanwhile, the study in the first report has proved that the factors contributing to worker's satisfaction in manufacuring originate from the following seven satisfaction factors-technical skill, interest, social contribution, creativity, subjectivity, feedback effect and diversity. In this paper, according to these seven satisfaction factors, MPVS has been evaluated by inexperienced workers, lathe skilled workers and NC lathe skilled workers using Information Integration Method. The results show that MPVS greatly improves worker's satisfaction and has immediate strong effect on feedback effect and creativity for all types of workers.

抄録全体を表示