Thus far, the pattern-matching method has mainly been adopted for visual recognition, applicable only to objects which can be put into patterns. Objects which have individually variable sizes are difticult to process with satisfactory results. For example, superconductive products are difficult to put into patterns because of their expansion, shrinking and cracking in the baking process. This is one of the reasons why the development of these kinds of objects still cannot be automated. To solve this problem, especially for automatic manipulation of these kinds of products, this paper proposes an image processing system including the six-surface-image integrating-method. Avoiding individual differences, the system can perform the reasoning and recognition of bending, twisting and cracks of a brick-shaped object through integrating the image information of its six surfaces. The effectiveness of the system proposed in this paper was confirmed by the results of experiments.

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The present paper deals with precision insertion for chamferless parts with uncertain positional information by heuristic search. The heuristic search is constructed of fuzzy pattern matching between fuzzy sets of search areas and one of the hole center positions. Fuzzy pattern matching evaluates the value of the heuristic function. The search of the hole is started in the search area having the highest value of the heuristic function. RCC (remote center compliance) and a force sensor are used in the search. RCC finely modifies the position of the peg and the force sensor detects whether the insertion has succeeded. The usefulness of this method is shown by experimental results.

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This paper describes a concept of a central modeling system for time information and a methodology to realize it. First, the importance of developing temporal modeling systems which are commonly used by application programs is discussed from the viewpoint of computer-integrated manufacturing. After analyzing the diversity of temporal information to be considered, a unified representation method of various temporal information is proposed and its mathematical formalization is explained. According to the proposed approach, an experimental system, time information manager, is implemented. The system adopts J.F. Allen's method as a consistency management algorithm. The system is also extended so as to deal with cyclic time intervals, the multiple time axes, and qualitative information. It is applied to some present methodologies concerned with time information to evaluate the effectiveness of the proposed methodology.

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The safety control system, which is defined as machine operation controlled according to safety confirmation information, is explained as an interlocking model that functions so that energy output from the machine is permitted only while the information (safety information) reports safety. The information transmission properties presented in this model are applied to all devices in this interlocking system, including the sensors for producing safety information and the devices for transmitting/outputting energy. A small energy-level signal signifying safety is normally produced in a pickup element in the sensor. Enormous power generated by amplifying the energy of the safety signal is supplied to the machine for use in its powerful operation. This paper discusses the condition of the energy transmission process in which energy is produced in a safety sensor as a signal indicating safety and is amplified in the interlocking system up to the sufficient level for performance of machine duties. Firstly, in this paper, the characteristics of information to be provided with the means of information processing in the interlocking system are clarified. Secondly, a logical fail-safe model is proposed for clarifying the production condition of the safety information. Lastly, this fail-safe energy-transmitting system with the safety information can be applied to not only electrically but mechanically processed safety information.

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A system to attenuate the sound or pulsating pressure in a duct which has a noise source with a variable exciting frequency, such as a compressor or a fan, is investigated. This system consists of a Helmholtz resonator whose cavity volume is automatically controlled by a personal computer such that the system retains the antiresonance. The steady-state and transient responses are investigated theoretically. The experiments are also carried out by making use of the harmonic sound radiated from a speaker and a pulsating flow caused by a centrifugal fan. In this autoadjusting system, the volume of the resonator cavity is controlled by making use of the fact that the phase difference between the pressure in the duct and that in the cavity changes 180degrees at the antiresonance. The sound can be reduced significantly, especially in the vicinity of the resonance frequency. When the tracking for the change of exciting frequency has a delay, the system may pass through the resonance point.

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Sensitivity analysis methods applicable to the eigenmodes and frequency responses of coupled acoustic-structural systems are proposed for the purpose of reducing vehicle interior noise. The concept of the left and right eigenvectors is introduced for treating coupled acoustic-structural problems, and four propositions concerning this concept are presented and proven. Based on these propositions, formulations are derived for conducting modal sensitivity and modal frequency response sensitivity analyses. The theoretical results and computation equations are verified through the application of the methods to a coupled acoustic-box structure and a practical vehicle interior noise problem.

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This paper deals with the active wave control of a flexible beam. It is the purpose of this paper to realize experimentally the active sink proposed in the previous paper, and to discuss the fundamental characteristics of the active-sink system. First, for the purpose of observing wave flow traveling along the beam, a visualization system is developed. Next, on the basis of the visualization system, an experiment is carried out to verify the existence of the active sink. Then, from an analytical point of view, this paper further investigates the characteristics of the active-sink system, showing that an active source also exists in addition to the active sink. It is also found that there are two suppression patterns in active wave control; that is, the progressive-wave type and the standing-wave type. Finally, by introducing both phase distribution and gain of the complex reflection coefficient over a flexible beam, the generation mechanism of these patterns is clarified.

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This paper is concerned with the study of the stable holding and movement of an object by the grasping action of a robot hand. A control algorithm is proposed for manipulating the jointed-finger hand while grasping an object and is applied to a hand with two fingers and four degrees of freedom developed especially for the study. In the experiment, an object on a plane is initially grasped by the hand and then moved along the restraining plane maintaining appropriate force. As a result, using the elastic-finger unit with contact sensors, the present hand successfully moved the object while absorbing the outside force from the restraining plane.

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In this paper, position and force control of constrained motion of robotic manipulators is discussed. First, issues related to decoupling position and force-controlled directions are discussed. The fundamentals of estimation of contact forces without using force or torque sensors are then presented, and a control scheme for position and force control of robotic manipulators without force sensing is proposed. The extension of this scheme to redundant manipulators is also discussed. Finally, the proposed control scheme is implemented on a 3-DOF planar redundant manipulator, and some experimental results are presented to illustrate the validity of the control scheme.

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This paper investigates the behaviour of a nonlinear vibrating system, i. e., van der Pol and Duffing's system, with a retarded argument under a harmonic stimulating force. An approximate analytical method, i.e., the averaging scheme, is used to analyse subharmonic oscillations of the order 1/2. The algorithm used to study periodic solutions and their stabilities with higher-order approximations, is presented. A computer simulation is used to obtain Poincare mapping and invariant manifolds. Through the application of the approximate analytical procedure presented here and numerical simulation, both symmetrical and unsymmetrical subharmonic solutions are observed in addition to period-doubling bifurcations and chaotic behaviour. In addition, one of the Lyapunov exponents, which is positive, has verified that the vibrating system possesses chaotic phenomena.

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Vibration spectra of the experimental 15m wind turbine of the Mechanical Engineering Laboratory were obtained in field operation to clarify the vibration characteristics of general teetered-rotor wind turbines. To investigate the causes of steady vibration, step response tests were also conducted, where excitations were made with the disk brake located at the high-speed shaft. As a result, a Campbell diagram for the system has been established. The tower-bending resonance with one-per-rev and two-per-rev excitations of the rotor, as well as the transmission-torsion resonance with two-per-rev excitation, has been observed. It has also been found that the one-per-rev gravitational force is predominant for the blade chordwise bending and that various n-per-rev components due to wind speed variation can be seen on the blade flapwise bending.

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This work considers the dynamic response of an elastic circular plate on a half-space viscoelastic Winkler foundation impacted by a moving rigid body at a lower initial velocity. A nonlinear Volterra integral equation on impact load F(t) is deduced, and a numerical method is used to solve the equation and calculate the deflection of the plate. As an analyzed example, the dynamic response of a solid circular plate with clamped edge on the Winkler foundation impacted centrally by a rigid sphere ls computed numerically.

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A mode shape identification procedure which yields mass-weighted orthogonal modes is proposed for application to a vibration test. The orthogonalization is accomplished by eliminating errors existing in the combination of measured forced response equations and an assumed mass matrix. A matrix decomposition technique is utilized for extracting the error coefficients, by which the modification of measured data is performed subject to the theoretical constraints of the forced response equation. The procedure presented herein is formulated for a base excitation test and demonstrated numerically in evaluating the mode participation factors of a component model using a simple plate model. The identified parameters are in good agreement with the exact values, and also, the identified mode shapes satisfy the orthogonality requirement. A comparison with Targoff's method and an evaluation using simulated measurement data with random errors are also presented.

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Recent progress in manufacturing techniques makes it possible to produce gears with mirrorlike tooth surfaces. This investigation is conducted to reexamine the changes in the contact surfaces and the surface durability of rollers which simulate the tooth surface of gears because the rollers used in earlier experiments are not ideally finished. A new bufting machine is designed and made by the authors and a method for producing precision mirrorlike-finish rollers with a roughness of about 0.02 μm R_max is presented. Using these rollers, endurance tests under heavy loads are conducted with five kinds of lubricating oils including traction oils. Almost full EHL oi1 film is formed between the mirrorlike-finish rollers soon after start of running. An interesting change in the contact surfaces is found when an oil with a high traction coefficient is used. It is estimated that the change is the result of irregular plastic deformation which is caused by irregular soldification of the oil film between the contacting rollers.

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Although optical methods have been proposed for the profile measurement of aspherical lens, further research is needed to improve the accuracy of the machining. A method for the measurement of small diameter lenses was developed using a scanning electron microscope. Photo semiconductors were used to detect backscattered electrons which were reflected on the surface of the lens. A new simple algorithm which makes it possible to derive direction angle and slant angle of the normal at the respective observed points was proposed. The slope of a plastic aspherical lens was measured in terms of the normal of the profile. The results were illustrated as contour circles of equi slope. The difference between the neighboring radii of the circles for the slope varied at constant intervals and was not made equal due to the asphericity. A profile of the asphericity along the radial direction was obtained by integrating the slope.

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Ground surface imperfections are often attributed to periodical marks caused by vibration in grinding. According to the mechanism by which the marks were formed, there are various characteristics which can be important clues to diagnosing the type of grinding vibration and making appropriate counterplans. By classifying the marks due to each type of grinding vibration experimentally as well as theoretically, they can be divided into two categories depending on whether the marks were formed chiefly by a shape error or by a roughness variation. In addition, the relationship between the presence of the marks and the speed ratio, and the marks'inclination to the wheel axis are generalized to correspond with the different grinding processes and types of grinding vibration. The generalized relationships make it possible to narrow down the possible causes to a few types of vibration. Also, an optical method which is necessary for the diagnosis is proposed for measuring the characteristics of the marks. Together with the principal counterplans for each type of grinding vibration, a system of knowledge for vibration diagnosis has been obtained.

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The successful implementation of fully automated and unmanned flexible machining systems requires in-process monitoring of the machining environment. The monitoring sensors should be capable of extracting multi-faceted information enabling a total grasp of the environment. However, most of the current systems are based on single-phenomenon monitoring, so their effectiveness is quite limited. A multi-func-tional, compact in-process monitoring system for machining environment has been proposed in this study. This system, based on heat flux sensing, can monitor multi-dimensional responsts of a machining environment. Mordover, heat flux being the time derivative of temperature is more sensitive than temperature itself. Thus, the proposed system is quite suitable for monitoring machining environment. Varied information concerning the machining environment extracted through this sensor strongly supports its suitability as an in-pfocess monitoring device. A comparative performance evaluation of this system has further substantiated its suitability and superiority over the currently available ones.

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A new method of calculating grinding-wheel profiles for finishing pinion cutters to shape spur and helical gears with an arbitrary profile is developed using the theory of the element removal method (ERM) previously proposed by the authors. In order to show the usefulness of this method, the profiles of the grinding wheel for finishing the pinion cutter (m_n = 3) for Novikov gears with concave teeth are calculated numerically, and then the profiles of the pinion cutter finished by the grinding wheel are calculated. The difference (calculation error) between the given and the calculated profile of the pinion cutter was less than O.1 μm before regrinding. Profile errors of the cutting edges after regrinding are shown in terms of the number of teeth, the helix and rake angles and the regrinding stock. The effective clearance angles of cutting edges, which produce some broblems in gear finishing, are calculated from changes in the profiles of the cutting edges before and after regrinding.

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This paper considers an optimal policy for an assembly system. In the system, a final product is assembled from two types of parts, each of which is ordered from an external supplier. The final product is in demand. Order lead time, assembly time and demand are assumed to be random. The cost structure consists of the shortage cost for the final product and holding costs for the parts and final products. We deal with the optimal control problem in which the optimal order policy for the parts and the optimal assembly policy for the final product are decided so as to minimize the expected cost. The optimal control problem is formulated as an undiscounted semi-Markov decision process. Numerical results are presented in order to study the influence of parameters such as mean order lead time, demand and costs on the optimal policies.

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