[in Japanese]

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Although many works have been reported on production scheduling method, no method has been proposed which makes possible to optimize the scheduling with respect to plural number of evaluation items such as delivery time, performances of machine tools, production cost and so on. This study proposes a new scheduling method using information concept. By this method production schedulings can be planned which meets plural evaluation items totally. It is also shown that this method is effective by simulation and the minimum slack rule is effective as a priority rule for saving calculation times. The method by which the best system is selected using information concept is called information integration method. This study suggests that this method can be applied to many other fields besides production scheduling.

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This paper describes a new mathematical theory for generating a sculptured surface defined by B-spline, and the application of this theory to practical design and manufacturing. The initial curved surface is constructed easily by blending two or more outlines. When outlines are blended, special functions introduced in this paper and implied in the equation for curved surfaces, control the shape of surfaces globally. It is possible to control the shape of those locally too. This method is analogous to the way used in early work. Namely, adjusting vertices of the polygon is used to control the shape locally. The system applied this theory can generate easily a sculptured surface desired by designers.

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The experimental modal analysis is defined for the linear mechanical structure. However the actual structure often has non-linear components such as friction, clearance and so on, resulting that the frequency response functions measured are distorted. This causes some trouble when applying a curve fitting technique to extract modal parameters based on linear theory. In this study the Hilbert transform which can identify the existence of non-linearity in the structure is applied to the measurement of modal analysis. First the numerical simulation makes clear the validity of the Hilbert transform, then the simple plate structure ad the complex motorbike are tested and the Hilbert transform based on measured frequency response function appears the very powerful tool for such non-linear vibration.

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Robot system with high speed object recognition ultrasonic sensor is constructed. Points which characterize the object can be detected by measuring the propagation time of ultrasonic impulse and azimuth which gives its maximum amplitude, and from these points shape, position and orientation of the object are deduced. Experiments of pick-and-place and homing tasks are made for known and unknown objects arbitrarily placed. It proves that a rotational scanning of sensor is sufficient for estimation of position and orientation, recognition of a simple shape object, and identification with one of several different objects, and that two or more scannings enable to recognize more complicated shape object. Satisfactory results of experiments are obtained which suggest the possibility of application of this system to many purposes in place of robot system with ITV vision sensor.

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Internal damping force, gyroscopic moment and driving torque are taken into account in equation of motion of rotating shafts. Using asymptotic method, the first approximate equations of motion are derived. Numerical calculation is carried out by Runge-Kutta-Gill's method. The main results obtained are as follows : (1) The amplitude and phase angle vary with the value i_p (ratio of polar moment of inertia of the rotor to moment of inertia of the rotor), and especially the amplitude varies with the characteristics of the driving torque. (2) When the value of driving torque is small, it is difficult for the rotor to pass through the critical speed, and also when the external damping coefficient is larger and i_p is smaller, this phenomenon is found scarcely. (3) When the rotating shaft is continuously accelerated with larger angular acceleration and pass through the critical speed, self-excited vibration of the rotor is apt to be genarated. (4) Above phenomena are not only experimentally found, but also confirmed by numerical analysis.

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This paper describes an on-line application of ultrasonics to the monitoring of the molding process of plastics. Some fundamental experiments were made using a set of simple metal molds in order to justify the proposed method based upon the pulse echo technique. In the holding process, the travelling time of ultrasonics through plastics decreases with the decreasing temperature of plastics. Also, the air gap between the mold and plastics can be detected by the variation of the amplitude of reflected waves at the interface. From these results, it has been clarified that the proposed method can be applied to the monitoring of the filling process as well as the holding process by a nondestructive way.

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This paper reports the two experiments which evaluate the reliability of screw tightening for fastened joints. One is the self-loosening test under transverse vibration and the other is the loosening torque test. In the self-loosening test under transverse vibration, loss of axial tension per one cycle is investigated. The loosening torque ratio is studied in loosening torque test. Some experimental results have been obtained using a newly made loosening tester under several experimental conditions. With the two tests, the reliability of screw tightening by means of vibration is compared with the conventional screw tightening using a DC servo-motor. From the results of these experiments, it has been found that with vibration a screw becomes tight due to the increase in axial tension and the coefficient of static friction at the end of screw tightening. Furthermore, with these self-loosening tests it has been confirmed that screw tightening using vibration is more reliable.

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The knife-edge type tape cleaner is generally adopted to high-density magnetic tape recording devices in order to remove such particle as dirt, oxide shed, wear debris of tape guide, etc., from the tape surface. This paper presents a design method of an efficient and reliable magnetic tape cleaner. Effects on cleaning efficiency of cleaning conditions, that is, tape contact force along the knife-edge, oblique angle between edge-line and tape width direction, edge curvature, are experimentally investigated. Also from the reliability viewpoint, tape damages after many times of cleaning are examined. Consequently the following results are obtained. (1) Cleaning efficiency defined as the signal dropouts reduction rate increases proportionally to contact force and oblique angle, while the effect of edge curvature is rather small. (2) The dominant condition for tape damages is contact force (p₀). The number of cleaning (N_c) where the number of signal dropout exceeds that before test is given as follows N_c∝p₀^-1.6. (3) Considering these results simultaneously, an efficient and reliable cleaning conditions applicable to practical use are determined.

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In this paper, an approximate equation which expresses the relation between the friction torque of double-nut type ball screw, T_d, and the mean coefficient of friction, μ (μ=(μ₁+μ₂) / 2, μ₁ ; the coefficient of friction under the forward drive, μ² ; that under the back drive), is derived, and a method to evaluate the friction characteristic of double-nut type is proposed. The friction torque of double-nut type, T_d, is measured experimentally under the preload of 653, 1 307, 1 960 N, and the revolution speed range of 20-1 500 rpm, for each oil of # 83, # 56, # 32, at two conditions of oiling (flooded ; A and dropped ; B). It is clear from these results that the mean coefficient of friction, μ, is from 0.002 to 0.007 within the limits of these experiments, and the relationship between μ and dimensionless number, ηN/ P_m is not always linear. In addition, the effects are discussed of the kinematic viscosity of oil and the revolution speed of screw shaft, being found that T_d is sum of load term, T_d, and the speed term, T., the estimated formulae are obtained of T_d and T_s at each condition of oiling A and B.

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Several experiments were run to determine the relations between shot peening variables (shot size, shot velocity, impact angle, peening time) and surface residual stress. The surface residual stress was measured by X-ray diffraction method. The results are as follows : (1) The surface residual stress increases with peening time and then approaches a saturated value (-350-400 MPa) before full coverage. (2) Surface residual stress after full coverage depends slightly upon the shot peening conditions. (3) Surface residual stress shows the size effect to the thickness for the thin sheet of specimen. (4) Residual stress induced in the affected layer exists together with the non-affected zone and falls to zero where the depth of affected layer equals to the thickness of specimen.

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In this study, a constant-load heavy grinding has been made using a specially designed snag grinding machine of 40 kW, where plate workpiece was used to keep pressure constant. The 455 mm dia. resinoid wheels were used for the experiment, and a 1 m long steel plate of different widths was used for workpiece. Thus, the effects of load, traverse speed, wheel width, work-piece width, and wheel type on grinding performance have been studied from standpoints of removal rate, wheel wear, G-ratio, and grinding force. It is evident that if load is identical the removal rate, as well as wheel wear rate, is always the same independently of wheel width or workpiece width. The ZS wheel is the best from a standpoint of stock removal, while the SR wheel showed the highest G-ratio. A wider workpiece causes higher tangential force for a given removal rate, while wheel width does not affect the force.

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New finishing method has been developed by using the electrophoresis phenomenon of fine grain suspehded in liquid, which yields the electrical double layer at the surface of the grain. When the electric power is supplied to electrode set into the polishing compound, the grain moves and causes the polishing action to the workpiece surface.- The developed polishing equipment consists of a rotary vessel containing the polishing agent. The experiments were conducted on silicon wafer and ferrous metal specimen using the distilled water or ethylalcohol mixed with fine abrasive grain (Al₂O₃, SiO₂) at the 10-2% volume concentration. The experimental results on the silicon wafer which is placed apart from the electrode showed that the stock removal rate increases with increasing the applied potential. Examination of the surface profile of the polished specimen indicated that the surface roughness decreases with increasing the potential. It can be said that the surface finishing characteristics are controllable by varying the current to the electrode.

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From the result of previous paper, it has confirmed that the bending strength has a better correlation for the wheel life than the grade and the modulus of elasticity of grinding wheel when the vitrified bond consists of different compositions. In this paper, the properties of the wheel surface, that is, the scratching force which is capable of holding the grains and the successive cutting point spacing are experimentally and simulatively investigated. The results are as followed. (1) The distribution of the scratching force fits to the Weibull distribution. (2) The distribution of the successive cutting point spacing fits to the Weibull distribution, too. And the same result is obtained by means of the simulation which the co-ordinate of the active grains are given through uniform numbers generated by the computer. (3) On the distribution of the ratios of scratching force to successive cutting point spacing, which are computed by the Monte Carlo method, a certain relation is observed between the mode and the relative frequency and the wheel life type (i. e. shedding, chattering and burning). (4) The scratching force has stronger correlation with the bending strength than the other properties of grinding wheel.

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Our research aims to realize high-precision grinding of the multi-track thin film magnetic head. The most important requirement of this grinding is uniformity machining of the gap depth of head. This machining must be achieved with an accuracy of micron order according to the prescribed finishing measurement. The machining method is as follows : The machining depends on the resistance value of the thin film in the head which changes with the machining process. As a stable relation exisits between the resistance value and the grinding quantity, this value is considered to be the controlled variable of grinding quantity. According to this value the feedback control is made, and the controlled algorithm of the angle correction is developed in order to correct the slant of machining. The grinding system for the realization of this machining method is developed and the following results are obtained : (1) It is possible to control the grinding quantity with an accuracy which is better than 1 μm. (2) The result of the angle correction appears with the definite delay concerning the control system. Therefore, it is proved experimentally that the controlled algorithm is suitable. (3) The grinding error due to the angle correction is better than 1 μm.

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