Free vibrations of rotating cantilevered thin twisted plates are investigated. First, the exact strain-displacement relationships in large deflections of thin twisted plates are derived and the principle of virtual work for free vibrations of rotating cantilevered thin twisted plates is formulated. Then, a numerical procedure based on the Rayleigh-Ritz method is proposed using algebraic polynomials as assumed displacement functions. The results of the present analysis are compared with those obtained using the finite-element method to verify the usefulness of derived equations. Finally, effects of rotation, setting angle and setting length on frequency parameters are studied for typical thin twisted plates.

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The analysis of axial vibration of rotating thick disk, the theme of this paper, is an important issue when one analyzes blade-disk-rotor coupled vibration by the substructure synthesis method. This paper presents (1) a proper method of treating shear deformation, rotatory inertia and centrifugal tension, and (2) how the individual effects of each of these three factors depend on disk geometry. The disk is treated as a distributed stiffness and distributed inertia system. Shear deformation is introduced according to Reissner's theory. Rotatory inertia is treated as a result of body inertia force. The centrifugal tension component perpendicular to the elastic curve is a resistance to deflection. Numerical calculations based on the transfer matrix show that (1) the larger the ratio of disk thickness to its outer-minus-inner radius becomes, the larger the effect of shear deformation and rotatory inertia, and the smaller the effect of centrifugal tension become, and (2) the smaller the ratio becomes the smaller the effect of shear deformation and rotatory inertia, and the larger the effect of centrifugal tension become.

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The vibration of a flexible tube induced by the steady flow of emulsion is studied experimentally. The emulsion is used as a substitute for blood because it has a similar property to blood. The vibration of the flexible tube and flow rate through it are measured using a highly sensitive gap sensor and an electromagnetic flowmeter, respectively. In addition, theoretical investigation based on the transverse vibration theory is performed. The results are summarized as follows. (1) The emulsion has the effect of decreasing the amplitude of vibration of the flexible tube in a high flow rate region. (2) The transverse vibration theory is effective for evaluating the frequency of dominant vibration mode. However, the reliability of this method becomes poor with decrease in the stiffness of flexible tube.

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This paper describes the optimum damping conditions for transient vibrations of a rotor-shaft system supported by flexible bearing pedestals. The transient vibration of a rotor can be effectively reduced by optimizing the damping ratio of flexible pedestals. The optimal damping ratio corresponds to the maximum value of the logarithmic decrement of a rotor. It is shown that the optimum damping ratio for the transient response calculated by the root locus method is different from the optimum one for steady-state response obtained from the principle of a dynamic damper, and the difference between these optimum damping ratios can be minimized by adjusting the controller gains and / or the dynamic properties of pedestals. The analytical results are confirmed by the experiment for a rotor system supported by flexible pedestals with electromagnetic actuators.

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Experimental identification of a mechanical system with character matrices has been the subject of several discussions. As the result, if the degree of freedom of identification is equal to that of the system to be identified, then almost complete character matrices can be derived. However, this condition is seldom satisfied and therefore some kind of compromise is required to obtain the matrices, that is, whether to ignore the physical meaning of the matrices or to ignore the discrepancy in frequency response functions. On the other hand, identification with character matrices can be considered as a kind of reduction of the degree of freedom. Consideration is given from this point of view, and an improved technique which avoids the conflicts is proposed and examined numerically and experimentally.

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An operational planning problem of district heating and cooling systems which are composed of gas turbine cogeneration and heat pump/thermal storage facilities is discussed. A sensitivity-analysis-based method is proposed to obtain the charging/discharging strategy of a thermal storage tank by simple means. The effectiveness of the method is investigated from the viewpoints of computation time and accuracy of the solution, by comparing it with other methods : dynamic-programming-based, decomposition-based, and scheduling-based ones. A numerical study shows that the sensitivity-analysis-based method is effective from the viewpoint of computation time while it keeps the accuracy of solution as compared with the dynamic-programming-based or decomposition-based method. This feature is advantageous for use of the method proposed in the from of an algorithm in real-time operation and system design.

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We propose a new crane system using the Interactive Adaptation Interface. This system can adapt to any operator considering the following two points. One is the operator's psychological state and the other is operator's skill. The former is estimated from the skin potential reflex (Galvanic Skin Reflex ; G. S. R. ), and the latter is estimated from the history of the oscillation and command inputs. In order to adapt to an operator, the system tunes its time constant by Recursive Fuzzy Inference. We also propose "Multi Display" for operational assistance. The Multi Display gives several items of information needed for operation of the crane. We constructed a computer simulator based on this crane system, present some experiments using this simulator, and show the effectiveness of the proposed operational assistance system based on the experimental results.

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This study deals with the velocity and the sway control of hydraulic truck cranes in elevating operation. In order to control the load sway, a velocity pattern which reduces the load sway in elevating operation is determined. The velocity of the elevating cylinder is controlled to follow the velocity pattern by a PID controller which replaces the acceleration of elevating angle with the cylinder thrust force. The good effect of velocity and sway control is proven by analytical and experimental results.

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A simple motion control scheme of a dynamical system driven with a stepping motor is proposed. The scheme is examined through posture control of a parallel biwheel vehicle that consists of an inverted pendulum supported by two coaxial parallel wheels. Posture of the vehicle is regulated by state feedback where a step rate of the stepping motor instead of a motor torque is used as control input to the system. The proposed scheme can produce steady vehicle motion around an unstable equilibrium position by numerical simulation. The simulated initial responses reveal that there is an appropriate range of peak static torque values of the stepping motor. A large peak static torque results in the increase of vibrational amplitude of the vehicle around the unstable equilibrium position, and a small torque causes step failure due to overload before appearance of unrecoverable tumbling motion. In experiments, the posture of the vehicle can be regulated within an inclination angle of ±5×10^-3 rad under the proposed scheme with a 5-phase 500 step/rev stepping motor. An optical rotary encoder of 1.75×10^-3 rad/pulse resolution is used as the inclination angular sensor.

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A new concept on "heredity and evolution of designs" was developed by the author and a general algorithm to simulate the heredity and evolution of designs is presented in this study with reference to engineering analysis. The ordinary design process is considered here to have a distributed hierachical structure and is modeled. The design in each level is optimized by the genetic algorithm to maximize the fitness function under some constraints. In some of the levels, engineering analysis can be involved. The fitness function and constraints to be used for the genetic algorithm in each level are modified by the resulting designs in the lower or upper level. The proposed method is applied to simple examples of car designs and demonstrated. Further studies will follow to examine and evaluate the proposed method from many points of view.

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In the 1st report, the parallel crank-slider mechanism for a joint of walking robots proposed by Emura was introduced, and its direct and inverse-kinematics problems were described. In this 2nd report, the statics and dynamics of the mechanism are described. From the analysis of the mechanism, it was proved that the singularity does not exist in its work space. Moreover, it was shown that the generalized moment of inertia of the mechanism is not smaller than the inertia of the robot due to its high reduction ratio. In the case of this mechanism, the generalized inertia tensor can be simply expressed using the Jacobian matrix.

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This paper deals with a self-organizing manufacturing system (SOMS) which is introduced the concept of cellular robotic system. This system consists of two major layers. The lower one is a self-organization module, which has self-organizing ability for fitting other processes and environments into the intelligent manufacturing system. The higher one is a decision-making module, which is activated by interaction among processes. The manufacturing environment includes many optimization problems which are defined as ill-defined structures. There are stochastic search methods for these problems such as the simulated annealing and the genetic algorithm (GA). In this study, a method for optimizing the manufacturing system using the age-structured GA (ASGA) as the self-organization ability is proposed. The ASGA is applied to a press machining line which is capable of reorganizing the machine in itself, as an example of the SOMS. The effectiveness of the proposed method is demonstrated through numerical simulations.

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This paper proposes a concept of an emergent type of micro swarm robotic system, and a programmable micro autonomous robotic system (P-MARS). We aim to design a swarm robotic system from which emergea swarm intelligence. Non linear feedback relations between parts and whole is important in our emergent system. For the first step in realizing our proposed emergent robotic system, we designed a P-MARS which has programmable function, communication device, CPU, actuator, and battery. Because of the programmable and communication functions, wireless transmittion of program to P-MARS from host computer, and communication within and between robot and robot is possible. The size is 20³. cubic.

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In this paper, it is shown that force control of the SCARA robot driven by stepping motors is possible by controlling the torsion angles of joints and the stiffness characteristics of the stepping motor. By means of this control method, the system of force control can be simplified, because the stepping motor does not require feedback control of the position. And it is also shown that the force always acts to the desired direction when time constant of each joint is adjusted rightly. Therefore, force control which does not depend on the orientation of the robot is possible. Moreover, in consideration of the dynamic characteristics of the stepping motor to control without the step-out phenomenon, the condition of the trajectory planning and that of feedback gain are described. As the experimental results, it is shown that the proposed methods are applicable for the force control.

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In the one period from legs landing to landing on the ground, a quadruped locomotion robot has two phases : the support phase and the swing phase. In the support phase, the foot is subjected to constraint force from the ground, and moment and force from the body, but not in the swing phase. Thus, in one period of walking, it is thought that the dynamics of the legs change greatly. It is desirable to construct a control design method taking account of the change in dynamics. In this paper, we deal with the change in dynamics as parameter perturbation. The H∞ control method, which is a robust control method against disturbance, is applied to the quadruped locomotion robot. First, we show the design method of H^∞ optimal tracking control. Next, we compare H^∞ and frequency-shaped (H²) optimal tracking control with conventional optimal tracking control in simulations and experiments.

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Friction in joint driving systems constitutes an important source of nonlinearity that makes it difficult to achieve high-precision control. In this paper, a method of estimating friction is proposed, which requires a joint torque signal, armature current and motor angular velocity. Considering disturbance rejection, a position control method is proposed as follows. Vibration is restrained by bandpass joint torque feedback, and high-precision position control is realized by friction feedforward compensation. Assignment of pole distribution is employed to determine three control coefficients, and the effect of disturbance rejection is compared and evaluated for three kinds of pole distributions. Properties of the proposed control are discussed, and experimental results are also Presented.

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In order to develop a robot arm possessing functional characteristics of bi-articular muscles, we performed theoretical simulation analyses of EMG patterns of human movements. In the present studies, the relationship between the force and the displacement and that between the stiffness ellipse at the end point and the stiffnesses of the six main muscles are described. Results obtained in these studies strongly suggest that the existence of the bi-articular muscles could contribute to improvement of compliant properties of the multi-articular extremity, and to independent control of position, force and stiffness at the end point of the extremity, promising smooth, tine and precise movement of the extremity.

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The shock-absorbing mechanism to minimize the vertical acceleration when jumping down onto a hard surface was investigated. The dynamic model of a human leg was built with a link joint. The muscle model consisted of a contractile element, a elastic element and a viscous element. The equivalent linear spring constant and equivalent linear damping coefficient decreased upon lowering of the hip by varying the bending angles of the ankle and knee. The numerical results showed that shock could be absorbed passively by deep bending, and to a greater degree actively in the same bending position.

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Presence of abnormal loads in the meniscus, ligament and articular cartilage of the knee joint has been suspected as one of the probable causes of osteoarthritis. Hence, the knowledge of the contact stress distribution at this joint in normal as well as abnormal states is necessary. In this study, an improved method of measuring dynamic contact stress using a set of microcapacitance pressure sensors is illustrated by means of in vitro experiments conducted on a knee joint of a cow's hind leg with intact ligaments, which was allowed to undergo simulated motion under preestimated normal loads. Several methods of deriving a mathematical function approximating the pressure distribution at the tibio-femoral joint are also illustrated on the basis of a set of experimentally observed pressure data taken at discrete points. The availability of such a mathematical function is likely to open a new avenue in biomechanical as well as etiological investigations of the knee joint.

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In the field of medical science, employment of intravascular neurosurgery with a (micro)catheter is steadily increasing. However it is usually difficult to guide a catheter safely inside blood vessels. In this study, we proposed and designed a new guiding system based on the fluid force of blood flow. The system consists of a cylindrical streamer (1 mm in diameter and l.5 mm in length), two supporting legs and one wire. Movement of the streamer can be controlled by adjusting the length of the wire. We studied the behavior of the cylindrical streamer by numerical analysis of fluid force, and investigated the characteristics of a model system by experiment. We found that the system can be used to control streamer movement including its forward or backward movement and its selection of its way in three types of both branched and bifurcated vessels.

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In this paper, we propose a method for lip extraction from face image by color image processing on the basis of the distribution of H and S parameters in HSV (hue, saturation, value) color space which shows a better fit with human color sense than RGB (red, green, blue) color space. Comparing the proposed method with the conventional lip extraction method using the signal ratio of G to R of RGB signals, on the basis of the defined lip extracting index, the effectiveness of the proposed method is quantitatively demonstrated. This quantification of face image by using HSV color space can be applied to the development of color data base of human face and virtual face image.

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Strange sounds generated by machines express trouble or poor condition of the machines. Especially, in automobiles and air conditioners, strange sounds are paid attentions carefully, and the sources of those sounds are investigated and improved. To express strange sounds in Japanese, many kinds of onomatopoeia are used. Onomatopoeia is characteristic of Japanese culture. In this paper, the relationship between onomatopoeia expressing impulsive sounds and beat sounds, and the real sounds of the phenomena, are studied from the viewpoint of acoustic physics.

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The vibrations of hybrid ceramic ball bearings having steel rings and silicon nitride balls were investigated and compared with those of conventional steel ball bearings. The test ball bearings were operated at several speeds under axial loads. The radial and axial vibrations on the outer ring were monitored by an accelerometer. The vibrations were examined using a fast Fourier transform analyzer. From the experimental results and discussion, the following conclusions were obtained. ( 1 ) The overall values of vibratory velocity for hybrid ceramic ball bearings are higher than those of conventional steel ball bearings. ( 2 ) The peaks of radial and axial vibration of hybrid ceramic ball bearings appear in higher frequencies compared with the corresponding peaks of conventional steel ball bearings. ( 3 ) The peaks are caused by the radial natural vibrations of arbor, the in-plane natural vibrations and the out-of-plane natural vibrations of the outer ring.

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The axial movement and load of a full floating-type piston pin were measured and the underlying mechanism was experimentally analyzed. Small bearing clearance of the connecting rod small-end or nonparallelism of big and small-ends led to deterioration of the lubricating characteristics of the small-end, which resulted in increasing linking degree of the piston pin and the connecting rod small-end and increasing axial load of the piston pin. The connecting rod mass was found to affect the measured load in the analysis of the relation between the load impulse and the piston pin velocity. These results indicated that the design factor of the connecting rod had a large effect on the improvement of the lubricating characteristics and the suppression of the axial movement and load of the piston pin.

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Hydrodynamic lubrication of an inclined slider bearing having self-affine fractal roughness is analyzed using the perturbation expansion of the Reynolds equation. Fractal characteristics are incorporated in the pertubation equations in terms of the power-law autocorrelation function defined by the fractal dimension and the correlation length. It is shown that the effect of transverse roughness in increasing the load capacity from that of smooth surfaces depends strongly on its fractal structure. The load capacity is larger for smaller correlation length, and the fractal dimension affects the load capacity in particular when the correlation length is larger than 1/BOO of the bearing length. Contribution of surface asperities with different wavelengths to pressure generation is explained based on a flow simulation for sinusoidal roughness. The present results suggest that the effect of fractal structure of surfaces should be taken into account not only when the overall load capacity of a bearing is considered, but also when microscopic film formation on small asperities and their behavior are of interest.

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In the use of micromachines, the scale of the machine is sufficiently small that microwear influences the machine properties. Since the most common material used in microfabrication processes is silicon, it is important to study its surface modification characteristics. In an attempt to improve the tribological properties of silicon, the effects of N⁺ implantation at various ion energies on the tribological properties were evaluated using a tribometer for the three cases of μN, mN and N loads. With microload (μN), N⁺ implantation at the lowest ion energy can result in a decrease in microwear, as evaluated by atomic force microscope. In contrast, N⁺ implantation at higher ion energy is more effective for decreasing friction and increasing the critical contact stress than N⁺ implantation at lower ion energy, with mesoload (mN) and macroload (N), evaluated using an oscillatory friction tester and a reciprocating friction tester, respectively. These results are attributed to the relationship between the depth of implanted N⁺ and maximum shear stress of elastic contact between spherical and planar surfaces.

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To clarify the seizure resistance of stainless steel balls of which the surface layer was thermally diffused after being Sn-plated, a four-ball test was carried out with grease lubrication. From the tests, the following results were obtained. The diameter of the wear scar of the ball lubricated with the grease containing a molybdenum disulfide additive was smaller than that of the ball lubricated with the grease without the additive, and the diameter of the wear scar increased with increasing concentration of the additive. The load at the incipient stage of seizure of the ball of which the diffused surface layer was about 6 μm thick was 2∼4 times larger than that of the ball without the diffused surface layer. Further, it was found that the seizure resistance of the balls could be estimated from the critical surface temperature and that the critical temperature increased with increasing concentration of the additive.

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This paper presents a study on the bending fatigue strength of ion-nitrided gears. The bending fatigue tests for the S 45 C and SACM 645 ion-nitrided gears with different hardened depths under uniform cyclic loading conditions were carried out, and the bending fatigue strength of ion-nitrided gears was found to be much higher than those of the normalized gears. The bending fatigue limit loads of the S 45 C ion-nitrided gears was found to be almost equal to those of the S 45 C tufftrided gears. Furthermore the bending fatigue characteristics of the S 45 C ion-nitrided gears under two-step loading conditions was discussed on the basis of Miner's hypothesis.

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Strain wave gearing which is a compact mechanical device producing high mechanical advantages and speed reduction, has been used to accurately position the arms and wrists of robots. It is important to clarify the mechanism of the rotational transmission error of strain wave gearing. In this study, rotational transmission errors of cup-type strain wave gearing are measured over one revolution of an output shaft, and the frequency analysis is carried out for the measured results. Furthermore, effects of assembly errors and torque on the rotational transmission error are deter-mined experimentally. The main results are as follows. (1) The main frequency components of the rotational transmission error are even multiples of relative rotational frequencies of the circular spline, flexible spline and wave generator. (2) The frequency component of rotational transmission error, which is 2 cycles per wave generator rotation, is easily influenced by the inclination of the circular spline. (3) The frequency components of rotational transmission error which are 1 and 2 cycles per wave generator rotation are easily influenced by the offset between the circular spline and flexible spline. (4) The frequency component which is 13 cycles per wave generator rotation is observed when a torque is applied.

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As described in the 1st report on this study, polyimide gears showed excellent characteristics in a high-temperature environment ; however, they had the demerit of being fairly expensive. Recently, an aramid has been marketed which is a plastic having high strength and heat resistance comparable to those of a polyimide. This plastic is available for about 80% of the cost of polyimide, so it appeared applicable for practical use as a gear material. It is described in this report how, as a basic study to obtain design data for aramid gears, operating tests have been carried out for them in two atmospheric environments at room temperature and high temperature, and various characteristics have been investigated in each environment.

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The behavior of cutting strain in a workpiece with a circular hole measured by a photoelastic coating method is described. An aluminum plate (JIS-1070) of 3 mm thickness with a hole of 2 mm diameter coated with birefringence material of 100-100-8 epoxy rubber was observed in orthogonal cutting. High-speed steel (SKH-4) of 300 rake angle was used under dry conditions. In addition, τ_max was obtained by applying elastic-plastic FEM. The distribution of τ_max around the hole obtained by computation is in good agreement with that obtained experintally by the coating method. The results are as follows. (1) After cutting, a peculiar strain distribution remains around the hole. (2) The cutting strain has little effect on residual strain around the hole which is close to the edge of entrance. (3) To maintain a high degree of accuracy, the location of a hole must be kept at a distance 2.5 times its diameter from the cutting surface or 5 times its diameter from the cutting end of the work piece.

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Welding is widely used for construction of many structures. There exists residual stress near the bead because of locally given heat. Tensile residual stress on the surface reduces the fatigue strength. Some methods of reducing residual stress have been presented. In this paper, a new method is proposed in which vibrational load is applied during the welding operation. The advantage of this method is that vibrational load is generated by a small shaker. This method is expected to be practical. By a simple experiment, it is clarified that tensile stress near the bead can be reduced by this method. Next, experimental results are examined by an analytical method. It is assumed that reduction of residual stress is caused by local plastic deformation because initial residual stress is high and nearly equal to yielding stress. Using an analytical model with a preloaded spring having elasto-plastic characteristics, reduction of residual stress is evaluated qualitatively.

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The flatness of a granite bed as a guide of the column in a CMM (coordinate measuring machine)has a great influence upon the accuracy of the movement, and the straightness measurement of the guide surface using an electric level is a laborious task. Therefore, a new optical straightness measurement of high speed and high accuracy has been proposed in this paper. "High speed" means that a measuring time of within 3 minutes for 50 points during a 400 mm traverse was accomplished by gliding the measurement head on a granite surface by the action of an aerostatic bearing. "High accuracy" means that a repeatability of less than 0.16 μm was realized by measuring the position of a laser beam as a datum on a photosensor. The straightness was evaluated in terms of the vertical displacement and the integration of the inclination angle of the slider. As a result the integration value coincided well with the measured value using an electric level.

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For computer-aided geometric design or for computer-aided geometric display, parametric curve segments and surface patches such as the Bezier form or B-spline form have been frequently used. It is very convenient if we can use the same parametric representations for the approximation of algebraic curves or surfaces, such as circles, ellipses, spheres and tori. Then we can perform unified treatment for all free-form and nonfree-form curves and surfaces. For the design, machining and inspection of accurate geometry such as precision machine parts, it is very important to know the qualitative and quantitative error of approximation from exact geometry. But up to the present, little work has been done on this error estimation. In this report, we treated the method of optimum fitting of rational cubic Bezier curves and rational bicubic Bezier surfaces onto algebraic and free curves and surfaces, and numerically examined the magnitudes of approximation errors.

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Standard computer input tools such as a mouse and keyboard do not provide users with a direct and intuitive means of 3-D shape operation. To solve this problem, this paper proposes a new concept of an interface system for 3-D shape manipulation using deformable real objects as input tools. By deforming the tool with bare hands with a tactile feedback, users can deform a 3-D shape modeled and displayed on a computer screen directly and intuitively. By adopting a free-form deformation-oriented approach, the interface enables various types of 3-D shape operations using a rather simple input tool. A prototype of DO-IT (deformable objects as input tools) interface using graphics workstation and a cubical input tool made of foam rubber and strain gauges demonstrates the effectiveness and potential of the concept.

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Constraint conditions of previously reported mathematical data models, geometric cell complex chains (basic models), are theoretically defined as a basis for verifying the integrity of topology-based shape representation model data. These constraint conditions are mainly classified into three conditions, called cell conditions, complex conditions and chain conditions. Constraint conditions of mathematical shape models, so-called well-formedness conditions, can be derived from these constraint conditions and shape model transformation of these mathematical data models. Methods for applying constraint conditions of these mathematical data models to the integrity verification of the topology-based non-manifold shape representation model data and so-called solid boundary representation model data are described.

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As the 21st century begins, Japan will have the largest ratio of population of advanced aged people in the world, resulting in a considerable depreciation of labor productivity in the present labortype intensive of work, This research presents a proposal to improve productivity while providing a more reasonable work area. The method of research was to observe and measure the vertical and horizontal movements of a typical sitting worker performing "get and place" actions. The valuation index used in the experiment was obtained by measuring the motion locus, the motion velocity, the amount of myoelectric energy, the motion time and the difference in the work burden from two directions : vertical and horizontal. The results indicated a regression curve expressing the relationship between the motion time and vertical/horizontal angles. This indicated that a work area which takes into consideration the vertical and horizontal positioning of the worker can minimize the motion time, resulting in a more efficient and reasonable work place.

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This paper describes the representation of an assembly architecture. A functional element is introduced to represent assembly architecture. By using this functional element, constraint of assembly architecture can be naturally described. This functional element is used to express relations among the parts. The constraint among assembly parts which interfere without touching can be described by the relation. The relation has an assembly method etc. and can describe constraint and interfernce. It is shown that the search space of the assembly sequence is reduced by using our representation of assembly architecture.

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