A numerical approach is proposed for analyzing forced vibration problems of a symmetrically laminated FRP (fiber reinforced plastic) composite plate. The numerical results for the forced vibration problem of a clamped symmetrically laminated plate are compared with experimental ones. First, we attempted to estimate numerically the steady-state response of a square plate, and the convergence of the results is discussed. The effect of structural damping factors on the steady-state response of the plate is numerically investigated. Second, by applying an experimental modal analysis technique to the beams produced from a lamina, the structural damping factors of the lamina are measured. Using the measured structural damping factors, the accelerance of the clamped symmetrically laminated rectangular plate is computed. Finally, the accelerance of the plate is obtained experimentally. Good agreement was observed from a comparison of experimental and numerical accelerances.

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We presents an extended theoretical study on the bouncing vibration of a single-degree-of-freedom contact slider model and the complete contact condition for high density contact magnetic recording. The relationship between bounce height and waviness frequency and the role of the top contact point necessary for stable bouncing vibration are discussed. Since the dynamic contact force increases up to ten times the static head load even when the bounce height is only one nanometer, complete contact sliding without separation is indispensable for reliable contact recording. The complete tracking conditions onto the disk surface under ten nanometer bounce height disturbances are calculated for various design parameter values, including the phase of the waviness. It is also shown that a collision model can predict almost the same complete tracking boundaries as the elastic contact model.

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This paper presents an active control of cantilevered pipes conveying fluid using an H^∞ control law based on normalized coprime factorization. The experimental setup consists of a pipe system, a laser sensor, an A/D converter, a personal computer, a D/A converter, and a DC servomotor which produces a transverse force for active control of the pipe. The transfer function of the control object which consists of the pipe system and the actuator is identified from experimental input-output data. From this mathematical model, the controller is calculated based on H^∞ control law. This controller is discretized and input to the personal computer in order to provide a command input voltage to the actuator. The experimental results show that the designed H^∞ controller effectively stabilizes unstable phenomena of a cantilevered pipe conveying water. Furthermore, it is found that the H^∞ controller is robust against the change in properties of the pipe system caused by increasing flow velocity, in comparison with a PID controller which we studied previously.

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In order to improve the robustness of conventional dynamic absorbers, we propose the multi dynamic absorber and its optimum design method. Although the design method for single and dual types of dynamic absorbers has already been established, their vibration control effects are very sensitive to changes of parameters such as the natural frequency of the controlled object and the damping coefficient of the absorber itself. The quadruple and sextuple types of dynamic absorbers designed by the proposed method are demonstrated. They are effective in controlling the vibration of the controlled object under changes of these parameters and maintain stable damping performance.

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A multi channel measurement system using a laser interferometer with 8nm accuracy was developed to measure the transient behavior of magnetic head sliders for magnetic disk drives. It features a laser-beam group converger, which focuses multiple laser beams on small areas of both the disk and the slider. This system also eliminates the influence of disk runout due to its high measurement accuracy. The main advantage of this system compared with white light interferometry and capacitance measurement methods is that it is applicable to actual disks and sliders. The system is useful for evaluating the slider's behavior during the contact sliding, take-off, steady flying, and landing processes.

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Elevator installation design includes an optimization problem in which the total floor area of a building occupied by elevator shafts is minimized. Due to the variations in nonformulaic restrictions and design options, this problem cannot be easily formulated using conventional optimization methods. Therefore we propose a method using GA to cope with this dificulty. The problem is coded into an integer-type chromosome with 9 different loci which represent all possible combinations of the design options. Through an evolution process, designs with large floor area or which violate restrictions are discarded, and the final survivor has demonstrated a good result.

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In the conceptual stage of structural design, the specified requirements are not sufficient for determining a unique solution, and subjective decisions based on a designer's preference play an important role similarly to the case of objective ones. Suggestions of various possibilities of design could assist the designer at this stage. In the conventional rule-based approach, the attributes of a design object are sequentially determined by referring to the design rules. Once the attribute values are determined, they work as absolute assumptions in subsequent decisions as long as backtracking is not activated. This is not beneficial in keeping the attention of the designer free from the tentative decisions made previously. In this study, the design case is considered as a phenotype of a chromosome that contains redundant information in morphogenesis. This enables us to reproduce the design candidates that have geometries/topologies varying from those of slightly different chromosomes. The past design cases are organized as the genetic case-base population and this population is modulated by referring to each of the design criteria and to the similarity to the candidate in terms of the design rules. The resultant population has heterogeneous individuals in this context, and the individuals generated from the population by genetic operations are delivered to the designer as suggestions. The preference of each design criterion is represented by the presence of the population correponding to the criterion through interactions with the designer. In this framework, the possibility, that is left behind on the conventional rule-based process, can be emerged by the genetic case-based approach, and a diversity of candidates is retrieved. The proposed idea is exemplified by a skeletal design of a bridge structure and the relaxation of determinancy in the rule-based approach is demonstrated.

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Based on the investigation of the generation mechanism of the unusual noise generated from a laser-beam printer, it has become clear that self-excited vibration is produced due to the friction between the photosensitive drum and the cleaner blade, and the noise is its vibration noise. The vibration system is that of the tortional vibration of the drum, and the vibration mode is secondary. The self-excited vibration in the secondary vibration mode is caused by the drum structure and the friction force applied to the drum. This drum is made of a thin-walled cylinder having inertia on both ends. The friction force is applied uniformly and axially to the cylinder surface. In this case, the energy can be applied to the tortional vibration of the secondary vibration mode in the drum, and the existence of negative damping friction force results in the generation of the self-excited vibration. Since the vibration frequency is the audio frequency of 10.65kHz, it lies in the audible range. To prevent the vibration and the noise without affecting the function, appropriate and positive damping needs to be applied to the vibration system. Also, the method using friction loss is investigated and verified to evaluate its effect. This method proved to be effective, and it is confirmed that self-excited vibration is discarded, and the generation of unusual noise is completely eliminated. The generation pattern of vibration and noise described in this paper is not limited only to the laser-beam printer. In equipment such as plain paper copiers, liquid crystal printers and so on in which the same mechanical structure is required, the same phenomenon can occur. The cause and the countermeasure described in this paper are expected to be practically useful for development and design.

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Pulse repetition durability of an element resistor in a thin-film thermal printing head is studied. There are three main findings of this study. (1) Cr-Si-O heating element deterioration is induced by electromigration of resistor materials and element lifetime is influenced mainly by the temperature of the heating element. (2) The peak temperature of the resistor in the pulse repetition durability test in air is 10% higher than that for actual printing, so this test can be used as an overload test. (3) The maximum power for Cr-Si-O resistor durability is sufficiently higher than the power required for printing. Thus, use of a Cr-Si-O resistor ensures a reliable thermal printing head.

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Almost all scanning probe microscopes (SPM), such as STM and AFM, use piezoelectric elements (PZT) as scanning and servo actuators. These elements have, however, some undesirable properties such as hysteresis, creep and nonlinear performance, which cause 3-dimensional distortion in SPM topography. In the present paper, two new methods are proposed to correct such image distortion of an STM. The first one uses calibration data of PZT actuators to correct the obtained STM image, which is called as 'software method'. The second one is to measure indirectly the displacement of the PZT actuator. The displacement of the STM probe is proportionally magnified through mechanical and electrical means and transferred to a reference point on a cantilever. This magnified displacement is measured by an accurately corrected sensor. This is called 'the external monitoring method'. Both methods were very effective for correcting the image distortion of STM.

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The aerodynamic noise generated by the rotating blade row of an electric fan generally consists of a broad-band vortex noise and a narrow-band rotational noise. The rotational noise, called blade passing frequency (BPF) noise, is annoying and its suppression has been considered at the design stage of many types of fans. The authors propose new design methods to reduce BPF level based on sinusoidal frequency modulation and M-sequence frequency modulation. Comparison by means of numerical simulation revealed that M-sequence frequency modulation is superior to sinusoidal frequency modulation with respect to spectral dispersion. Furthermore, it was confirmed that M-sequence frequency modulation realizes successful reduction of the BPF level of the cross-flow fans used in air conditioners.

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A sound source identification technique based on the acoustic double holography method was proposed in the previous paper. This method can achieve high resolution in sound source identification compared with the acoustic holography method. Furthermore, this method is more convenient than the nearfield acoustic holography method for measurement and calculation. However, this method still has the problem that comparatively high-level subsidiary source images appeared in the reconstructed image patterns which might have caused misjudgment. In this paper, a specific zone filtering technique applied to reconstructive calculation for reducing the subsidiary source image is proposed. By this technique, the level of subsidiary source image can be reduced without decrease in resolution of a real noise source image. Finally, in order to examine the effectiveness of the filtering technique, computer simulation and experimentation are carried out.

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A system for active noise control, ANC, uses a secondary speaker to cancel the sound pressure at an error microphone which is place at a control position in the space. This conventional ANC creates a quiet zone, QZ, around the physical error microphone. However, the QZ becomes unstable if a small change occurs in the acoustic path from the secondary speaker to the error microphone. Recently, to create the QZ virtually and to expand it spacially, a new arrangement for ANC, called the 'virtual microphone system', has been proposed. In this study, some fundamental characteristics of the virtual microphone method are clarified by both computer simulation and experiment. The difference between the acoustic pressure at the physical error microphone and that at the virtual microphone is analyzed in a three-dimensional space, and the limiting condition to be satisfied in the system is obtained. The noise reduction level of the system is compared with that of the conventional system and it is clear that they coincide very well.

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Recently, model output-following control systems based on simple output feedback have been considered by several researchers. These are basically composed of a feedforward controller based on the command generator tracker (CGT) and an output feedback controller with parallel feedforward compensator (PFC). In these cases, it was difficult to remove the influence of the PFC from the output tracking performance. In this paper, an effective design method of the CGT based model output-following controller is proposed to remove such a bias effect caused by the introduction of the PFC. As a result, we can realize a perfect model output-following by output feedback type controller.

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Electro-rheological (ER) fluids change their apparent viscosity according to the electric field strength. Using ER fluids, it is possible to directly interface between electric signals and fluid power without moving parts. This study aims at practical applications of ER fluids to fluid power systems, especially to control valves (ER valves). In this paper, first, static characteristics of a two-port ER valve is experimentally clarified to obtain basic characteristics of ER valves. Secondly, making the best use of the features of the ER valve, a three-port pressure control valve using ER fluids is proposed and manufactured. Static and dynamic characteristics of the manufactured pressure control valve are measured. Thirdly, using the manufactured pressure control valve, a one-link manipulator with FHA (Flexible Hydraulic Actuator) is driven. As a result, it is experimentally confirmed that the pressure control valve using ER fluids is applicable to use in driving actuators.

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Active shape control of a flexible structure consists of estimating the deformed shape from multipoint spatially distributed measurement of the structural deflections and restoring the desired shape actively by means of electromechanical or piezoelectric control actuators. We present a method of determining the structural deflections accurately and of designing the optimal control forces to restore the desired shape. The estimation algorithm is based on an infinite-dimensional approach, where the necessary finite-element truncation and approximation are introduced after solving the estimation problem. Using the same approximation functions the proposed method yields the optimal control forces that minimize the overall restoration error in the sense of least squares. We apply the proposed shape estimation and control method to an experimental tendon control system for a flexible beam and study the optimum moment-arm location.

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Genetic algorithms (GAs) with rough evaluations can prompt the evolution of neural networks that are able to control unstable dynamic systems. The proposed control method exploits the advantage of GAs that time-varying evaluations can be easily incorporated. First an easy evaluation in GAs induces the appearance of neural networks with controllability. Second, an evaluation of settling time prompts the evolution of neural networks that show high performance. The method is applied to the stable control of a bicycle. Neurocontrol of the steering at direction change causes reverse response like that of a human cyclist.

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This paper presents the modeling and control of transfer of a cylindrical liquid container along a curved path. Sloshing of (1, 1)-mode in the container is represented by a mechanical model using a spherical pendulum or a dual pendulum composed of two simple pendulums. An optimal control method for the liquid container transfer is determined through simulations and experiments using an optimal servo control system with a Kalman filter. Using this method, the optimal transfer control of the liquid container is obtained for practical performance specifications. The optimal control gain along a curved path has been obtained and is different from the control gain along a straight path. The usefulness of the present work has been demonstrated through the control simulation and laboratory control experiments.

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We develop a self-tuning fuzzy controller with dynamic absorbers for large-scale buses using the concept of fuzzy set theory. The model is a nonlinear system with six degrees of freedom subject to irregular excitation from a road surface. In the self-tuning fuzzy controller, the active control forces of principal and supplementary controls are determined where the vertical velocity and its time increment for a vehicle in each of suspension location are treated as input variables for the principal control, and the pitch-angle velocity and its time increment for a vehicle are treated as input variables for the supplementary control according to the fuzzy control rules. The output membership functions for the fuzzy control rules are changed using current vertical accelerations of the vehicle. The suspension performance is improved by dynamic absorbers fitted to the frout and rear axles.

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It is advantageous to apply overhead view monitoring of a vehicle and its surroundings to automatically navigate a vehicle, and for human intervention if necessary. Here, human operation is investigated to incorporate it's characteristics into automatic operation. Computer simulation programs which deal with the acquisition of human ideas, in overhead view monitoring, for regulating the movement of a vehicle and for collision avoidance, are adopted. Operations by human operators (subjects) are experienced by the automatic navigation system as sets of instances in the form of (vehicle state, steering angle). The effectiveness of human operation is discussed and the characteristics in the results are analyzed.

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The objective of this study is to describe effects of nonlinear aerodynamics on the stability of the longitudinal motion of a high-speed surface transport. This paper focuses on the aerodynamic nonlinearity due to ground effects or wall effects that are often observed for high-speed vehicles. First of all, 1 DOF (degree-of-freedom) calculations based on the inherent nonlinearity of the aerodynamic characteristics near the ground are presented. Then, 2 DOF analyses taking into account the interactive nonlinear effects of the aerodynamics are discussed. The trajectories are examined on the phase plane and the center manifold theory is applied to the analyses. It is shown that the stability of motion depends not on the nonlinearity of 1 DOF but on that of 2 DOF.

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It is difficult to drive an actuator using muscular voltage measured by the conventional method, which is based on medical treatment and is not intended to elucidate the movement of an arm. In this paper, we propose a suitable measuring method to elucidate the movement by changing the position of an electrode. We also propose two evaluation values calculated from measured voltage to represent the movement of an arm. Using a fuzzy method based on these values, we can represent the movement of an arm fairly well. We applied this fuzzy method to driving an arm-type actuator, which can reproduce the movement of an arm.

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An ionic conducting polymer gel film (ICPF) actuator, which is a kind of high polymer gel actuator, is a composite that has a 184-μm-thick perfluoro-sulfonic acid membrane sandwiched between platinum layers. In this paper, modeling of the actuator is investigated. First, the modeling strategy of the actuator dynamics is considered because the principle of the actuator is unknown. The assumption of division of its characteristics between input (voltage) and output (displacement) into three stages: an electrical stage, a stress generation stage and a mechanical stage, is reasonable according to observation and consideration of the actuator responses. The electrical characteristic model involves surface resistances comprised of porous platinum layers, resistance of the gel membrane permeated with water, and a characteristic resembling a 1st-order delay that is expressed in terms of series connections of a resistance and capacitance. A distributed parameter system consisting of the above elements can be used to represent the electrical dynamics of the actuator.

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We propose a force control algorithm for a Stewart Platform parallel link manipulators. First, we design a control scheme for a one degree-of-freedom hydraulic actuator, then we extend the control scheme to the parallel link manipulator. The hybrid force/position control scheme for the parallel link manipulator is also proposed. The control scheme design is based on a velocity based force control algorithm so that we can use velocity-controlled hydraulic actuators as parallel link manipulators. The proposed algorithm is applied to an experimental system and the results illustrate the validity of the system.

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We propose a control method for redundant manipulators for working to unknown objects. When a manipulator's hand tracks a desired trajectory on the surface of an object of unknown shape, trajectory tracking and obstacle avoidance should be controlled at the same time. Real-time operation to an unknown object requires to achieve measurement, path planning and control simultaneously. We present a new method which controls redundant manipulators based on the planning of a collision-free arm form assuming a system for 3-D measurement of the object's configuration. The planning problem can be solved by the penalty method as a nonlinear planning problem with restricting conditions. The penalty method gives the collision-free arm form for the desired future trajectory utilizing an imaginary manipulator. We realize the functions of operation and collision-free movement for unknown objects, using a preview controller which changes the current arm form referring to the future arm form, using its redundancy. Effectiveness is confirmed by simulation experiments.

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This paper describes state estimation for vibration suppression control of a flexible macro/micro manipulator system in which the flexibility of the link is considered. This macro/micro manipulator system consists of a macro and flexible manipulator and a micro and high-performance manipulator carried on the macro manipulator, like a hot-line work robot system. A vibration suppression controller using a state observer is designed based on the dynamic model. A state observer for a flexible manipulator is influenced by forced deflection and multiple vibration modes, so an observer which takes into consideration static deflection and pole assignment is proposed. The proposed observer is a hybrid of those designed for a flexible link and a rigid link. Results are composed with those from an observer for a rigid link. Simulation results for the estimation show the effectiveness of the proposed observer.

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Recently, there have been many theoretical studies on classifier systems and their engineering applications. However, the learning architecture of classifier systems has brittleness about multi purpose environment. Namely, the learning is not convergent in a multi purpose environment. We consider a cause of those phenomena is that changing purpose in the environment causes to break previous learning results. The objective problem is how to improve the learning architecture of classifier systems in a multi purpose environment. For this purpose, this paper introduces the concept of organized rules which are formed virtually by combination of primitive rules. Using the concept of organized rules, we propose to extend the framework of classifier systems which can form and learn organized rules. Computer experiments show that the proposed method enable effective learning in a multi purpose environment through comparison with conventional classifier systems.

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In this paper, we propose a new reinforcement learning algorithm to generate fuzzy controller. This algorithm generates a range of continuous real-valued actions, and the reinforcement signal is self-scaled. This prevents the weights from overshooting when the system receives very large reinforcement values. The proposed method is applied to the problem of controlling a brachiation robot, which moves dynamically from branch to branch like a gibbon swinging its body in a pendulum fashion.

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We describe an autotuning method of feedback gain for a small-diameter tunnelling robot. We have already proposed a directional control method in which the head angle of the control input is the sum of the deviation multiplied by the feedback gain K_p and the angular deviation multiplied by the feedback gain K_a. We used a neural network to automatically optimize the feedback gains K_p and K_a. However, this conventional method required too much learning time in the neural network. Therefore, in this paper, we use a genetic algorithm to automatically optimize the feedback gains. This genetic algorithm is a search algorithm based on the mechanics of natural selection and natural genetics. The problem of optimizing feedback gains in this paper can be regarded as the problem of searching for a combination of feedback gains which is a individual making the best fitness in individuals. We designed individuals which have an artificial gene consisting of a string expressed by the binary digit vectors of K_p and K_a. We simulated evolving individuals using the genetic algorithm to search for optimum feedback gains. This method finds a solution more quickly than the conventional method. We show computer simulation results and verify the applicability and usefulness of this method.

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A sliding mode control scheme with a discrete time control model is applied to posture control of a parallel biwheel vehicle (PBV) which is driven with a stepping motor operated in an open-loop mode. Both equivalent and discontinuous control inputs are applied to the PBV. The former brings states on a sliding surface to the origin of state space along the surface. The latter causes states off the sliding surface to move toward the surface and be bound on it. Posture of the PBV can be controlled within ±0.005 rad around an unstable equilibrium position when the PBV starts from an initial inclination of 0.1 rad off the perpendicular. Trajectories of the initial response in state space reveal that the state of the PBV is closely bound on a sliding surface, hence the sliding mode is established. The stable initial responses are also maintained under additional weighting of up to 1.5kg, which is almost equal to the weight of the PBV, near the center of mass or on the bottom of the PBV. The vehicle can easily recover stable posture when the body is pushed from the stable position. Consequently, the occurrence of the sliding mode is confirmed using the PBV with the step rate as the control input. The sliding mode can result in quick response, stable posture and robustness of the vehicle motion.

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We present the vibration control of a self-standing quadrupedal walking robot with one-degree-of-freedom mechanisms which are called YT-mechanisms. Our developed robot walks with trot gait, in which its weight is supported by each pair of diagonally opposite legs alternately. The experimental results show that the natural frequency of first-mode vibration changes with the rotational angle of the mechanisms. The movement of feet's position generates imbalance force which makes the elastic displacement of legs and the vibration during walking. In order to reduce the vibration, we propose to use dynamic absorber as a passive vibration control device and investigate the influence of the tuned frequency of it. Experimental results show the advantages of this method.

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Manipulator motion on a spacecraft disturbs the stability of the spacecraft attitude. It is not realistic to control the spacecraft and the manipulator as one dynamic system since the number of degrees of freedom becomes too large to be handled by the onboard computer. The coordinated control of the spacecraft attitude control system and the manipulator control system is a realistic engineering solution. This paper introduces the concept of coordinated control of the spacecraft attitude and the manipulator. A method for the real-time estimation of the manipulator reaction for the coordinated control is also discussed.

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During earth-to-space teleoperation, time delay seriously reduces the operator's ability to perform given tasks. Time delay effects appear in both the visual feedback loop and the force feedback loop. Using visual feedback with time delay, the operator is forced to adopt the strategy of "move and wait." On the other hand it is well known that time delay in the force feedback loop causes instabilities. To overcome these problems, we propose a predictive display technique based on the concepts of optimal approach velocity and virtual beam. Experimental results show that a peg-in-hole task, which includes a contact task, is performed very effectively by our method even with long time delay. The effectiveness of our method has been verified from various viewpoints. As a result, we show that our predictive display of the end-effector for noncontact mode is helpful not only for noncontact tasks but also for contact tasks.

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In this research, we address the organization of group behavior on decentralized autonomous robotic systems. Collective group behavior is exhibited in the natural world, such as by ants and fish, in teamwork in sports and by the human society. Therefore, research on group behavior of decentralized autonomous robotic systems can be regarded as one the research fields of Artificial Life. Decentralized autonomous robotic systems refer to multiple robotic systems including many autonomous robots, such as the Cellular Robotic System (CEBOT). The CEBOT, which has been studied by the authors, consists of a number of robotic units called "cells". In research on the CEBOT, it is necessary to evolve a cooperative group behavior effectively in the system, since a well-organized group behavior is required to carry out given tasks efficiently and influences its performance ability. In order to organize the behavior in a dynamic environment, we proposed a concept of the "self-recognition" for the decision making of the behavior in a robotic group. In addition to the proposed concept, this paper will show a construction mechanism of group behavior using the character of the attractor. Based on this idea, we present the behavioral evolution of a group robotic system.

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In this paper, path planning for robots by the distributed autonomous robotic system (DARS) in an unknown or partially known environment is described based on distributed sensing. We believe that the basic problem of optimality for path planning and replanning in an unknown or partially known environment is related to the environmental information robot acquired. In particular, the key to increasing the efficiency of path replanning is to enhance the ability of the robot to sense its environment. Considering the characteristics of sensing information in DARS, distributed in time, space, and function, we propose that it is practical for each robot in DARS to use (integrate) sensing information of other robots so as to compensate the lack of a single robot's ability to sense. Through our simulation experiment, it is shown that the efficiency of path planning and replanning for a single robot in DARS is clearly improved based on distributed sensing. In considering the uncertainty of sensed environmental information, methods of handling uncertainty in sensing information exchanges among robots and environmental representation, and approach for path planning and replanning are also described.

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Sliding wear tests of carbon steels and stainless steels were conducted in various environments. The mild and the severe wear modes, and their transition occur in NaCl and Na₂SO₄ solutions as well as in dry conditions for every test materials. The transition loads of SUS304 and SUS630 are smaller than those of carbon steels and SUS440C in NaCl and Na₂SO₄ solutions. The ranking of the transition loads among these steels can be estimated from their corrosion potential, that is, less noble steels show high transition loads. The mild wear rates of stainless steels at low load, which are smaller than those of carbon steels, decrease with an increase in corrosiveness of liquid. From the experimental results, criteria for selection of antiwear materials in corrosive liquid environments are proposed.

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To clarify the seizure resistance of stainless steel rollers of which the surface layer was thermally diffused after being Sn-plated, a two-roller test was carried out with grease lubrication. From the tests, the following results were obtained. The coefficient of friction of the roller with the Sn-diffused layer at the incipient stage of seizure, when lubricated with grease containing molybdenum disulfide additive, was considerably higher than that without a diffused layer. The load at the incipient stage of seizure of the roller with the diffused layer was larger than that of the roller without the diffused layer, and the effect of the diffused layer on the increase in the seizure resistance of the roller was recognized. However, the seizure resistance of the roller was decreased due to the molybdenum disulfide additive. The critical temperature of the roller with the diffused layer was higher than 400°C, and this was higher than that without a diffused layer.

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The authors proposed the hourglass worm gearing with helical Involute gear wheel, and made the numerical simulation and the experiment and confirmed the usefulness of the proposed gearing in the 1st report. The authors tryed to get the initial tooth contact mark at any point on the middle plane on this worm gearing. The authors tryed to analyze the contact marks appears on the wheel tooth, when the both teeth were attached with each other during the rotation of the gearing. This contact marks are so colled the moving tooth contact. The authors developed the soft wear of this moving tooth contact containing the cutting and the assembling errors. This soft wear can also analyze the rotation angle errors.

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We have developed a system of theoretical analysis to predict the vibration behavior of a gear system which takes into account the dynamic properties of gears, shafts and bearings. To verify the proposed theory, the vibration of helical gear units with various gear ratios has been investigated experimentally. The dynamic transverse, rotational, tilting and axial vibrations of helical gears are measured using acceleration pick-ups mounted on the gear blanks. The experimental and analytical data show good agreement. Some observations on the vibration characteristics with various gear ratios have been made.

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This paper presents an analytical procedure for simulating torsional vibration in a power circulating-type internal gear testing machine. The differential equations for the rotation in the system were derived, and the root stress of the internal gear and the torsional vibration of the gear shaft were calculated. Then, the calculated results were compared with the experimental data. The relationship between dynamic tooth load and torsional vibration in a power circulating-type internal gear testing machine was discussed.

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This paper presents a study on vibration and noise of gears made of damping alloy. The logarithmic decrements of damping alloy were measured and compared with those of conventional steel. Vibration acceleration and sound pressure of helical gear pairs and spur planetary gears of damping alloy were measured under various running conditions using a power-absorbing-type gear testing machine, and the results were compared with those for conventional steel gears. Furthermore, the sound intensities of planetary gears made of damping alloy and conventional steel were also measured. The vibration and noise characteristics of these gears were determined. The vibration and noise of helical gear pairs and spur planetary gears made of damping alloy were found to be smaller than those of conventional steel gears.

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A new flexible CNC bending machine which is based on the penetration bending method (called the MOS bending method), was invented and developed by the author. The machine can bend a circular tube to the required bending radius, using only one penetration die rather than many bending dies for the corresponding bending radii. The distortion of the tube cross section, the bending force and bending limit are experimentally investigated for different die inclination angle and tube materials. Using an inclination angle of 25°, the bending limit is maximized, and the bending force, bending radius and distortion of tube cross section are minimized. The tube material does not affect the bending limit, bending radius or distortion of cross section. Bending radii and bending forces are affected by the tube material. The characteristics of circular tube bending are clearly explained, using the MOS bending methed.

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A new process for tube ironing, the "planetary conical rolling" (PCR) process, is proposed. A number of rollers rotate around the cone while revolving around their respective axes, preventing sliding friction which is the main cause of galling and breakage in the conventional ironing process. In the case of marked thinning, bulging occurs at the inlet, producing an unsteady process. In this study, PCR forming is improved by suppressing bulging during radial expansion. Keeping the reduction constant, R=0.42, the radial expansion ratio E was varied as 0.025 and 0.049. Two motions, forward and backward, of the tube and die, were tested. The deformation characteristics were discussed based on the strain measurements and stress conditions on the equilibrium equation. From the discussions it was clarified that bulging is suppressed by the bending tensile stress and circumferential extension. Furthermore, the optimum conditions for suppressing bulging and the mechanism of producing a mirror finish were discussed.

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A method for determining the appropriate range of roll speed in twin roll strip casting, from the results of the finite-element simulation, is proposed. In the simulation, metal flow and temperature distribution in twin roll strip casting are respectively calculated by the viscoplastic and the heat conduction finite-element method. The upper limit of the roll speed is given when the final solidification point is located at the exit of the roll gap, and the lower limit is determined as the point of onset of backward flow of the solidified shell into the pool of molten metal. The upper and lower limits of the roll speed are also obtained from the solidification coefficient and the drawing limit of the solidified shell into the roll gap, respectively. The predicted ranges of the roll speed for various thicknesses of the strip agree well with those determined from model experiments using paraffin wax. In addition, the roll speed for providing a desired strip thickness in the case of variable roll gap is predicted from the roll separation force.

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Deep hole drilling with a depth of ten times a small hole diameter is used in the automobile industry. In the previous paper the author investigated drilling of holes with depth of up to five times the diameter, and showed that vibration drilling is effective for this. This paper concerns chip formation and disposal in drilling of holes with depth of ten times the hole diameter. The results are as follows. When a deep hole is drilled, contact resistance between chip edges and the hole wall increases and produces chip congestion. Increase of the feed speed helps to prevent this congestion. Vibration drilling disposes of chip easily at a fast feed speed because it accelerates the penetration of oil and produces a large variation of chip thickness. Easy chip disposal in vibration drilling extends drill life in comparison with conventional drilling.

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This paper presents an optimal tool replacement procedure in automated multi-stage machining systems. In multi-stage machining, if one of the k(≥2) tools fails during the cut, the workpiece in-process becomes defective and an interruption of the cut occurs. A statistical model for the design of optimal tool replacements and cutting speeds is constructed using the minimum production cost criterion. A numerical example of the optimal design is given in the case of a k=2 stage machining system.

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The application of a focused gallium ion beam to cutting of a free-standing nickel-titanium alloy film pipe was studied. The pipe was first cut at the part where beam irradiation angle was 40-50 degrees to the normal line of its upper side when a beam was scanned with an intersection angle of 90 degrees to the axis of the pipe. The beam penetrated from the kerf, and the underside of the pipe was cut from the inside. It took a long time to cut both the right and left ends of the pipe. However, they could be cut in a short time by scanning the beam so as to increase the number of ions irradiated to them in a unit time.

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This paper proposes a simple and practical procedure for estimating the cutting temperature and the heat flow rate into the workpiece for arbitrary cutting conditions in three-dimensional cutting. In the analysis of cutting temperature, numerical approaches proposed by Lowen and Shaw, which were originally intended for orthogonal cutting, are extended to three-dimensional cutting operations. Cutting temperatures so obtained are found to be in good agreement with the experimental data under various cutting conditions. The heat flow rate into the workpiece is evaluated experimentally using a radiation pyrometer, and is also analyzed by a finite difference method. It is concluded that the heat flow rate is influenced not only by the thermal number and the shear angle but also by the ratio of the corner radius to the length of the major cutting edge.

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This paper deals with fundamental research on the development of human-oriented CNC machine tools which allow workers to feel pride and pleasure in making full use of their abilities in manufacturing. As a step toward realizing human-oriented CNC machine tools, we tried to extend the sense of touch of workers by developing cutting a torque feedback handle through which workers can feel the rotational resistance corresponding to cutting torque. This system has been evaluated by inexperienced and skilled workers of engine lathes and CNC machine tools using the information integration method. The results show that use of the cutting torque feedback handle greatly improves workers, satisfaction when carrying out NC lathe work.

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The shape of cutting edges on a wheel surface is an important factor which affects the grinding characteristics. We investigate the shape of cutting edges on the surface of a resinoid-bonded CBN wheel just after truing with a rotary diamond dresser, and its influence on the grinding force, wheel wear and surface roughness. Through stereo-SEM observation of the wheel surface, the following results are obtained. (1) In an up-cut truing operation where the rotation speed of the CBN wheel and the dresser is negative, bond material and CBN grains are removed at the same time. Therefore, the operation shows a high truing performance, and results in a large flat area on the individual CBN grains. In the next dressing operation, the layer which contains the flattened CBN grains has to be removed to obtain a better grinding result. (2) In a down-cut truing operation where the rotation speed ratio is positive, CBN grains are crushed and fractured on a large scale, or released from the bond surface. Therefore, in a down-cut operation precise truing is impossible.

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