This paper deals with analysis for acoustic properties of three-dimensional closed sound fields having sound absorbing materials. In this analysis, the sound absorbers can have arbitrary shapes and can be located anywhere in the fields. The fields involve gas and sound absorbers which are modeled using Finite Element Method. A new three-dimensional element are developed for the absorbers. This element has two damping parameters which are complex density and complex volume elasticity. The elements are constructed, and then the corresponding simultaneously coupled equations are solved to obtain the frequency response. Further, a new expression is also derived to get distribution of contribution to modal damping for each element. These approachs are applied to three-dimensional rooms where the absorbers exist in different positions. The results are compared with the experiments carried out by Utsuno and are discussed.

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This paper proposes an efficient method for estimating natural frequencies of roll-tensioned disks. In addition, initial stress stiffness matrices necessary for calculating natural frequencies are efficiently estimated. The proposed method based on SDM (Structural Dynamics Modification) technique estimates the natural frequencies after roll-tensioning from the natural frequencies and mode shapes before roll-tensioning and initial stress stiffness matrices by roll-tensioning. The examples show that when small rolling load is applied, a one-dimensional eigenvalue problem produces the accurate estimation. When the estimation errors by the one-dimensional eigenvalue problem are large, the coupled eigenvalue problem must be solved. In this case, a small-sized eigenvalue problem is sufficient because the mode shapes after roll-tensioning are expressed by the mode shapes before roll-tensioning with the same number of nodal diameters and the different number of nodal circles.

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Using the infinitesimal loop model that is moving through the nonuniform magnetic field in space, the effective expression of the magnetic damping force is derived. This method has an advantage of calculating no scalar potential and it is easy to compute the magnetic damping force by using the static magnetic field obtained by FEM, measurements and so on. By the way, a magnetic damper used in turbo-molecular pump and so on in order to reduce vibration sometimes generates unstable vibrations. In this report, it was made clear that the Jeffcot rotor with the magnetic damper generated the unstable vibration in the experiment over a critical speed, and the present method was available for investigating the cause of the unstable vibration due to asymmetric stiffness matrix. Then a good agreement between the analytical and experimental results was confirmed.

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This paper is concerned with the conical mode instability of a rotor equipped with flexible cantilever beams in the radial direction at regular intervals. The stability of the disturbed whirling motions of the system is investigated both by theory and experiments. The major results obtained are as follows: When the bending stiffness of the attached beam is isotropic, the conical mode whirling of the rotor can excite the beams only in planes containing the rotating axis of the rotor. In such a case the first natural frequency is always higher than rotating speed of the rotor so that the conical mode whirling motion is stable at any rotor speed. However, when the beam stiffness has a strong anisotropy, the vibration of the beam is excited in the most flexible direction where the first natural frequency can be lower than the rotor speed. Thus, the system can be unstable. A selfexcited whirling motion of the conical mode can be induced when and only when the rotor speed is nearly equal to the sum of the natural frequency of the forward-precession of the rotor and the first natural frequency of the beam. The theory is verified by the experiments.

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This paper studies bifurcation set of a nonlinear system with time delay. It is known that it is difficult to investigate this system by analytical methods, because this system is described by a difference-differential equation which is usually difficult to solve. To analyze this kind of a system, we have already introduced an averaging method for the functional differential equation. The previous work showed that this averaging method is effective for nonlinear system with time delay. Applying this averaging method, this paper studies bifurcation set of this kind of a system with a fundamental harmonic response. The result shows that this system have a simple harmonic motion, when a delay is small and an angular frequency of external force is large. Furthermore, it is shown that this system have a derivative point from which the Hopf bifurcation curve, a saddle-node bifurcation curve and homoclinic bifurcation curve are derived.

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A new vibration-type mass measurement system using an undamped dynamic vibration absorber was developed. In the developed system, a measurement object is attached to the inertial mass of the vibration generator instead of the absorber mass. It has an advantage that the tuning condition of the absorber is not influenced by the mass of measurement objects. The measurement accuracy of the developed system was estimated experimentally when it was fixed on a rigid base and on a flexible structure. The results demonstrated that measurement accuracy was almost same in both the cases. It was also shown that the vibration of the table in transient states was reduced by increasing the excitation signal gradually from zero to an amplitude for measurement.

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This study discusses the positioning and vibration control of time-varying vibration systems whose parameters are time-varying. We assume that the time-varying parameter of a vibration system is detected by an on-line measurement or Wavelet analysis. This paper treats two control methods using nonstationary optimal regulators (NOR) for this problem. The first method is a gainscheduling of NORs. An actual controller is obtained by the interpolation of plural NORs designed a priori. The other one is an NOR design based on Wavelet analysis of the vibration system. In the second case, single NOR derived from the analysis result is applied. This study shows the effectiveness of these methods by numerical calculations and experiments. From the comparison of these methods, this paper suggests suitable applications of NOR according to the characteristics of each control problem.

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In this paper our proposed design method of a gain-scheduled controller is verified for vibration control of a multi-degree-of-freedom structure by using of an active dynamic vibration absorber with actuator constraints. We formulate the linear parameter varying system taking account of both the maximum control input and the maximum stroke of the actuator by using nonlinear functions of hyperbolic tangent. As the feedback signals of the gain-scheduled control system we use the relative displacement of the primary structure or the acceleration of that as well as the stroke of the auxiliary mass. From the experimental results, it is shown that the closed-loop system has good performance even if saturation phenomena of the actuator occur against not only an impulsive disturbance but also the nonstationary random disturbance such as earthquakes.

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The flexibility of the mechanical system is one of the factors of the bandwidth limitation. Especially, it is known that an out-of-phase vibration mode makes the closed loop unstable with the negative feedback of the positioning error. In this paper, a novel mode shaping method for in-phase design of flexible structures is proposed. From the relation between the modal analysis and the statespace representation, we classify in-phase mode shaping into two types based on the boundaries which are passed across during the shaping process. By the proposed method, the out-of-phase modes are shaped into in-phase in order of the natural frequencies applying a task priority based modification scheme. We also propose a method of selecting the boundary, so that the vibration mode is shaped into the arbitrary type of in-phase design.

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Rotary crane control based on several discretizing methods has been proposed in this paper. The motion of the crane load is described by a discrete time system by assuming zero order and trapezoidal hold for the boom rotation. The stabilization of the load boils down to a finite settling time problem with constraints. This problem is reduced to solving a 6-th order equation for five step case, and an optimizing problem with constraints for more step case. Various simulation results have been given to show the effectiveness of the proposed method.

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The dynamic vibration absorber (DVA) is a passive vibration control device which is attached to a vibrating member (called a primary system) subjected to exciting force or motion. In this paper, we discuss an optimization problem of the three-element type DVA on the basis of the H₂ optimization criterion. The objective of the H₂ optimization is to reduce the total vibration energy of the system over all frequencies; the squared area under the frequency response curve of the system is minimized in this criterion. If the system is subjected to random excitation instead of sinusoidal excitation, then the H₂ optimization is probably more desirable than the popular H_∞ optimization. In the past decade there has been increasing interest in the three-element type DVA. However, the previous study on this type of DVA was based on the H_∞ optimization design, and no one has been able to find the exact solution. We propose the closed-form exact solution for a special case where the primary system has no damping; whereas numerical solutions are present for the general case when the primary damping is not negligible. The solutions obtained here are compared to those of the conventional Voigt type DVA.

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Experimental results are presented for self-excited vibration of an automotive wiper. The self-excited vibration is generated by a stick-slip motion. It is of practical importance to suppress the self-excited vibration of the wiper. To find out modal coupling in the vibration of the wiper, simplified wiper is constructed. Movement of simplified wiper is separated into horizontal and vertical directions to simulate a motion of the actual wiper. The simplified wiper and the actual wiper are used for experiments. Static deformation of a wiper blade is measured. The blade is pressed on a glass surface. The wiper blade shows characteristics of soft-hardening spring involving a buckled deformation. Modal coupling in the self-excited vibration is examined by sweeping the wiper on a rotating glass table with constant angular velocity. Increasing a load pressed on the blade, coupling vibration is generated due to self-excitations along glass surface and parametric movements in vertical direction. The vibration amplitude is suppressed extremely when the load is close to the buckling load. Moreover, the maximum Lyapnov exponent of the dynamic response shows least number of the modes contributed to the self-excited vibration.

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The 1995 Hanshin Awaji Earthquake caused enormous damage to Container Cranes at Kobe Harbor. It was reported that a behavior of container crane under strong earthquakes involved uplifting and slipping of their legs. However, such behavior is not taken into consideration in the seismic design of crane, because of the difficulty due to its nonlinearly. The purpose of this study is to present a new method of the seismic isolation system for the container crane by comparing the horizontal isolation system. This paper presents the rocking type of vibration, its performance is investigated by the nonlinear transient analysis of 3-D FEM. The results show the availability of the rocking type of isolation system as well as horizontal isolation system.

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The restitution characteristic of fiber string in axial direction was analyzed with considering the visco-elasticity of yarns. An impact test was developed that one side of string was fixed in load cell, the other side was fixed in hammer. The hammer moves along the slide rail. When the hammer was struck, the impact speed of hammer was measured with the laser sensor, and the restoration ratio was obtained. In experimental range for all samples, the restoration ratio became small with the impact speed. A dynamic restitution model considering tensile non-linear visco-elasticity of materials was suggested. The good agreement was obtained between the experimental and the theoretical values. It was also shown that the repulsion of tennis strings could be evaluated with the parameter of the proposed model.

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It is important for senior brass instrument players to study the detailed control parameters for embouchure building. While many investigators have reported the preliminary data on the muscle behavior, the precise aspects are unrevealed so far. The purpose of the present paper is to study dynamic perioral muscle behavior of French horn players and to investigate their lip valve function by measuring the contact pressure on teeth buccal surface during playing. It was shown from the experimental results that the advanced players contracted depressor and levator angulioris especially for high tone playing. The combined contraction by these muscles may contribute to smaller lip aperture formation appropriate for higher tones. Inversely a strong contraction of m. buccinator was found insignificantly from the results for the advanced players while it is well known that m. buccinator contracts hard during playing.

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This paper proposes a control method of a flexible arm using virtual joint model. The virtual joint model of a flexible arm has many parameters that have to identify from measured dynamic and static characteristics. An adaptive control scheme is introduced to avoid a difficulty and complexity of this identification. But, a model reference adaptive control system cannot be applied for a tip position control of a flexible arm due to its non-minimum phase characteristic. Then, we designed an adaptive-type predictive control system to achieve the tip position control. Simulation and experimental results demonstrate an effectiveness of the proposed control system.

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Pneumatic motors have not so far been well-studied in the robotics literature, despite their many advantages. In particular, vane-type pneumatic motors have the advantage of high power-to-weight ratio. In this paper, we develop light-weight pneumatic motors in order to enhance the power-to-weight ratio. We have ptopose a sliding mode control method using difference pressure to improve control performance of vane-type pneumatic motors. Effectiveness of the proposed method has been demonstrated through some experimental results. However, this method has a significant steady state error. Therefore, we propose the development of hybrid pneumatic/electric motors where a small electric motor is used to reduce the steady state error. We explain the design methodology for hybrid pneumatic/electric motors. And we propose control algorithms for position control. The performance of the proposed hybrid motor is demonstrated by several experimental results on position and force control.

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A parallel impedance control architecture with force-reflection is proposed, in which a telemanipulation system is partitioned into an [operator+master] part and a [slave+object] part, and is named as two parallel subsystems, i.e., O-M subsystem and S-O subsystem. Consequently the virtual impedance of master and slave can be set independently to enable that the stability problem can be decoupled from the transparency problem. In order to realize the ideal response, the detailed policy for setting the virtual impedance of master and slave is given respectively with the consideration of keeping the impedance characteristics of the two parallel subsystems identically. Besides, a virtual input which is calculated based on O-M subsystem is fed into S-O subsystem in order to guarantee that the two parallel subsystems have the same input. The proposed control architecture is applied to a hydraulic master-slave system and its validity is proved by the experimental results.

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It is important in practice use for robots to contact an object or environment around the robot. At the moment of the contact, an impulsive force, or impact, may cause a discontinuous change of the state of the robot. Since the impact strongly depends on the configuration of the robot at the moment of the contact, the precise control of the configuration of the robot is needed. Authors have proposed a path following control method based on dynamic parametrization, that makes the robot follow the desired path efficiently. In this paper, the above method is applied to a manipulator system with impact. And it is shown that this controller with high feedback gain can stabilize the system with impact. Results of computer simulations validate this result.

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We have been developing a casting manipulator which includes a flexible string in the link mechanism to enlarge the work space of a manipulator. In this paper we deal with the mid-air trajectory control of the gripper after throwing it. First, we examine dynamic characteristics of a flexible string against impulse. A flexible string is modeled as a viscoelastic model. We estimate model parameters of a flexible string through free fall experiments. Then we propose the utilization of impulsive force applied to the gripper in the air through the string by restricting the motion of the string. Investigating the generation of the impulsive force through experiments, we confirm the effectiveness of the method, which is evaluated by comparing the results of numerical simulations with those of the experiments using our experimental casting manipulator hardware.

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We have been developing a casting manipulator which includes a flexible string in the link mechanism to enlarge its work space. In the casting manipulation, a gripper, which is attached at the end of the string, is thrown to a target by releasing the string at suitable time after generating enough motion by swinging. In this paper we deal with the posture control of the gripper after the throwing motion. After we point out a problem of throwing the gripper while considering its posture at catching, we propose a method of applying an impulsive force to the gripper in the air through the string by restricting its motion. Investigating the characteristics of the string through experiments, we confirmed the effectiveness of the impulsive force. This method was evaluated by comparing the results of numerical simulations with those of the experiments using our experimental casting manipulator hardware.

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In order to investigate the problems related to soil and construction machinery, such as a hydraulic excavator, an understanding of the physical interactions between the soil and the machine is essential. The purpose of this study is to experimentally examine actual excavation processes by observing a variety of physical parameters, with the aim of realizing intelligent excavation machinery whose performance is not only to be automated but also optimized in terms of specific task criteria such as, energy consumption, operation time and excavation trajectory. In the previous three reports, we measured and analyzed excavation processes from the viewpoint of force interactions. In this article, we developed an automated excavator based on the knowledge acquired through the previous study and investigated essential factors for intelligent excavation machinery. As the final report of this study, we discussed how intelligent machinery should be realized from a design theoretic point of view.

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In this paper, we propose a motion planning method for cooperative transportation of a large object by multiple mobile robots in a complicated environment. We must plan the motions of the object and mobile robots to avoid obstacles in a three-dimensional environment. A computation time to solve this problem is exploded, since we need search a solution in a high dimensional configuration space (C-space). Accordingly, we reduce the dimensions of C-space using the feature of the transportation by multiple mobile robots. In our method, all things (the object, the robots and the obstacles) are represented by an octree that is the approximate cell decomposition method for a three-dimensional environment. We can find a solution with A^* search algorithm in this smaller dimensional C-space using the potential field. We verify the effectiveness of our proposed motion planning method through simulations.

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This paper presents a 3D positioning method for mobile robot. Three landmarks, each of which consists of two tilting reflectors, are placed in an environment. The robot senses bearing angles relative to the reflectors using the on-board laser scanner, and it finds its own 3D position and attitude based on geometry. In this paper, the laser based positioning system is integrated with a 3D dead reckoning based on wheel encoders, yaw-rate gyro and inclinometer. The integrated system can maintain highly positioning accuracy by reliably identifying the landmark reflectors in a real environment where any reflected objects except them may exist. Simulation and experimental results validated the proposed positioning method.

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This paper deals with a theoretical and experimental study of parametric vibrations of flexible bellows subjected to oscillating internal fluid pressure excitation. In the theoretical analysis, the bellows are treated as a Timoshenko beam including the effect of the internal fluid pressure. And the Mathieu's type equation is derived from the basic equation of the bellows. The transverse natural frequencies of the bellows and the parametric instability boundaries are calculated. As a result, it is found that the transverse natural frequencies of the bellows decrease with increasing the internal fluid pressure and that primary and secondary parametric vibration occur in the bellows due to the oscillating internal fluid pressure excitation. And the theoretical results of the parametric instability boundaries agree well with the experimental results.

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This paper discusses an experimental study of the propulsion performance of an aquatic mobile robot using waving motion of a flexible plate modeled on the flexible caudal fin of fish. In the experiment, the propulsion force and side force generated by the waving motion of the flexible plate are examined in stationary water in a channel. And the propulsion speed and efficiency are examined with varing the length and flexiblility of the plate. As a result, it is found that the propulsion performance of the robot becomes high when the traveling-wave motion occurs in the flexible plate. And high propulsion performance of efficiency of 62% is obtained by using the traveling-wave motion of the flexible plate.

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If a mathematical model is provided for an oil hydraulic device, its stability can be analyzed on the basis of the poles of the governing transfer function derived from the model. When the device is connected to pipes where the changes of pressure and flow are propagated as waves, however, the transfer function becomes too complicated to find its poles even numerically. The present paper intended to break through this difficulty by utilizing "Locus Method", which is a calculus of roots formerly developed by one of the present authors. The method was tested for a sample circuit consisting of a poppet valve, a tank and a pipe connecting both, proving capable of accurately calculating the eigenvalues. With those eigenvalues it became possible to examine how the stability of the circuit depends on the pipe length and other model parameters as well. In consequence, it turned out that the viscosity cannot be neglected for stability analysis of an oil hydraulic circuit including pipes. Finally, the self-excited vibration of the poppet valve was actually measured and was compared with the analysis in terms of the excitation frequency.

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In this study, we proposed a new method to calculate the fractal dimension by using a wavelet transform which is a time-frequency analysis method and try to evaluate the change of the similar structure in an unsteady signal. The procedure of our method is: 1) carrying out wavelet transform of the unsteady signal and obtaining the information about both time and frequency. 2) calculating the fractal dimension at each time from the wavelet transform of the unsteady signal. 3) evaluating change of the similar structure in the unsteady signal by using the fractal dimension obtained. Then the unsteady turbulence, such as jet flow and tumble flow in an engine were analyzed by using our approach. As a result, the change of the eddy structure can be shown very well.

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As elderly society progresses, development of machines for assisting human to walk is getting more important nowadays. Authors have already developed a cart-type machine to assist walking on a flat ground and have evaluated the effect of this machine on the muscle tension and energy consumption of the user. In this paper, we have estimated the energy consumption during walking on slopes based on the muscle-skeleton model. It is shown that 10% and 15% decreases of energy consumption are achieved by using the assisting cart during gaits up and down slopes, respectively. Our evaluation method will be useful for developing a walker for practical purposes.

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Mobility of elderly people is important for their life style to be active. In order to get their QOL higher level, tools for self-sustainable life should be prepared in first priority. The authors examined elderly people's life style, their physical characteristics and their ability for driving. The data of 41 subjects who live in rural areas where public transport is poor and private cars are main transport tools, reveal that the mobility level and active level for life are highly related and vehicle fitted for their ability is necessary. The vehicle design function is discussed.

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One of the main requirements for the successful use of Statistical Energy Analysis (SEA) is to divide a whole system into proper subsystems. It is assumed that the couplings between subsystems are weak in SEA. An SEA model without proper subsystems often provides unpleasant analytical results. This paper described a new method to judge whether the part on a system can be divided into two subsystems. On the basis of numerical study of a coupled beam system with Finite Element Method, an indicator for the judgment was defined as the ratio of initial slope of response on receiving subsystem to that on driven subsystem. The indicator was verified to be useful for determining the necessity of subdivision on two simple coupled beam, coupled plate systems and a complex floor panel of an automobile.

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Speech recognition technology could help an electrical wheel chair to run easily and safely. Up to now, two methods about command mode have been used for study. In this study, we proposed two new methods by combining good points of two conventional methods. A remote controlled car was made to run by voice instructions, along test course including straights, a right curve, a left curve, a right turn, and a left turn. New methods were compared with two conventional methods in terms of maneuverability and accuracy. It has beenproved that our present methods were superior because frequency of instruction was less and accuracy of running was excel.

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Recently, ITS is researched all over the world for the realization of a traffic efficiency and a safety. This paper deal with a technique ahout vehicle tracking, which is the one of the ITS technical field, especially about measurement technique of relative position. As a method to measure relative position from proceeding to following vehicle, stereovision system is used in this system. By using the license plate on the proceeding vehicle, our system can track proceeding vehicle certainly, because OCR module in our system recognizes the license number. It was confirmed that our system could measure relative position precisely. Additionally, it was also confirmed by experiment using real experimental vehicle that this system is effective for vehicle tracking.

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The author showed that helical gears with bias tooth surface modification, a kind of three-dimensional modification, can secure quietness within the wide range of transmitted load in the previous paper. This paper discusses robustness of bias tooth surface modification against the manufacturing variation as a continued paper of the previous one. For this purpose, a Monte Carlo simulation that estimates the worst mesh exciting force under the specified manufacturing variation is established. Then, tooth optimization procedure that minimizes the worst mesh exciting force is developed and applied to gear pairs with various contact ratios. The result is shown by the contour map on the contact ratio plane and compared with that of two-dimensional modifications. As the result, the effectiveness of the proposed three-dimensional modification is clarified.

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The influences of the overlay on the seizure resistance of the crosshead-pin bearing for large size diesel engines were evaluated by using a dynamic load bearing apparatus. The running-in property was also evaluated by measuring the electrical resistance of the oil film. The major results are: (1) The seizure resistance of the aluminum-tin bearing plated with the tin-copper overlay using the tin bonding layer is much higher than that of the conventional lead-based overlay plated white metal and aluminum-tin bearings; (2) Increasing the copper content in the tin-copper overlay is effective in improving the seizure resistance. If the copper content becomes too high, however, the running-in property is degraded, thereby causing the seizure resistance to decrease; and (3) Increasing the overlay thickness is advantageous for improving the running-in property, and thereby raising the seizure resistance. If the overlay becomes too thick, however, seizure occurs within the overlay, thereby causing the seizure resistance to decrease.

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Low-cycle compressive fatigue tests on wave springs were carried out. In the experiment, two types of wave springs named L spring (large wave-radius of 10.5 mm) and S spring (small wave-radius of 1.5 mm) were tested. The influence of wave-radius and deflection applied during the tests on fatigue life was investigated. In order to clarify deformation characteristics, numerical simulations were carried out by a general 3D FEM. It became apparent throught the fatigue tests and the numerical analysis that the fatigue life depends on the wave-radius and deflection amplitude. The number of cycles to failure increased with decreasing the deflection amplitude. A force required to compress L spring becomes larger than S spring with increasing the defection. However S spring fails earlier than L spring. The reason for such phenomena was well explained due to the difference in the deformation behavior of the two springs from the FEM analysis considering the geometrical nonlinearity as well as the material nonlinearity.

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As a basis for improving the thermal shock resistance of brittle tools in high-speed intermittent cutting from the cutting condition's viewpoint, pure thermal shock was applied to the rake face of a cemented carbide tool by CO₂ pulse laser beam irradiations. The states of thermal crack appearance were observed with a high-speed video camera. The crack was generated during laser beam irradiation off time within 1/9000 s. The influence of the off time was examined experimentally on the number of irradiation cycles to the thermal crack initiation. A decrease in the off time caused an increase in the number. This was more remarkable in cutting edge laser beam irradiation, which corresponds to intermittent cutting, in comparison with internal laser beam irradiation. The cutting edge irradiation was a more difficult condition of the crack generation.

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Deposition method of thick film with low residual stress was investigated. The method controls residual stress by depositing compressive and tensile residual stress films in tum. Fundamental examinations were performed using plasma enhanced CVD in order to form thick SiO₂ film as an insulation layer with low residual stress. The influence of RF power of plasma enhanced CVD on residual stress was examined, and changes in residual stress according to the progress of time after deposition was observed. As a result, it was clarified that the tensile residual stress changes after deposition, and the compressive residual stress film on the tensile stress film is necessary in order to get stable tensile residual stress. When the processing pressure is kept at 120 Pa, the residual stress is proportional to RF power and is controlled freely in tensile or compressive condition by adjusting RF power. The method also can correct the substrate bow, which occurs during the fabrication process of ultra small electromagnetic motor. It was demonstrated that the initial substrate bow of 12 μm was corrected to approximately 1 μm using this method.

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Etching conditions of SiO₂ were investigated in order to fabricate the insulation layer of coils used for electromagnetic micro motors. The effects of cooling temperature of substrate, pressure, RF power, and the amount of reactive gases on the shape of insulation layer were examined using ECR-RIE method. CF₄ and CHF₃ gases were selected as reactive gases, and 18 μm thick insulation layer was processed. In coil fabrication process, Cu is electroplated after the etching of the insulation layer. The additional etching conditions of the insulation layer were investigated to get the uniform electroplated Cu film. From these experiments, the following conclusions were obtained. (1) The amount of side etching of the insulation layer was minimized under the conditions of RF power of 125 W and the flow rate of CF₄ and CHF₃ gases of 30 SCCM. (2) The selectivity of SiO₂ and Cu metal mask reached 20.6, and the aspect ratio of 9 (18 μm in height and 2 μm in width) was obtained. (3) During the etching process, ion bombarded the electrode film that was used for electroplating. The material etched by bombarded ion adhered on the surface of the insulation layer, and as a result, Cu was not electroplated uniformly in the cavity of the insulation layer. It was clarified that the electroplated Cu film grew uniformly after the cleaning process by O₂ gas.

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The fabrication process of coils used for ultra small electromagnetic motor was investigated, and flexible multi-layered coils were formed using the micromachining technique in order to make the cylindrical stator. Three kinds of process, that is, the flexible sheet forming process with wiring pattern of coils, the multi-layered spiral coils process with SiO₂ insulation layer deposited by the residual stress control method and the removal process of a silicon substrate, were proposed. According to these process, 5-layered coils with ten turns in each layer were fabricated on the flexible sheet with the wiring pattern. From the observation results of fabricated coils, it was clarified that coils of 18 μm in thickness and of 8 μm in width in one layer were formed and stacked. The substrate bow or 12 μm was also corrected less than ±2 μm by the residual stress control.

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A fabrication process was proposed to achieve ultra small electromagnetic motor of radial gap type. Based on this process, the motor stator was formed by such manner that flexible coils were rounded and fixed around the cylindrical core. A rotor consisted of a permanent magnet was made, and then, this rotor and the stator were put together. The fabricated ultra small electromagnetic motor was 1.6 mm in diameter and 2 mm in length. As a radial gap type electromagnetic motor with core, it is the smallest in the world. The torque, efficiency, and losses were evaluated, and the performance of the motor was investigated. From these experiments, the following conclusions were obtained. (1) The efficiency reached the maximum, when the radial gap between the rotor and stator was kept at 20 μm. (2) The power density of the fabricated micro motor was seven times larger than that of small size DC motor used in a cellular phone, and the torque of 1.5×10^-6 Nm was achieved. (3) The mechanical loss due to the friction of bearings occupied approximately 90% of the total losses.

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An investigation into the effect of fluctuations in environmental conditions on the degradation in the form accuracy of finished product is carried out when using ultra-precision aspheric generator with laser interferometric measurement system. It deals mainly with the profile error of finished surface and the relative displacement between tool and workpiece during raster flycutting. In order to correlate the surface profile with the change in air pressure, cutting experiments are carried out in a precisely air-conditioned environment of temperature change within ±0.06°C, humidity change ±1% and natural pressure fluctuation for up to 18 hrs. The relative displacement between tool and workpiece, the nominal positions of which are fixed respectively for long period of time (144 hrs), is carefully measured and analyzed by correlating with change in refraction index of air. Experimental results indicate that the deviations of surface profile from the reference line increase in proportion to those of air-pressure drift, and that the form accuracy is determined solely by the peak-to-valley of air-pressure deviations. Comparing the measurement with the analysis, it is confirmed that the linearity in the above profile-pressure relation results from the incorrect tool positioning due to the laser measurement error in proportion to change in air pressure during machining.

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The grindability of materials is investigated based on thermo-elastic-plastic finite element simulations of orthogonal cutting with negative rake abrasive-grits. First the cutting mechanism of steel SK-5 with negative rake is clarified. In high speed grinding, adiabatic shear, which lead to serrated chip formation, is observed. Then the influence of material properties of SK-5 and cutting conditions on the cutting states are analyzed. Analysis shows a critical uncut chip thickness, under which chip forms with great difficulty. The critical uncut chip thickness changes complicatedly when material properties including the strain hardening exponent, yield stress, thermal conductivity, and initial temperature, are changed. Finally, grinding performance or grindability is evaluated by means of the critical uncut chip thickness and chip geometry.

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In this paper, a Method of Selecting the Stratagems to Achieve Benchmarking Plant Efficiency Level Efficiently is presented. We propose AREA Theory which indicates Achievement Ratio Evaluation of the effected theoretical Area. It is proposed officially for the first time, based on the principle that improving the efficiency level in a shorter period contributes higher profitability. DEA Methodology is used to indicate Production Control Efficiency level of the Plant, and Benchmarking level is recognized as DEA equal to 1. The methodology to prioritize factors of the improvement to allocate limited resource is proposed as Weighted-Preferential Efficient Ratio. Then AREA Theory is adapted for Analyzing Effectiveness of the Improvement of the Plant. We demonstrate a Method of Selecting the Stratagems through the practical data of the plant which contains 8 major production controlfactors of the improvement.

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This paper deals with a simultaneous optimization of the layout of the functional modules and routing for their connection. To shorten the route length, a renovated routing method, the direction-oriented maze routing (DOMR), which has a function of divergence and confluence of the transportation routes is proposed. This method is applied to the design of module layout for automatic teller machines (ATM) including the layout of bill circulation routes as well. In the optimization process, the layout of module is first searched by the Bottom-Left (BL) algorithm; since the module layout depends on the order of operation in the BL algorithm, a genetic algorithm is used to determine the best order of the BL operation keeping pace with the DOMR. The obtained design solution is compared with the existing actual ATM and the effectiveness of the proposed design method is evaluated.

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This paper investigates the integrated optimality and optimal structure changeover of hybridtype systems. The environmental issue on the earth forces engineering design to configure new machines or equipments to reduce energy consumption or carbon dioxide gas release. While there are a few successful design implementations, it is essential to establish rational design scenario or methodology to accelerate a new design paradigm. This paper demonstrates the importance of system-based design and system-level optimality, which are accessed with any mathematical means, with an example of leading design of vehicles toward life-cycle optimality. After providing general conception, the system structure of vehicles are compared among gasoline internal combustion engine vehicle, THS-type hybrid electric vehicle and genuine electric vehicle in the aspects of fuel economy, total cost and life-cycle-based environmental impact. Furthermore, the influences of battery performance progress and the external changes such as environment taxation system or fuel price on the system structure optimality are outlined as examples of the utility of system-based optimal design methodology.

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