This study deals with the trajectory tracking control of a three-degree-of-freedom semiconductor wafer transfer robot arm driven hybrid stepping motors. The desired trajectory of the end of the robot is set to be a straight line, and the desired posture of the third link is constant. The high-precision control of the hybrid stepping motor is executed with the microstep drive technique. The desired joint angle is obtained by the microstep technique and the trajectory planning method based on the inverse kinematics. From the numerical calculation results and the experimental results, it is confirmed that the trajectory tracking control of the three-degree-of-freedom semiconductor wafer transfer robot arm can be successfully executed by the present high-precision control system with microstep drive technique. Furthermore, the error of the end of the robot arm is theoretically investigated.

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A new type of a tractor's continuously variable transmission (CVT), which consists of a 2 K-H type differential gear and a hydrostatic power transmission (HST) is devised. The hydrostatic power transmission (HST) consisted of a hydraulic pump and motor, which is a kind of CVT, has been applied to the smaller horsepower range of the tractor recently. One of concerns of the current HST system is lower efficiency on the power transmission. Then, further improvement for efficiency of the transmission is required more recently. The purpose of this development is to devise an adequate CVT providing with higher efficiency of the transmission in comparison with the current HST systems. Theoretical velocity ratio and efficiency of the CVT are investigated. And a prototype CVT is manufactured and incorporated into the tractor. The experimental results show that the efficiency of prototype CVT is several percent lower than theoretical value, but very nearly value. Then, the high efficient transmission for the tractor is offered. And the design method for the tractor's CVT that has high efficiency is built up.

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A printed circuit board (PCB) is equipped with electronic devices. PCB is a laminate composite made of copper and resin. Electronic circuit in PCB is made of copper. PCB is heated in a furnace in order to fix electronic devices. This process is called a reflow process. PCB deforms in a reflow process by thermal extension difference between copper and resin. An analytical model was proposed to calculate deformation of PCB. Laminate mechanical model and micro mechanical model were used in the modeling. Area of copper circuit pattern was optimally decided in order to minimize PCB deformation. The analytical model and the method of feasible direction were used in the optimization. Upper and lower limits of copper area decided by circuit design were taken into consideration in the optimization.

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Free vibrations of the clamped circular laminated plates containing double disk-shaped delaminations of different sizes are analyzed on the basis of the theory of a small deflection of plates. Embedded circular delaminations are placed at the plate center and a crack model assuming the contact of the two crack faces is then considered. Radial in-plane forces induced by bending in the parts of the plate above and below the delaminations are determined by modeling the crack part as two lapped discs hinged at the edge. Analyses and experiments are carried out for the effect of size difference of the delaminations on the natural frequencies. Theoretical and experimental results agree well, which validates the analytical models assumed in the present study.

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In this paper, we deal with transient nonlinear vibrations of a three-degrees-of-freedom vibration isolation system during passage through resonance. The DC motor with a limited electric current directly drives an unbalanced rotor in the system with/without '2-1-1' internal resonance. The basic equations governing such a transient vibration of the system, which take into account the second order geometrical nonlinearities of the displacements, are derived. The first order ordinary differential equations, which describe the electric current, the unsteady angular velocity of the rotor, the amplitudes and phases of the vertical, horizontal and rotational vibrations of the system are led with the use of the averaging method near the resonance frequency of a vertical vibration from the basic equations. The characteristics of the displacements, an angular velocity of the rotor and the electric current are theoretically examined during passage through resonance, in order to clarify the influences of the internal resonance and the limitation of the electric current. Finally the transient vibrations during passage through resonance are observed using the three-degrees-of-freedom experimental setup, and compared with the theoretical ones.

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An estimation method of damping properties for woven fabric composite materials has been proposed. To obtain the material damping of woven fabric composites, the maximum strain energy and kinetic strain energy are calculated by finite element method based on the strain energy method. The proposed method has been applied to plain woven fabric composites plates and compared with experimental results to evaluate the validity of the method. It is recognized that the computational results have agreed well with the experimental ones. Next, the effect of the angle of fiber bundles on material damping properties of plain woven fabric composites has been investigated by proposed method. From these points of view, the proposed simulation method is very useful for the estimation of material damping properties.

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We have developed an active roller guide system to suppress the lateral vibration of high-speed elevators. Lateral vibration is mainly caused by guide rail deformation and guide rail alignment error. We proved that the active roller guide system is theoretically better than other active vibration isolation methods from a point of electric consumption view. We have developed an original digital-filtering algorithm that enables to avoid waste of electric power due to low frequency noise of accelerometers. These optimum designs enable the development of low electricity consumption system. We manufactured an active roller guide and conducted experiments with actual elevators in experimental towers. Experimental results show that the active roller guide system is capable of reducing the lateral vibration of elevator cars to nearly half with low power consumption.

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In this paper, we propose a new Electric Power Steering (EPS) control and its design method. This control enables to transmit a vehicle motion information to a driver through a steering wheel. First, kinetic equations including characteristics of both EPS system and vehicle lateral motion are shown. Control-design policies are then derived from the frequency responses and the step responses of the vehicle equipped with EPS. In particular we regard the vehicle motion which is caused by a disorder of a lateral force balance between front and rear wheels as an important information that should be transmitted to a driver. A generalized plant is designed based on those equations and policies, and H-infinity controller is calculated from it. Finally, its effectivenesses are shown by vehicle experimental results.

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This article reports a full-scale structural simulation of flow-induced mechanical noise in a 5-stage centrifugal pump. An interior flow field is simulated by a LES-based CFD code individually, which can be found elsewhere. This paper focuses on data interface, and a structural vibration analysis. We developed a data interface tool to enable mesh match as well as data interpolation between fluid and structure meshes. The vibration of a structural portion is simulated using a parallel explicit dynamic FE code, providing the time series of fluctuating pressure on internal surface as force boundary conditions. The calculated vibration of outer surface of the structure agrees reasonably well with measured one. By Fourier transformation, the vibration modes at the blade passing frequencies were extracted and visualized. The simulation clarified the mechanisms of resonant noise generation and propagation.

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Experimental results are presented on chaotic vibrations of a cantilevered beam under vibroimpact. A rigid bar that is located close to the free end of the beam limits the amplitude of the beam under lateral periodic acceleration, and then asymmetric vibroimpacts are induced. In the frequency region of the impact vibration near the fundamental resonance of the lowest mode, two regions of chaotic responses are observed. There is one impact in an excitation cycle in the higher frequency region of the chaos, while occurrence of impacts in the lower frequency region is less frequent than the former one. The maximum Lyapunov exponent of the chaotic response in the higher frequency region takes higher value than that of the chaos in the lower frequency. Mode contributions to the chaos are inspected by the principal component analysis. The lowest mode of vibration prevails in the vibroimpacting response. In the regions of the chaos, contribution of the second mode of vibration to the chaotic responses increases up to 5%. As the exciting frequency is increased, the contribution of the second vibration mode to the chaos becomes larger owing to the increase in the amplitude of impact vibration. Furthermore, contribution of the second vibration mode drastically increases as the super-harmonic resonance of the second mode is generated. The maximum Lyapunov exponent increases as the contribution of the second mode increases, which implies the close relation between the complexity of the chaotic responses and the participation of the higher modes of vibration.

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The accuracy of simulation for automotive structure is increasing more and more. However, it is difficult to find out a few good design variables under a mass constrain, since there are tremendous design variable candidates in a large-scale Finite Element model. Therefore we have to select some effective parts as design variables before solving an optimization problem. In this paper we propose a new basic concept of contribution analysis for minimizing a target response using mutual mean compliance. First, we present how to calculate a contribution rate to a static target response after clarifying the difference between elastic strain energy and mutual mean compliance. Secondly, we expand the above method to a dynamic problem. Then, the dynamic contribution rate is divided into 3 components, which are mass, damping and stiffness ones. Finally, we demonstrate the proposed method using a cantilever model.

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This paper is concerned with an approach for avoiding the fictitious eigenfrequency problem in boundary element analysis of two-dimensional acoustic problems governed by Helmholtz equation. It is well known that in solving without any care the external acoustic problem by means of the boundary integral equation, the solution is violated at the eigenfrequencies of the internal problem. The present paper shows the effectiveness to circumvent the fictitious eigenfrequency problem by using the combined integral equation, which is originally proposed by Burton-Miller for constant elements, when employing the quadratic boundary element. On the other hand, we also propose a new approach to avoid that problem, which is for the quadratic boundary element. In this new approach, the Burton-Miller integral equation is used at the end points of element, while the normal derivative boundary integral equation multiplied by some parameter is applied to the other node of element. The proposed approach is implemented, and its effectiveness is demonstrated through comparison of the numerical results obtained by the developed computer code with other solutions.

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Recently, many researchers who work with time-frequency analysis using wavelet transform have focused on analyzing wavelets that are derived using a mathematical approach. In the present analysis, a measured signal is adopted as the wavelet, and we analyze the correlation between acoustic signals in the car cabin and suction noise signals by applying the proposed system. Because traditional calculation of correlation repeats the averaging procedure, the original signal must be stationary. Consequentially, a technique for separating and identifying noise from each part of the engine is used for noise source contribution analysis. To apply the method to time-varying signals, the concept of an instantaneous correlation factor (ICF) is introduced, and we prove that a dominant feature of the correlation can be estimated by the ICF. The time-varying correlation for the noise source contribution analysis of an accelerating car is analyzed. And the fundamental experiment about its subjective evaluation in that case is also conducted.

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The new sealant layer is presented, which is easier to include into the manufacture process of the tire in comparison with the previous research. The performance of the present tire was investigated, and it was clarified that there was no air leak when nails broke it. Vibration characteristics of the present tire were analyzed theoretically and experimentally, and the effects of the sealant on the road-ability and the road noise were investigated. Using the analysis, it is shown that vibration transmissibility decreases in the present. The impact characteristics are also discussed. The transmissibility is also decrease when the impact load applies to the tire, and load noise is also decreased.

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In order to develop a high-speed and high-resolution thermal printer, it is required to improve a heat conduction in a thermal head which leads to a uniform temperature. On the other hand, a moderate heat insulation might make thermal printers more energy-saving. Thermally anisotropic materials seem to be promising for these purposes. It can flatten the temperature distribution in a desired direction while preventing heat flow to the other direction. In this study the feasibility of the anisotropic sub-layer substrate is examined both experimentally and computationally. Carbon fiber composites are used to make thermal heads and the distribution of temperature is evaluated. The result shows that a control of the heat conduction in a desired direction is possible. To improve the controllability of heat conduction, the neural network is applied to seek the optimum composition of heat conductance.

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This paper discusses on optimal current and velocity functions which minimize the dissipated energy of a servo system with a reduction gear train. Coulomb friction of the gears is represented by the efficiency of the gears and assumed to be proportional to the absolute value of the current of a motor. The optimal functions can be obtained from an optimal control theory by introducing a zero cross time t_c, when the current is changed from positive to negative. As the dissipated energy can be given as a function of t_c, the optimal zero cross time t_c^* minimizing the energy can be represented by a simple function of the efficiency of the gears. This method is expanded into the case including the viscous friction in addition to the Coulomb friction. The influence of the viscous frictional coefficient upon the optimal zero cross time t_c^* is examined by simulations. The expression of the Coulomb and the viscous frictions is verified by experiments using planetary gears with a DC motor.

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All wheel drive vehicles with in-wheel motors can control the yaw-moment of the vehicle by utilizing force distribution. When the power output of the in-wheel motor stops or the rotation clings, the vehicle becomes unstable by the unbalance of the right and left driving forces. The yaw rate and the lateral acceleration were measured when the motor broke down using an electric vehicle with in-wheel motors on all of its wheels. Not small influence was occurred on the test when the motor breaks down while accelerating. It was effective to stop the motor power output on the same axle when one of the motor broke down, Even if one motor were to break down, the control algorithm with high redundancy and safety features makes possible for the vehicle to keep running using the other motors.

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Stability of two-wheeled vehicles depends on their running speed. The running vehicle at high speed is stable but the vehicle in a state of stillness is unstable. In order to stabilize two-wheeled vehicles in the state of stillness, center-of-gravity movement and handle operation by the rider are indispensable. Then we develop a stationary self-sustaining two-wheeled vehicle which is a two-wheeled vehicle equipped with a cart system to move a center-of-gravity of the vehicle for stabilizing the system. We derive a state space model of system based on Lagrange method and identified model parameters by control experiments. A robust attitude controller is designed via H_∞. Loop Shaping Design Procedure (LSDP). Experimental results show an effectiveness of the derived mathematical model and the designed robust attitude controller compared with LQ controller.

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We have developed catheter simulation system in blood vessels for surgical planning and intraoperative assistance. In this study, we evaluated the effect of the fundamental parameters of the guidewire and blood vessel models for the simulation system. The model of the guidewire was constructed with viscoelastic springs and segments to avoid complicated mathematical procedures as the dynamic deformation of a flexible structure. The vessel is an elastic circular cylinder, whose shape is defined by the centerline and the radii. Collisions between the guidewire and the vessel are calculated and the contact forces are determined according to the stiffness, damping and friction of the vessel wall. Using these models, the trajectory of the guidewire tip and the reaction force were calculated. When friction coefficient between the guidewire and the vessel is large, the guidewire tip vibrates. When deformation property of the vessel is changed, the trajectory of guidewire tip also changes. Bending of the guidewire tip decreases the reaction force at bending points of the vessel. When the guidewire becomes stiffer, the deformation of the vessel becomes large. These findings should facilitate determination of the parameters of the simulation system.

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This paper discusses the integrated design of structural shape and controller of high-speed positioning actuators for magnetic recording test stands. To allow highly flexible shape design of the mechanism for the positioning actuator and to improve the calculation efficiency in the structural shape optimization, this paper proposes an integrated design method in which a structural shape is defined like as a skeleton and meats and a genetic algorithm is used to search the combination of the skeleton and meats for obtaining better performance of the closed-loop system in iterative design procedure. The iterative optimization procedure includes the shape and the controller updates. It is shown in design examples that the proposed integrated design method can improve the performance of the positioning actuator according to the performance indices, and the effect is verified.

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At present, the Sensing and Access Control R & D for Humanitarian Mine Action project has been carrying out by the Japan Science and Technology Agency (JST). our group joins to this project. Our group is taking charge of the development of the manipulator for mine clearance assistance. Now, with the system constructed, positioning and trajectory following performance of the hydraulic manipulator are extremely important areas of development. Existing research on the control of the hydraulic manipulators uses a combination of sliding mode control and disturbance observers for handling of peculiar nonlinearities in the hydraulic system. Based on the results of previous research, we propose a new model for our hydraulic manipulator that shows the characteristic of the hydraulic system based on previous model, and attempt to improve the control performance by applying a sliding mode control and a disturbance observer.

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This paper presents a new assist control method for positioning tasks using a master-slave manipulators with the elasticity on the slave arm. This manipulator is called a flexible master-slave manipulator (FMSM). When the operator performs the positioning task using the FMSM, the remote operation becomes too difficult owing to the elastic vibration of the slave arm. In order to reduce the operator's load, we design a new assist control method. Then by introducing strain feedbacks to the conventional (force reflecting servo type) bilateral control, (i) an autonomic vibration control and its switching control are added to the slave controller, and (ii) a force feedback depending on the elastic vibration to an operator is added to the master controller. We examine the stability of the closed-loop system with the human model and the proposed control system. And we evaluate the maneuverability and the operation feeling of the proposed assist control method on the basis of the task success time and using the SD method and the principle component analysis. These evaluation results show the improvements of the maneuverability and the operation feeling and confirm the effectiveness of the proposed assist control method.

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The purpose of this research is the construction of a practical master slave system which uses EMG signals. Using a linear multiple regression model, joint angles are predicted, and the motion pattern discrimination is conducted. The experiments were conducted to verify the validity of this technique. Consequently, in all five subjects, these motions were discriminated with a high rate of discernment. Moreover, the joint angle was predicted from EMG signals and a robot arm was controlled intuitively and accurately. From these experiments, the usefulness of processing EMG signals with a linear multiple regression model was proved.

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This paper presents the optimal path planning for a single-link flexible manipulator to suppress the residual vibration. In order to obtain a mathematical model properly, the manipulator is modeled by considering the axial displacement, due to large bending deformation, based on inextensibility condition. The Lagrangian approach in conjunction with the assumed modes method is applied to derive the equation of motion of the manipulator. Parameters of the equation are obtain from an identification experiment by using a genetic algorithm. In the path planning, we express the joint angle by cubic spline function, and then use a tabu search method to find an optimal path. The optimal path thus obtained has minimum vibration requirement. The effectiveness of the proposed method is verified by comparing simulation results with experimental ones.

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In this paper, we propose a motion control algorithm of a passive-type intelligent walker based on environment information. The passive-type walker we developed consists of a support frame, two casters, and two wheels with servo brakes. This system has a passive dynamics with respect to the force/moment applied to it, because it does not have any actuators for driving it, so that this system is intrinsically safe for using it based on the physical interaction between the system and the human being. In this research, we control the motion of the passive walker by adjusting the brake torque of each wheel based on the environment information, so that a user could avoid the collision with obstacles, prevent missing his/her step, and compensate the gravity of the system as if the user could use it safely on any roads such as the road with steep sloop. The proposed control algorithms are applied to passive-type walker referred to as RT Walker experimentally, and we show that RT Walker can be utilized successfully in environments with stairs, steps, obstacles, and slops.

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Central Pattern Generators (CPGs) are considered as the neural controllers for cadent human movements. Several walking simulators have been successfully constructed with CPGs. Although the CPGs serves as a reflex function of the neural system to generate rhythms of walking, it does not have adjustability to changes in the environment. It has been proposed as a hypothesis that CPGs will be modified to adapt when sensory organs sense a change of the environment during walking. According to the hypothesis, we propose to introduce a mechanism for modifying CPGs into a walking simulator in this paper. The proposed mechanism is tested in stair climbing. The signal patterns for input to CPGs are tuned according to the height of step. The proposed mechanism allows the walking simulator to adapt to different heights of step.

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Considering the emergency of pursuing the front car when a traffic signal is changing. The operation and behavior characteristics, such as response time, break pressure and stopping distance were quantificationally measured and analyzed between the passive driving of a car equipped with ACC (Adaptive Cruise Control) and the active driving of a car without ACC. According to the results, while there was a dependence between the speed and the headway distance in the active driving, it was not found in the passive driving, with respect to the response time. In the case of the time of break pressing, the results were reversed with respect to the response time. Furthermore, during passive driving, even at the emergent conditions, such as fast speed and short headway distance, the breaking pressure can achieve greater value in a shorter time.

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A passive walker can walk down shallow slope in a natural gait and can exhibit a stable limit cycle. In our earlier work, we have demonstrated the physical structure which forms the fixed point and the mechanism of its stability. A collision phenomenon is essential to the leg-exchange which is one of the important factors determined the fixed point. In general, the collision is undesirable because it causes troubles of precision sensors and instruments. In many studies, the leg-exchange is modeled by some assumptions and the validity of that is not sufficiently evaluated. In this study, the general model is qualitatively and quantitatively evaluated by the experiments. By observing actual collision phenomenon through the high-speed camera, we realized that the legs are not instantaneously exchanged and the loss of angular momentum is caused by the impact force during the collision. Based on this fact, the accurate modified leg-exchange model is proposed.

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Occupant protection systems for automobiles are currently highly publicized. An airbag inflating at high speed impacts occupant with great force. Airbag safety relies on their construction with primarily woven fabrics. We have referred to a typical pressure-time history of an airbag, and developed a device to measure impact load when the fabric airbag inflates at high speed. When interior pressure in the airbag increases, impact load increases. Also, the impact load on a body increases as the distance between the body and airbag decreases. The relation between indenting ratio and pressure ratio gives a common parameter for different samples and different experimental conditions.

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An air-spring type active anti-vibration apparatus has been widely used in the field of precision positioning. In order to avoid the deformation of main body supported by air springs and to compensate the incline of this body due to the mounted positioning unit, the pressure feedback was especially implemented as a minor loop. However, the frequency band of this loop was restricted by a pair of anti-resonance and resonance characteristic appearing in the pressure response. Then, this paper proposes to add the positive feedback for canceling the pair and shows that the frequency response of pressure loop can be flattened. Moreover, the overall control system including the proposed positive feedback is shown and the design conditions for this system are clarified. It is clear that the transmissibility from the floor vibration to the isolated table vibration is not affected by the proposed positive feedback.

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An articulation-type mechanical constraint is a planate bag containing articulating thin plates. It can be freely contracted and bent to fit an arbitrary rounded surface. Evacuation of the internal air renders the bag rigid so that it maintains whatever shape it has been given. The stiffness of the articulation-type mechanical constraint is proportional to the reduction in internal pressure below atmospheric pressure. The stiffness is higher and more stable than that of other passive elements that function by vacuum pressure. As an application of the new passive element, we developed an orthopedic cast that is easy to remove or change in shape. The passive element is also applicable to wearable force displays. Passive elements fixed on an operator provide a sensation of reaction force by constraining his or her motion. The new passive element is suitable for wearable mechanisms, by virtue of being lightweight, soft, and safe.

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Bolted joints sometimes suffer bolt loosening and may sometimes induce accidents. Therefore. bolt loosening detection technologies are essential for many machines and structures having bolted joints. Authors have proposed a new bolt loosening detection sensor using a natural frequency change of a thin plate and validity of the sensor is shown by experimental results. However, it is difficult to detect the bolt loosening on early stage because the sensor is not so sensitive in high axial tension condition. In this paper. the mechanism of natural frequency change of the sensor induced by axial tension change of bolt is investigated with numerical and experimental results and two sensitivity improvement methods, using conical spring washers and size change of the sensor are examined. The results show that size change of the sensor is not effective for improvement of the sensitivity on early stage of bolt loosening and that conical spring washers change the contact area on each sensor surface and can improve the sensitivity on early stage of bolt loosening.

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A method to detect minute flaws on metal parts is proposed to remove the defective parts before assembling in a factory. The input gray-scale images of metal parts are used directly to recognize flaws without any image conversion to shorten recognition time. The recognition problem to find flaws and detect their positions on the metal parts is converted here to another problem to search for maximum peak and the variables giving the peak. Then the recognition problem can be treated as an optimization problem, and this conversion allows us to utilize the high performances of Genetic Algorithms in the optimization. The recognition rate of the proposed system was improved by changing the lighting condition so as to emphasize the contrast between the metal surface and the bruise using the reflection character of the hairline on the metal resulted by polishing process. The effectiveness and problems of proposed method are analyzed on standing points of recognition speed and quantitative recognition ability.

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A new method is proposed to measure the useful field of view (UFOV) when one can recognize the objects by visual task. Since the distance from fixation point to target mark is the strength of stimuli, the psychometric curve is utilized for UFOV by the statistical estimation by Probit and Staircase methods. An approximation by ellipse is also applied to represent the contour of the UFOV. The proposed method enables one to estimate the threshold of recognition with probability that means the UFOV with the detection probability. Therefore, it is proposed in this paper to determine the threshold in any direction from fixation point of the UFOV with visual task by psychometric curve. The availabilities of the proposed method are examined for accuracy and efficiency by the experiments.

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This paper proposes a method to recognize connected direction of a buried pipe's end using a surface-normal sensor. The method uses a range sensor and a pair of wedge-prisms for the purpose of collecting three or more distance data in a small surface of measurement object. To make a laser beam shift a little bit from main optical axis of the range sensor, a driving mechanism is assembled for rotating the pair of wedge-prisms. We attach the sensor at entrance of a pipe and measure the connected direction of a linked pipe at the other end making an elbow. Firstly we describe the measurement principle of the surface-normal sensor. Then, we apply the sensor to recognize the direction of life line pipes feeding gas, water, steam and so on. We simulate the measurement of tracking an elbow connecting water pipes to collect its direction data. Comparing the data with experimental data, shows usefulness of the method for tracing unknown pipe arrangement.

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Swarm algorithms such as Particle Swarm Optimization (PSO) are non-gradient probabilistic optimization algorithms that have been successfully applied to obtain global optimal solutions for complex problems such as multi-peak problems. However these algorithms have not been applied to complicated structural and mechanical optimization problems since local optimization capability is still inferior to general numerical optimization methods. This paper discusses new swarm metaphors that incorporate design sensitivities concerning objective and constraint functions and are applicable to structural and mechanical design optimization problems. Single- and multiobjective optimization techniques using swarm algorithms are combined with a sequential linear programming (SLP) method. In the proposed techniques, swarm optimization algorithms and SLP are conducted simultaneously. Finally, truss structure design optimization problems are solved by the proposed hybrid method to verify the optimization efficiency.

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We developed a knowledge-based engineering system for designing automotive fuel pump module. This system enables fuel pump module to be designed faster with greater reliability. The system has following four main features : (1) database that enables systematic organization of design knowledge, (2) a design process navigator that guides design procedures, (3) a structural evaluation tool that supports the setting of boundary condition for finite element method (FEM) analysis, and (4) fuel gauge character design and suction performance simulator that are connected to a 3 dimensional computer aided design (3 D-CAD) tool. The effectiveness and reliability of the system was confirmed by designing a test fuel pump module. The total design time was decreased by 1 690 minutes less than manual operation, and the system contributed to improvements in design reliability.

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The purpose of this paper is to suggest a benchmark selection index of production control system based on multiple evaluation items. One of the characteristics of benchmarking which is widely used in recent year is to improve procedure by analyzing best business process which is so called 'best practice'. In the benchmark selection process, the weighted sum of multiple evaluations is widely used for benchmark selection index. Yet, generally speaking, the weighted sum assumes that a decision maker accepts trade-off between multiple items. Therefore, there are many cases that the system which has excellent performance in an unimportant item is selected. As a result, it may tend to cause problematic outcomes in benchmarking selection because improvement procedure in benchmarking tends to keep the performance of selected system. In order to avoid these kinds of problems, this paper proposes the benchmark index of production control system which consists of three ; 1) direction index ; 2) balance index ; and 3) improvement index.

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Most of CAD systems can treat free-form curves and surfaces in the mathematical formula called NURBS (Non Uniform Rational B-Spline). Some NC controllers can handle NC data written in NURBS interpolated formula by using G 06.2 code. The use of NURBS expression enables us to decrease the amount of NC data, to eliminate the error due to the linear interpolation and to get rid of rapid acceleration and deceleration. However, little CAM systems can create NURBS interpolated NC data for 5-axis controlled machine tools. Therefore, the paper deals with the development of the main processor of CAM system, which creates CL data expressed by six-dimensional Non-Uniform B-Spline curve. The main processor can generate the CL data directly from CAD modeling data, while considering the interference between a ball-end mill and a workpiece and keeping the designated tool posture as long as possible so that the machined surfaces can be smooth.

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Ball bar instruments are often used for the measurement of the trajectories of the circular interpolation motion of NC machine tools. This paper describes a new method which is an alternative method of the ball bar. The proposed method consists of a master steel ball and a linear variable differential transformer (LVDT). The method was applied to the measurement of the geometric deviations inherent to five-axis machining centers with a tilting rotary table. The master ball is mounted on the main spindle through a tool holder and the displacement detector is also set on the rotary table. In order to identify the geometric deviations circular arc trajectories which are measured under different four kinds of simultaneous three-axis motion are needed. Especially, the eccentricities of the trajectories obtained by the proposed method have important meanings. For this reason, the eccentricities were calculated from the measured trajectories of a quarter circle as well as a full circle by the least square method. The measurements of the deviations were actually carried out on a five-axis machining center and then the deviations were identified. The proposed method is compatible to the ball bar system from the view point of the measurement accuracy.

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In this paper, the performance of various emulsions in water-soluble cutting fluids for hobbing was investigated with TiN and (Al, Ti) N coated tools, in terms of flank wear, crater wear and finished surface roughness. Experiments were carried out using a fly tool. The results helped clarify the following points ; (1) With both TiN and (Al, Ti) N coated tools, an emulsion containing synthetic lubricating additive is effective for decreasing the flank wear and the crater wear, irrespective of the change in the cutting speed. (2) It was suggested that a polyalkyleneglycols contained in the emulsion has a tool wear reduction effect, and the reason why the decrease of the crater wear when using the emulsion is due to the protective action by the deposited metal on the rake face. (3) There was no difference in the finished surface roughness obtained with the various emulsions even when changing the cutting speed. (4) In the view point of the tool wear and the surface finish, the emulsion containing synthetic lubricating additive is available for the (Al, Ti) N coated tool in hobbing.

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A calculation method of tooth surface-errors equivalent to axis displacements caused by bending and torsional deformations of gear shafts is proposed. An axis layout, shaft shapes, gear dimensions and applied torques for a cylindrical gear drive are described into one data file. The developed program can calculate the equivalent tooth surface as a contour line diagram. Through the calculation examples, it was shown that the equivalent tooth surface is changed complexly by the axis layout, the rotational direction, etc. Finally, the effects of the tooth surface modification based on the equivalent tooth surface were investigated through the calculation of the contact stress at the meshing teeth and the transmission error under the loaded condition.

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Optimum designs of the groove dimensions of spiral-grooved journal bearing applied to the spindle of precision equipments are discussed in the course of the study, and the NRRO (non-repeatable run-out) characteristic of the bearing is focused in this paper. The NRRO is formulated as an indicial response of the rotor against an external impulse load, so that three kinds of evaluation indices, i.e., “maximum displacement E_max”, “displacement integration Σ” and “displacement composition E_c”, are introduced to evaluate the characteristics of the indicial response of the rotor. The optimum values of groove parameters are calculated through minimization of each evaluation index value. The performances for the bearings with the obtained groove dimensions are examined, concluding that the groove design according to the “minimizing E_c” criterion is recommendable rather than that to the conventional “maximizing K_xx” criterion.

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Metal joining by brazing or by diffusion bonding is mostly practiced at temperatures up to around 1573.K. At such temperatures, atmosphere furnaces or vacuum furnaces are required to avoid metal oxidation while heating. The drawbacks of atmosphere furnaces are their use of explosive gasses including hydrogen and that metal conveyance belts are not usable above 1 423 K. In this study, a non-oxidizing continuous furnace, which uses only inert gas atmospheres and is combined with a carbon/carbon composite conveyance belt that can run up to 2 873 K, was developed and applied to metal joining technology. The principle and features of the furnace, process of furnace development, and applications of the furnace to the brazing and diffusion bonding of stainless steel are reported with some experimental data.

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The impact of wafer edge roll-off on CMP performance was investigated. Distributions of removal rates at the periphery of wafers were estimated by pressure distributions of front-side surfaces of wafers calculated by FEM analysis. Results showed that the edge roll-off influenced distributions of the removal rates at periphery of the wafers when both a stacked pad and a solo pad were used. The influence was reached 4 mm from the edge of a wafer with a stacked pad, and 10 mm from the edge with a solo pad. When ROA was 1.27 μm, ratios of surface pressure near the edge compared to the center part of a wafer, were about 30% with a stacked pad and about 23% with a solo pad. Moreover, in the case of a stacked pad, we found that the influence of the wafer edge roll-off to CMP process could be compensated by adjusting a pressure of a retainer ring. Also, ranges of allowable ROA with the stacked pad were not uniform when the pressure of a retainer ring was changed from 23 kPa to 30 kPa. On the other hand, in the case of the solo pad, the ranges of allowable ROA did not change very much, which was from 0 to about 0.4 μm, even if the pressure of a retainer ring was changed.

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