Market trends state that most of product sales happen near the beginning of a product release. The purpose of this research, “Mold Design System synchronized with Product Design”, is to create a system that maximizes the production output. Analyzing previous cell phone production molds, we have been able to categorize mold design factors into two functional engineering elements “Fixed Standard Engineering Elements” and “Adjustable Standard Engineering Elements”. Fixed standard Engineering Elements are parameters and shapes defined as 3 Dimension (3D) models. Adjustable standard Engineering Elements are Experts' know-how and thought processes defined and parameterized as variables in a 3D model. Combination of these 3D models is called the “Master Data”. As a result, using the Master Data we have successfully reduced the lead-time of cellular phone Mold-Design from 60 hours to 1 hour.

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Eigen frequencies for two dimensional beam structures are investigated under initial axial displacements. When the beam structures are consisted of extremely thin flexible components, the shapes of the structures are changed due to the initial axial displacement. And then, their eigen frequencies are affected by the axial displacements. To analyze these phenomena, discrete equations using finite elements with consideration of geometrical nonlinearity are derived as cubic simultaneous nonlinear differential equations. First, large static deformations of the structures due to initial axial displacement are calculated using the proposed FEM. Linear natural frequencies for the deformed structures are investigated secondly. In the numerical analysis, both ends of the beam structures are clamped. The calculated results for straight beams with initial compressive displacement using the FEM are consistent with the theoretical results carried out by the authors previously. Further, the influences of initial axial displacement on eigen frequencies of the plane structure which is comprised of five straight beams are clarified.

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A new optimum design method of dynamic vibration absorbers is proposed for the cases when the primary system has some uncertainty in dynamic characteristics and excitation frequency fluctuates in small range. When the excitation frequency is constant, it is well known that an undamped dynamic vibration absorber is very effective to attenuate the vibration amplitude of the primary system. However, when the excitation frequency fluctuates in small range, such an undamped absorber does not always suppress the vibration amplitude. In this paper, we find out that upper limit of the vibration amplitude of the primary system can be estimated easily by using the imaginary part of the dynamic stiffness of the absorber. We derive very simple equations which give the optimum natural frequency and damping ratio of the absorber for given excitation frequency range. Calculation results of the frequency response for some examples designed by the proposed method are demonstrated and they show the usefulness of the proposed method.

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Free vibrations of the clamped circular laminated plates containing multiple disk-shaped delaminations of a same size are analyzed on the basis of the theory of small deflection of plates. Analysis of a model assuming the contact of the two crack faces is presented. For non-axially symmetric vibrations, the equations of motion are solved by neglecting the in-plane displacements of the reference-surface and by modeling the crack part as two lapped discs hinged at the edge. Axisymmetric free vibrations are studied by taking account of the radial in-plane displacement of the reference-surface. Analyses and experiments are carried out for the natural frequencies. It is shown that the effect of the in-plane displacements of the reference-surface on the free vibration characteristics of laminated plates is very small.

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Pneumatic cylinder servo systems are characterized by high nonlinearities such as the compressibility of air and friction in their sliding parts. An approach to enhancing the control performance of such systems is to construct a pressure feedback control loop in their innermost. However, this requires the acquisition of the pressures in each cylinder chamber, and this acquisition typically depends on the use of costly pressure sensors in practical situations. This paper presents the development of a nonlinear observer to estimate the cylinder chamber pressure from the position sensor output and the valve operating command for replacing these sensors. This observer is designed based on the Lyapunov approach in order to ensure the convergence of the error between the actual and estimated pressures to zero. By incorporating not only designed pressure observers but also a friction observer into a pneumatic servo system for position control, a pressure sensorless control system equipped with only a position sensor is constructed. Experimental results show that this system provides good performance in spite of low cost.

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This paper proposes a modeling method of an Extended Reduced-Order Physical Model (Extended Model) with arbitrary boundary condition. The Extended Model is proposed to apply to the simultaneous motion and vibration control of elastic structures. The Extended Model consists of some rigid bodies which are called as rigid body elements and stiffness elements. To design rigid body elements, four dynamical conditions are used ; (1) Total mass and Total moments of inertia, (2) Position of center of gravity, (3) Modal mass and Orthogonality, (4) Modal momentum and Modal angular momentum. The (1) - (4) values of a modeling object are needed to identify masses and moments of inertia of rigid body elements. In the case of that an elastic body has free boundary conditions, the values of the Modal momentum and the Modal angular momentum are zero. On the other hand, in the case of that an elastic body has general boundary conditions, these values are not zero and needed to be identified by any means. However, it is not always any to identify these values. Therefore, a novel formulation to identify mass and inertia matrices is presented that utilizes dynamical conditions for the original object subjected to free boundary conditions. The effectiveness of the presented formulation is examined by using a simple beam. Numerical analysis is carried out and the effectiveness of the presented modeling procedure is verified.

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This paper deals with the effectiveness of an Extended Reduced-Order Physical Model (Extended Model) with arbitrary boundary condition for motion and vibration control system design. The Extended Model is proposed to apply to the simultaneous motion and vibration control of elastic structures. The Extended Model consists of some rigid bodies which are called as rigid body elements and stiffness elements. To design rigid body elements, four dynamical conditions are used (1) Total mass and Total moments of inertia, (2) Position of center of gravity, (3) Modal mass and Orthogonality, (4) Modal momentum and Modal angular momentum. The (1) - (4) values of a modeling object are needed to identify masses and moments of inertia of rigid body elements. In the case of that an elastic body has general boundary conditions, the Modal momentum and the Modal angular momentum are not zero and needed to be identified by any means. However, it is not always easy to identify these values. Therefore, a novel formulation to identify mass and inertia matrices is presented that utilizes dynamical conditions for the original object. subjected to free boundary conditions. The presented formulation is applied to the modeling of the two-link flexible robot arm. Each flexible link is modeled by using the proposed modeling method. The two-link flexible robot arm is built by combining two independently identified link models. The effectiveness of “an Extended Model with an arbitrary boundary condition” is shown through the simulation and experimental control results.

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In this paper, the authors propose a new type hybrid damper with effect of magnetization and demagnetization. The damper consists of a ball screw, electromagnets, rare-earth magnets, and a conductive disk. The core of the electromagnet is combined with the rare-earth magnet. It is called a hybrid electromagnet. The damper has a controllable damping force that is magnetized in case of positive magnetic fields created by the electromagnet, otherwise demagnetized in case of negative one. The validity of the damper is to utilize by a fail-safe mechanism at a time when electric power is lost under the device malfunction. In order to investigate the resisting force characteristics of the damper, the vibration tests are carried out. The test damper has a function of increasing and decreasing magnetic flux density from a neutral position. The experimental results well agree with the theoretical results. Next, to estimate the damping effects of the damper, a one-degree-of-freedom system which is connected to the damper is proposed here. The simulations of seismic response under a semiactive control based on Linear Quadratic Regulator are calculated, and the damping effects of the damper are confirmed numerically.

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In this paper an active knee bolster is proposed for the purpose of injury protection of passengers on his/her lower extremity in vehicle collision. Control objectives are not only to reduce the load to femur less than the passive knee bolster but also to suppress the pelvis movement and the pelvis deceleration to the same level as the passive one. The feedback control system is applied to follow a reference signal of the contact force between the knee and the instrument panel. The appropriate reference signal is decided to the step reference signal lowered like the ramp at the latter time of the duration to suppress the pelvis deceleration. It is demonstrated that the proposed active knee bolster can improve the performance of the passive one by carrying out simulations and experiments.

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The promise of airbags for crew protection when automobiles collide has been realized. However, an airbag inflating at high speed impacts an occupant with great force. Impact force when airbag inflates at high speed is simulated by a nonlinear FEM combined with an incremental method, where the sample is modeled as an elastic membrane. An experiment was conducted to verify the theory and this calculation method. Good agreement was obtained between the theoretical and the experimental values of two type fabric samples. This demonstrates that the mathematical technique developed here is satisfactory for predicting the impact force when an airbag inflates at high speed. The impact force when airbag inflates at high speed depends appreciably on mechanical properties of fabrics.

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Various structural measures against vibration and noise were taken in a ship. However, an unpleasant sound persisted in the mess room, where crews take their breaks. In order to reduce the noise, active controllers were investigated and one of them, the phase corrected filtered error LMS algorithm, is corrected to satisfy causality on its update processes. Some of them were preconditioned using the inverse of the plant because their convergence rates are limited by the dynamics and coupling within the plant response. The algorithms were compared under the same conditions to investigate differences in their properties and also corrected to satisfy the causality of their update processes. Simulations for a control system were introduced using plant responses measured from a loudspeaker to a microphone in the mess room inside the ship. After investigating the convergence speed in various gradient descent adaptation algorithms, the results were integrated with the actual plant response and applied to the active control of ship interior noise.

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In this paper, an incremental learning algorithm based on extraction of action sequence is proposed. The proposed method extracts action sequences from experience obtained through learning in previously encountered environments and uses them in current environments. The proposed method is constructed by two modules. The first module is an action module that uses neural network and genetic algorithm to adapt to a given task autonomously. The second module is an extraction module that uses self-organized map to solve similar tasks quickly. Experimental simulation to evaluate the proposed method is conducted. The proposed method is applied to two tasks of the autonomous mobile robot and its effectiveness is shown. The first is a steering task including time lag and the second is a sweeping task. In addition, the experiment of a real robot is conducted and it is confirmed that the proposed method can be used for practical usage.

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Reinforcement learning (RL) has been proven to be a promising approach to behavior acquisition of an autonomous robot. However, it holds the unwanted character of over-fitting such that a RL robot often loses its stable behavior to a change occurred in an environment after successful learning. To overcome this problem, we propose the mechanism for a robot that transforms an implicit knowledge collected as a result of RL into the form of a probabilistic network model as an explicit knowledge and preserves it for future use. We expects that a robot tends to show more robust behavior against various changes in an environment with the increase of the knowledges. The computer simulations are conducted to illustrate the effectiveness of the proposed knowledge collecting mechanism. The physical experiments with a small autonomous mobile robot called Khepera are also examined to validate the effectiveness of the proposed method.

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A mobile robot system with an automatic effector changer is proposed. This robot system accomplishes various tasks by docking with an effector which is designed for a target task. This paper describes techniques of automatic docking with an effector for the mobile robot. They include position alignment technique proper to docking by PWS type mobile robot using simple sensor and mark, and firm holding mechanism between the robot and the effector. Experimental results of effector changing operation using two kinds of effectors in the real environment are illustrated.

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This paper introduces a high-performance tactile sensor capable of simultaneously measuring 1-axis force and 2-axes moments, which is produced by MEMS technology. We create a Tactile sensor Embedded Soft fingertip (TES) for the future application to robotic manipulation problems. We give the intimate explanation of the sensor during the fabrication process and the basic configuration of the total electric circuit. Finally, we demonstrate the effectiveness of the TES by performing its compression test, and verify that this sensor is applicable to the robotic handling and its feedback system.

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To utilize limited USB bus power for robot control, total power of a robot including multi motors should be restricted. Namely, power of each motor should be reduced. To tackle this problem, a time sharing motor control is proposed in this paper. This technique drives just one of motors whose required power is less than a limited power source, and switches a driven motor with very short period like a multi task system in UNIX. As a result, human beings recognize robot motions with natural feeling even only a motor is driven at once. To confirm the proposed approach, a wearable robot named as wearable telecommunicator T2 including 3 RC servo motors is employed with USB bus power.

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This paper describes applicability evaluation and parameter design of SmarTrack Algorithm in the case where actual paths are transformed. SmarTrack is the spatial path generation algorithm based on the complementary use of nominal path data and sensory data of an actual path proposed by the authors to realize a high reliability seam tracking robotic system which can operate even under poor sensing environments. SmarTrack is basically premised on that a nominal path and an actual path have a relation of rigid body motion. To evaluate applicability of this algorithm in the case where actual paths are transformed, path transformation is modeled by three kinds, bend, arc and cyclic, then the position error and the orientation error of the generated path by SmarTrack to the three kinds of path transformation are investigated in the simulation. As a result of the simulation, relation between the amount of transformation and the algorithm parameters, and the position error and the orientation error of the generated path by SmarTrack was clarified quantitatively. This result indicates that by using the revision matrix obtained in the partial section which sandwiches a tool, SmarTrack can apply to the case where actual paths are transformed. Also it is shown clearly that SmarTrack has the applicable domain to the amount of transformation of the actual path which happen by arc-welding. Based on the results, algorithm parameters design criterion appropriate to the task specification is described for SmarTrack algorithm.

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This paper describes the characteristics of tactile sensation scale and adaptation recovery process measured under vibratory-pin stimulation for tactile virtual reality. Sensation scaling was performed with a dual mode stimulator which controlled both length amplitude and force amplitude of its contact pin that simulated a display pin of a tactile texture display the authors developed. The results of scaling experiment indicated that the force control produced higher absolute threshold and finer difference thresholds at large mean contact force region than the length control, which suggested appropriate mean contact force was necessary for delivery of vibration to mechanoreceptors (PCs) in the lower layer of the skin. The absolute threshold and the number of sensation levels of 50 Hz stimulus were inferior to those of 150-350 Hz despite its frequency range of Meissner Corpuscle densely resident in the skin. The higher frequencies were effective for their diversity in sensation and high intensity discrimination. The adaptation experiment reveled that small increase in absolute threshold was observed at 50 and 150 Hz where recovery from adaptation was fast so that they are relatively tolerant to extended use. Subjective numbness was lower at 150 and 250 Hz. Two frequency bands (about 50 and 250 Hz) correspond to two classes of mechanoreceptors which have independent sensitivity to adaptation. These characteristics obtained in the present research provide a good basis for the design of vibratory tactile display.

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The mental workload during the use of lever type wheelchair (Wijit) in terms of EEG and fluctuation of finger pulse were analyzed. In the analysis of mental workload with a view to EEG, it was observed that the power level of α wave was higher and β wave was lower in a use of Wijit than in a use of standard hand-limb type wheelchair. This means that the parasympathetic nervous system in a use of Wijit was more activated than in a use of standard hand-limb type wheelchair. The physical workload of arms and busts in terms of %MVC was also analyzed. It was clarified that the physical workload of arms during the use of Wijit is much lower than that during the use of normal hand-limb type wheelchair. It is possible to conclude that low physical workload at arms, meaning the operator does not have to grab the hand-limb tightly during the use of Wijit, is relevant to low mental workload for operating wheel chair.

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In sports that are one of the life science fields, the performance of tools such as wear, shoes, clubs and so on advances remarkably, and the record has improved spectacularly. However, it tends to the restriction of “tools that expand distance of a jump” in golf that is one of ball sports toward the target in the distance. The improvement of the sports skill will need not only improvement of tools performance but also improvement of human's sports skill in the future. In the previous paper, we related the golfer's cock-roll motions in the golf driver swing and eight club head and/or ball motions (head velocity, ball velocity, upper angle, side angle, back spin, side spin, carry and traverse) by experiment and multiple regression analysis method. In this paper, the club performance is newly added to the explaining variable. Moreover, by using measured variables and/or factors, the estimated system at head and ball velocity based on the neural network is proposed. When the estimated value by the suggesting method is compared with the measurement value, the maximum error margin and the average error margin are smaller. When the presumption value is compared with the measurement value, the maximum and the average error of the suggesting method are smaller than that of the previous method. Using the sensitivity analysis, we found that the most important factors in improving the head velocity and ball velocity

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Rapid aging of society has aroused a great interest in the disorder that affects the function of knee. This painful and crippling condition requires total knee arthroplasty (TKA) frequently. However, mechanism of wear generation in polyethylene is still unravel because knee movement during normal function involves a complex set of coupled translations and rotations. This study was therefore aimed to determine the kinematics of polyethylene insert on the mobile bearing TKA during walking using artificial knee joint simulator. Mobile bearing artificial knee joint with (posterior-substituting (PS) type) and without (cruciate-retaining (CR) type) cam/post were used for the experiment. Motion of the polyethylene insert mounted on tibial component was measured by the coordinate of markers on the insert and six degrees of freedom motion simulator during walking motion. In addition, the polyethylene insert was liquored lubricant among measurement. Both the static analysis at each time step and dynamic analysis during the gait cycle were performed respectively. The distribution of contact pressure between femoral component and polyethylene insert showed different results by setting it from static condition to dynamic conditions (0.5 Hz and 1.0 Hz). Dynamic analysis revealed that the cam of femoral component in PS type dynamically contacted on the post of polyethylene insert, which made the polyethylene insert detached from the motion of polyethylene insert in mobile bearing TKA. Additionally, it would contribute to the improvement of TKA design.

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Jitter motion of imaging-type instruments is one of the significant sources of image degradation. The stabilization mechanism is often specified by requiring that image motion be less than some value over certain time interval. In the case of observation satellites, pointing stability of the attitude control system is specified. This is an excellent starting point, but may result in the attitude control system with more capability, hence higher cost and longer development period. Therefore in this paper, a virtual pointing stabilization method is proposed. In this method, the pointing error closely related to the image spatial resolution is numerically compensated at the image processing phase in place of the mechanical stabilization. The pointing error includes both deterministic elements and stochastic ones, and both of them degrade the spatial resolution. In the proposing method, multiple images for a same target are acquired with short exposure time. Then they are composed after compensation of the deterministic pointing error. At last, effects of the stochastic pointing error are compensated by an image restoration filter. Effectiveness of the proposed method is verified through both experiments with a grand test bed and numerical simulations with a complex attitude dynamics model.

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Differential gear machine is often used for a car to smooth cornering. For the complexity that four bevel gears in a differential gear device engage at the same time, there are few papers that gathered up an analytic study about load distribution and tooth root stress distribution on bevel gears. In the case that three bevel gears in differential gear device engage at the same time, authors analyzed load distribution and tooth root stress in previous report. However, we did not consider the influence of side gear shafts and bearings in previous report. Therefore, in this study, by using FEM, deflection and stress of side gear which include influence of gear shafts and bearing were investigated and load distribution and tooth root stress distribution were derived. In addition, the crowning was examined and the influence of the crowning were clarified quantitatively.

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This paper presents two numerical methods for an inverse problem in hydrodynamic lubrication. In the inverse problem, the film thickness profile is estimated from a given pressure distribution. In this study, the finite element method and CIP method (Cubic-Interpolated Profile method) are used to solve the inverse problems. Calculated results are presented for unsteady one-dimensional plane inclined bearing and seal in reciprocating motion. In the plane inclined bearing, it is shown that the steady-state film thickness profile is obtained as an asymptotic solution in unsteady-state. And it is shown that the periodic film thickness profiles calculated for seal in reciprocating motion are in good agreement with results given by Hirano and Kaneta. The calculated results show that the numerical methods presented in this study can be used to one-dimensional inverse problems.

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A slider-crank mechanism whose coupler curve is the approximate ellipse is designed so that the human may perform the pedaling of the elliptical motion of the foot. The set of the frame, the crank of the usual bicycle and the foot, the shank, the thigh of the man's leg to be pedaling composes the planar five-link mechanism with two degrees freedom. The set of the frame, moving links and the foot, the shank, the thigh in slider-crank pedaling composes the planar seven-link mechanism with two degrees freedom. Kinematic and static analyses of planar five and seven link mechanisms above-mentioned are possible to perform with given values of the angular displacement of the foot (the pedal angle) and ones of joint moments at the hip and the knee during a crank rotation. Then, a new procedure is proposed for analyzing motion, forces and moments of components in cases of ordinary pedaling (simple crank pedaling) and slider-crank pedaling and for evaluating their performance of pedaling. Simulation results of the pedal angle, the pedal force and the crank moment are verified experimentally.

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This paper describes a method for identifying geometric deviations using measured trajectories of simultaneous five-axis motion in five-axis machining centers with a tilting rotary table. The method for identifying the geometric deviations by using measured data have not been reported although the methods using the results of the simulation have been reported. As the mechanical errors such as pitch error and backlash of worm gears are included in the measured trajectories besides the components of geometric deviations, the accurate values of geometric deviations have not been identified. In this paper, the effect of those errors on the identified values is investigated through simulation. It is found that the backlash which is a non-linear error largely affects the identified values, but the pitch error does not affect them. If the backlash in the tilting axis can be compensated completely, the inherent geometric deviations to the five-axis machine can be identified from the measured data using the observation equations and geometric relations.

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Recently, some machines with linear motor were developed for high productivity. Feed behaviours of these machines were high speed, high acceleration and stable behaviour for feed. Other hand, mirror surface was required for adding high quality on the most products. We thought that this machine suit well for manufacturing on the mirror surface. Therefore, in this paper, turning using the lathe with linear motor was investigated for mirror surface. Two new cutting methods were also proposed and evaluated for manufacturing of the mirror surface in this study. In the first cutting method, plural turnings with different phase on the same cutting place were performed by the lathe using synchronized control of both the Z axis and the C axis, at that time, other cutting conditions are with the same feed speed and the same cutting speed without cutting depth such as spark-out grinding. In the second cutting method, ordinary turning was first performed, then turning using bit with little and flat edge was performed for finish cutting. Brass and steel (S45C) were used for evaluation in the experiment. It is concluded from the results that (1) Both turnings with the first and second methods could improve the surface roughness respectively, (2) The second method using both the lathe of linear motor and bit with little flat edge could machine the mirror surface.

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In order to solve some problems relating to airflow caused by rotating chuck of a CNC lathe or turning center, the airflow in a closed space assumed a machining space is observed by means of the tuft and tracer methods. Flow visualizations are carried out when chuck rotating speeds are 2 000, 3 000, and 4 000 min^-1, and also the rotating directions of chuck are clockwise and counterclockwise. The investigation shows some characteristic airflow patterns in the closed space ; (1) The radial-like flow exists in the region where the airflow blown from chuck or passed through concave area formed by two panels collides vertically with the panel. (2) The vortex-like flow is occurred by the interference of the flow near the tailstock panel side. (3) The region of weak airflow due to the separation exists on the upper, right, slant, and bottom panels. Furthermore, it is clearly that these characteristic airflow are closely related to the accumulation of chip and the leakage of chip or cutting fluid in the CNC lathe.

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Component arrangement in space satellites is an important design process at the conceptual design stage, since component location influences a range of fundamental characteristics of a satellite, and design change in the latter detailed design stage is quite difficult. In this research, a preliminary study for development of systematic design methods for such component arrangement based on optimization techniques is conducted. The component arrangement design problem is formulated as a two-objective optimization problem, and this optimization problem is solved using a bi-level optimization procedure. At the first optimization step, the genetic algorithm is applied to obtain the approximate location of components, and the second step uses the successive quadratic programming to determine the detailed positions of the components. Furthermore, this paper proposes a competent genotype representation technique for handling a variety of component arrangement patterns during the genetic algorithm optimization process. Finally, the proposed method is applied to component arrangement design of a practical small piggyback satellite in order to illustrate effectiveness of the proposed method.

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