This paper deals with investigation to determine optimum vehicle deceleration in order to reduce occupant injuries for frontal impact of vehicle at the primary design phase. The first purpose of this investigation is to calculate occupant chest deceleration under one degree of freedom spring and mass model by using convolution integral when various frontal crash impact of vehicle occurs. Next we developed and found out how to reduce maximum chest deceleration by analyzing unit impulse response and influence curve of chest deceleration sensitivity by changing small range of vehicle deceleration fluctuation. Further we also conducted three patterns of vehicle deceleration curve sled test for frontal impact under the Hybrid III dummy restrained by the rigid seat and seatbelt. As the result, this paper reports that this method can be estimated, as for the relative comparison of occupant chest deceleration when the frontal crash impact of vehicle changes even though the real world occupant safety restraint system of seatbelt is equipped.

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Several rehabilitation robots for upper limbs have been proposed so far, and clinical effectiveness was reported in several studies for the aged people or patients with stroke. However most of them have only 2-DOF for its active motion. It is important for designing a rehabilitation system which trains in the 3-DOF space because the upper limbs of humans works in 3-DOF space even expect for the wrist. We developed the quasi 3-DOF rehabilitation system which has 2-DOF force-feedback function in working plane but its working plane can be adjusted the inclination. And we named it Hybrid-PLEMO for it can be switched between active type and passive type. Hybrid-PLEMO is a compact, low-cost rehabilitation system for upper limbs with high safety by using ER brakes or ER actuators. Additionally, in Hybrid-PLEMO, we take direct-drive linkage mechanism by adding sub links and manipulability ellipsoid and polyhedron which means possible velocity of end effector are done for the evaluation of Hybrid-PLEMO arm mechanism. In this paper, we describe the mechanism of Hybrid-PLEMO.

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The purpose of the research, driven by shortening of product development cycle and increasing number of new product developments, is to capture design process, knowledge, know-how standardization, knowledge build-up, and to create a system, which enables an inexperienced designer to design a product above acceptance level, in short development cycle. For this purpose, (1) Visualization Analysis was done to define design processes, which are now a tacit knowledge of experienced designer, and to develop a development process based on logical chain of each process, (2) Design know-how, needed for each design process, were defined for inexperienced designers to comprehend and complete their tasks, and (3) defined design process and design know-how from each process was integrated with 3-Dimensional CAD to establish 3D Knowledge Design System. The system has been applied on design of Shock Absorber for cars, for verification. As result from using the system, 92% of 599 processes were able to be completed by young designers. Moreover, young designers were able to complete the design, without any support from skilled designer, and reduce 66.7% of the design time compared with design time without the system.

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This paper presents a new algorithm for a single-input single-output (SISO) system identification including non-zero initial states response in the time domain using impulse response. Eigensystem Realization Algorithm (ERA) realizes a SISO system with zero initial states, therefore we modify the method and first estimate system matrix and initial states using free decay response. In the process, system matrix is obtained by the singular value decomposition as same manner as ERA, and initial state values are refined by recursive least square iteration. Next, deducting initial states effect from the measured impulse response data, we reconstruct ideal impulse response, then identify the input and output matrices using another recursive least square iteration in the time domain analysis. Numerical simulations are performed to verify the new algorithm. Results of examples clarify the validity of the new identification scheme. Finally, we apply the new algorithm to an actual on-orbit data of Engineering Test Satellite-VIII (ETS-VIII) in orbital control mode (OCM), which was launched in December, 2006 and injected into geosynchronous orbit, for the system identification.

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With increased automation in the manufacturing industry, the demand for a quick and accurate mass measurement system is growing. Currently, an active belt conveyer is in demand by many enterprises. However, there is a problem that the active belt conveyer causes mechanical noises. The main noises are three kinds, which are the natural oscillation of measurement conveyer, oscillation by rotation of motor and belt pulley. They cause observable signals within the active belt environment. Therefore, we have to remove those noises to acquire a greater accuracy. In the current mass measurement system, the moving average method is used to remove those noises. Unfortunately, it is not able in the current system to give a method for more quick and accurate measurements. In this paper, we propose a frequency analysis method using the LMS algorithm. Moreover, we develop the system using this method and the moving average method. Finally, we use a device actually marketed in order to verify the utility of the system by comparative experiment between current system and proposed system.

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Finite element method has been used in multibody dynamic analysis for flexible bodies. A conventional finite element method has employed displacement vectors and rotations as nodal variables. Absolute nodal coordinate method, proposed by A. A. Shabana et al., has employed position vectors and spatial derivatives of nodal displacements as nodal variables. Since the spatial derivatives are expressed in terms of an angle between beam axis and reference frames, they are dependent variables. The dependency of spatial derivatives has not been fully discussed in the existing papers. The effects of dependency on numerical results are discussed in this paper. An expression for internal forces has been an important issue in the absolute nodal coordinate method. An accurate expression for axial forces is proposed in this paper. The number of degrees of freedom remain unchanged in this formulation. Numerical examples show the effectiveness of the proposed formulation.

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Introducing the mesh stiffness variation and higher harmonics of driving torque into the equation of motion of one pair of helical gear system, the effects of the mesh stiffness variation, the ratio of static torque to dynamic one and higher harmonics of driving torque on the rattle are studied by numerical analysis. As a result, the followings were made clear. (1) Because of interaction of dynamic torque and mesh stiffness variation, resonance occurs in low frequency region. (2) The ratio of static torque to dynamic one influences the occurrence of higher harmonic resonance. (3) When the dynamic torque is larger than the static one, vibration with larger amplitude than that of fundamental resonance occurs in extremely low frequency. (4) The acceleration amplitude of resonance at low frequency, and that of higher harmonic resonance are large enough and comparable to the amplitude of main resonance. (5) By the interaction of 1st harmonics and higher harmonics of driving torque, amplitudes of higher harmonic resonances become large. (6) When the higher harmonics exist in torque variation, region of chaos generation becomes wide.

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This paper proposes a method of frequency response analysis of a vibration system with parametric excitation of damping coefficient and external harmonic excitation. A simple base-excited vibration system with a variable damper whose coefficient is changed like sine wave is considered. By the product of the damping coefficient and the input velocity, new two vibrations that have another frequencies besides the input frequency arise. Therefore, the oscillation of the damping coefficient with a suitable frequency can generate new vibration that has the natural frequency of the vibration system. As a result, the vibration amplitude increases because of resonance phenomenon. In our prior study, we have confirmed the phenomenon by numerical calculation. In this paper, we carry out theoretical analysis and obtain frequency response of the system. Finally, we confirm the effectiveness of the proposed analysis method by comparing the analysis result with the previous simulation results.

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The floating roofs are widely used to prevent evaporation of content in the large oil storage tanks. The 2003 Tokachi-Oki earthquake caused severe damage to the floating roofs due to liquid sloshing. The structural integrity of the floating roofs for the sloshing is urgent issue to establish in the petrochemical and oil refining industries. This paper presents the sloshing characteristics of single deck floating roofs in cylindrical storage tanks. The hydrodynamic coupling of fluid and floating roof is taken into consideration in the axisymmetric finite element analysis. It is assumed that the fluid is incompressible and inviscid, and the roof is linear elastic while the sidewall and the bottom are rigid. The basic vibration characteristics, natural periods and vibration modes, of the floating roof due to the sloshing are investigated. These will give engineers important information on the floating roof design.

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The characteristics of the pressure pulsations in the drum connected to the piping system excited by centrifugal compressors or blowers at blade-passing frequency were investigated. In this study, the equivalent resistance of a compressor and that of piping systems were introduced to the three dimensional calculation model, so that the non-linear damping proportional to velocity squared in the system is properly incorporated. As a result, the pressure response in the drum as well as pipe can be well evaluated by this model. Furthermore, the effect of the acoustic dynamic absorber on the pressure pulsations in the pipe and drum is evaluated. It is shown that the maximum pressure amplitude in the drum is obtained when the resonant frequency in the pipe is slightly shifted from the resonant frequency in the drum under the small damping conditions. The effect of the damping in the drum and the mode shape in the drum on the maximum pressure amplitude in the drum is discussed.

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The theoretical and experimental study is carried out to investigate the static characteristics of the liquid annular seals with a square-hole pattern in seal stator. The momentum equations with turbulent coefficients and the continuity equation, which are averaged across the film thickness, are numerically solved to obtain the pressure distributions in the seal clearance and the leakage flow rate. Semi-empirical pressure jump coefficients are used for evaluation of both pressure jumps due to the expansion at the passage of the fluid from the land to the square-hole region and the contraction from the square-hole to the land region. The numerical results of the pressure distribution and the leakage flow rate agree well with the experimental results, which proves the validity of the numerical analysis. The pressures decrease in the axial direction and their distribution has periodical unevenness due to the square-hole pattern in the seal stator. The square-hole pattern seal as well as the parallel-grooved annular seal yields a lower leakage flow rate than conventional seals with smooth surfaces. This reduction of the leakage flow rate is attributed to the pressure jump phenomena with energy loss induced by the axial flow passage across each step between the land and the square-hole region.

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This paper presents an unified design method of nonstationary sliding mode control system for the positioning problem of a conveyance system. In the positioning control of conveyance system high-speed and high-accuracy are required, the system possesses the dynamical characteristics of a flexible structure. In this case not only positioning but also vibration due to movement has to be controlled. The purpose of this study is reduction of vibration and high-speed positioning for the flexible structure by nonstationary sliding mode control method. The conveyance system has three constraints for control such as the maximum output of actuator, the number of observable states and the sampling time of the sensor. Solving these problems, we propose the nonstationary sliding mode control system which is constituted by using time-varying switching hyperplane, nonstationary VSS observer and integral sliding mode controller. The effectiveness of the designed controller is verified through a numerical calculation to compare with sliding mode controller and nonstationary optimal controller. Moreover we demonstrate the performance of nonstationary sliding mode controller with an experimental conveyance system.

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Reducing the weight of industrial rotational machinery equipped with Active Magnetic Bearings (AMBs) has been shown to accomplish efficient hydraulic performance and a high-speed rotation for improving space efficiency and cost reduction. One of our solutions for increasing rotational speed is to experimentally demonstrate passing of the 3rd bending critical speed. In this paper, a flexible rotor supported by AMBs is introduced. The controller design for mode separation control is studied and the stability margin is evaluated according to ISO 14839-3. After checking the stability, we successfully perform the rotation test to pass a total of 5 critical speeds, i. e., 2 rigid modes and 3 bending modes, by using modal balancing technique (5 correction planes and 1 vibration sensor). This paper proves that stability and balancing are key technologies to complete the high-speed rotation.

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The purpose of this study is to establish a dynamic control procedure that utilizes the kinetic properties of a control subject as much as possible. The subspace control method detailed in the first report is one method that could satisfy this criterion. In subspace control, the state equation of a system is represented by modal coordinates, and certain modes that need to be controlled are selected and controlled This control method allows for the simplification of control subjects and for increased flexibility. In this report, subspace control is applied to the swinging-up and stabilization of a double parallel inverted pendulum system. More specifically, there is a process that the system is working to stabilize a pendulum while during the up-swing of another pendulum. Due to the interference between the two, it is difficult to control the system in the process. In order to reduce the influence of the interference, a new swing up technique that employs a nonlinear resonance is proposed. This technique causes the nonlinear resonance of a pendulum by moving a cart vibrationally. The effectiveness of the proposed control method is verified by numerical simulation and experiment.

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This paper presents a practical control methodology of the shaking tables for earthquake simulators. Reaction force generated by a nonlinear specimen on the shaking table generally deteriorates the motion performance of the table, resulting in the lower control accuracy of the seismic tests. In order to provide the precise table motion, therefore, a compensator for the reaction force is designed by using a force sensor. The compensator can be designed under considerations of the relationship between the reaction force and the compensation signal, to achieve the desired disturbance suppression performance. The proposed approach has been verified by experiments using an prototype shaking table system.

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It has been shown in our first report that DYC is not compatible with the tire force usage equalization and it is important to consider total tire force F_x and F_y as feedback signals for DYC being compatible with the tire force usage equalization. Also, the control logic devised then has been found very effective in simulation. In this report, an attempt has been made to clarify whether the control logic as predicted by simulation is effective or not for real vehicle by conducting real electric vehicle run tests. It has been found that the control logic of this study is very effective for the independent wheel-in motor electric vehicle. Also, handling has become neutral steering by using our control logic, and consequently, the vehicle could be neutrally steer up to higher speed than without control.

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The tire cornering behavior running on uneven roads, which induces the tire vertical load change, is presented in this paper. At first, the side force and aligning moment responses under time-varying vertical load at a given slip angle were measured to investigate the wave form change due to the wavelength change of vertical load. Then, the tire model was developed, where the small slip angle was assumed. The calculated results showed good agreement with experiments in the range of wavelengths not less than about two meters. Next, the model was improved so as to cover the wide range of slip angle. For the improvement, the functional expression of the so-called relaxation lengths depending on the vertical load and the equivalent slip angle was newly proposed. It was concluded that the improved model predictions agreed well with the experimental results in a wide range of slip angle. The calculated side force response seemed to agree with measurements even in the range of wavelengths less than two meters.

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A new design index for the air-suspension system of bogie vehicles, which is derived from the existence of the firmness point in the transmissibility of the air-suspension and body mass oscillation system, is described in this article. It is obtained as the point of same frequency response, whenever the damping coefficient by the orifice has any value, and devised as the simple equation by the bellows and reservoir volume ratio. From the point of view in the improving the ride comfort, the ratio of the primary and secondary suspension stiffness and the damping ratio for each can be optimized numerically in a evaluating process of the vertical oscillation by using this index. The calculated results in the power spectrum density of car-body vertical acceleration are evaluated in comparison with the real data derived from the high-speed running test of Shinkansen, and the accuracy and conveniency of this calculation methodology are shown in detail. Furthermore, an alternative specification of the vehicle suspension for the reduction of the vertical ride index and the car-body bending oscillation, are described as the successful manner.

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In this paper, several diameter of solid glass spherical grain was dealt. Each diameter grain has the each characteristic impedance and the complex wave constant. At first, the characteristic impedance and the complex wave constant for each grain diameters were measured. Then, the normal incidence absorption coefficient of each grain diameters for arbitrary layer thickness can be calculated. Likewise, the normal incidence absorption coefficient for multilayer with different grain diameters and arbitrary thicknesses can be calculated. This calculation process is comparatively lengthy, so the experiments for real multilayer and the calculations were compared. Result of the calculations coincided to the experiments. Consequently, calculation result of normal incidence absorption coefficient for multilayer with different grain diameters is useful.

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This paper proposes a new method for the trajectory planning of a flexible manipulator in a point-to-point motion. The Lagrangian approach in conjunction with the assumed modes method is applied to derive the governing equations for the manipulator, in which the axial displacement due to large bending deformation is considered. In order to obtain accurately the mathematical model, the coefficients of the obtained equations are identified by an experiment. In the trajectory planning, we express the desired joint angle by a cubic spline function, and then use a particle swarm optimization to minimize the joint driving torque. We show that the residual vibrations of the manipulator can be suppressed as a result of the minimum driving torque requirement. The effectiveness of the proposed method is verified by experiments.

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Image shape of road and image motion of optical flow are two different types of critical visual information for drivers. As for information of road, Land and Horwood (1995) reported that drivers utilize far point of their road for finding future direction as well as near point for controlling current position of the vehicle. We investigated the effect of optical flow in addition to the effects of near and far points of road on the driver's performance using a driving simulator. In results, though the optical flow in far depth contributed to comprehension of driving direction and decreased drivers' load, the optical flow in near depth made their steering inaccurate. Based on these findings, we developed a new device to decrease visual disturbance in near optical flow, and applied it on an actual vehicle. We found that the device improved the driver's head stability and steering stability. Thus, it is suggested that we can improve driver's performance by controlling visual information.

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In this study, we develop a pneumatic cylinders-driven arm wrestling robot system known as ForceRobot, which comprises a 5-DOF force display system with 4 pneumatic cylinders and a force sensor and a human-like head robot with stereo visual servo mechanism. The head robot can display facial expressions by using its eyes, eyelids, lips, and by changing its facial color. We use the system to analyze the movements of the arm during arm wrestling in which a human pushes against a quantitative load. On the basis of the measurement results, a force display response model that is based on the impact absorption features of the human hand is proposed. We introduce this model into our system and verify the effectiveness of the force display by means of behavioral analysis and sensory evaluation. The effectiveness of our system is evaluated from the viewpoints of enjoyment and user-friendliness by children.

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In this paper, we plan the collision free motion when generating the walking pattern of a humanoid robot. Our motion planner can take into account several features of the walking pattern generator. We first run the walking pattern generator by considering the contact wrench applied to the robot while monitoring the collision among the links and the environments. Then, we plan the motion of the robot avoiding the collision. In our motion planner, by considering the constraint condition which are the functions of time, we can plan the motion of the robot with keeping the horizontal position of the COG as well as the feet/hand position. By using the proposed planner, the robot can avoid the collision with keeping balance. The effectiveness of the proposed method is confirmed by simulation and experiment.

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In riveting, it is very important to make the plate's deformation small as well as to obtain the high joint strength. Therefore, we proposed the new riveting process using the washer in the same way as the bolt joint in order to accomplish both purposes. In this paper, first, by changing the combinations of hardness and flow stresses of the rivet material and the plate, we investigated the deformation and strength of the joints in detail and clarified the characteristics of the joints. Next, by considering these experimental results, the new method using the washer in riveting was proposed and the effectiveness of the proposed method was examined. The obtained results show that the joint strength is improved while the deformation of the joint decreases. The usefulness of the proposed method was confirmed from those results.

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Face gears can be substituted for bevel gears or hypoid gears. They can be used only in restricted applications today. Recently, a new application of face gears for helicopter transmissions has been proposed and face gears have attracted special interest. The geometrical design method for face gear was also clarified. Especially, it was clear how the inner and outer diameters of ring gear are defined. In this paper, for avoiding the influence of machining and assembling error on tooth bearing, the design method of point-contact face gear is described. Concretely, the gear tooth surface is generated by the cutter gear with the same module as and larger number of teeth than the pinion. A numerical example was presented based on the proposed method and the method was validated by tooth contact analysis (T. C. A.).

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The present study proposes a new fine-positioning mechanism with piezoelectric actuators and a fine-positioning method for this mechanism. We realized a long stroke path and an ultraprecision positioning simultaneously with a single apparatus. A positioning apparatus with a fine-positioning mechanism attached to the displacement extension mechanism was developed. Actuators were used sequentially for the extension mechanism and the reduction mechanism. Fine positioning is obtained with cooperative positioning that is performed by combining extended displacement positioning and reduced displacement positioning. As a fundamental experiment, the positioning characteristics of extended displacement positioning and reduced displacement positioning were examined individually. A value of 4.63 times the displacement magnification in extended displacement positioning and a value of 0.19 times the displacement magnification in reduced displacement positioning were obtained in comparison with displacement of an actuator unit alone. Cooperative positioning using displacement feedback with PI control was then examined. As a result, even though the stroke was extended, high-resolution positioning was realized simultaneously. In addition, under the condition that the overshoot is not allowed, shortening at the settling time in comparison with only the extended displacement positioning was confirmed.

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This article deals with the sound generating mechanism of ball splines in operation. The results of specific experiments and analyses led to the following conclusions : (1) In the sound wave forms of the ball splines, sound pulses with ball passage period Tp are observed. (2) The main cause of the ball spline sound is the collision between the ball and spline shaft or spline nut at the entrance of the load zone. (3) The sound peaks (the frequencies of peaks are not affected by the linear velocity) are caused by the radial-bending natural vibrations of the spline shaft and spline nut. (4) In the ball splines in operation, the collision between the ball and spline shaft or spline nut produces the radial-bending natural vibrations of the spline shaft and the spline nut, and it results in ball spline sound.

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A logarithmic profile is an essentially optimal geometry for rolling machine elements such as bearing rollers and raceways. Under most conditions of loading, it yields less stresses to give longer endurance. Lundberg first suggested the basic profile, and some researchers followed him by modifying it to suit engineering requirements. The authors also proposed a mathematical optimization method for various profiles including a logarithmic one in roller bearing applications. In this paper, rolling contact fatigue life tests are carried out to make a comparison of logarithmic, standard partially crowned and modified partially crowned rollers when they are applied to cylindrical roller bearings. Results show that the logarithmic and modified partially crowned rollers are comparable in fatigue life, and outlast the standard partially crowed rollers if they are fully lubricated. On the other hand, under poor lubrication, the logarithmic rollers are found to yield outstanding fatigue life over the modified partially crowned ones.

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In recent years, the demand for lightweight composite materials based on aluminum is rapidly increasing in the transport industry. Generally it is considered that aluminum alloys are easy-to-cut materials due to their low hardness. However, it is noted that, some serious problems exist. Because of low lubricity against the cutting tool surface during deep-hole drilling, milling and tapping, aluminum adheres strongly to the cutting edge of the tool, which leads to the tool breakage. To solve the problem, our previous research proposed a cutting tool with micro-textured surfaces to investigate the role of the textured surfaces play in a) retaining cutting fluid, and b) reducing the actual contact area between the tool and chip. These effects lead to increase lubricity and promote anti-adhesive effects at the tool/chip interface. A cutting tool with a segment-structured diamond-like carbon (DLC) was also developed, and it was found that the cutting tool maintains good lubricity in wet conditions. However, the adhesion problem remained. This study developed a DLC coated cutting tool with nano/micro-textured surface utilizing femtosecond laser technology in order to overcome the above-mentioned problem. A series of face milling experiments for aluminum alloy revealed almost no adhesion on the tool surface when cutting with the newly-developed cutting tool. This demonstrated that the nano/micro texture, namely, periodic nano/micro scale grooves significantly improved the anti-adhesive effects of the tool surface.

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Manufacturing industry needs to supply services more than materialized products to customers recently. In marketing field, customer value and human activity are main topics in service system. However, literatures of this research lack the perspective on effect and meaning of activities to the customer. In traditional engineering field, effect and meaning of artifacts can be commonly represented by function. Hence, the authors have mainly modeled service contents as a set of functions to change states of the receiver. This paper focuses on integrating the function model and the activity model so as to evaluate service deliveries according to the customer's point of view. In this paper, we describe activities of service with Service Blueprint by BPMN (Business Process Modeling Notation). We also correlate some of activities with functions as behaviors that realize these functions. The above method is implemented on Service Explorer, which is a CAD system to analyze, evaluate, and design services. Demonstrating an example, the followings are found : (a) separate function models are integrated through activities; (b) interactions between customer and provider are represented; and (c) functional activities and support activities are both incorporated into the delivery process of services.

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This study develops an intelligent mark and its recognition system. Robots need information about its environment and/or objects in order to do effectively the tasks required. Intelligent marks are used by attaching on objects and can send the information such as object category, weight, and so on by an infrared ray communication. Robots get the data of an object by the recognition system. The recognition system also measures relative position of an object by calculating the difference of reaching time between infrared rays and ultrasonic waves sent from the intelligent mark. This study evaluates experimentally the communication range and the accuracy of relative position measurements to confirm the applicability of the intelligent mark and its recognition system.

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