Resonances in flexible fluid conveying pipes have been theoretically and experimentally analyzed from the practical and physical points of view. The excitation mechanisms for the resonances of a fluid conveying straight pipe have been given considerable attention. There are many study of analysis of the fluid conveying straight pipe. But, in contrast with the analysis of the resonance phenomena of fluid conveying straight pipe, there are few studies on the fluid conveying curved pipe. There are some studies which tried to introduce governing equations of the fluid conveying curved pipe. These studies however, have obscure points about fluid force and geometric relations in deriving governing equations. These studies put in fluid force as apparent force without introducing fluid force from the fluid acceleration and take no account of case analysis about Euler angle. In this paper, we derived equations governing spatial motions of a fluid conveying curved pipe with consideration for fluid force and geometric relations. From governing equations, we show in-plane motion is generated.

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Analytical results are presented on nonlinear vibrations of a post-buckled beam constrained by an axial spring under axial and lateral excitations. Equations of motion of the beam are derived including the term of parametric excitation due to the axial excitation. Nonlinear periodic responses are calculated with the harmonic balance method. Effects of the amplitude and phase of the axial excitation are examined on the nonlinear periodic responses of the beam. Amplitude of nonlinear periodic responses deeply depend on the phase difference between the dynamic response of the beam and the axial excitation.

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The accuracy of the frequency response functions for the amplitude ratio and the phase of a Duffing oscillator is investigated. The authors proposed the criterion to distinguish the states of the stochastic jump phenomenon using wavelet transform and the phase of the frequency response function which is derived by the method of multiple scales. But, the amplitude ratio is verified in many studies, the phase is seldom examined. So it is necessary to confirm the accuracy of the phase of the frequency response function. In this study, the amplitudes and phases of approximated frequency response functions are compared to the results of numerical integration. The amplitudes ratio by the numerical integration are evaluated from the maximum value of response and the discrete Fourier transform at the frequency of the excitation, and the phase is evaluated only from the discrete Fourier transform. These results agree well, and the accuracy of the approximated frequency response function for the phase as well as the amplitude ratio is confirmed.

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It has recently observed that microbubbles coated with a lipid monolayer on their surface oscillate non-spherically under driving acoustic pressure. In addition, the oscillations have been proved to make substantial effects, in particular, on acoustic scatterings, collapse phenomena, and life spans of the bubbles. However, it is so complicated to take mechanical properties of a lipid coating into consideration that further study focusing on the lipid coating is needed. Notably, surface tension varies due to the existence of the lipid coating. In this study, firstly we investigate parametrical instability of a free gas bubble oscillating spherically. In general, the coupling of the radial oscillation and the surface oscillation is one-way coupling so that the two systems exchange energy each other when the surface oscillations are parametrically excited. Secondly, how the effective surface tension changes the unstable regions in which surface oscillations are parametrically excited is discussed, using numerical simulation.

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Microbubbles are used as imaging agents to scatter effectively ultrasonic wave. Insonified microbubbles show oscillation including expansion and compression. Considering the effect of the nonlinear oscillation on their reflective wave, it is important to study about dynamics of microbubbles. A shell microbubble especially shows complicated oscillation called "compression only behavior". Such dynamics is often analyzed by using a model based on the experimental report, in which the surface tension of the bubble membrane decreases with compression of the bubble, leading to a buckling. However, this is a phenomenological model, and then, its theoretical background is not clear enough yet. In this research, we studied two different approaches about membrane molecules in micro domain of boundary surface neighborhood. Firstly, the stability of an array of membrane molecules was calculated with the Lennard Jones potential for a simplified molecular model. Secondly, the array of membrane molecules on some calculation conditions for different molecular densities was investigated on molecular dynamics simulation. The results clearly show a possible buckling of a membrane molecule to the outer side or the inner side of the bubble surface.

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Microbubbles oscillate nonlinearly in the ultrasound field. By irradiating ultrasound, microbubbles reflect superharmonic or subharmonic signals. In particular, microbubbles coated by a protein, lipid, or polymer shell show a mechanical property different from that of microbubbles without shell. In this research, nonlinear oscillation of shell-coated microbubbles was compared with that of gas microbubbles. We use the modified Rayleigh-Plesset equation introduced by P. Marmottant, et al. It describes the dynamics of microbubbles coated with lipid shell that has viscosity and elasticity. The dynamical behavior of insonified shell-coated microbubbles was investigated by numerical simulation. Our numerical results suggest the possibility that the oscillation center shifts to the side of bubble compression, and that the response of a shell-coated microbubble has both hardening and softening effects depending on the excitation amplitude and the initial radius of the bubble, because the surface tension changes with the bubble radius if the bubble shell exists. Moreover, these results are in qualitative agreement with experimental ones.

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This paper concerns an analysis of the global stability of a quasi-passive dynamic walking (quasi-PDW) on level ground. In this study, "a simplest walking model" is adopted as the biped walker model, and the constant torque inputs at the hip joints which simulate the effect of the gravity on a slope are introduced to enable a periodic walking motion. A swing leg control is further introduced to improve the global stability, which is evaluated by the area of basin of attraction of the stable periodic solution on the Poincare map. The influence of the swing leg control gain as well as the amount of the constant torque inputs is investigated in terms of the location of the equilibriums and global stability.

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It is necessary to clarify the vibration characteristics of a seated human body for the interpretation of the influence on the seated human body exposure to whole-body vibration. The results of a lot of past studies have informed that the difference of seated postures changes vibration characteristics such as the resonance frequency and the resonance amplitude of a seat-to-head transmissibility and a driving-point apparent mass. However, the seated postures of their subjects in these studies are not necessarily explained in detail. Though the evaluation of human exposure to whole-body vibration are specified by ISO2631, the seated postures at the experiments aren't specified in any ISO standard. In order to make good use of the results of the human vibration experiments, a technical report about the seated postures at the experiments are being discussed. Therefore the purpose of this paper is the expression of the seated postures at the experiments by the index values for seated posture defined by the technical report and the mention of the relation between the seated posture and resonance frequencies of the transmissibility and the apparent mass. The vibration of the experiment was the vertical random vibration whose frequency is from 2 to 30 Hz. The experiments of two different seated postures, an upright posture and a relaxed posture, were performed. In the result, these resonance frequencies in the relaxed posture were lower than those in the upright posture. It is suggested that the lumbar curvature has a relationship with these resonance frequencies.

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With the development of computing technology in recent years, numerical simulation system is developed to calculate the body behavior on a computer. There are some advantages of applying numerical simulation in vehicle development. For example, the cost reduction, safety and easiness of changing parameters. On the contrary, it is difficult to validate the numerical model. Therefore, the experiment to measure the behavior of the human body it is necessary. In this research,s fundamental experiment is performed in order to investigate the body behavior when seated in a vehicle. A fundamental experiment is performed for investigating the influence of the lateral acceleration on human body and the characteristic behavior of the human body is found.

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We already formulated a dynamics-switching three-link and three-joint (an upper body, two thighs, and two lower legs) optimal control model that reproduces human rising movements from a chair, and clarified its effectiveness and the existence of the optimal relation between two factors (input weight and dynamics-switching time t_1) indispensable for sit-to-stand movements. In order to quantitatively evaluate physical stress during rising movements from a chair, this research clarifies the relation between sit-to-stand movements and joint torques: the influence of the input weight and dynamics-switching time on the three-joint torques. Consequently, the following results are obtained: (1) as the degree of the upper body's forward tilt increases, i.e., the input weight becomes smaller and the switching time becomes larger, the magnitude of the joint torque changes from the tendency to decrease in the order of knee, ankle, and hip joints to the tendency to increase in the same order; (2) in an infinite number of optimal combinations of input weight and dynamics-switching time, there exists the optimum condition for the maximum of absolute torques in each joint to take a minimum value, and the sit-to-stand movements reproduced under the three optimum conditions for three joint torques are very close to measured movements. These results suggest that human rising movements from a chair can be quantitatively evaluated in terms of joint torques.

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The objective of this paper is to provide a force/torque transmission model of the human musculoskeletal system (HMS) that can be applied to justify a method of physical therapy for malfunctions/distortions of human body, called Somatic Balance Restoration Therapy (SBRT). To achieve this objective, methods of the multi-body dynamics combined with a system engineering approach have been applied to bridge the gap between mechanical modeling and therapy. The model developed here has proven to be helpful for therapists to identify the problematic areas of the human body with adequate visualization while maintaining a mechanical engineering thoroughness.

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This paper presents theoretical investigation concerning modeling of a human body, seat, steering wheel and pedals system. We have developed a new model of human body that the evaluation of ride comfort is able to estimate. The model of human body consists of six parts: the head, body, thigh, shin, upper arm and fore arm. Each part of the human body is composed with the same fundamental element which is called as a dumbbell model. The dumbbell model is the one that two mass is connected with a flexible bar that has the coefficient of spring, dumper, and plasticity. The movement of the dumbbell mode is considered in the vertical and horizontal direction and rotational movement at the point of center. Each part of the dumbbell model has different parameters and is connected to compose human body. Connected point of each part is considered the friction moment that depends on displacement, relative angle, and relative angular velocity. The functional model is applied in modeling. The analytical result is compared with the measurement result and it agreed extremely well. Some results are presented in the form of parametric graphs. It is shown that the model of human body that has newly developed is able to apply to evaluate the ride comfort.

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We have already formulated a human three-joint arm's optimal control model with a freezing-like mechanism in its hand joint and clarified the model's effectiveness in reproducing two-point reaching movement characteristics. An obstacle-avoiding movement is not only a kind of two-point reaching movements but also one of fundamental arm movements. However, there has been formulated no mathematical model for reproducing obstacle-avoiding movement characteristics. This research formulates a new optimal control model for simulating obstacle-avoiding movements through adding an obstacle-avoiding condition to the three-joint arm's optimal control model and examines how the proposed model can reproduce human arm's experimentally measured obstacle-avoiding movement characteristics. The obstacle-avoiding condition is an equality constraint representing that the model's hand point intersects with the circumference of a hypothetical circle with a radius (obstacle-avoiding radius) of rab around the obstacle at time (obstacle-avoiding time) of t_1. Consequently, the following results are obtained: (1) the proposed model can reproduce human arm's experimentally measured obstacle-avoiding movement characteristics by selecting appropriate values of the obstacle-avoiding radius and time; (2) the model's obstacle-avoiding radius and time can be factors for realizing obstacle-avoiding movements. These results suggest that the proposed model can be an effective and plausible model for the human arm's obstacle-avoiding movement mechanism.

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We have already formulated a human three-joint arm's optimal control model with a freezing-like mechanism in its hand joint. There are the following two discrepancies in reproducing performance of reaching movements between the three-joint model and conventional two-joint models: (1) for the energy minimization criteria, whereas the torque-sustaining energy of the three-joint model is not involved in reproducing reaching movements, that of the two-joint model is involved; (2) for the torque-change minimization criterion, whereas the three-joint model can not reproduce reaching movement characteristics, the two-joint model can do. In order to clarify the reasons for the above discrepancies, we measure human two-joint and three-joint arm's reaching movements and examine the both models' reproducing performance. Consequently, the following results are obtained regardless of subjects and the number of the model's joints: (1) for the energy minimization criteria, it is highly possible that the torque-sustaining energy is not involved in reproducing these measured movements; (2) the torque-change minimization criterion can improve the reproducing performance by adjusting the physical parameters such as the coefficients of the model's joint viscosity or the moment of inertia of the model's links. These results mean that the discrepancy in the energy minimization criteria can be resolved, where that in the torque-change minimization criterion can be caused by inappropriate physical parameter values. Therefore, they suggest that human arm system executes reaching movements based on a criterion that it moves its joint angle as little as possible.

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This paper describes a micro device which applies cyclic strain to focal adhesions of a cell. In recent years, evidence has been growing that focal adhesions act as mechanosensors of cells which convert mechanical force into biomechanical signaling. However, there are no effective micro devices which can directly apply mechanical stimulation to each focal adhesion. Here we develop a micropillar substrate embedding micron-sized magnetic particles and enabling the micropillars to be deflected by external magnetic field. The top of the micropillars were coated with a fibronectin, a kind of protein which promotes the adhesion of cells. Moreover, we stained this protein to check the condition of the coating and to detect the position of pillars. Using the magnetic micropillar substrate, we observed the deformation of an osteoblast cell at its focal adhesions. The findings indicate that the present micro device can be used to investigate mechanosensing systems of a cell.

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Cell nucleus is full of various components, and inside of the nucleus has complicated and heterogeneous structure. Though most functions of nuclear domains have been well studied, nuclear mechanical properties have been scarcely studied. The reason is because it is extremely difficult to construct the experimental system which can measure mechanical properties of the minute nucleus. Additionally, the relation of nuclear configuration and mechanical properties is not clarified. In this study, the experimental system was developed to measure the stiffness of the nucleus of living cell in order to verify the inhomogeneity of the cell nucleus. The system is composed of two devices: one is a glass micro probe sensor which can measure stiffness of cell nucleus, and the other is a rotatable device which can move the cell nucleus to the center position of the microscope and can rotate the nucleus horizontally. The devices are assembled on the stage of an inverted phase contrast microscope. Experimental studies have been carried out using normal human osteoblast. The method has shown capability to detect difference of stiffness on cell nucleus. Comparing the three-dimensional configuration and local stiffness of the cell nucleus, it is found that nucleolus is a high stiffness domain and is involved in the structure of the cell configuration. As mentioned above, mechanical inhomogeneity was confirmed in cell nucleus.

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Mechanical stimulation to bones affects bone formation such as decrease of bone mass of astronauts under zero gravity, walking rehabilitation to bone fracture, and fracture repair with ultrasound devices. Bone cells have been reported to sense and response to mechanical stimulation at cellular level morphologically and metabolically. In the view of mechanical vibrations, bone cells are deformed according to mechanical stimulation and their mechanical characteristics. In this study, sinusoidal inertia force was applied to cultured osteoblasts, which are a type of bone cells, and effects of mechanical vibration duration at 0.5 G and 25 Hz on the cells were investigated in respect of the cell proliferation and alkaline phosphatase (ALP) gene expression. The results to be obtained are as follows. With respect to the cell proliferation, cell saturation density monotonically increased with mechanical vibration duration. With respect to ALP gene expression, bone generation was significantly promoted at the 12 h/day vibration group.

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In this study, a sensor-actuator is developed to enforce stimulation and to detect change of mechanical properties of cultured mouse iPS (induced Pluripotent Stem) cells. The glass micro probe is fixed on the micro sensor-actuator. This probe is improved to direct contact with differentiated neuron cells from iPS cells. The device can apply arbitrary stimulation and measure stiffness of single cell. In order to check sensing ability of the developed device, evaluation experiment was performed with silicone rubber blocks whose Shore hardness (Hs) is known. Experimental studies have been performed in the process of the mouse iPS cells differentiating to neuron cell. In this process, mouse iPS cells are applied dynamic and static stimulation and the measurement of stiffness lasts for 7 days every 12 hours before and after stimulation. In the experiment, the neuron cells responded sensitively with dynamic and static mechanical stimulations and that the cell morphology and stiffness change depending on stimulation.

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A cochlear model including a nonlinear function for somatic motility of the outer hair cell (OHC) has been proposed for compression relating to cochlear nonlinearity evolved by a tone. However, the mechanisms of two-tone suppression, also known as cochlear nonlinearity, are not yet clear. The present study investigates the mechanisms of two-tone suppression in a simulation using the previously proposed cochlear model. Twotone suppression by an OHC model is thus presented. The simulation results are consistent with the results of physiological experiments and show the possibility that two-tone suppressiona is generated by the somatic motility of the OHC.

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To erect the method that rates the dynamic deformability of erythrocytes, we propose a new dynamic model of an erythrocyte with formulation of the external force distorts erythrocytes as be proportional to the velocity of the moving plate of experiment system through viscosity coefficient. In this research, we entertain the possibility of our new dynamic model to discern clinical condition mice from normal. By experiments using the rheoscope method with parallel glass plate, we got time series of images, which comprehends deformation and travel distance of erythrocytes. To identify parameters in the model, we used the least square method and the optimization method based on deformation and travel distance of erythrocytes in the experimental data. We validate our method applying to normal mice erythrocytes and hardened by glutaraldehyde. Then we apply our method to clinical condition mice to recognize the dynamic deformability of erythrocytes in clinical condition.

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In this paper, it is a target to measure a mechanical characteristic of a living body and to detect the foreign object such as a tumor in a body. First, a living body is modeled as a concentrated mass model. This model consists of masses, springs, and dampers. Then, a frequency response is measured when a surface of a living body is excited by a vibrator. We propose the identification method of a mechanical characteristic by comparing the measured frequency response with the calculated frequency response by using the concentrated mass model. In addition, we propose an identification method of a mechanical characteristic, and a distance from a surface to a boundary plane when a living body has two different physical properties. We performed the vibration experiments that a silicon was excited by a vibrator and an acceleration was measured on the opposite side to the excited surface. Then, we confirmed the validities of these identification methods.

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A reduction level against higher frequency noise is not sufficient while using ordinary active noise control (ANC) technique in general living space. In order to control broad frequency noise, active noise barrier has been proposed. Both an active and a passive control effect are expected in such active noise barriers. In the ordinary ANC, it is necessary to put a microphone (error microphone) at the point where the noise should be reduced. However, the error microphone often disturbs the movement of the person. Against this problem, virtual error microphone system (VMS) was proposed by Elliott. In the previous studies, we investigated one-channel VMS with active noise barrier, and obtained good results. In this paper, to obtain wider control area, a two-channel VMS with active noise barrier is investigated and its effectiveness is confirmed in the experiments. In the experiments, average control effect in 80cm × 80cm area is measured with various intervals of two control sound sources.

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Noise control has been developed to establish the comfortable soundscape even if our house life. Floor impact noise such as the sound of footsteps or falling object becomes a problem in an apartment house. Floor impact noise has a peak at the low-frequency range. Passive noise control is not effective against low-frequency noise. Therefore, the purpose of this paper is to control the impact noise using active noise control. In our previous research, the situation of fixed vibration source and control point was considered. In this paper, we consider about changing vibration source and control point. First, this research focus on changing control point. In this paper, the effectiveness of active noise control using frequency domain adaptive algorithm with processing that compute the control noise through the use of vibration modes is confirmed through simulations.

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This paper deals with active acoustic enclosure for preventing vibration of the precision measuring equipment, e.g. Atomic Force Microscope (AFM), due to surrounding sound noise. In our previous work, we proposed active control method of transmitted sound power though a panel and demonstrated the high performance of the method both theoretically and experimentally. The prototype acoustic enclosure for AFM which the proposed method is applied has been developed. In this study, the acquisition method of the reference signal for the acoustic enclosure is investigated experimentally. In order to get reference signal of the sound waves with every incident angles, the reference microphone is placed above the center of the each panel. Furthermore, the Multi Input Single Output feedforward control is applied. The experimental results are shown, demonstrating the validity of the active acoustic enclosure.

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Active noise control (ANC) system with extremely high sampling frequency such as 100kHz was proved to be effective for reducing the distance between the reference microphone and the secondary source, by using Field Programmable Gate Array (FPGA), in our previous works, long impulse responses were also realized by using parallel computing technique of FPGA and the above compact ANC system was proved to be effective for low frequency range down to 200Hz. In this study, this ANC system was applied to Active Acoustic Shielding (AAS). This AAS system was constructed wish many AAS cells set in an array and it can attenuate the sound passing though an open window.

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It is difficult to reduce the noise of a moving evaluation point with Active Noise Control (ANC) technique. This is because that ANC technique can control only narrow area. Therefore to expand quiet area is necessary. Although we showed that it is possible to expand quiet area against pure tone in the previous study, but it is not yet capable against random noise. In this paper, we propose the new method for expanding quiet area against random noise. Two conditions, noise reduction and noise passage conditions, for an error microphone are investigated. Under the noise reduction condition, noise is reduced at the position of error microphone. On the other hand, under noise passage condition, all control sound are cancelled each other at the position of error microphone. These conditions depend on a standard frequency. When the standard frequency is same to the noise frequency of pure tone, it makes noisier area narrow to set error microphones meeting these conditions. Accordingly, we think that to meet these conditions at many standard frequencies make noisier area narrow in random noise effectively. The control effect is shown by the numerical simulations.

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In three-dimension acoustic field, it is difficult to control in the whole room using active noise control (ANC) technique. Instead, around-head-control is investigated in this paper. It can make around the head quiet locally with simple equipments. To realize around-head-control, it is necessary for a controller to follow the head movement. However, there is a problem that the control effect during the movement is worse, and the recovery of control effect after the movement is slow by conventional ANC. Against this problem, we propose the new method of improving the adaptation speed when an evaluation point moves. The algorithm can control by interpolating the secondary path of the Filtered-x Algorithm while moving. In the algorithm, the updating size appropriate to each coefficient of the adaptive filter is calculated by using a step size vector. The step size vector is calculated from the coefficient of adaptive filter before updating. The accuracy of interpolation is verified by comparing with the measured secondary path characteristics. The validity of the proposal method is shown by the numerical simulation.

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It is strongly required to reduce noise at moving person's ears in a noisy room by some active noise control (ANC) techniques. In the case of using fixed secondary sources, some Multi-channel control methods are necessary. Various methods have been proposed for this on-line system identification, but it takes time to identify the error paths and the system can't follow quick movement of the error microphones, in the case of Multi-channel system. On the other hand, Wave Synthesis (WS) Method was proposed by G. B. B. Chaplin at the beginning of 1980's and applied to reduce purr of engines and tones of fans, very successfully. This method is useful only for periodic noise, but has a feature that the system identification of the error path is not necessary. This means that the transfer function of the error path is automatically estimated in this algorithm. Therefore, this method is supposed to be very useful in the case that an error point is moving. The single channel WS method has been developed and applied to engine noises and fan tones as mentioned above. However a multi-channel system using WS algorithm has not been established. According to these backgrounds, the final target of this research is to develop multi-channel WS ANC system and apply it to reduce noise at person's ears who move in a noisy room with periodic sound. In this paper, a newly developed multi-channel WS ANC algorithm is proposed, and some experimental results using dual channel WS system are reported.

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The present paper describes the numerical investigation of characteristics of adaptive feedforward active control systems of broadband noise in ducts. Active control systems using delayless subband adaptive filters have been proposed to improve the performance of the active control. Proposed delayless subband system can achieve relatively large attenuation in wide frequency range. The load of processing for active control may be able to further reduce by a low order adaptive filter with a low sampling rate.

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This paper represents a spider coil winding system of contact-less power transfer for transmitting electric power required for rotor levitation. This proposed system substitutes permanent magnets by rare earth with rotation control. In the previous studies, the problem encountered with limitations of dimensions while winding a coil around stator or rotor. This proposed spider coil winding method offers better solution by increasing number of turns 70% greater than that of flat spiral coil when the diameter of winding material is same. On the other hand, the proposed method with increased number of coil turns helps to transmit more electric power. In case of spider coil winding system, the rotor levitation force was found 7 times higher than conventional coil winding system. This new system also helps to stabilize the levitation of rotor by providing required magnetic force. The validity of this proposed spider coil winding system was confirmed by performing various experiments and comparing the results with conventional and spiral coil winding system.

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The magnetic flux concentration method is a method for making magnetic flux and magnetic field gradient large by using the following phenomena. When the magnetic material plate is put between repulsed permanent magnets, the nearby magnetic flux is concentrated, therefore large magnetic flux and magnetic field gradient is generated. The restoring force of the Hi-Tc superconductor is different according to the constrained magnetic field, and the larger constrained magnetic field is, the larger restoring force is. As a result, the restoring force of the Hi-Tc superconducting magnetic bearing can be enlarged by applying the magnetic flux concentration method to the rotor. In this research, it develop synchronous motor with Hi-Tc superconducting magnetic bearing that applies magnetic flux concentration method, and driving experiment was done. Because the pitching generated in the rotor was large as a result of the experiment, the magnetic damper was developed. The excitation experiment and driving experiment was done, and the effect of the magnetic damper was confirmed.

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A magnetically levitated motor can realize non-contact support of a rotor using magnetic force. Therefore, it has many advantages over conventional mechanical bearings. In order to accomplish complete magnetic levitation of the rotor, it is necessary to control five degrees of freedom actively. However, this gives rise to major issues such as a complicated a control system and associated electronics, resulting in enlarged equipment size. The proposed magnetic levitated motor uses a radial bearing-less motor to control both radial translation motion and rotation, and an axial magnetic bearing to control both axial translation and tilt motion. Moreover, stators were installed on the inner side of the rotor, such that the flux path of the axial magnetic bearing and radial bearing-less motor are partially-shared. Therefore, the proposed magnetic levitated motor is small, while achieving five degrees of freedom active control. The prototype device was designed using FEM. According to this analysis, the device had sufficient magnetic force to control the rotor within a designed airgap of ±0.6 mm. Moreover, in order to verify the performance of the device, numerical simulations were carried out, which demonstrated stable five degrees of freedom active control and fast settling times of 0.007 sec for radial direction and of 0.013 sec for axial direction control. In addition, it showed good capability for an impulse disturbance.

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Bearingless motors are practically applied to centrifugal pumps in industries where contamination of wear particles in pumping medium should be avoided. In such pumps, protective covers are attached to the rotor and stator surfaces to prevent the medium contamination and the material corrosion. These covers should be as thick as possible to enhance mechanical robustness and reliability. Therefore, magnetic gap between the rotor and the stator is designed to be wider than that of conventional bearingless motors, although the wide magnetic gap may cause a reduction in suspension force and torque. In this paper, an influence of the wide magnetic gap on the suspension force and torque of a two-degrees-of-freedom positioned bearingless motor has been investigated, based on the three-dimensional finite element method analysis. The basic structure of this bearingless motor was previously proposed by the authors. The calculation results have demonstrated that the proposed structure possesses a superiority in the suspension force performance to the conventional structure and produces sufficient force and torque under wide magnetic gap condition.

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This paper addresses novel control strategy for 6 salient-pole active magnetic bearings (AMBs). Since 6 salient-pole type AMB has less number of poles as compared with usual 8 salient-pole type AMB, it becomes advantageous to a miniaturization and a low cost. However, since the magnetic circuit has not been independent in x and y direction, bearing forces for coil currents become complicated. Previous research introduced a minimum energy control method which makes the copper loss in coils the minimum. However in the minimum energy control method, the maximum bearing force of specific directions is less than that of the other directions. In order to solve this problem, the maximum bearing force control method is proposed in this paper. Analysis and experiments confirm that the proposed method provides stable rotor levitation and larger bearing force than that of minimum energy control method.

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This paper deals with a new magnetic bearing in order to decrease an axial eccentricity. The proposed bearing system consists of moving frames, suspensions, permanent magnets, electromagnets and Zero Power controller. The system enables to avoid axial touchdowns. A clearance between an axis and our proposed bearing may be increased compare to conventional electromagnetic bearings, since permanent magnets are used in new bearings. However, if Zero Power controller is applied to magnetic bearings, a severe problem is emerged. When a levitating axis is subjected to external steady force, to keep equilibrium between external force and magnetic force, a position of levitating axis may be changed. To overcome this difficulty, this paper proposes a new magnetic bearing structure with moving frames and suspensions. The structure enables to decrease an axial eccentricity. The paper shows the experimental results to verify the system.

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This paper presents a new modeling method and a control system design procedure for a flexible rotor with many elastic modes using active magnetic bearings. The purpose of our research is to let the rotor rotate passing over the 1st and the 2nd critical speeds caused by flexible modes. To achieve this, it is necessary to control motion and vibration of the flexible rotor simultaneously. The new modeling method named as Extended Reduced Order Physical Model is presented to express its motion and vibration uniformly. By using transfer function of flexible rotor-Active Magnetic Bearings system, we designed a Local Jerk Feedback Control system and conducted stability discrimination with root locus. In order to evaluate this modeling and control method, levitation experimentation is conducted.

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Autonomous robots that replace humans are currently in more demand in the manufacturing sector worldwide. However, they cannot be used in random or unknown environments because most of them are controlled by only sequence controls. Two cameras are needed as vision sensors that can recognize the outside environment to solve this problem. When the vision sensors are fitted to a material handling system, cameras are needed to accurately recognize the shape and position of an object from the image information. In this research, we aim at improving the camera calibration accuracies in order to accurately calculate the shape and position of an object from the image information obtained by camera. These accuracies contain the 2D and 3D calibration accuracies. It is known that these calibration accuracies are affected by the calibration methods, environmental conditions, and positions of the two cameras. Therefore, we propose the experimental optimization method for the two cameras' positions and angles. First of all, we examine the influences of the two cameras' positions and angles for the calibration accuracies. In addition, we determine the optimal ranges of the factors that affect the calibration accuracies and make a choice of optimal camera position and angle.

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It needs a lot of workload, skill and cost to inspect and maintain bridges. Especially, in a small city, it is very difficult to do this work regularly because of a lack of fund and man power. This is the reason why so many old bridges will be damages and out of use in the near future. In this paper, we proposed the method to inspect a crack in a bridge by using camera and solving inverse problem. First, deflection along a bridge was precisely measured by camera and then stiffness of each element of a bridge was estimated by solving inverse problem with regulation technique. Finally, we showed that deflection was measured with accuracy of 0.5mm and stiffness was estimated with high accuracy.

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This paper presents a method to identify the geometrical shape and the location of the debonding failure embedded in a concrete structure by processing nonstationary thermal images of the structural surface captured by an infrared thermography camera. In the proposed method, the structure is modeled as a homogeneous infinite plate whose boundary condition on the observed surface is known. The temperature field in the plate is represented by a truncated power series with respect to time, and a layer-by-layer inverse analysis scheme using a regularized interlayer transfer matrix based on 2D Fourier transform is carried out to obtain the sharper image of the failure as well as the depth of the damaged layer. The estimated depth is mapped as a depth image which displays the shape of the failure as well as their depth. The influence of the truncation order as well as the time interval of measurement is investigated by numerical simulations and experiments.

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A high-accuracy measurement technique for plate tension distribution on the process line would potentially lead to improved steel, aluminum and copper plate qualities. We propose an identification method by using natural frequencies and vibration modes, which are related to tension distributions of thin plate. In this paper, a new tension identification method in a thin plate using characteristics of vibration is investigated. We develop a simplified dynamic model of thin plate, and tension distribution is modeled by springs. A simplified model spring constants are obtained by the least-squares method to minimize the difference between a simplified model modal parameters and the given values. We apply the proposed identification method to a thin aluminum plate based on FEM analysis results considering added mass effect of air. As a result, it is shown that identified tension distributions well corresponded to the FEM results.

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Defects of a pantograph might cause widespread damage of overhead contact lines. Among these defects, there is an abnormality of the dynamic characteristic of a pantograph. This abnormality causes increase of contact loss between the pantograph and the contact lines, resulting in increase of wear of the contact strips and the contact wire. Although the abnormality is caused by damage, loss, or degradation of components of the pantograph such as springs or dampers, it is sometimes difficult to detect them by a visual inspection. Therefore, the method to detect the abnormality frequently, which does not depend on the visual inspections, has been required. The authors have developed a method to detect the defect by quantitative evaluation of the dynamic characteristic of pantograph by using sensors placed on catenary. We performed a test to verify the measurement accuracy of this method. As a result, it can be confirmed that dynamic characteristics of a pantograph can be quantitatively evaluated by this method.

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The tendency by which the budget assigned to construction of an infrastructure is reduced continues in our country in recent years, and it increases in the importance of the maintenance for life prolongation of existence structures. It is also increasing in the importance of the roadability of a vehicle and something such as maintenances for comfort securement in conformity with the user's needs as well as maintenances for safety on the freeway. The smoothness of the pavement surface is concerned with the comfort which is at the time of a vehicle run on the freeway, and IRI(International Roughness index) is set as the index to estimate from the viewpoint of the ride quality of the vehicle which runs a road surface. Authors have developed the IRI instrumentation system in which algorithm by sequential processing methods on the time axis was included. In this paper describes real time processing methods for non-stationary vibration which has mutual conversion between time and spatial frequency, to estimate the special quality about the running through road surface profile in a run road surface from vibrational data of an included run vehicle there.

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The adhesion state of a heat seal used for a cup type container is evaluated only by viewing now. The purpose of this study is a nondestructive evaluation of the adhesive strength of the product using the heat seal. Therefore we evaluate the adhesion state of a heat seal, using ultrasonic wave. The ultrasonic frequency is affected by passing the object inside. We take notice of the frequency modulation of ultrasonic wave. Therefore we apply Hilbert conversion and calculate the frequency modulation of ultrasonic wave. Then, we estimate the state of the adhesion layer from the change by the frequency modulation.

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Induction motors are used extensively in many plants, and play important roles. Especially, in nuclear power plants, there are about one thousand and three hundreds induction motors. In order to keep health of them, the technologies of condition monitoring and diagnostics, which are simple and high-integrity, is needed. In recent years, the technologies of condition monitoring and diagnostics with signals of acceleration and current are introduced in nuclear power plants. With a view to verifying condition monitoring and abnormal diagnosis technology for the important instruments as induction motors and pumps, Japan Nuclear Energy Safety Organization (JNES) has installed the equipments for abnormal simulated tests in Japan Nuclear Safety Training Center (JNTC), and JNES has tested abnormal diagnosis technology by experiments. So far, JNES has evaluated the applicability of monitoring and diagnostics technology with signals of acceleration and current. We tested abnormal simulated induction motors of bent shafts and bearing outer ring creep, which are difficult to detect from outside in operation, and we made sure of effectivity of leakage flux analysis. Here we report the facts.

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This paper concerns the estimation method of damage location based on the nonlinear wave modulation demodulation which has attracted much attention in the field of structural health monitoring. When a structure containing a contact-type damage is subjected to a low-frequency vibration, a high-frequency wave which propagates through the damage may undergo amplitude and phase modulation at the damage location because the scatter characteristics of high-frequency waves in the vicinity of the damage may fluctuate in synchronization with the low-frequency vibration because of the contact acoustic nonlinearity. Since this modulation propagates through the structure with the group velocity, it may be possible to estimate damage location by measuring the modulation and performing an inverse analysis based on the wave propagation model. In this paper, a mathematical model of the modulation propagation on a Timoshenko beam is constructed, and by considering the damage as a source of the modulation, an estimation algorithm of damage location which utilizes the time difference between the modulated waves measured by sensor arrays located at both sides of the damage is proposed, and examined experimentally.

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This paper discuses a acceleration response model of a cracked plastic gear using rectangle pulse train and reveals the effect of the pulse train on the Fourier coefficients. First of all, by using a high capacity endurance-testing machine, a rotation fatigue testing of a POM (Polyoxymethylene) gear is carried out. The Effect of the crack at the dedendum on the acceleration waveform is analyzed and the frequency analysis of the data is also performed. The obtained revelation is examined, and the acceleration response model of the cracked plastic gear is proposed. The proposed model is consisting of the rectangle pulse train expressing the normally meshing gears and the other rectangle pulse train representing the crack at the dedendum of the gear. The theoretical Fourier coefficients of the pulse trains are derived and the relationship between the coefficients and the frequency analysis results of the experimental data are explained.

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In the operation of industrial plant, it is essential that we ensure the piping integrity and safety. A serious problem of pipe is wall thinning because of erosion and corrosion (mechanical process and chemical process). Sometimes, the damage bring about the wholesale destruction of pipes, which will harm human on a large scale. In general, the wall thickness of pipe is measured with the ultrasonic test now. However, we expend much time and effort on the test and there are damages, which aren't measured by the test. In this study, we pay attention the pipe's surface vibration by fluid vibration of tube, and suggest that the measurement vibration analysis for piping integrity. If method of this study is available, it is expected that we will make an examination of pipe in operation of plant, grasp the condition of extensive pipe, and reduce the time of test. This paper has research findings of fundamental study for new method measuring wall thinning (transition of frequency distribution and frequency response). The analysis method is Fast Fourier Transform and Transfer Function by MATLAB.

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This paper describes a method for constriction of three-dimensional (3D) cellular microstructures powered by cell traction forces with origami folding technique. Origami, the traditional Japanese art of paper folding, has remained popular over the centuries because it enables the production of various 3D sculptures simply by folding 2D sheets. We seeded cells onto biocompatible microplates produced by MEMS technique. The cells were adhered and stretched onto the plates. Immediately after detaching the plates from a glass substrate, the plates were lifted and folded up into 3D microstructures due to the traction forces caused by stretched cells between two microplates. Using this method we produced various 3D microstructures such as cubes, regular dodecahedrons and cylindrical tubes. We believe that this method is useful to fold 2D plates into 3D cellular microstructures. Also, it is expected to be useful in biotechnological applications such as cell-based medical devices.

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For the reason that general three-dimensional geometry origami structures are very complex, how to give a mathematical summary of combination of node point, fold line and making crease pattern for developing three-dimensional origami structure and establishing design method have become an important issue. In this study, we are not limited to the particular conditions for design origami structure such as Ori-tatami folding and axial symmetry. Plenty of three-dimensional origami structure are analyzed from the geometrical perspective and the common features among them are extracted as Parametric Origami Module. By using this feature, conical structure is able to be represent and simulation algorithm for generating animation for origami structure is proposed. In the end, we compared the proposal with other methods in further discussion and the effectiveness of the proposed method is confirmed.

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Several software programs for designing origami shapes, which is made by folding a single sheet of paper, have been recently developed. We can now obtain a variety of origami pieces by using them. However, the basic forms of the shapes are still limited since a software program bounds the forms by its algorithm. In this paper, we propose a new approach for designing origami shapes based on the sweep and reflection operations. As an example, a column-shaped origami object with a relief structure is designed using our method. The shape is defined by a profile polyline and a trajectory polyline that are input by the user. We developed a system on which the user inputs and edits the polylines to generate both the crease pattern and the 3DCG model of the origami object in real time. With the tools implemented in our system, the user can design a wider variety of shapes in a trial-and-error manner while seeing the effects of their operations. Thus, users can easily design stable and geometrically attractive shapes. We indicate the effectiveness and the potential of our system by showing some examples.

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