Computer simulations using the combination of finite element method and modal analysis are now useful methods for vibration prediction of machineries such as vehicles. Macroscopically, characteristic modes of vehicle bodies, which mainly consist of frame structures and attached panels, are regarded as combinations of global and local deformations. As these deformations differ in priorities and countermeasures in design phase, it is essential to evaluate these deformations individually. However, when it comes to a large and complicated model, it is time consuming to analyze whole modes one by one. Therefore, it is essential to analyze these deformations respectively and efficiently from characteristic modes. In this study, an analytical method to automatically extract global and local deformations from a frame-panel structure model is presented. This method focuses on the difference of spatial frequencies, as global deformation has lower spatial frequency and local deformation has higher spatial frequency. Each deformation is extracted from characteristic modes by means of three dimensional discrete wavelet transform (3D-DWT) and multiresolution analysis. This method enables to evaluate each deformation individually without considering its specification. In this study, a 3D finite element model is converted into voxel space in order to apply 3D-DWT. Then, proposed mode extraction method using 3D-DWT is demonstrated by a frame-panel structure model of automobile body.

We propose a method with a controllable ability of amplitudes and frequency ranges in excitation forces generated by laser-induced plasma (LIP) shock wave. To control these amplitudes and frequency ranges, we use an acoustic lens to focus the shock wave spreading spherically. When the pulsed laser beam is irradiated in air, reaching a threshold of 1015 W/m2 in air, plasma is formed. Then plasma is rapidly expanded through the ambient, resulting in shock wave generated at the origin of LIP position. A portion of the shock wave is applied to target structures as an impulse excitation force, because the LIP shock wave is a spherical wave. We generate Lamb waves on an aluminum plate using the shock wave focused by an acoustic lens, adjusting the amplitudes and the frequency components of the excitation force. From this, we realize that the generated Lamb waves have approximately three times larger amplitudes and lower frequency components compared with the conventional LIP excitation method.

Conventionally, experimental modal analysis has been conducted with physical sensors such as laser displacement sensors and accelerometers. However, the number of sensors and their placement locations are limited. Therefore, it is difficult to measure the vibration of large-scale structures with physical sensors. Thus, large-scale experimental modal analysis by image processing is drawing attention. In this study, we propose a novel experimental modal analysis method based on Phase-based motion magnification (PBMM) that can magnify the vibration in a specified frequency and visualize the vibration shapes. In this report, we discuss the validity of the vibration mode shapes of cantilever beam visualized by PBMM.

The purpose of this study is to evaluate the vibration response of the piping system at the early stage of design more rationally and efficiently than before. The piping system has the in-phase and antiphase vibration modes, and if conventional method using the participation factor is applied, the vibration may be underestimated. Therefore, a new evaluation method using the partial participation factor focused on specific part is applied. By using this method, supported positions of the piping system with dampers are determined. Then, the vibration response calculation was carried out by the conventional method and the proposed method, and the effect was compared.

In recent years, machine tools are required to reduce their work time by increasing the processing speed. However, this transition tends to decrease the processing accuracy due to the vibration. Therefore, understanding the vibration characteristic of the machine is important to be compatible the speed with the accuracy. In this study, we then attempted to know the main input force and the transfer path of a simple gear processing machine model by using a transfer path analysis. The input force was estimated by employing the transfer function and the vibration at the operational condition. In addition, the contribution was calculated by multiplying the estimated input force with the transfer function. Through the verification in which the input force and transfer function were modified, the method was clarified to be able to obtain the contribution well.

This study proposes a new pantograph testing method for railway pantograph/overhead contact lines (OCL) systems, based on hybrid simulation consisting of a physical pantograph and a numerical OCL model. The dynamically substructured system (DSS) testing method is applied to a real shinkansen pantograph, using an actuator/DSS configurations that have been implemented at the Railway Technical Research Institute. The DSS method is used in conjunction with new ‘High-Speed Test Facility for Pantograph/OCL Systems’ that is arranged to be in dynamic interaction with the shinkansen pantograph head. This novel experimental system enables the investigation of dynamic interactions between the contact wire of the OCL and the pantograph head, due to span-passing. The contact force between the rotational disc and the pantograph head is estimated based on strain measured at the pantograph head. Results from this experimental investigation are compared with those generated by a numerical simulation of the emulated system, i.e. the system to be represented by the DSS experimentation.

In this study, we proposed a structural health monitoring and diagnosis method using the frequency response function between layers of a layered structure, that is, the transmissibility function. The method focuses on the fact that the transmissibility function of the top floor when the ceiling or foundation of the first floor of a layered structure is vibrated in the horizontal direction is constructed only with the characteristics of the top floor, and in the case of the lower floor, the function is constructed only with the characteristics of the interested floor. To verify the validity of the proposed method, we considered a three-layer structure as a numerical example. To compare the identification accuracy, the characteristic parameters were also identified by the sensitivity analysis method. As a result, correct diagnosis is possible with either method, but the method using the proposed transmissibility function is effective for early detection of local abnormalities, and the sensitivity analysis method was found to be effective when multiple abnormalities have occurred.

When a damage is generated in a mechanical structure, its elasto-mechanical characteristics change, resulting in the change in its vibration response. Therefore, if the change in the vibration response can be associated with the information of the damage, it is possible to identify the damage based on the vibration response. Based on this concept, we propose a damage detection method based on the minimization of the differences between the vibration response of the damaged structure and that obtained by finite element analyses. For solving the minimization problem, we utilize topology optimization with Solid Isotropic Material with Penalization (SIMP). To avoid spurious damaged areas and minimize the effects of measurement noise, L1 regularization, or Least Absolute Shrinkage and Selection Operator (LASSO) is applied. In this report, we present the results of the application of the proposed method to rectangular cantilevered plates with rectangular notches that imitate damaged areas. It is shown that the proposed method can identify the damaged areas of the plates.

In the automobile industry in recent years, engine noise has been decreasing due to the spread of HVs and EVs. However, low-frequency noise such as road noise and wind noise is prominent. further, Due to issues such as fuel efficiency regulations for automobiles, the development of lightweight and high-performance sound absorbing materials is urgently needed. Therefore, aluminum sintered material is attracting attention. It is known that its performance changes depending on the particle size and porosity of aluminum powder. In this study, we created a microscopic structure model of the aluminum sintered material, calculated the sound absorption coefficient and flow resistance using the homogenization method, and affected the porosity of the aluminum sintered material and the particle size of the aluminum powder on the sound absorption characteristics. Is examined. The purpose is to design a higher performance sound absorbing material.

To improve the acoustic characteristics of porous materials, we calculated the sound absorption coefficient using the homogenization method. The homogenization method can evaluate the sound absorption coefficient directly from the microstructure of porous materials. On the other hand, since this method uses representative volume elements, it cannot calculate the microscopic variation of porous materials. In this study, we proposed methods to calculate the probability distribution of the sound absorption coefficient considering the microscopic variation by using the homogenization method and probabilistic methods. We applied four stochastic methods, Monte Carlo simulation, Perturbation method, Gaussian quadrature method, andB ayesian quadrature method, with the homogenization method, and compared the probability distributions of the sound absorption coefficient. This comparison clarified the characteristics of each stochastic method. The results showed that the perturbation method had the lowest computational cost, but the accuracy was not sufficient when the variability of random variables was large. The Gaussian quadrature method and theB ayesian quadrature method were able to predict the sound absorption coefficient distribution with high accuracy even when the variation of random variables was large. Still, the computational cost tended to be larger than that of the perturbation method. By choosing these methods appropriately, we can evaluate how the variation of the microscopic structure of porous materials affects the sound absorption coefficient.

In recent years, with the spread of hybrid and electric vehicles, the number of vehicles with low engine noise has been on the rise. as the engine noise decreases, low frequency noises such as road noise and wind noise, which were not noticeable in the past, have become more prominent. in this study, we will focus on fiber based sound absorbers consisting of several diameters to predict the sound absorption characteristics. in this study, we use thinsulate as a fiber based sound absorbing material, and create a model based on the data obtained from the observation of microstructure. from this model, the sound absorption coefficient and flow resistance are calculated using the homogenization method, and the validity of the evaluation method is examined by comparing the results with actual measurements.

In recent years, the electrification of automobiles has progressed in response to environmental problems, and the number of automobiles equipped with large and large-capacity batteries such as electric vehicles and hybrid vehicles is increasing. These batteries take in air from the passenger compartment using ducts for cooling, but since the cooling fan operates regardless of the running condition, sound may leak to the indoor side through the ducts. In order to reduce these sounds, we examined using a sound absorbing material for the duct. We made four types of test pieces with conventional PP resin, compression felt, and film on the inside and outside of the compression felt, and measured the insertion loss in two ways, one on the opposite side and the other on the outside from the entrance of the duct. The acoustic attenuations were measured. In addition, we will introduce the results of creating and calculating a similar FE model.

This paper describes numerical simulation of the dynamic characteristics of a bead panel equipped with a new vibration control device. The device includes blocks of viscoelastic gels and a constraint layer having a box cross section. The gel blocks are sandwiched between the constraint layer and the test structure. The modal analysis is carried out numerically using the finite element method with Modal Strain Energy (MSE) method. The effects of the stiffness of the constraint layer on the vibration characteristics of the bead panel were evaluated using the eigen modes, modal loss factors and resonance frequencies.

This paper deals with vibration damping analysis using finite element method with Model Strain Energy Method for a plate with a crater type acoustic black hole. On the region of the acoustic black hole, viscoelastic vibration damping material is laminated. The plate with the crater type acoustic black hole is fixed at all edges. The damping layer is modeled by linear solid finite elements in consideration of complex modulus of elasticity. We calculated modal loss factors and eigenmodes including coupled deformations among substructures in the damped plate with the crater type acoustic black hole. We clarified effects of the acoustic black hole on the modal damping for each eigenmode

In the automobile market in recent years, the demand for vehicles with a small environmental load is increasing. in addition, with the stricter regulations on noise outside the vehicle, it is becoming more necessary to take measures against noise originating from the vehicle. the purpose of this study is to measure and predict the sound transmission loss of the actual exhaust pipe, focusing on the acoustic performance of the DPF・GPF. in accordance with ASTM E2611, the sound transmission loss of the actual exhaust pipe is actually measured, and the material properties of the DPF・GPF are acquired from the SEM image, etc., and the microscopic structural model is examined. the sound transmission loss is calculated from the calculation by the homogenization method. the validity of the evaluation method is verified by comparing the measured value and the calculated value.

In HEV and EV, which have become popular in recent years, noise such as road noise, which used to be masked by the noise from the engine, is relatively conspicuous and prevents the improvement of interior quietness.Improvement of the performance of the sound insulation can be achieved by increasing the mass or volume of the sound insulation, but this must be avoided in order to reduce the weight of the vehicle. double-wall structure with an air layer between the walls is a method to improve the sound insulation performance without increasing the thickness or mass of the sound insulating material, but there is a problem of resonant transmission, in which sound penetrates at a certain frequency due to resonance in the intermediate air layer.In this study, we investigate the improvement of the sound insulation performance by suppressing the resonant transmission of the double-walled structure with acoustic metamaterials.

A topology optimization method to design micro structures of sound-absorbing poroelastic media utilizing the homogenization method based on an asymptotic expantion is proposed in this study. Design sensitivities of homoginized propoerties with respect to design variables defined on nodes of a microscopic finite element model are derived by using the homoginization method and the adjoint variable method. Then, design sensitivities of macroscopic objective function, which is dissipated power in this study, with respect to design variables defined on nodes of a microscopic finite element model are derived by using the adjoint variable method. The design variables are updated by using Method of Moving Asymptotes (MMA). Here, the design sensitivities both in microscopic and macroscopic scales are verified by a numerical examples.

Polyurethane foam for sound absorption is used to reduce noise in automobiles, houses, home appliances, etc. Using a 3D printer, we created a model with a simple structure of urethane foam. We created multiple types of shaped objects with spherical cavities with a diameter of several millimeters connected by small cylindrical holes with different diameters of spheres and cylinders, and measured the vertical incident sound absorption coefficient using an acoustic tube. We also created an FE model with the same shape and calculated the sound absorption coefficient. It was confirmed that the peak frequency of the sound absorption coefficient approximately coincided with the Helmholtz resonance frequency. In addition, the above test piece model was created with a finite element model, which was in good agreement with the experimental results. A skeletal parameter study was conducted to investigate the effect on sound absorption.

This paper describes vibration analysis using finite element method with Model Strain Energy Method for structures having T-shaped cross section supported by nonlinear concentrated springs under impact load. The structure is composed of steel layer having a new Acoustic Black Hole in the T-shaped cross section with residual thickness. A viscoelastic damping layer is covered on the acoustic black hole. Finite element for the nonlinear springs with hysteresis are expressed and are connected to the structure modeled by linear solid finite elements in consideration of complex modulus of elasticity. We calculated modal loss factors and transient responses including internal resonances in the eigen modes including coupled motions between the non-linear springs and the structure. From the dominant eigen modes and the time histories, we clarified effects of the new Acoustic Black Hole with residual thickness and nonlinear springs on the nonlinear damped responses.

Vibration suppression is an important technology both industrially and environmentally to realize a comfort industrial product with a safe structure. In this paper, we carry out for numerical simulation of damped vibration structure having porous material sandwiched by double walls. The cover plate in double walls has a Krylov type acoustic black hole. All edge where the black hole exists, has free boundary. Damping material is on the surface of the black hole. Numerical analysis is performed to clarify changes of vibration reduction and vibration transmission from the base plate to the cover plate due to the acoustic black hole using FEM and MSKE method proposed by Yamaguchi et al.

This paper deals with vibration damping analysis using finite element method with Model Strain Energy Method for flat plate having new type acoustic black holes． The new black holes have shapes like half of craters． Viscoelastic vibration damping materials are laminated on the plate at the acoustic black holes． The flat plate is fixed at two edges where the acoustic black hole doesn’t exist． The damping layer is modeled by linear solid finite elements in consideration of complex modules of elasticity． We calculated modal loss factors and eigenmodes of the models using Modal Strain Energy (MSE) method． We clarified effects of the new acoustic black hole on the modal damping for each eigenmode．

This paper describes hybrid vibration analysis using Statistical Energy Analysis（SEA）and FEM for two panels connected in L-shape with an acoustic black hole having a damping layer. The size of acoustic black hole in the L-shaped panel structure is changed. We focused on effects of changing the size of the acoustic black hole in the L-shaped panel structure on wave transmission characteristics between the two panels and damping effects due to the acoustic black hole.

Numerical analysis is performed to obtain damping responses for double wall structures inserted sound absorbing material. The cover plate of the double wall structure has an acoustic black hole with residual thickness. The boundary at the opposite side of the black hole is fixed. This double wall structure and the acoustic black hole were modeled and numerically analyzed by FEM. Using the MSKE method proposed by Yamaguchi et al., we computed the vibration reduction and changes in vibration transmission of an acoustic black hole with residual thickness. By giving the residual thickness, in the lower frequency band, larger damping effects of the acoustic black hole for the base plate were obtained. However, less damping effects were appeared in the base plate where no acoustic black hole exist.

Living organisms have autonomous motions that do not require the on-off switching of external stimuli such as heartbeats and brain waves. In order to realize soft actuators that can generate such autonomous motion, we are developing BZ gel actuators. The BZ gels are synchronized with the Belousov-Zhabotinsky (BZ) reaction. The BZ reaction requires strong acidic condition. which is dangerous to the human body with a low pH. In this study, we tried to drive BZ gels using solid acid instead of strong acidic solution, glucose and acetone. The oscillating behavior of the BZ gel at 20°C, 25°C, and 30°C was observed, and several cycles of oscillation were observed. Finally the pH of the whole solution was low. We assumed that the hydrogen ions of the solid acid were exchanged with sodium ions and diffused into the solution, causing the entire solution to become strongly acidic.

Soft underwater robots mimicking motions and structures of aquatic animals are promising systems for exploration and rescue work in the ocean. In soft underwater robots, normally their actuators are individually designed. This approach allows us to use the most appropriate actuator for the desired behavior. On the other hand, it lacks versatility. In this contribution, we introduce dielectric elastomer fiber actuator (DEFA). DEFA is an electrostatic actuator that has a tubular shape, from which high versatility is expected. For example, the fiber actuators could be gathered to mimic skeletal muscles or braided to cover a large area. We fabricated a DEFA and analyzed their actuation characteristics. The result shows the successful implementation of the actuation of tubular structure in water environment.

In this study, we propose a biomimetic actuator module with an endoskeletal structure using dielectric elastomer actuators (DEAs). DEAs are a type of soft actuators whose characteristics are similar to those of natural muscles. The proposed actuator has an elastic hinge connected to a rolled DEA. These parts are further attached to endoskeletons made of carbon rods. We characterized a prototype of the endoskeletal DEAs in terms of hinge angle as a function of the applied voltage. We observed that the prototype exhibited actuated angle of 5.9° at the applied voltage of 2 kV.

Many types of flexible and stretchable sensors, which can be used to measure strain and pressure, are applied to various devices. A dielectric elastomer sensor (DES) is flexible and stretchable, which has been attracting much attention in recent years. In this study, we measured the response of vibration in the DES and characterized the performance of the DES. The response of a vibration in a circular membrane-shaped DES was limited to up to 10 Hz experimentally. In this experiment, we fabricated a DES using a PDMS membrane as a silicone elastomer and carbon powder as stretchable electrodes. We used an electromagnetic shaker to vibrate the DES. We then recorded the capacitance value using the LCR meter. We found that the DES responded to the vibration up to 10 Hz. Our DES would lead to new applications.

Many methods to assess a ripeness of fruit have been studied because its grades add further value in the marketplace. The ripeness correlates a firmness of fruit in general. A vibration testing using a shaker, a pendulum, a hammer, etc. evaluates the firmness of fruit during natural frequency measurements of 0S2 mode. The authors have developed the assessment method based on non-contact and non-destructive excitation force generated by laser-induced plasma shock wave, preventing damage by hitting the contact excitation devices to fruit. However, it might be hard to measure the ₀S₂ mode of fruit that is soft one such as mango. In this paper, we assess the firmness of a soft mango measuring a propagation velocity of Rayleigh wave on a fruit skin. Furthermore, we elucidate that the propagation velocity of Rayleigh wave decreases as their storage time increases.

In recent years, ecology, sustainable, ethical, etc. have been paid attentions. From this aspect, the developing of foldable aluminum beer cans is expected, however it has not been realized yet so far. Here, it is conceivable to use folding characteristics of origami structures such as a reversed spiral structure. A diamond-cut can with the Yoshimura pattern is similar to origami structure. In the case of aluminum, processing the folding lines deeper affects the durability. And so, the folding lines for the Yoshimura pattern is very shallow and cannot be folded as it is. To fold actually, the lines of diamond cut should be thinned with nails etc. First, it is confirmed here how much load is required to crush the current diamond cut can and the usual one in the axial direction by both experiments and FEM simulations.

Origami structures have been paid attention to realize energy absorption structure with load uniformity. Among origami structures, Tachi-Miura polyhedron (TMP) based cellular structures have unique mechanical properties such as switchable load-bearing capability by transition between collapsible and load-bearing states. This paper investigates energy absorption performance of TMP based cellular structure. The cellular structures are designed to realize collapsible and load-bearing states and fabricated by 3D printer as specimen of impact testing. As a result of the testing, deformation behavior of the cellular structure corresponds to collapsible and load-bearing motions designed based on TMP, which leads to significant energy performance difference. Therefore, we can design the variety of energy absorption performance using TMP based the cellular structures.

The deployable origami structure is suitable for space structures because it is highly storable and has high specific rigidity. In addition, by printing electronic circuits on the thin film used for origami structures, the possibility of application to various space missions will increase. In this study, the authors investigate space missions using the deployable cubic structure based on origami. This paper reports three validation for space mission using the deployable cubic structure. Firstly, comparison of the performance of the cubic deployment structure as an extension boom with other extension booms is reported. Although it is inferior to the SMC boom and coilable mast in terms of storability, it is considered to have the same performance in terms of weight and boom diameter. Secondly, the effect of plasma drag by a thin-film electromagnetic coil mounted on the cubic deployable structure is reported. The results show that there is an deorbit effect even at low orbits, and that a higher drag coefficient can be obtained by arrangement of two coils. Finally, the design restrictions of a thin-film coil for wireless power transmission system is reported. It was found that the arrangement and orientation of the coils greatly affect the performance.

In the case of automobiles, the high initial peak force value sometimes causes harm to the occupants. In the case of a rockfall guard fence, the rope that receives it on the first surface and converts it in the axial direction of the pillar will be cut. The most efficient way to absorb energy in a car collision or kinetic energy of falling rocks is to crush the column structure in the axial direction. In order to achieve high energy absorption characteristics efficiently and while suppressing weight increase, it is examined whether the energy absorption capacity of the foam-filled double structure has sufficient collision energy absorption performance.

We have developed many types of transport boxes by origami-operation and space filling operation. But it has not been solved that the fruits and vegetables such as strawberries, cells, blood and a bottle of sake are damaged, broken during transportation. It is the greatest factor in the situation that there is a vibration frequency range where these are easy to scratch and these are prone to death. If there are eigenfrequencies within the frequency range, it is re-designed such that the eigenfrequencies within the frequency range are moved out of the range. But it is difficult to apply the existing topology optimization. The traditional method, it is difficult to select a great number of eigenfrequencies and set several each objective frequency depending. For example, if it is making any hole arbitrary point, some eigenfrequencies are high, and others are low. When it making any hole in each section, it is important to understanding that the eigenfrequency is higher or lower in advance. First, it clearly articulates the kinetic energy density or the strain energy density. And, the method to control the eigenfrequency by identifying the position of the hole from the energy density is proposed in this paper.

Deployable structures require both of flexibility during deployment and load bearing after deployment. Origami structures are promising approach to satisfy these properties. On the other hand, flexible creases of origami structures tend to be weak. Therefore, this study proposes control method of crease stiffness based on layered jamming. The jamming phenomenon provides high bending stiffness by friction caused by vacuum pressure. To demonstrate the load bearing capability of the proposed method, we envelop an origami structure fabricated via three-dimensional printing and layered aluminum sheets. Furthermore, the load-bearing capability of the proposed structure is investigated via compression test, resulting that layered jamming increases load-bearing capability of the origami structure.

In this study, origami-based deployable cylinders are used to change the neck length of Helmholtz resonator. The cylinder is constructed by folding a pattern with regularly aligned parallelograms and joining the side edges of the pattern together. Acoustic modal analysis using the finite element method was performed on four resonators with different design variable β. The resonance frequency of the resonator with small β monotonously increased by shortening length of the neck. While, the resonant frequencies of the resonators with large β decreased and then increased by the change in the neck lengths. It was revealed that small β was appropriate for providing a unique neck length to achieve a target resonance frequency. Under the given conditions of this study, the variable β must be 35°or less. To investigate the noise reduction effect, the frequency response of sound pressure level was measured on a simple acoustic tube without and with the resonator changing the neck length. The proposed resonator mitigated a sound pressure peak and showed the same acoustic properties as the conventional Helmholtz resonator. Furthermore, it possibly functions effectively at different target frequencies by adjusting the neck length.

We have proposed a simulation method for obtaining sound insulation performance with good accuracy using finite element method for elongated acoustic tubes that can be considered as one-dimensional. This is due to the separation of the sound pressures in front of the sound insulation wall between incident waves and reflected waves by Helmholtz's equation. In this study, we consider whether the "two-point microphone method", which is mainly used during experimental measurement, can be used for finite element simulation. In addition, by this method, the effect at low frequency by the core height in the vertical core which is one of the core shapes advantageous for sound insulation is confirmed and optimized.

The elements that are perceived as beautiful in the beautiful gait are based on personal sensibility. Therefore, clarifying "elements of beauty" quantitatively requires analyzing the cognitive structure of individuals who perceived beautiful and why they evaluated as beautiful. However, the appearance, clothes, and background of a person who performs walking may affect the viewers' evaluation criteria. This study examined the effect of background on sensory evaluation of walking movements. We used an optical motion capture system to measure kinematic data such as joint angles during walking. The two types of gait were measured during the experiment; “slow (90 bpm)” and "fast (120 bpm)". Then the videos which were taken in the gait measurement were edited by adjusting the color saturation and brightness. The four videos were prepared; “slow – high color saturation and bright”, “slow – low color saturation and dark”, “fast – high color saturation and bright”, and “fast – low color saturation and dark”. Furthermore, we conducted a questionnaire survey as the subjective evaluation experiment. The evaluators watched the four videos and answered the questions how they felt. From the results of the kinematic data and the subjective evaluation experiment, we have concluded that the evaluators' impression for the walking movement might change depending on the walking speed and background color.

In the endoscopic surgery, the forceps attached many kinds of gripping clip have been used, but it has been pointed out that there is a difference in the operability of the endoscopic forceps in the actual operation. In addition, the gripping clip of the forceps for endoscopic surgery is used according to the application purpose and the object to be grasped, it is assumed that the grasping sense characteristics change according to the characteristics of the object to be grasped. In this study, to consider the design policy of forceps shape that reduce the difference in sensation between direct palpation and using forceps, a sensory test was carried out by Scheffé’s methods of paired comparison with the measurement of thumb joint angle. The specimens were used a silicon rubber with different stiffness and thickness as a substitute for materials as an object of the sensory test, and they were used elastic strain sensor in the measurement of the angle of the thumb joint. From the experimental results of the sensory test, all forceps were most sensitive to stiffness difference at a sample thickness of 5 mm, and forceps B is more sensitive to stiffness differences when the sample thickness is 1 mm and 5 mm. As a result, we clarified the effect of thumb movement on stiffness discrimination by classifying the subjects according to the correlation coefficient between thumb movement evaluation parameters and point by Scheffé’s method.

For staffs of nursing institutes, taking vital signals of residents is one of the most time-consuming tasks, and it is expected to be supported by robots. In this study, we propose a system that uses a robot arm mounted on the top of the head of an autonomous mobile robot to bring the robot's vital measurement device closer to the patient. The robot calculates the three-dimensional position of the patient's hand from depth sensors and image analysis, and lowers the robot arm close to the hand. A blood oxygen saturation (SpO2) sensor and a pressure sensor are affixed to the gripping handle at the end of the robot arm, and measurements are taken while ensuring that the sensor is touching the finger. As an experiment for use in a facility, we had healthy adults to be taken vital signals in four different postures (standing, end sitting on a chair, end sitting on a wheelchair, and long sitting on a bed), and searched for conditions in which subjects could take measurements by simply holding out their hands in a comfortable posture.

By considering the Lotka-Volterra polynomial model (LV agent model), which is known as a prey-predator model, as an agent model that grows or shrinks in proportion to the density product, we attempted to manage the autonomous periodic solution of the encounter-decreasing agent in a better coexistence state. Next, some case-studies are considered how to manage the autonomous periodic solutions of agents with decreasing encounters in a better coexistence state. First, we manage the center shift and amplitude reduction by switching the encounter rate parameter in the discrete model and manage the timing for dead-beat control (finite settling control) of the priority coexistence of encounter-decreasing agents by feedback linearization.

Humans perceive external environmental information using the five senses of sight, hearing, smell, taste, and touch. Since we perceive most of the information about the external environment based on visual information, measuring the line of sight is expected to clarify how humans relay visual information to their motor control system. However, it is not possible to evaluate the gaze position quantitatively unless the absolute coordinates of the line of sight are obtained. Therefore, in this study, we propose a new sensor fusion to estimate the absolute coordinates of the line of sight. The absolute coordinates of the line of sight were estimated by a Kalman filter using a portable 9-axis motion sensor and a gaze measurement system. We evaluated the accuracy for the absolute coordinates of the line of sight estimation in the experiment. This analytical method is anticipated for use in estimating the absolute coordinates of the line of sight in sports and healthcare applications.

This paper deals with the modeling of error by attachment of inertial sensor system, and we conduct the identification of model. The measurement information of inertial sensor systems attached on wrist and forearm segments were used. The transfer functions defined as error compensation model were identified using by the measurement information, and the degree of numerator and denominator in the transfer functions were adjusted. The 3-axis angular velocity and 3-axis acceleration were compensated, and the results indicated the effectiveness of this model.

There are two types of modeling of the human body: a rigid link model, which does not consider muscle activity, and a musculoskeletal model, which includes the force exertion characteristics of muscles. The musculoskeletal model is a mathematical expression of the dynamic properties of the musculoskeletal system. Combined with information obtained in measurements using an optical motion capture system and a force plate, they can be used to estimate muscle tension. Electromyography (EMG), which is the acquisition of the electrical signals generated by muscle contraction, is used to measure muscle tension. However, the measurement of surface EMG does not allow to measure individual muscle activity or deep muscle activity. Although needle electrodes enable individual muscle measurement, their use is highly invasive. Furthermore, because musculoskeletal models enable the non-invasive estimation of muscle tension, their use is promising in a wide range of fields. In musculoskeletal analysis, it is necessary to adjust the standard model to correspond to individual subjects. Different scaling settings yield different muscle tension results. Therefore, more accurate estimation of muscle tension can be expected by applying slightly different scaling settings for each segment, such as the thigh and lower leg. In this study, the musculoskeletal model software OpenSim is used to calculate the lower limb muscle tension during walking. Multiple scaling patterns are performed correspond to individual subjects to verify the effect of the determination of each bone length in scaling on the results of muscle tension.

Childbirth support is important in Japan, where declining birthrates is one of the social issues. Delaying of progress of labor have been occur due to the lack of basic mother’s physical strength and is the risk of affecting the prognosis of the mother and fetal. In addition, there is a risk of urinary leakage and prolapse of the pelvic organs after childbirth due to the burden on the pelvic floor during childbirth. For smooth delivery avoiding such risks, it is desirable that the pelvic floor muscles located near the fetal delivery exit are as relaxed as possible, even when the mother is exerting abdominal pressure during childbirth. In clinical practice, the baby is generally delivered in a supine position on the delivery table with both legs open. In recent years, various delivery postures have been recommended, and the opportunities for pregnant women to choose their postures are increasing. However, there is no case of scientifically verifying the progress of labor in some posture, especially focus on the relaxed state of the pelvic floor muscles. In addition, it is difficult to confirm the contraction and also to be aware of the contraction by oneself since the pelvic floor muscle is a deep muscle. Therefore, contraction state of the pelvic floor muscles during pushing was evaluated by using of an ultrasound imaging system in this study. Furthermore, the relationship between the delivery posture and the change of state of the pelvic floor muscles was examined by using a statistical analysis method.

In playing the golf, using suitable golf club is important to put out high scores and to hit the correct shot. So, various studies have been conducted on golf clubs and swings to select an appropriate golf club. However, only a few studies are available on how the swing changes when the physical characteristics of the club are changed. The purpose of this study was to analyze the torque data during the swing by using the short-time Fourier transform (STFT) to clarify how the mass change of the shaft affects the swing. First, we measured the golfer's swing at the time of change in shaft mass using a motion capture system and created a three-dimensional rigid body dynamics model consisting of arms and clubs. Next, we calculated the torque data exhibited during the swing using inverse dynamics calculation. After we applied the STFT, confirmed the main frequency component and extracted common points between testers by ANOVA and multiple comparison test. Finally, we confirmed the effect of shaft weight on the spectrogram in each tester.

This study covers pulmonary hypertension known as refractory disease. Currently, pulmonary artery occlusion is calculated by measuring blood flow velocity and blood pressure using an invasive catheter and measuring the phase difference between them, but recently, non-invasive diagnosis has become desirable. In our previous study, we proposed a non-invasive diagnostic method that measures the vessel outer diameter instead of blood pressure using an ultrasound system. However, in experiments using clinical data, an unacceptable phase angle difference exists between the vessel outer diameter and blood flow velocity. The measurement of blood flow velocity is highly reproducible, while the measurement of vessel outer diameter is less reproducible. Since the pulmonary artery is located close to the heart, the center position of the artery changes due to pulsation. Therefore, in this study, it is necessary to eliminate that oscillating waveform component from the arterial diameter measurement waveform. Therefore, a program to calculate the arterial diameter considering the oscillation will be created and its practicality will be examined.

In recent years, research has been conducted to extract 3D images of blood vessels using CT (computed tomography) and MRA (Magnetic Resonance Angiography) and apply them to diagnostic and medicinal support by analyzing blood flow using CFD (Computational Fluid Dynamic). However, CFD analysis takes a long time to calculate, and since the blood vessel wall is regarded as a rigid body, there is a problem that the stress inside the blood vessel wall cannot be calculated. In this report, we propose a method with a small computational load to analyze the coupled analysis of blood vessel wall and blood flow in the frequency domain.

In this study, by constructing a 3D transplantation system of human neurons in vitro, we aim to reproduce the process of neural fusion and find the possibility of application to intractable diseases of the nervous system such as Parkinson's disease and ALS with the aid of regenerative transplantation. In addition, we investigate how giving the vibration, which is one of the dynamic mechanical stimuli, affects this system. The system is constructed by gel-embedded culture of neuronal cells. Two neuronal cells colonies were sown with distance of 1400 to 1700 μm, and three-dimensional tissue formation between the two neuronal cells colonies was observed. A separately developed small piezo vibration stage was used to give vibration stimulation. The vibration conditions are with amplitude of 60 μm, frequency of 10 Hz, and of 8 hours vibration- 4 hours static repeated for 168 hours. Two patterns were conducted, one in which vibration is given only in the horizontal direction, and the other in which vibration is given every hour in the horizontal and vertical directions. As a result, using the "Neurolucida360", which is neuronal cells three-dimensional structural analysis software, it is confirmed that neuronal cells grow three-dimensionally, bind and fusion between recipient cells and donor cells. It is also confirmed that extension and sprout of neurites as well as fusion between neurites was promoted by giving the vibration stimulation.

Neuronal cells, which are generally said to be hard to recover from physcical damage, are equipped with function of a sensor that senses stimuli and extends axons has been elucidated. In this study, we investigated the effect of the dynamic stimulation on damaged human neuron colonies in neuronal network reconstruction. The neuronal cells differentiated from iPS cells are cultured for 5 days, and after the cells have sufficiently grown, the neuronal cells colony is physically damaged. Next, dynamic stimulation is applied for 6 days after the damage applied. To apply dynamic stimulation, we use a small piezo electric vibration stage. The vibration condition is set as the amplitude of 60 μm, the frequency of 10 Hz, and the interval stimulation with 16 hours stimulation : 8 hours static in the direction perpendicular to the damaged surface. As a result, it was confirmed that the neurites are reconstructed from the damage by the applied dynamic stimulation.

Cells adhere to a substrate and/or other cells to proliferate, meaning cell adhesion is one of the most important mechanical properties of cells to be quantitatively measured. In this study, we developed a method to quantitatively measure the difference in cell adhesion by utilizing the peeling phenomenon observed when cells are irradiated to surface acoustic waves. By using the proposed method, we demonstrate that the adhesion force of myoblasts cultured on a surface acoustic wave device can be regulated by changing the PBS immersion time before detachment. The detachment force becomes able to be quantitatively compared by the proposed method.