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In this article, a novel optimal design method for segmented modification of cycloid gear tooth profile was proposed to improve transmission efficiency. Firstly, the cycloid tooth profile under segmented modification was analyzed. Secondly, the mathematical model of the meshing phase angle of the working segment of the cycloid gear with the highest transmission efficiency was established, and such optimization was achieved by the particle swarm algorithm，and the important indexes were calculated and compared with the basic segmented modification method. Finally, the tooth profile of the cycloid gear under the new design method was obtained by numerical solution. To verify the method, the processing technology of cycloid gear is designed, and the comparison of performance testing between the new proposed method and conventional basic segmented modification was conducted and analyzed by the assembled RV reducer prototype in accordingly. The results show the temperature rise of the RV reducer under the optimized method was reduced by 1.2℃ under the rated load, and the torsional stiffness and transmission efficiency were increased by 0.03N·m/" and 1.8%, respectively, compared with the basic segmented modification method, which shows that this method can effectively overcome the disadvantage of low transmission efficiency under the basic segmented modification method.

Aiming at the phenomenon that the glue output of the time-pressure pneumatic dispensing system decreases with the decrease of the glue allowance in the glue storage tube, this paper presents method of a glue allowance prediction for time-pressure dispensing systems. This method takes the gas pressure data sequence and the dispensing pressure value at the outlet of the solenoid valve of the time-pressure dispensing system during dispensing, and uses the deep neural network to predict the glue remaining value in the glue storage tube of the current dispensing system. Moreover, according to the nature of different input data, a network architecture combining Gated Recurrent Unit (GRU) and Fully Connected Neural Network (FCNN) is proposed, and two different neural networks are used to process temporal input data and non-temporal input data. This method solves the problem that the traditional glue dispensing system model and control method cannot obtain the glue residual value in real time. And through the measured data experiments, the algorithm is better than the traditional machine learning model in terms of root mean square error and mean absolute error performance indicators.

We investigated the damping mechanism of granular material dampers when using a structure with a relatively high natural frequency and small vibration displacement as the target of vibration damping. For powder or granular material dampers, the movement of the powder or granular material is the basic principle of damping. Damping ratios were calculated and compared by individually modifying each parameter (other than diameter) that affects the granule’s motion. As a result, it was found that when the moment of inertia of the granules is 1/2 and the Young's modulus is 1/100 of steel, the damping effect is improved in the region where the total body weight is heavy. In addition, as a specific example of reducing the moment of inertia and optimizing Young’s modulus, when the effect was examined by calculation and experiment using rubber ball with steel core, it was found that the damping ratio can be improved in the region where the total mass of the granules is large. Furthermore, we obtained new knowledge that the hardening spring characteristics of rubber balls containing steel balls have a positive effect on damping characteristics.

In the construction work, flat plates for building materials are transported by a suspension mechanism using wires in air flow. Then, a flutter could be caused to the suspended plates due to the interaction between plate motion and fluid flow. The violent vibration due to flutter loses the efficiency and safety of the operation. To improve the efficiency and safety of the operation, a detailed understanding of the flutter characteristics is crucial. In this paper, the flutter analysis and experiments of a flat plate suspended by wires in air flow are carried out. In the flutter analysis, the Doublet-point method based on the unsteady lifting surface theory is used to calculate the unsteady fluid force acting on the plate surface. The equation of motion of the plate suspended by wires considering restoring force due to gravity is derived based on the Lagrange equation. The flat plate is modeled as a rigid body. The flutter velocity and frequency are examined through the root locus of the characteristic equation of the system with changing the flow velocity. Moreover, wind - tunnel experiments are conducted to verify the analytical results. The influence of a suspending angle on the flutter velocity, frequency and mode are investigated in detail. Finally, the work done by the fluid force acting on the plate surface is examined.

This paper proposes a novel path planning algorithm designed for efficient lunar water exploration. The proposed algorithm leverages a Bayesian network-based sensor model in combination with the RRT* algorithm. It is well-known that water is highly likely to be present in permanently shadowed regions (PSRs). However, during exploration within these regions, the rover must escape to illuminated areas within a limited time to recharge its battery. Therefore, it is crucial to develop a path planning algorithm that ensures both timely battery recharging and efficient water exploration. To address this challenge, we first introduce a sensor model based on a Bayesian network for the neutron spectrometer. Subsequently, we propose an algorithm that utilizes this sensor model and the RRT* algorithm to effectively explore water on the lunar surface. The paper provides a numerical simulation, using real data about time-variant illumination areas and time-invariant PSRs on the lunar surface, to illustrate the effectiveness of the proposed algorithm. The results reveal that the algorithm accurately and efficiently detects water under realistic illumination conditions.

In the present study, we have elucidated the behavior of a suspension composed of magnetic disk-like particles that flow in a Hagen-Poiseuille flow in a gradient magnetic field and the trapping characteristics of the magnetic particles by means of multi-pairs of magnetic poles. Brownian dynamics simulations were performed in order to clarify the dependence of the trapping characteristics on a variety of factors such as the magnetic interaction between particles, the strength of a non-uniform magnetic field, the strength of the flow field and the separation distance between two pairs of magnetic poles. The main results obtained here are summarized as follows. An increase in the magnetic field strength improves the trapping characteristics of disk-like particles if the influence of an applied magnetic field is sufficiently more dominant than that of a flow field and also that of the magnetic particle-particle interaction. In the case of a strong magnetic particle-particle interaction, thin chain-like clusters are formed from an anchored particle trapped around a magnetic pole. Moreover, if the separation distance between the two poles is sufficiently near, an arch-type cluster is formed between the magnetic poles, and is located in a vicinity area nearer to the wall surface due to the influence of a flow field. For the case of a small aspect ratio rp=3, in the situation that the particle volumetric fraction is constant, an arch-type cluster formed between the magnetic poles can remain trapped in the vicinity of the wall surface even under the influence of the strong flow field. Hence, we understand that the use of disk-like particles with a small aspect ratio may be able to improve the trapping performance of particles.

In this study, we proposed a structural health monitoring and diagnostic method for layered structures using the Autoencoder (AE). This method belongs to the primary diagnosis one, and its purpose is to identify the location of abnormality quickly after abnormality detection. An abnormality represents a decrease in the stiffness characteristics (spring constant) of the outer wall of a hierarchical structure when it deteriorates or is damaged. The proposed method has the following two features. The one is that the AE learns only the Frequency Response Function (FRF) under normal conditions calculated by the mathematical model of the layered structure. The FRFs of the actual structure under abnormal conditions are not required for the learning data. The other is that the FRFs under abnormal condition computed by the mathematical model are input to the learned AE to obtain a standard of the initial abnormality. The location of abnormality is identified by checking that the abnormality in the actual structure fits the standard of the initial abnormality. First, we considered a three-layered structure as a numerical example and verified the validity of the proposed method. When the method was applied to the three types of abnormal conditions, it was shown that the abnormal diagnosis could be performed correctly. Next, we constructed an experimental model of a three-layered structure, and realized three types of abnormal states similar to the numerical examples. We verified the applicability of the proposed method and showed that correct abnormal diagnosis was possible. As described above, the validity and applicability of the proposed method were clarified.

With the recent spread of 3D printing, its application has been widely discussed from automotive industries to small-scale and individual manufacturing. In general, additive manufacturing is used as a 3D printing process. Using this process, defects in one layer can easily spread to the next layer, deteriorating the overall quality of the final product. Therefore, to ensure the quality of 3D printers while maintaining a large workspace, it is important to monitor the process online. In this paper, a coarse-to-fine strategy is implemented for Fused Deposition Modeling via the dynamic compensation module attached to an industrial robot arm, and the 3D printer-specific multi-ROIs image processing method is proposed for printing monitoring and compensation. The dynamic compensation module consists of two high-speed cameras, an extruder, and a 2-axis actuator that can monitor previously printed material to compensate for the movement of the main system as a high-frequency sub-system. For evaluation of the developed system, a defection detecting test using the multi-ROIs method and dynamic compensation tool path planning test was made. Consequently, it was shown that the dynamic compensation system can be applied by dynamic compensation of the developed 3D printer system, and the prediction and inspection can be made simultaneously by using the multi-ROIs method.

The co-sintering of multilayer ceramics, produced by tape casting, is a cost-effective process for manufacturing electrodes in solid oxide fuel cells (SOFCs). Hence, understanding the deformation kinetics of multilayer ceramics during co-sintering, originating from the different shrinkage rates of individual layers, has become critical. In-situ monitoring of the sintering process using an optical device is a promising non-contact method that enables the deformation tracking of both monolayer and multilayer ceramics. However, the material emits thermal radiation at various levels during sintering, which leads to a time-consuming image processing procedure, because the intensity of thermal radiation changes significantly when shifting from low to high temperatures. This study presents deep learning techniques that employ convolutional neural networks to segment and detect objects in the image processing associated with in-situ monitoring. We verify that the DeepLab V3+ network accurately segments the sintered body, even when images are severely affected by mixed brightness or noise. Furthermore, the presented network can also quantify shrinkage profiles over a wide temperature range within a short time. In addition, we demonstrate that the YOLO V4 network can monitor the warpage behavior of co-sintered laminates by evaluating the curvature profile over a broad range of temperatures without requiring image binarization, despite the limitations of curvature detection. Finally, we demonstrate how the developed networks can potentially be utilized to predict the time evolution of warpage deformation in SOFC anode/electrolyte bilayer systems.

Overhead crane is a product used to transport heavy objects in a factory, and advanced operating skill is required to operate safely and with less equipment failure. However, the shortage of skilled operators has been pointed out in recent years. The purpose of this paper is to develop a method for estimating tense state of rope and weight of suspended load at the same time with the aim of improving the safety of overhead cranes without relying on operator skills. When estimating multiple states using independent estimation models, the issue is the lack of computer storage space and calculation speed due to the increase of the parameters. Therefore, the authors adopted a method that simultaneously estimates several states in a single model. To estimate the tense state of rope and weight of suspended load from the driving signals of the induction motor mounted on the overhead crane, a multi-task neural network that can express the nonlinearity of motor characteristic was used. The teaching data used for learning network parameters was created by using object detection technology to quantify the transportation of markers attached on load block and suspended load. As a result, it was clarified that the rope tension state and the load can be estimated simultaneously by inputting the driving signals of the motor to the multi-task neural network. Moreover, it was shown that the rope tension probability and the estimated load increased synchronously as the motor signals change, and the tension detection was output.

In order to design fast reactors, it is necessary to consider high cycle fatigue of structural materials up to 1×109 cycles. Since the fatigue usage factor (UF) is calculated down to the order of 0.01 in fast reactor design, it is necessary to develop fatigue curves applicable up to 1×1011 cycles to evaluate high cycle fatigue at 1×109 cycles. In this study, the applicability of the best-fit fatigue curve of JSME up to 1×1011 cycles was verified in order to develop a high cycle fatigue evaluation method for Mod.9Cr-1Mo steel, which is a candidate material for fast reactor structural materials. In the applicability verification, high cycle fatigue tests were first conducted at 500 °C, 550 °C, and 600 °C under strain-controlled conditions, and ultrasonic fatigue tests were conducted at 550 °C. The test results were then evaluated and showed that there was no rate dependence and no difference by product types for high cycle fatigue strength of Mod.9Cr-1Mo steel at high temperatures. It was also clarified that there was no difference in high cycle fatigue strength of Mod.9Cr-1Mo steel at high temperatures even if the failure mode changed from surface origin to internal origin. A best-fit fatigue curve was developed from test data obtained in high cycle fatigue tests up to 1×109 cycles. And based on the high cycle fatigue mechanism discussed from the ultrasonic fatigue test results, the best-fit fatigue curve of JSME was confirmed to be applicable to Mod.9Cr-1Mo steel up to 1×1011 cycles regardless of product types.

The atomization process of fuel spray injection in internal combustion engines affects the spray mixture formation process, the combustion characteristics, and the formation of toxic substances. Therefore, several optical measurement procedures have been developed and applied to capture spray features, including imaging methods and laser diagnostics. It has been concluded that the spatial resolution of fine spray droplets detection in imaging with silver halide film is much better than with a CCD imaging device. Therefore, the authors previously developed a novel imaging technique called Super High Spatial Resolution Photography (SHSRP), which allows for whole spray imaging while maintaining the spatial resolution of tiny droplets. This is a wide-field, high-resolution imaging method that can measure the entire spray area at the droplet scale. However, the image analysis method analyzes the intensity gradient of the outer edge of the droplet, and the accuracy of droplet analysis deteriorates as the droplet diameter is small. In this study, a new image analysis method with wide-field and high-resolution images acquired by SHSRP was developed to improve the analysis accuracy of spray droplets. The analysis method of depth of object field, which depends on droplet size, was changed from one-dimensional analysis of the intensity gradient of the outer edge of the droplet to two-dimensional analysis using the intensity deviation of the entire droplet area. For the developed analysis method, analysis of error based on scattering theory was conducted and the droplet capture ratio in diesel spray was analyzed to verify the accuracy. As a result, it was found that the particle size distribution obtained has no peaks due to noise effects, and that the presented analysis method is accurate enough to characterize the particle size distribution of diesel spray.

A series of numerical material tests based on homogenization theory are carried out to characterize the anisotropic elastoplastic and hardening behavior of thermoplastic resin reinforced in one direction by carbon fibers (UD-CFRTP), and a new constitutive model is proposed to describe the characteristic material behavior. First, macroscopic stress-strain curves are obtained from numerical material tests (NMTs) conducted on a unit cell model, i.e., a representative volume element of periodic microstructures, to which uniaxial and combined stress states are applied under various conditions of stress ratios and stress paths. Using the obtained NMTs results, the initial shape of the yield surface and its evolution are investigated in detail. The results suggest that even if a resin has isotopic hardening characteristics, UD-CFRTP exhibits complex anisotropic post-yielding or, equivalently, hardening behavior. Then, a constitutive model that can describe such material behavior is originally formulated, and a step-wise identification strategy is presented to determine the material parameters. Finally, by carrying out verification analyses, we confirmed that the macroscopic stress-strain curves represented by the proposed model can be fitted to those obtained by NMTs with sufficient accuracy for practical use and that the performance of the proposed model is much better than that of a conventional constitutive law.

The purpose of this study was to clarify the factors that make transitions efficient using the positional information of the players. The independent variable in this analysis was the positional data gathered from the Vector X7 system (10 Hz) during 20 official matches of the second division of the Japan Professional Soccer League for the 2022 season. The positional data included metrics such as team convex area, length, width, foremost position, rearmost position, rightmost position, and leftmost position. Statistical analysis revealed that the team convex area, foremost position, rearmost position, and width were significantly higher during successful transitions than failed transitions (p = 0.032, p < 0.001, p < 0.001, and p = 0.030, respectively). Conversely, the leftmost position was significantly lower during successful transitions than failed transitions (p = 0.012). Moreover, the results obtained from the decision tree analysis demonstrated that the rearmost team position emerged as the most influential factor determining the success or failure of transitions. The results of the present investigation demonstrated that the positional information of the players at the time of ball recovery is an explanatory factor for efficient transitions. The novel contribution of this study is that the factor that determines efficient transitions was found to be the rearmost position and the leftmost position of the team at the time of ball recovery.

When mascot suits or plush fabrics are used to cover a human-friendly robot, frequent sterilization may be required, depending on the use of the robot. However, the effects of such sterilization are not sufficiently understood. In this study, variations in the strength and color values of plush fabrics were measured and quantitatively evaluated following 50 cycles of sterilization by ethylene oxide gas (EOG). The fabrics were composed of boa fabric, which is commonly used in mascot suits and plush dolls, and cloth reinforced with polyurethane foam. The tensile strength and the elongation were measured by the tensile strength test for clothes or clothing seams, in accordance with the standard JISL1096. In terms of appearance, red-green-blue (RGB) color values were obtained from photographs taken under the same light conditions to evaluate the color tone. A friction test was used to evaluate the tactile sensation. These results showed that EOG sterilization did not notably affect the properties of the fabrics; however, a single cycle of autoclave sterilization degraded the fabrics. Notably, the boa fabric shrunk and hardened. Thus, EOG sterilization, which does not feature elevated temperatures, may be an effective sterilization approach for these materials.

A conservative design methodology which results in overweight winding of helical layer in Type 4 hydrogen tank has been employed since the rupture phenomena in the vicinity of metallic boss of the tank is too complicated to predict precise burst pressure. The complexity comes from both the meso-scale structure constituted by overlapped carbon fiber bundles and local bending deformation in the part. Authors have developed a meso-scale based methodology for precise prediction of the burst pressure of Type 4 hydrogen tank, where carbon fiber bundles and matrix resin are perfectly distinguished for modeling. We investigate resin fracture model for the improvement of burst pressure prediction initiated by the rupture in the vicinity of metallic boss, assuming the reinforcement by means of Automated CFRP Tape Placement to realize ultimately light design of the tank. Specimens representing meso-scopic structure in the part are manufactured and submitted to the three-point bending tests. Through the validation of meso-scale fracture simulations corresponding to the tests, we demonstrate compressive fracture model of resin is decisive for precise description of terminative fracture phenomena in bending test specimen.

The effect of the nozzle orientation and the nozzle spacing on the flow characteristics of twin rectangular jets were studied experimentally. The nozzle spacing ratio S/de of a rectangular nozzle with an aspect ratio of 2 was varied from 2.75 to 6.875. Two nozzle orientations were tested, i.e., twin nozzles oriented along the minor plane (TwinMinor) and twin nozzles oriented along the major plane (TwinMajor), and the results were compared with a single round jet, a single rectangular jet, and a twin round jet. In each case, the Reynolds number based on the maximum jet velocity and the equivalent diameter was 1.5 × 104. The nozzle orientation has no influence on the flow characteristics of twin rectangular jets along the jet centerline. However, the velocity and turbulence intensity of the twin rectangular jets of TwinMajor increases more than that of TwinMinor near the symmetry line of the twin jets, and the location of the combined point (CP) becomes upstream. The twin rectangular jets with a small nozzle spacing ratio, i.e., S/de = 2.75 merge upstream. The velocity near the jet centerline in downstream becomes relatively higher compared to that with a large spacing ratio. The vortex shedding frequency of the twin rectangular jets depends on the nozzle spacing ratio. The flow characteristics of the twin rectangular jets with a large nozzle spacing ratio, i.e., S/de = 5.5 and 6.875 are similar to the single rectangular jet.

Rail corrosion is one of the causes of rail breaks. The relationship between rail corrosion state and fatigue strength is still unclear. Therefore, to accurately estimate the fatigue strength of corroded rails, the prediction method for fatigue strength of corroded rails with pitting corrosion by actual stress and stress gradient was investigated. Bending fatigue tests were performed on the rails with pitting corrosion on the bottom surface. At this time, models based on the shape of the rail bottom surface were created, and actual stresses and stress gradients generated at the rail bottom surface were evaluated by the finite element method. When the fatigue test results were evaluated by the actual stress, the bending fatigue strength appeared to be higher when the fracture origin position was inside of pitting corrosion than when it was outside. This was an apparent phenomenon due to the use of actual stress, which could be explained in terms of stress gradients. Furthermore, using the relationship between the correction factor of time strength q, which expresses the relationship between the fatigue strength of new rails and the apparent fatigue strength of the corroded rails, and the stress gradient χ, it is possible to estimate the number of loading cycles that the corroded rails break in the fatigue tests.

Since the boiling heat transfer is much affected by the nucleation of bubble and its growth, estimation of such process is essential for the accurate prediction of the heat transfer. In this study, molecular dynamics simulations were performed in order to clarify the effect of the wall conditions, i.e. the wettability and the slip between fluid and solid wall, on the bubble growth. The simulation results show that the evaporation near the contact line is enhanced and the vapor jet from contact line is observed. The direction of the vapor jet from the contact line is along the solid wall surface in the case of large slip and is along the liquid-gas interface in the case of small slip. The difference in the direction of the vapor jet is due to the flow in the adsorption layer on solid wall surface (in solid-gas interface). In the case of large slip, the fluid molecules in the adsorption layer flow with larger velocity in the direction away from the contact line. The vapor jet thus can develop along the surface of the adsorption layer. In the case of small slip, by contrast, the flow in the adsorption layer is prevented by the wall shear stress and the layer held on the wall surface invokes shear stress between the layer and the vapor jet. Consequently, the slip affects the vapor jet from contact line.

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 this situation that there is a dangerous vibration frequency range where these are easy to scratch and are prone to death. If there are eigen frequencies within this dangerous frequency range，it is good to be redesigned such that the eigen frequencies within this dangerous frequency range are moved out of the range. But it is difficult to apply the existing topology optimization methods using homogenization method or density method or thickness distribution method. As fundamental research, it is demonstrated the effectiveness of the proposed method based on the strain and kinetic energy density distributions of the targeted eigen modes for a flat plate compared to the conventional topology optimization method using thickness distribution as follows. (1) It is possible to control plural eigen frequencies by deciding interactively how the topology should be changed from the observation of kinetic and strain energy density distributions of the targeted eigen modes in a very short time compared to the conventional topology optimization method. (2) In the case of the proposed method, it is not necessary to get a new topology from the thickness or density distribution after the optimization results. (3) It can be checked the validity of the task set for the conventional topology optimization method by observing the strain and kinetic energy density distributions of the targeted eigen modes which are actively used in the proposed method.

With the recent development of additive manufacturing technology represented by 3D printers, various lattice structures have emerged because their mechanical properties can be designed artificially according to their structural characteristics. This study aims to develop knowledge that will contribute to the design of lattice structures with tailored and desired mechanical properties. Among the many unit cell topologies in the lattice structures that have been designed in numerous studies, there are several basic structures and a variety of additional structures that were derived from these basic structures. However, there is a degree of ambiguity as to which of these structures should be regarded as the basic structures. In this study, the basic structures of a lattice structure with orthogonal symmetry were derived by determining the edges of the struts using a mathematical combination approach. Then, the deformation characteristics of them were evaluated through elasto-plastic finite element analysis. Five basic structures were determined by designing the unit cell of the lattice structure such that the struts pass through the vertices, the midpoints of the edges, and the centers of the faces in the cubic design region. It was found that structures with the same strut directions in their unit cells have similar stiffness distributions, and the basic structures obtained can be classified accordingly into three types. Finite element analysis of the compression of a micro-lattice structure composed of these basic structures confirmed that different deformation characteristics appeared during plastic collapse for each type of classified basic structure, and that the strut deformation type determined the overall deformation characteristics. Evaluation of the stiffness and the plastic collapse stress showed that with stretch-dominant strut deformation, lattice structures can be made lighter in weight while still maintaining some stiffness and some plastic collapse stress.

The variation in stride length is an important index of gait stability. The evaluation requires a device that can accurately measure the stride length during ground walking. However, there are currently no practical and reliable measurement systems for clinical use. The purpose of this study was to improve the stride estimation method using a single inertial sensor and to verify the accuracy of stride length estimation. Stride length was estimated by integrating the horizontal acceleration at the ankle joint. To reduce the impact acceleration at ground contact, which is the primary factor causing estimation errors, we mounted an inertial sensor on the lower leg. In the present method, the following four factors contribute to the stride length estimation error: the sensitivity of the inertial sensor, consideration of the directional angle, detection of integral intervals, and estimation of the relative position vector from the inertial sensor to the ankle joint. This study presents solutions to these problems and verifies the accuracy of stride length estimation by comparing it with optical motion capture measurements. The results indicated that the sensitivity of the inertial sensor improved the accuracy of the stride length estimation. Furthermore, we found that the standard deviation of stride estimation per step was approximately 32 mm, regardless of cadence and stride length. We conclude that the stride length estimation by the acceleration integral method is applicable to the estimation of the average stride length; however, it is difficult to apply it to the evaluation of stride variation from step to step.

In this paper, the mechanical properties of two-dimensional linked zig-zag structure subjected to in-plane compressive load was investigated. This structure has two counterphase layers consisted of inclined plate. The stiffness and the stored strain energy during the deformation were solved analytically based on the flexible bar theory proposed by Frisch-Fay(1962). In particular, the effects of micro-architecture of the zig-zag model on these mecahnical properties were discussed. The obtained theoretical results agree fairly with FE results. In addition, three cases of the compressive response of a connected zig-zag structure were examined in order to clarify the effective parameters on the equivalent elastic modulus and strain energy stored under certain constraining conditions.

To evaluate stresses including stress concentration at weld toes for fatigue evaluation of complex shape welded structures such as railway bogie frames, previous studies proposed the stress assessment procedure through measuring strains of actual structures by attaching strain gauges with its edges to be at weld toes. This paper evaluates design fatigue strength in terms of the measured stress from published fatigue data and re-analysis of those fatigue tests. The obtained fatigue strength fell into danger side by 12-29% if compared to the fatigue strength estimated based on the current version of JIS. The result also showed that fatigue strength at 2×106 cycles with 0.13% failure probability had a similar value with that at 1×107 cycles with 2.3% failure probability. The fatigue strength in terms of the aforementioned strain measuring system was comparable with those in terms of structural hot-spot stress approach.

To support engineers in solving engineering problems utilizing digital twin, we are proposing ‘digital triplet’ concept. We are also developing a problem-solving process support method by using the Log Level Description (LLD) that describes an executed problem-solving process and the Generic Process Model (GPM) that describes a generalized and prescriptive process. This paper illustrates a support method for describing LLDs to put the proposed method into practical use. Through an attempt to describe LLDs, three time-consuming operations were identified: viz., interviewing, structuring the information, and relating each action with the GPM. To save the labor of these operations, we propose the method that the engineer who executes the process sequentially describes the LLD by oneself based on the GPM. This paper also illustrates an LLD description support system based on the proposed method. Finally, a case study was conducted to describe the actual fault detection system design processes with the developed support system. By comparing the LLDs created with the support system in the case study with the ones created manually, the effectiveness of the proposed method was discussed. In addition, by interviewing engineers who created the LLDs in the case study, the usefulness and feasibility of the proposed method were discussed.

Aiming at the problem that the basic impedance control has great impact force and is difficult to cope with environmental changes when it contacts with the tooth surface of worm gear, an adaptive impedance control method based on genetic algorithm was proposed. The influence law of spindle speed, feed speed and grinding force on the surface quality of worm gear tooth surface is analyzed. With material removal rate as the optimization objective, an optimization model of grinding process parameters is established based on particle swarm optimization algorithm, and the optimal grinding process parameters for industrial robot grinding worm gear tooth surface knife marks are obtained: Spindle speed (n=3087.82r/min), Feed speed (vf=0.51mm/s), Normal grinding force (F=19.9N). The experimental results show that the roughness of worm gear tooth surface is increased from 0.941 to 0.719 by using the optimized grinding process parameters. Moreover, this method can effectively suppress the external force influence of industrial robots in the process from free space to constrained space, and the force fluctuation is significantly reduced after contact stabilization, and it has stronger environmental adaptability and force control performance.

Due to the high precision and high speed of spindles for machining centers, thermal issues cannot be avoided. The temperature rises of the spindle shaft, which is the rotating component, causes issues such as increased thermal displacement in the tool axis direction and an increase in friction torque, leading to limitations on the spindle speed. Heat removal or heat diffusion methods are effective in reducing the temperature of the spindle shaft. The former method of removing heat from the rotating shaft requires complex peripheral devices for cooling. Here, the latter method of diffusing heat is examined. Specifically, a method for reducing the temperature of the high-temperature part and the temperature difference generated in the shaft will be examined. In order to diffuse the heat of the spindle shaft, it is necessary to increase the thermal conductivity of the shaft. In this study, highly oriented pyrolytic graphite (HOPG), which has recently attracted attention in the semiconductor field, is used for the spindle shaft instead of heat pipes (HP), which are generally used for heat diffusion. The temperatures of the rotor and bearings during rotation of the HOPG spindle shaft and the normal steel spindle shaft were measured. Under the conditions of Dmn value of 1.53×106 mm/min, the hot part of the normal steel spindle shaft is 42°C and the generated temperature difference is 8K. On the other hand, with the HOPG shaft, it was able to reduce to 40°C and the generated temperature difference was reduced to 5K. By using a spindle shaft with high thermal conductivity by HOPG, it was found that the temperature of the high temperature part can be lowered and the temperature difference occurring in the shaft can be reduced.

In this paper, a Genetic-Artificial Bee Colony Algorithm (G-ABCA) for mechanism optimization synthesis is proposed to improve the accuracy of the dimensional synthesis of the 4-bar mechanism. Firstly, the plane coordinate of the 4-bar mechanism was determined. Then, the relevant design parameters of the link motion were analyzed. The objective function was constructed to minimize the position error between the actual trajectory of the mechanism and the target trajectory, constraints of the 4-bar plane mechanism were added. Then, by means of the improved artificial bee colony algorithm, the length, size and angle variables of the 4-bar mechanism were optimized. The parameters of the classical case were optimized. Finally, the optimization results of the algorithm were simulated for the optimized parameters of the 4-bar mechanism. The results were compared to other optimization algorithms. The results show that the trajectory error obtained by the improved artificial bee colony algorithm is smaller and the optimization effect of the parameters of the 4-bar mechanism is better. The proposed algorithm improves the crossover rate between food sources, extends the population optimization space, improves the local search ability and prevents the premature convergence of the genetic algorithm. The validity and accuracy of the method are proved, which provides a theoretical basis for the in-depth study of the trajectory error of the 4-bar mechanism.

Workpiece rigidity during end-milling processes decreases monotonously. Reduction rates of the rigidity become large when the end-milling operations have large cutting stock such as carve out machining. It becomes popular to utilize side-face clamping methods because of large accessibility of cutting tools. However, workpiece rigidities directly affect to clamping force and workpiece deformation when workpieces are clamped with side-face clamping method. This research deals with transitional workpiece deformations considering workpiece rigidity reduction. At first, measured results of clamping force reduction during machining operations are investigated. Secondly, measured workpiece profiles during machining operations are investigated. Finally, FEM analysis of workpiece deformation considering workpiece change is discussed. From the results of the evaluation, it becomes clear that it is necessary to consider the influence of transitional workpiece rigidity to achieve reliable estimation of machining accuracy.

Virtual sensor, which is one of the applications of the digital twin, is effective for estimating physical quantities that are difficult to measure. This paper deals with estimation of real-time tool edge temperature by virtual sensor. The tool edge temperature is estimated by inputting the temperature data of the endmill shank obtained from the pyrometer installed in the machine tool to the simulation model created in cyber space. The simulation performed in cyberspace is an unsteady heat transfer analysis, and a state space model with a reduced order of the finite element model using Krylov subspace method is adopted as the simulation model in order to allow real-time simulation. In addition, unknown heat input to the cutting edge was calculated by state feedback control using the temperature data obtained from the pyrometer and the simulation model. The tool edge temperature during cutting was estimated in real time using the developed virtual sensor with the heat transfer analysis block and the input estimation block. The estimated tool edge temperature changed significantly in response to changes such as chipping of the tool edge. The estimated temperature and the measured temperature by the thermocouple method generally matched.

A machining center is a common machine tool that can machine complex free-form surfaces such as the press mold, automobile’s cam profile. When these curved surfaces are machined by the conventional machining center and/or the grinding machine, it takes lot of time to complete with enough accuracy. In order to solve this problem, this study aims not only to improve the machining accuracy of this curved surface but also to make it possible to shorten the machining time using a CNC lathe. In this study, the NACS-Turning (Non-axisymmetric curved surface turning) method that we proposed originally was used. The spindle of C-Axis, the moving table with the cutting tool of X1-Axis, the other counter moving table of X2-Axis (without involved in shape creation, only used to suppress inertial force), the head stock of Z-Axis, and the tool rotation axis of B-Axis are adapted. In this 4-Axis machining method, all the axes are controlled with the synchronized manner. This method can machine the same rotational position of workpiece with the same cutting edge of the rotary tool. As an experiment, we compared 4-Axis machining with synchronized spindle and tool rotation, 3-Axis machining, and machining without synchronous rotation. Our new 4-Axis machining method with synchronized spindle and tool rotation reduced the form error from 323 ㎛ to 247 ㎛ and the surface roughness from Rz 9.6μm to Rz 3.7μm. Moreover, the repetitive machining resulted in error of 99.6μm and a surface roughness of Rz2.9μm.

Metal shock absorbers of nuclear spent fuel casks for storage have been developed. The shock absorbers are equipped at both ends of the cylindrical cask to reduce the impact force and maintain the safety functions of the cask in the event of an unexpected drop accident. As a countermeasure to meet long-term storage requirement (against material degradation), the shock absorber was designed with metal instead of usual wood and its energy absorption performance against 2.5 m height drop (maximum hypothetical handling height in nuclear power plants during storage) was evaluated. With the aim of reducing compression stiffness the metal shock absorber was designed from a perforated aluminum block. Two tests were done for static compression characteristics using cubic specimens and energy absorption capacity against 2.5 m drop using 1/4 scale mockup of metal shock absorber. In addition, a drop test using 1/10 scale mockup cask with metal shock absorbers confirmed that it could deform as assumed and reduce the applied acceleration on the cask to a safety level at crash. As a result of the finite element analysis of the cask with designed shock absorbers dropped from a height of 2.5 m that was verified by the drop test, the fitting portion between body and primary lid in the cask remained within elastic deformation thus confirming the design’s validity.

In recent years, there has been active development of robots that play a role in people's lives. These robots require actuators that have high responsiveness and high output force in addition to being small. Furthermore, safety and contact affinity are also required for these actuators. An actuator that can balance high responsiveness, high output, and contact affinity is developed in this study. The proposed system is a hybrid system of hydraulic and pneumatic systems. Hydraulic systems are generally used in machines that require large forces, such as construction machinery, because they have high responsiveness and high output force. However, hydraulic systems have poor contact affinity. On the other hand, pneumatic systems are used in machines that come into contact with people, such as power assist suits and massage chairs, because they have high contact affinity, although their output is inferior to that of hydraulic systems. Generally, the mixing of air bubbles into hydraulic oil is a problem. However, as the pressure increases, the rigidity of the working hydraulic oil mixed with bubbles approaches that of pure working hydraulic oil. If this characteristic is appropriately modeled and controlled, bubbles mixed into the working hydraulic oil can create a cushioning effect. Firstly, the relationship between the pressure and rigidity of hydraulic oil mixed with bubbles is demonstrated in this paper. Secondly, the mechanism of the hybrid system and the prototype model are explained. Lastly, the results of performance evaluation through analysis and experiments are presented. From these results, this paper shows that the proposed system has the potential to balance high responsiveness, high output, and contact affinity.

All-terrain wheelchairs are assumed to be used under such conditions that are on the roads along mountain topography, steep slopes, bumpy roads, muddy roads, etc. It is often used for people with disabilities to enjoy outdoor activities in nature with friends and family. In order to deal with such conditions and usages, all-terrain wheelchairs have different structures and features from normal wheelchairs. In this paper, we focus on the type of all-terrain wheelchair that needs to keep the pitch posture during turning. Here, the pitch posture means the state that the front wheel is lifted. It is hard to keep a stable pitch posture on a steep slope and a bumpy road even though the wheelchair is manipulated by an experienced operator. This paper proposes an electric power assist control that keeps this pitch posture stable and reduces the manipulating load of an operator. The most important feature of the control is to control the kinetic energy of the wheelchair, the sum of the energies of longitudinal and pitch motion. This control is implemented on an electrically power assisted wheelchair, and the effectiveness of the control is demonstrated by the experimental results.

This paper describes computational study to investigate the aero-acoustic mechanism observed in Hartmann generator when under-expanded supersonic jet is blown from a convergent nozzle. The Hartmann generator, composed of a nozzle and a resonance tube with small distance, is known to radiate much higher amplitude of tonal sound than a free jet without any interaction. Aiming at establishing compact and efficient fluidic actuators, the authors tried to clarify the fluid-dynamic and acoustic behaviors of this special device by use of computational tool, i.e., UPACS-LES of Japan aerospace exploration agency（JAXA）. The computational results suggested existence of the JRG mode, an alternative flow motion between the nozzle and the resonance tube. This flow motion drives strong pressure fluctuation and forms sound field in the far field. The computational results complied with the fundamental acoustic characteristics in the former studies, such as far-field sound directivity and radiated acoustic power. Based on the results, it was confirmed that some parameters such as nozzle pressure ratio are predominant to intensify the acoustic power in the far field. Especially, the open-end location of the resonance tube governs the acoustic power when it is between Mach disk and shock cell end in the under-expanded supersonic jet.

In recent years, automobile manufacturing requires both weight reduction for environmental measures and high strength for safety. For this reason, the use of ultra-high tensile strength steel sheets for frame components is increasing. For the application of ultra-high tensile strength steel sheets, it is necessary to pay attention to measures to ensure dimensional accuracy for press forming. Among them, wall curvature countermeasures are very important technologies. In this study, a novel forming method without generating wall curvature was developed using a simple hat model, and then a prototype mold was produced and confirmed. This novel forming method is a combination of the advantages for draw forming and cam bending forming. To form a shape so as not to fracture or wrinkle in a process similar to drawing, and to prevent wall curvature of a vertical wall part of a hat section in a process similar to cam bending. The forming motion consists of downward descent and multi-step sliding while holding the specimen in one forming process. In the FEM analysis before the production of the prototype mold, the conventional forming method and the novel forming method were evaluated from the viewpoint of the wall curvature, and the novel forming method gave the best results with the minimum wall curvature. The evaluation of the formed panel using the prototype mold also gave the same results as the FEM analysis. This paper shows that the developed forming method hardly generates the wall curvature even when the ultra-high tensile steel sheet is used.

This paper presents a conceptual design approach for planar link mechanisms by utilizing continuum topology optimization based on micropolar continuum theory. To effectively simulate the behavior of link mechanisms as continuum elasticity, we introduce a mathematical model utilizing micropolar elasticity. Although topology optimization is commonly used for single mechanical components, extending it to mechanisms with multiple interconnected parts presents inherent challenges. To address these challenges, we model the link mechanism using micropolar elasticity, leveraging its bendiness-related material property, which can apply to topology optimization. Subsequently, we formulate a topology optimization problem to generate link mechanisms using our proposed model. The optimized structure achieves the desired motion and deformation characteristics like traditional linkages with proper degrees of freedom while minimizing the objective function that considers both output motion error and link compliance. The design variables of the topology optimization problem are defined using the Solid Isotropic Material with Penalization (SIMP) method, which is further updated using a gradient-based optimizer. The governing equations of linear micropolar elasticity are solved using the Finite Element Method (FEM). The effectiveness and validity of our proposed method are evaluated through numerical examples, which conclusively demonstrate its ability to synthesize the number, dimensions, and structure of link mechanisms.

This paper presents numerical solution to shape design problems of viscous flow field for unsteady fluid-structure-interactive (FSI) fields. In the FSI analysis, a strong coupled analysis is used to analyze the governing equation of the flow domain and the structural domain considering nonlinearity of strain. A minimization problem for total dissipation energy is formulated for the shape optimization of viscous flow domain in the FSI fields. Also, a shape design problem is formulated to control the flow velocity distribution in the sub-domains of the flow domain. This latter problem can be treated as an inverse problem for minimizing the square error integration between the actual flow velocity distribution and the target flow velocity distribution in the sub-domains. Shape gradient of these shape design problems are derived theoretically using the Lagrange multiplier method, adjoint variable method, and the formulae of the material derivative. Reshaping is carried out by the H1 gradient method proposed as an approach to solving shape optimization problems. Numerical analysis programs for these shape optimization problems are developed by using FreeFEM, and the validity of proposed method is confirmed by results of 2D numerical analyses.

In recent years, condition monitoring methods have been widely developed. Any failure of the overhead catenary system or pantographs will raise the long downtime of railway operation. Therefore, condition monitoring methods of pantograph failure is required with the overhead catenary system. Furthermore, wear mechanism of contact wire has not been clarified yet due to its complex kinematics between contact wire and pantographs. For preventing these failure efficiently and finding out the wear mechanism of contact wire, the authors have developed a method to measure contact forces of all pantographs during trains passing on sections with sensors installed on the catenary. In the developed method, the contact forces are measured from the sum of dropper forces, inertia force of the contact wire and vertical components of the tensile force of contact wire in measurement section. However, some difficult issues have been left in the method measuring the inertial force from contact wire acceleration at some measurement points. This paper proposes a method selecting effective measurement points of contact wire acceleration. LASSO regression, which is known as one of the sparse modelling technique, is applied to the proposed method so that suitable acceleration measuring points are selected to measure inertia force. The results obtained by the proposed method are shown using dynamic simulation data. It also reports that the proposed method is effective even when the measurement frequency is changed.

The present study discusses the effects of wheel steered trailer with stability control for multi-articulated vehicles on the lane-keeping performance. For the stability control, the vector follower control is applied to align the direction of the velocity vector at the articulation point with the trailer centerline by steering each trailer wheel. 16 simulations for the tractor and four-trailer combination model, combining with and without a wheel steering of each trailer, are performed. Trailer wheel steering suppresses the direction difference angle at the articulation point and reduces the lateral deviation of the trailer. The forward trailer wheel steering also suppresses the lateral deviation of the unsteered rearward trailer. Based on the relation between the amount of steering input required for stability control and the lateral deviation of each trailer, the lateral deviation is suppressed by steering, however, the steering input required for the stability control is also generated, so the control efficiency depends on the balance between the reduction of the lateral deviation and the required steering input.

A simulation technique adaptable to calculating a laser-machined profile was proposed to develop microfabrication techniques for a cemented carbide using a focused picosecond pulsed laser. An experiment to obtain a defocus diagram, which shows the relationship between defocus and removal depth, was conducted by shifting the focal point upward to the work surface. The concept of zero cut, in which the laser beam was scanned repeatedly in the same path, was proposed, and it was verified using the proposed simulation technique that zero cut is useful for residual stock removal. In addition, a simulation technique adaptable to calculating both the laser-machined profile and the machining process conditions was developed using the defocus diagram as a machining condition. It was verified through a machining test by fabricating half-cut columns with radii of 30 and 50 μm formed on the upper half of a large base column that the dimensional error of the columns was less than 1% and the surface roughness was less than 0.1 μmRz. This means that the simulation technique using the defocus diagram as a machining condition is useful for the microfabrication of the cemented carbide using the focused picosecond pulsed laser.

The shortage of drivers for trucks and buses has become a critical problem in recent years, leading to active research and development on unmanned and manpower-saving operation of heavy-duty vehicles. However, due to their larger overhangs compared to passenger cars, heavy-duty vehicles are more difficult to maneuver on narrow roads and sharp curves, especially those commonly found in urban areas or parking lots. Consequently, path tracking control systems commonly applied to passenger cars cannot be directly used for heavy-duty vehicles. Thus, the objective of this study is to develop a path planning and motion control system for autonomous driving of heavy-duty vehicles on roads with large curvatures. To design the control system, a risk potential is utilized to express the driver's sense of danger towards obstacles and road boundaries. Simulations are conducted on a course that replicates an actual intersection, and a parameter study is carried out. Finally, the simulation results of this approach are compared with those of a conventional path-following method. The results demonstrate that the proposed method is effective for obstacle avoidance in intersection situations.

In this study, we are attempting to create self-adhesive moldings made entirely from bamboo fibers extracted by a machining center in order to solve global environmental problems and the destruction of ecosystems caused by bamboo. However, the mechanical properties of the moldings are still insufficient. In the present report, we clarify the molding conditions that can improve the mechanical properties of the molded plates. First, the cause of fracture of the plates during tensile testing was investigated. As a result, it was considered that the cause was the fracture at the adhesion area or fiber withdrawal. To enhance the adhesive action, we focused on lignin, an adhesive component in bamboo, and its flow process during molding. We investigated the effects of in-mold temperature and pressure and molding time on the thermal flow of lignin. As a result, it was found that the thermal flow of lignin progressed and the mechanical properties improved as the time and pressure were increased. Therefore, we attempted to determine the molding conditions that maximize the tensile strength of the moldings by referring to a manufacturing process model for fiber-reinforced composites. Five specimens were fabricated, and a tensile strength of 32.37 MPa was achieved with a standard deviation of 0.55 MPa, which is equivalent to that of general-purpose plastics.

Focusing on the cooling of the arc splitter plate after arc generation in the pole mounted switchgears, the heat transfer phenomenon was clarified. Experiments were carried out on a pole mounted switchgears with load currents of 600 A and 800 A, and the heat transfer phenomenon was evaluated from the surface temperature of the iron arc splitter plate measured with a radiation thermometer. From the analysis results, it was found that the plate was cooled by forced convection due to the expansion of the air due to the arc for about 5 s after arc interruption, and then cooled by natural convection. Immediately after the start of the experiment (about 600 s from the start), the effect of the arc on the air is large, and the ratio of cooling by forced convection to total cooling amount is about 0.5 to 0.75. When the melting area of the iron arc splitter plate increases, the ratio of heat transfer rate by forced convection becomes about 0.3 to 0.55. In addition, after the experiment with a load current of 800 A, it was confirmed that the iron arc splitter plate melted and melted down over a wide area. It is thought that at a load current of 600 A, the melting area of the iron arc splitter plate was small enough to melt down, but at 800 A, when the arc energy increased, the melting area of the iron arc splitter plate increased and melted down. It was clarified that the heat transfer phenomenon in the arc-extinguishing plate is affected by melting.

Epoxy resins, one of the high-performance polymer materials, have been widely used as an adhesive because of their excellent strength and durability due to their cross-linked network structure. It is necessary to understand the adhesion mechanism to ensure their reliability as structural adhesives. It is concerned that environmental attacks, such as high temperature and humidity, degrade the bonding strength of the adhesive structure. In order to understand the degradation mechanism by environmental attacks, it is necessary to evaluate the intrinsic bonding strength of adhesive systems by a quantitative test method. This study proposed a novel test method to evaluate the shear bonding strength using a small columnar resin formed on the metal adherend's surface and investigated the adherend and environmental degradation effects on the bonding strength using the proposed method. The experimental results revealed that the bonding strength of the epoxy adhesive was affected by the environmental attack. The bonding strength increased regardless of the substrate material after the low-humidity and high-temperature exposure. On the other hand, the effect of the high humidity attack on the bonding strength was different depending on the adherend: the bonding strength of SUS304 decreased, on the other hand, that of A5052 increased. The fracture morphologies also changed in the case of A5052 adherend after the high humidity and temperature exposure. AlO(OH) was formed on the A5052 adherend surface after high humidity and temperature exposure, which might have affected its bonding strength.

The axle spring vibration isolator rubber installed on the axle box that encloses the axle bearings is subjected to loads corresponding to the wheel weight and vibration of the axle box during running. It is thought that the running condition of the bogie can be monitored by utilizing the axle spring vibration isolator rubber as a sensor to grasp the load and vibration. Therefore, we investigated a method of monitoring the running condition of the bogie by incorporating a piezoelectric element, which generates electric signals in response to applied loads and vibrations, in the axle spring vibration isolator rubber. In this paper, we made the rubber isolator with a built-in piezoelectric element (RIBP). As a result of running tests with the RIBP installed on a bogie, we found that the running condition of the bogie can be monitored by the time waveform of the electrical signal obtained from the piezoelectric element, and that the condition of the axle bearing can be monitored by the result of frequency analysis. In addition, as a result of examining the actual method of monitoring the running condition of a bogie using a RIBP, it was found that the condition could be monitored even if the number of RIBP installed on the bogie was reduced.

In this study, we aimed to stabilize premixed flame behaviors in a circular pipe with swirling flow. We constructed a system that automatically changes swirl vane angles according to the flame tip positions keeping the air ratio and flow rate. In addition, we tried to stabilize the flame behavior using this system, and simultaneously employed time-series PIV measurements in the flow fields in the circular pipe. The findings obtained in this study are shown below. (1) Under this experimental condition, it was shown that there was a positive and strong correlation between the flame tip positions and the integrated scattering intensity of tracer particles in a circular pipe with swirling flow. (2) Using the integrated scattering intensity of tracer particles as an index, the change of the flame tip positions was judged, and the swirl vane angle could be changed according to the behavior of the premixed flame. It was shown that keeping the flame tip positions within the circular pipe was possible. (3) While operating the flame position stabilization system, time-series PIV measurements simultaneously measured the flow fields near the flame tip. From the results, when the swirl vane angle was changed in the positive direction, an upstream-direction velocity region appeared by increasing the swirl intensity. After that, the flame propagated upstream along the formed upstream-direction velocity region.

In a section which a wireless train control system is installed and the track circuit is removed, it is difficult to detect rail broken. Under such circumstances, the vehicle is assumed to run repeatedly on rail gaps until rail broken is found by rail inspection or other means. Therefore, this study investigated the strength of the track components under condition of repeated passage at a rail broken section. Specifically, we fabricated a new falling weight test equipment which can apply the impact load of a vehicle passing through a rail broken section and then, the strength of track components was experimentally investigated by conducting repeated falling weight test. This test evaluates the plastic deformation of the rails and functional deterioration of the rail fastenings system in response to impact loads. In addition, in order to evaluate running safety considering repeated passage at a rail broken section, we created a vehicle running simulation model that takes into account damage condition of track components after a falling weight test. The results of the running simulation confirmed that the plastic deformation of the rails and damage to the rail fastening systems considered in this study do not have a significant impact on running safety.

In the installation process of an elevator, work performs to correct the bending of the rail in order to suppress the lateral vibration of the car due to the irregularity of the guide rail. In this work, each rail bracket is adjusted so that the cutting edge of the rail is in the specified horizontal position with respect to the piano wire. However, since the rail is bent at the joint, irregularities remain even if the brackets are lined up in a straight line. Such a method cannot suppress the lateral vibration of the car and may worsen it. In this research, we proposed a method of optimizing the rail shape to minimize the vibration of the car based on a rail behavior model in that adjustment process and a car vibration model. The effect was verified in an experiment using an actual elevator. In the elevator system, large vibration had been occurred because the periodic excitation force determined by the running speed and rail bending period matched the natural frequency of the car. By adjusting the rails based on proposed method, we avoided resonance and reduced lateral vibration by 37%. This verification showed that the use of the proposed method enabled significant vibration reduction in a short period of time.