In this study, microscopic visualization imaging of microscopic microbubbles in water was conducted to elucidate the cleaning mechanism of oil and grease stains. We constructed a visualization experimental apparatus using a microscope lens and succeeded in taking microscopic images of microbubbles adhering to fiber surfaces. To elucidate the cleaning mechanism of oil and grease stains, visualization experiments were conducted on oil and grease coated on glass surfaces. Fluorescent paint was added to the grease and LIF measurements were performed. In this experiment, it was not possible to accurately evaluate the detachment with video images, so the visualization method will be improved in the future.

The handwriting drafting of the first grader meets it and is easy to instruct it. There is a demerit to be hard to revise a drawing to give priority to learning of the trigonometry. It was decided that the problem to be hard to revise a drawing supported by the CAD of the second grader. As COVID-19 measures, we met it after preliminary examination for shortening of the waiting time of the student by the drawing instruction and instructed it. There were many mistakes of corner R which was available by CAD in the point that was easy to be wrong. Furthermore, we taught improvement of the letter quality to a drafting experienced person for shortening in waiting time and taught a document to an inexperienced person after a reception desk. As waiting time decreased, we made practice of the trigonometry the meeting instruction with the 3D printer samples. As a result, the small test pass rate of the trigonometry improved in 46.2% from 28.3%.

Piezoelectric ceramics are embedded in metal with an inner electrode using interphase/forming bonding method to overcome their brittleness, fabricating metal matrix piezoelectric composites (MMPCs) a candidate sensor for structure health monitoring. However, the increase in the number of sensors increases the probability of failure and compromises the reliability of the system. The solution is to use a single sensor to measure multiaxial stresses. The objective of this study is to provide a single sensor with piezoelectric effects in multiple directions by locally controlling the polarization of piezoelectric ceramics using internal electrodes, thereby enabling measurement of multi-axial stresses. In the first step, in the fabrication of MMPCs with two internal electrodes, the temperature rise rate during sintering, compression pressure during compression molding, and powder input were studied, and actual embedding and polarization with aluminum were performed. The results showed that the temperature increase rate of 20 K/min, the compaction pressure of 100 MPa, and the powder feed rate of 3.0 g and 3.6 g suppressed the occurrence of cracks during sintering the most, but not completely. Although no damage to the inner electrode and ceramics was observed, polarization could not be performed due to dielectric breakdown during polarization.

In recent years, development of automatic driving technology utilizing AI has been progressing. There is an urgent need to train engineers with knowledge and experience in automatic driving using AI, in addition to expertise in electrical and information systems, as well as vehicle motion and control. The authors have developed AI automatic driving training materials and have conducted practical training in conjunction with AI education. In AI human resource development, we are also trying out new developments, such as competitions（KAIT Racer GP) that are open not only to students specializing in automobiles, but also to mechanical, electrical, and information students. The effort required to acquire training data for automated driving and the long learning time for AI are factors that reduce motivation for learning. Therefore, we developed an off-line learning tool that can generate and train training data not only on an in-vehicle microcontroller (nVIDIA Jetson NANO) but also on an external personal computer equipped with a high-performance GPU. Furthermore, the effectiveness of this tool was confirmed through its practical application in a competition (KAIT Racer GP).

Handwriting is an important skill, but it is very difficult for upper limb disabled who cannot move their hands due to neck injuries. Self-help devices are welfare equipments that compensate for the difficulty of movement caused by the deterioration of physical functions due to disability or aging. The design of self-help devices is empirically carried out by occupational therapists. In this study, we propose a method of personalized adaptation of self-help devices for writing, based on hand model of paitents by 3D scan. The work achieves its main goal: to improve handwriting skills of patients. In this study, the final result is the 3D printed self-help device for writing by using PLA(polylactic acid) as material.

There are two types of personality test methods in common use: verbal and non-verbal, each with its advantages and disadvantages. If a new personality test method that can compensate for the disadvantages of both methods is developed, it would be used worldwide. To develop a new method to estimate human personality, we have attempted to measure human motions using the optical motion capture system (OMC) and group them by feature points. However, it was found that OMC is inconvenient due to camera calibration and attachment of infrared markers to subjects. In this paper, to make it more efficient, we compared OpenPose, which can detect the position of human joints with a video camera, to OMC. As a result, it was confirmed that OpenPose is more effective than OMC in analyzing human motion. In addition, we attempted transfer learning for classifying test scores of a personality test based on “Big Five personality traits” from walking trajectory graphs from OpenPose.

In recent years, the demand for precise measurement of dynamic torque has been increasing. Therefore, it is necessary to investigate evaluation methods of responsivity of torque measurement devices used to measure dynamic torque. In this study, we developed a dynamic torque generation machine using electromagnetic force based on the principle of Kibble balance. Dynamic torque can be generated by changing the applied current. The generated torque can be traceable to the International System of Units (SI) by referring to the national standards of voltage, current, angle, and frequency.

In recent years, a method for measuring sound absorption coefficient by parametric speakers has been proposed. In previous study, we proposed a method using particle velocity sensors for this measurement, but it was an expensive method. Therefore, in this study, as a new method for measuring sound absorption coefficient using inexpensive microphone, we propose to derive the sound absorption coefficient from the sound pressure of ultrasound at two points and the sound pressure of audible sound at one point of a parametric speaker. The width of the microphone used to measure the sound pressure is taken into account. Then, the validity of the proposed method is confirmed by numerical calculations.

The thermochromic liquid crystal (TLC) particle has been used to measure planar or volumetric temperature distribution in water based on its color dependence on temperature. In this study, we simultaneously captured multiple images of a single TLC particle from many different directions, evaluated the temperature from each image, and aimed to reduce the random error by taking the ensemble average of the evaluated temperature. A single 3CCD color camera recorded the multiple images through a mirror array of 90 flat mirrors (10mm x 10mm) arranged in an axisymmetric ellipsoid. The calibration curves defining a relationship between the temperature and hue of particles were evaluated for each mirror. The RMS of the history of measured temperature of a single TLC particle traveling in water with uniform temperature was reduced by a factor of three when the number of mirrors was 71 compared to one.

Inclinometers（bubble tube sensors）used in laser marking machines at construction sites are capable of high-resolution angle measurement, but have the problem of picking up minute vibrations and frequently issuing errors. Therefore, we have developed a ball lens tiltmeter that follows the structure of an electronic leveling system and have considered that the introduction of a viscous fluid into the lens system would reduce disturbance vibration through a damper action. In this study, we examined the effect of the introduction of viscous fluid on vibration and confirmed the effectiveness of the viscous fluid.

As a seafloor visualization technology, sonar technologies based on underwater acoustic propagation has become mainstream and common. On the other hand, even if a high-performance sonar is applied, its resolution is limited, and it is difficult to capture detailed conditions, shapes, and phenomena of seafloor. In addition, underwater mobiles are generally equipped with various acoustic devices that use sound waves for communication, positioning, velocity detection beside sonars. They are affected by acoustic interference. Moreover, since some steering rudders, thrusters, and hydraulic drive devices are installed, their movements become noise sources. Therefore, without using sound waves, a new method that has high resolution and can visualize seafloor over a relatively wide range and long distance is required for seafloor visualization. Based on this, JAMSTEC has been working on the development of a new underwater laser scanner which has advanced higher performance. So far, we have verified each technical issue and new function using an evaluation system. As the next step, we are now developing a demonstration system that is installed on an actual underwater vehicle and assumes performance evaluation in deep sea area. It equips some new technologies and functions including an optimized optical system and an automatic gain controller using optics.

The forms of industrial products have become increasingly complex with the advancement of machining techniques, such as multi-axis machining and 3D printing. To assess the performance of different machine tools, the products should be accurately tested using 3D measuring systems, such as coordinate measuring machines (CMMs). To ensure the accuracy of test results, the measurement uncertainty of 3D measuring systems is evaluated by measuring the gauges calibrated with small uncertainty. Nevertheless, conducting freeform measurements with small uncertainty using the CMMs is often difficult because of the difficulty in achieving accurate probe radius compensations. Additionally, although uncertainty evaluation methods have been developed for simple form measurements, the uncertainty evaluation method for freeform measurements is still under development.

In this study, we proposed an advanced gauge, improved the probe radius compensation method, and developed the uncertainty evaluation method. Accordingly, the gauge can be calibrated within an uncertainty of 1.5 μm. In this conference, we will report the details of the developed gauge, the calibration method, and its application.

In this study, numerical simulations are conducted to establish a method for organizing the discharge coefficient of high-pressure hydrogen. Similar to the experiment, the numerical simulation also confirmed that the discharge coefficient decreases with increasing Reynolds number at high pressure (40, 70, and 100 MPa). The experimental and numerical simulation results are in close agreement with each other, and thus the validity of the results can be confirmed. By using the value of the critical flow function at high pressure for the calculation of the theoretical mass flow rate, it is clarified that the discharge coefficient is an increasing function of Reynolds number. However, since the values of the discharge coefficient are not consistent with the ISO proposed equation, and the value of the discharge coefficient exceeds 1.0. Therefore, there is room for the improvement in the derivation method of the theoretical mass flow rate.

The purpose of this study is to develop a non-contact temperature distribution measurement system for automotive transmission fluid using the two-color LIF method. The advantages of this method are that it can be easily applied to minute measurements by using a color camera for image acquisition, simplifying the measurement process, and enabling measurement at low cost. Focusing on the fact that the fluorescence wavelength of a single type of phosphor changes with temperature, the fluorescence of one phosphor is measured spectroscopically with a filter built into a color camera as in the two-color LIF method. In the experiment, pyrromethene597 was used as a temperature tracer, and an arbitrary cross section was made with sheet light at a wavelength of 532 nm, and the image was analyzed. A temperature test curve was obtained from the luminance ratio of the red and green images, the temperature distribution was visualized, and its accuracy was evaluated. From the visualized temperature distribution image, the temperature distribution of low temperature oil injected into high temperature oil was successfully obtained.

Pulsating flow within an elastic cerebral aneurysm model was visualized by particle image velocimetry (PIV) to clarify the effect of wall elasticity on flow instability and wall shear stress(WSS). In the experiment, we used a full - scaled patient - specific cerebral aneurysm phantom with a thin transparent silicone wall fabricated by soaking a plaster mold. In order to clarify the effect of elastic deformation, a comparison was made with an experiment conducted while suppressing volumetric deformation by applying pressure. The results showed that in the middle plane, the wall deformation reduced the maximum TKE by about 26% and the average TKE by about 22% in comparison with the less - deformation model. In addition, the wall deformation reduced the maximum WSS by about 13% and the average WSS by about 17% in comparison with the less - deformation model. This finding suggests that the wall deformation of cerebral aneurysm attenuates flow turbulence and affects the magnitude of WSS.

Because of the difficulty in measuring airflow dynamics, computational fluid dynamic (CFD) simulations were being performed to investigate in detail the upper airway airflow in obstructive sleep apnea syndrome (OSAS). However, the relationship between the severity of OSAS as measured by the apnea hypopnea index (AHI) and airflow dynamics is unclear. In this study, to investigate the correlations between AHI and pressure drops in the nasal cavity and throat and the minimum cross-sectional area of the throat, CFD simulations mimicking human snoring during sleep were performed. The 3D models were reconstructed based on computed tomographic images of OSAS including four mild and six severe cases in the open-mouth state that is a common form of snoring. Each relationship was evaluated using Spearman’s correlation coefficient. The correlation between AHI and pressure drop in the nasal cavity was 0.745, indicating a significant correlation. There was a tendency for weak correlations between AHI and throat pressure drop and the minimum cross-sectional area of the throat. These results suggest that nasal cavity pressure drop affects the severity of OSAS.

Recently, Micro Air Vehicle (MAV) has been actively developed. It’s used in various situations, such as exploration of Mars, intelligence gathering at the scene of a terrorist attack. In these situations, MAV needs to be able to keep flying in strong crosswinds and turbulence. These conditions can be seen during flight of flying animals such as birds and insects. Their flight has the characteristics of high maneuverability and robustness for disturbances such as high winds and gusts. The purpose of this study is to research the aerodynamic characteristics of bird’s flapping wing and to develop a small bird-like flying robot depending on a biomimetic approach. We mainly focused on the structure of primary feathers. In the upstroke period, small gap is created between each of primary feathers. This structure allows the birds to reduce drag and get thrust. We designed and manufactured bird-type wings that mimic this structure and compared them with an elliptical wing by aerodynamic force measurement. As a result, the bird-type wings showed good aerodynamic characteristics such as reduced drag and more lift-drag ratio effectively. In addition, we tried to develop a small bird-like flying robot using the birds’ wing structure that can wireless control. Currently, we carry out flight experiments using the robot and develop automatic stable flight control system using barometric pressure sensor and 9-axis sensor.

In a previous study，a material model was proposed in relation to viscoelasticity based on stress-strain diagrams of urethane rubber under repeated compression．However，when the stress-strain diagram was reviewed，it was found that a hysteresis loop was drawn，but it did not depend on strain rate．Based on the experimental results，we propose a material model of urethane rubber by dividing the relationship between stress and strain into terms for hyperelasticity and internal friction terms．From the results of cyclic compression tests，values related to hyperelasticity were subtracted from the results to clarify the relationship to internal friction，and the model equation was discussed．

Aluminum alloys are being used for structural members of transportation equipment because of their high specific strength. Multi-directional forging (MDF) method, one of the severe plastic deformation methods in which the forging axis is repeatedly changed by 90 degrees during MDF process, can be performed to strengthen relatively large alloys. In this presentation, the effects of MDF method and subsequent aging on the development of three types of 7000 series aluminum alloys with different Zn contents were investigated by tensile tests, Vickers hardness tests, and microstructural observations. Under the same processing conditions, higher Zn content resulted in higher strength and hardness, with a similar reduction in elongation. However, the workability decreased with increasing Zn content. The improvement in strength and hardness were observed when MDF and aging were used alone. No significant effect was observed when MDF and aging treatment were used together.

In this study, the effects of microstructure and high temperature exposure on fatigue crack initiation morphologies in TiAl alloys were investigated. The SPF test increasing the microstructural sensitivity at the specimen surface combined with the microstructural observation on the specimen surface was used to investigate the effect of microstructure. In addition, specimens were exposed to high temperatures under decompression and nitrogen displacement to investigate the effects of high temperature exposure environments. The experimental results showed that the crack initiation life was significantly affected by the microstructure at the crack initiation potion; particularly, the crack initiation life of the lamellar phase with the lower tensile strength was shorter than that of the other phases. The growth rate and type of oxidation scales formed on the TiAl alloy surface, as well as the effect of the microstructural phase on it, varied depending on the oxygen and nitrogen concentrations in the high temperature exposure environment and the atoms contained in each phase. The crack initiation life was significantly reduced by the oxidation scale formed during high temperature exposure; however, there were few differences in crack initiation lifetime depending on the environment.

The effects of applied current density on the growth of extrusion formed by persistent slip bands (PSBs) and the defects in PSB were investigated. The cyclic plastic strain within a PSB causes extrusions and intrusions, called persistent slip markings, to appear on the surface. A crack initiates at the tip of the intrusion. Fatigue tests were performed while applying current every 2000 cycles. The current density conditions are 60 A/mm² and 120 A/mm². The height of the extrusion before and after current application was observed by atomic force microscopy. In the case of 60 A/mm², the growth rate of extrusion was suppressed and electrical resistivity decreased. On the other hand, in the case of 120 A/mm², the growth rate was not suppressed and there was no change in electrical resistivity. The growth of extrusion was suppressed as the vacancy concentration decreased. The experiment suggested that there is an optimum value for current density.

This study presented the technical process of robotic roll hemming used in the automotive industry. The hemming process is widely used in automotive manufacturing to assemble outer and inner closure panels by folding the outer panel flanges over the edge of the inner panel. Hemming process using roller hemming, which differs from conventional press hemming, requires the selection of processing conditions that take into account the mechanism of each defect. Although the process of hemming is rapidly developing, there is a lack of relevant research on the subject. Considering that the effect of pre-bending is significant in the hemming process, we consider how plates are bent by roller hemming by machining using a straight mold with a simple geometry that is easy to compare with other conditions. The bending behavior of the plate is discussed based on the distribution of work hardening of the material, observation of the shape, contact points with the roller, and the distribution of strain and stress by FEM analysis.

Foreign ships came into the territorial seas in the late Edo period forced the shogunate to revitalize the plan of defending the country. Defending with cannons was planned as a strategic choice and manufacturing of cannons was promoted in that period. Material processing especially under manufacturing of cannons has already been researched. Cannons require structures for their deployment, which were mainly batteries called Daiba. They were constructed on the sea and by the seashore all over the country. This series of research mainly focuses on material processing under manufacturing related to coastal defence. Cannons and batteries are generally deployed in an integrated plan, so how they were deployed relatedly composes another important issue. Defending by firing also requires defending against firing and supplying for firing, components for which also had to be deployed between multiple cannons on batteries. The aim of this paper is to research cannons, structures and defence system.

The scientific balloon experiment B22-07 which contributed to the development of a more efficient ballast mounting method was conducted in June 2022. In the balloon experiment, DREAM2 (Demonstration Experiment of Alignment Monitor 2) was mounted as a piggyback on a balloon gondola to demonstrate the function of displacement measurement under the balloon experiment environment including sunlight. Two-dimensional relative displacements (orthogonal to the laser optical axis) between the laser-unit including laser source/PSD (Position Sensitive Device) and the retro reflector, which were 0.6 m apart, were measured. The major factor of measured displacements would be thermal deformation of the gondola and DREAM 2 itself. This paper shows the evaluated results of measured displacements based on the measured temperature data on the gondola.

In this study, we development a novel technique to estimate plastic strain by image discrimination using ResNet, one of the convolutional neural networks. The input images to ResNet were prepared from the crystal misorientation data obtained by the electron backscatter diffraction method corresponding to the degree of plastic deformation. Since the logarithmic values of the crystal misorientation in each region followed a normal distribution, machine learning was performed using images normalized by the mean and standard deviation of the logarithmic values of the crystal misorientation. The results revealed that the standardized images indicated the local strain distribution due to plastic deformation and became smoother according to the increasing plastic strain. The standardized images also clearly showed the difference in damage distribution between unloaded and loaded conditions. The developed machine learning system identified five different levels of plastic strain applied to austenitic steel with an accuracy of 68%. It is expected that the plastic strain can be predicted from the average value of the estimated plastic strain calculated from the machine learning results if a sufficient evaluation area is available.

This paper describes fabrication of a cylinder type gas-liquid phase change actuator. Pneumatic actuator is used for endoscopic surgery support robot. However pneumatic actuator have some faults. Its peripheral equipment is large and makes oscillation and electromagnetic noise. These adversely affect medical equipments. We think that new actuator which does not have those faults is necessary. We suggest a gas-liquid phase change actuator. It is an actuator which big power is got from in the small size. And it can work only with DC power supply such as dry cells. Its device is small and has a small influence to give medical equipments. In this study, we aim to improve the cooling characteristics of the actuator by comparing and examining several working fluids in the actuator. We created a cylinder-type actuator that can move a piston using a gas-liquid phase change. Using an actuator and a DC power supply, a voltage was applied to two different working fluids to check their generated force response. The results showed that the two fluids had nearly identical heat dissipation performance.

This paper presents the fabrication of a rehabilitation device using pneumatic actuators. When a finger is injured, it is difficult to regain normal movement. Therefore, rehabilitation according to the symptoms is necessary. In this study, a prototype system of a device to support hand rehabilitation was developed. The rehabilitation device is driven by a single board computer. We confirmed that the prototype system worked properly.

This paper presented a fabrication of a hand rehabilitation device driven by pneumatic soft actuators. When a hand or other parts of the body become paralyzed due to disease or accident, rehabilitation is necessary to improve social reintegration and QOL (Quality Of Life). We are developing a prototype of a rehabilitation support device using pneumatic soft actuators so that a patient can perform rehabilitation alone at home. We report that the computer-controlled device enables Bending and extension of the fingers, and hand grasping and opening movements.

To achieve higher performance in spark-ignition engines, it is necessary to further improve combustion conditions. For this purpose, stepless control of the intake and exhaust valves in accordance with engine speed is required. Our research group has been continuously studying the electromagnetic drive valve system using linear actuators. In this report, we have designed a linear actuator with a dual Halbach array of permanent magnets in the stator in order to further increase the thrust of the actuator. The thrust characteristics of the proposed model were investigated by changing the applied current using electromagnetic field analysis based on the finite element method. The results of the analysis showed that changing the applied current affected the thrust characteristics of the actuator.

We focused on the elastic and highly deformable structure of euglena in order to create a propulsion device with low environmental impact and adaptable to all environments. In this study, we hypothesized that the driving force of the euglena movement is a contractile structure inside the pellicle band, and that this contractile force causes the bending movement of the pellicle band and the passive sliding of the adjacent parts, thereby realizing the euglena movement. Based on this hypothesis, we proposed a complex structure of bending and sliding that mimics the pellicle, and used SMA actuators as the power source. This paper describes the fabrication of an SMA actuator, the creation of a skin mechanism using the SMA actuator, and the evaluation of the SMA actuator as a preliminary step in the development of a basic mechanism for the propulsion device.

In this paper, we describe the made of an in-pipe traveling robot that can measure the load to the pipe wall and run with appropriate force. Direct inspection of piping is an effective way to check for damage and health conditions in pipes. In recently years, a method using a small robot has been considered for piping inspection. However, in inspection by a robot, it is necessary to apply a load to the pipes to obtain propulsive force. Therefore, a sensor was installed in the piping contact area of the robot to construct a system that can examine the transition of the load applied in the piping, and the robot was operated with appropriate force based on the measured data. The robot consists of three rubber bellows, two friction brake mechanisms, and a sensor to check the load.

In this paper, we describe the made of snake type in-pipe traveling robot. To inspect the inside of water and gas pipes, a robot is inserted into the pipe. But there are tubes with varying inner diameters. In order to realize a robot that can travel in pipes with different inner diameters, we have proposed a pipe traveling robot that mimics the accordion motion of snakes, which is a method of moving inside pipes and vertical holes. The snake-shaped pipe traveling robot is composed of three body segments to realize accordion motion. The front and back body sections consist of actuators that can flex, and the flexing of the body sections serves as a braking section that can hold the tube. The center section consists of actuators that provide the displacement necessary to drive the robot and is configured as the displacement part.

In this study, we develop a biomimetic robotic hand for use in manipulation by humans. It is known that humans can use tools as if they were part of their own bodies and can perceive tools as if they were part of their own bodies. Therefore, we think that if a robotic hand is operated by a human, it can be as versatile as a human hand if it has a structure and functions like those of a human hand. As a pilot of this robot hand, we created a 1 DOF joint system that uses Pneumatic Artificial Muscle (PAM) by biomimeticing author's left hand. However, we found a problem that the parameters need to be changed for each target joint angle. To solve this problem, we develop a PAM Smart Actuator that can estimate the contractile force by using the pre-calibration data and measuring the displacement of the PAM.

5G communications are characterized by eMBB (enhanced Mobile Broad Band), URLLC (Ultra Reliable and Low Latency Communication), and mMTC (Massive Machine Type Communication). These communication areas are expected to be applied to industrial fields in the future. In network-based teleoperation systems, 5G has the potential to realize stress-free real-time video transmission by a camera on a mobile robot and robot control from a base station. To evaluate the communication performance of 4G and 5G, this study first measured and compared the delay time per packet and the time required for data transfer in the transfer of random data equivalent to the image size. The measurement results showed that the amount of data that can be transferred within the allowable transfer time for remote operation of a mobile robot is about 2K for 5G and about HD for 4G. Future tasks will be to show the evaluation of the usefulness of 4G/5G communication by comparing the transfer time of random data including retransmission requests by TCP/IP and the video transmission time including codec processing time.

In this research, We provide communications infrastructure for remote control of construction machinery and monitoring of surrounding conditions in disaster areas. Specifically, the project develop technology to establish communication over a large area using a mesh network with appropriate placement of wireless devices.And, we put redios as few as possible to reduce installation cost. In addition, the usefulness is examined and evaluated after the placement plan by radio propagation simulation.

We proposed a method to realize mechanisms with multiple operation modes, and developed a prototype model of 2DOF manipulator with three operation modes. The manipulator equips with five water hydraulic cylinders, and two of them are driven by electric motors. The water flow path is switched by six solenoid valves. The kinematics properties of the mechanism can be switched by controlling the valves. We verified that the prototype model could change kinematic properties by the experiments. To analyze the kinematic properties, we used manipulability polytope that expresses possible output velocity or force in each direction at a hand position. Moreover, we discussed desirable design parameters for maximizing the effect of mode switching based on two types of criteria. One is the scalar criterion that expresses the ratio of XOR area to OR area of three manipulability polytopes corresponding to the operation modes, the other is the vector criterion that expresses the percentages of the operation modes that construct contour of three manipulability polytopes. We calculated these criteria for all the combinations of candidates for five design parameters and presented two examples of desirable design parameters.

In this paper ,we describe the made of an In-pipe Mobile Microrobot for the Intestine.The drag force applied to the tube wall by the robot was measured to estimate the frictional force. We also compared the running speed of the robot with the running time in the colon model to confirm the effect of the running environment.Among various testing methods for early detection of colorectal cancer, endoscopy is said to be the most accurate. However, endoscopy has problems such as infection by resistant bacteria and deformation of the intestine. To solve these problems, this laboratory proposes to use a robot that runs inside the intestine. We did the following. We fabricated a robot body using bellows rubber and a nitrile butyl rubber friction brake plate. We measured the drag force on the friction brake plate with a force gauge. Measured and compared the running time of the robot in the gut model.

This paper presented a fabrication of a hand rehabilitation support device driven by pneumatic soft actuators. When damaging a finger, it’s difficult to take back usual movement. The rehabilitation added to the symptom is needed. We propose the new support device with which rehabilitation of a hand is supported. A support device for move winding and extension motions.

Vehicle-type robots used in urban areas and public facilities, such as for delivery work, disaster exploration, and firefighting, require the ability to climb steps and high travel speed on flat terrain. We developed a vehicle that combines these advantages by combining normal wheels, Omni wheels, crawlers, and flipper arms and conducted driving and step-climbing tests. Furthermore, we derived the necessary friction coefficients for stepping over steps higher than the wheel axle position using statics, showing the effect of the flipper arm.

Stink bugs are pests that damage crops such as beans, cruciferous vegetables, and eggplant. When fruit is sucked by stink bugs, the fruit may deform and fall. In addition, when it sucks on shoots, deformation of new leaves, stem bending, and perforation of leaves can occur. Damage to beans and fruit trees caused by stink bugs occurs every year. Farmers are therefore uncomfortable with stink bugs, and there is a need for early detection of damage caused by stink bugs and early countermeasures. In this study, a recognition model was generated using YOLOv5, a type of deep learning software, and successfully detected stink bugs individually by body part. Once the robot recognizes the target pest, it sprays chemicals and tries to prevent damage caused by stink bugs.

Numerical solutions of nonlinear finite element analysis of large-deformation elastic-plastic problems are often compared with experimental solutions. However, they sometimes do not match. Therefore, the purpose of this study is developing a method for analyzing the reason why numerical and experimental solution do not match. We developed a parallel parametric analysis method to realize the purpose. In this study, we performed a parametric analysis for the crack problem of the compact tension (CT) specimen. We selected the crack length, the yield stress and equivalent plastic strain curve and the number of incremental steps as parameters for the parametric analysis. The result of the analysis showed that the load-line displacement is changed by the crack length and the yield stress and equivalent plastic strain curve. And we investigated the computational time and the speedup. As a result of the investigation, we found the proposed method can reduce the computational time.

As buildings become taller and taller, the speed of elevators is increasing, and elevators with a speed of over 1200 m per minute have been introduced. However, since the ride comfort worsens at higher speeds, improvement of the ride comfort is also required. The ride comfort of an elevator is evaluated by the vibration acceleration of the cabin, and the vibration acceleration is generated when the elevator travels on a guide rail with steps and distortions. Therefore, instead of running on the guide rail with roller guides, the elevator is supported by suction-type magnetic levitation, which improves the ride comfort by raising the elevator from the guide rail. However, the suction type magnetic levitation has a characteristic that the suction force changes depending on the amount of air gap, so it is necessary to control the suction force. In this study, the suction force is controlled by controlling the current flowing to the electromagnets. The purpose of this study is to reduce the vibration acceleration of the cabin while preventing the cabin from contacting the guide rail.

Our research group are studying a highly efficient small hybrid race car for the purpose of improving its dynamic performance. Since hybrid vehicles are equipped with multiple power sources with different characteristics, they can improve not only their fuel efficiency characteristics but also their dynamic performance by optimizing their operation. For this reason, hybrid systems combining ICEs and electric motors are beginning to be used in competition vehicles, where lap times must be minimized in order to win the competition. In this report, a lap time simulation including a nonlinear tire model and a two-track model that takes into account the forces of four tires are constructed to achieve a highly accurate simulation that is useful in the development stage of a small hybrid race car, and the simulation is compared with the previously used point mass model. Simulation results are compared to the traditionally used point mass model and actual logged data, and the validity of the two-track model is asserted.

The continuous steel plate production line of the steel mill is several kilometers long, and the continuous steel plate is transported by contact support by rolls. In such a continuous steel plate transfer line by rolls, problems such as deterioration of surface quality due to contact between the steel plate and the roll can be mentioned. In our research group, we were able to obtain high induction performance in experiments by installing the electromagnet on the side of the steel plate on the path to convey the electromagnet. However, the shape of the steel plate has not yet been obtained analytically. Therefore, we are focusing on multibody dynamics and studying the optimal placement position of electromagnets. In this research, the restoring force of electromagnet unit in off‐plate direction was changed according to steady current. When the steady current increased, the vibration of continuous steel plate could be suppressed by the electromagnet unit. This tendency could also be obtained by free vibration experiments. From these results, the effectiveness of the proposed electromagnetic guideway was shown.

Various methods have been proposed for mass measurement in microgravity space. One of them the estimate mass from the limit cycle of a displacement feedback type relay control system. In the previous report, the effect of the nonlinearity of the spring was investigated, and the mass measurement accuracy was improved by keeping the spring stiffness constant. However, the error of the estimated mass still remained. To further improve the accuracy, the influences of the center of mass of the object and temperature are investigated experimentally. The measurement accuracy is improved by attaching mass at the middle of the suspension and connecting the value of spring stiffness according to the measured temperature in calculation.

In the Accelerator-Driven System (ADS), the beam window is suspended in a coolant pool and cooled by a coolant jet. When the coolant jet impinges on the beam window, it may vibrate due to the coolant jet. With the phenomenon in ADS in mind, basic study was done dealing with the vibration of a rod due to an impniging jet. The vibration characteristics of the model of the beam window was investigated by using the experimental apparatus including the suspended model of the beam window and a water jet nozzle. Hereafter, the model of the beam window is called as a beam window model. The water jet from the nozzle impinged the beam window model and vibrated it. The acceleration of the vibrated beam window model was measured by an accelerometer and the frequency characteristics of the vibration of the beam window model was analyzed. The vibration included major components at a high frequency band of 25 to 30 Hz and a low frequency band of about 2 Hz. The low frequency band was around the natural frequency of the beam window model in stagnant water. The amplitude of the vibration at the low frequency band was much larger than that at the high frequency band.

To contribute to accident managements of water-cooled nuclear reactors, we quantified the interfacial behavior of a vortex-like flow in a wall-impinging liquid jet in a shallow pool in a liquid-liquid system by extraction of the feature points on the interface. We also considered forces acting on the liquid film and its interface in the vortex-like flow on the basis of the interface shape and its feature points. To investigate the mechanism of the vortex-like flow as the next step, we considered that quantification of the forces acting on the interface and fluid in the flow is useful.

Feedback reactivity caused by core deformation is one of the inherent safety features in a sodium-cooled fast reactor. Negative reactivity is inserted in case of increase of the core temperature according to raise of the reactor power. However, the feedback reactivity is affected by the variation of the gap width among the fuel assemblies in the fuel region in accordance with the constraint conditions and the deflection of the core support plate. The degree of inclination of the fuel assemblies may depend on the constraint systems and the deflection of the core support plate which supports the whole fuel assemblies. In this paper, the structural mechanics analyses of the core support plate in high flowrate and low flowrate conditions were conducted to investigate the variation of the inclination of the fuel assemblies due to the deflection of the core support plate.

An evaluation method for reactivity feedback due to core deformation during reactor power increase in sodium-cooled fast reactors is being developed for realistic core design evaluation. In the core structural deformation analysis of the evaluation method, the fuel assembly bowing was modeled with a beam element of the finite element method. Assembly’s pad contact between adjacent assemblies was modeled with a dedicated element which could consider the wrapper tube cross-sectional distortion and the pad stiffness depending on pad contact conditions. A core support plate was modeled with a shell element to simulate the variation in pitch of fuel assemblies due to the thermal expansion of the core support plate. The fuel assembly bowing analysis model was verified for thermal bowing of a single assembly and assembly pad contact between adjacent assemblies in a 127-assembly core defined as past benchmark problems. The calculation results of displacements and pad contact loads by this model showed good agreement with those of reference solutions of theoretical solutions or results by participating institutions in the benchmark. This study proved that the analysis model was able to calculate displacements and pad contact loads appropriately.

In the sodium-cooled fast reactor (SFR), decay heat removal system under natural circulation (NC-DHRS) using dipped type direct heat exchanger (D-DHX) installed in the upper plenum of the reactor vessel is considered as one of the most effective methods to enhance the safety. The numerical estimation method which can predict thermal hydraulic phenomena in operation of the NC-DHRS with the D-DHX under various plant operating conditions including the severe accident is required. The numerical analysis model named RV-CFD is being developed for the computational fluid dynamics (CFD) code. The numerical analysis of a sodium test conducted at the scaled sodium experimental facility named PLANDTL-2 was implemented to validate the RV-CFD model. The predicted characteristic phenomena in the RV during the D-DHX operation were discussed and the numerical results were compared with the experimental results. The applicability of the RV-CFD for the sodium test simulating the NC-DHRS operation with the D-DHX was confirmed.