To prevent the outflow of dangerous materials in emergency, valve closing is an important task at large-scale plants such as natural gas. However, it is a challenging task to correspond the same time in the accident at plural points from a huge site and lack of specialists at large-scale plants. In addition, correspondence among workers becomes complex when there are risks to be connected for casualty that human error assumes a cause, the second disaster by occurring fire accidents. Therefore, valve closing using a robot has been required. The purpose of this study is to develop an autonomous mobile control application used for a disaster working robot. This paper presents an object detection method to judge valves that conduct it from a visual remarkable degree by autonomous work. We consider that the degree is similar than that of using template matching used conventionally improved by our comparing experiment.

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Recently, for the maintenance of the public infrastructure, a new method to check a large-scale structure is demanded. The image processing decreases the staff and can reduce costs. A purpose of this study is to detect an outside damage and to measure crack width on the structure by image photography. We used image processing and measured the extraction of the crack and the width of the crack. Our method uses edge processing, the dynamic threshold method and luminance correction formula. A robot photographed the concrete surface of the bridge from ground and was able to extract a crack of the width of around 0.2mm. This report describes that accuracy of the extraction of the crack and the width of the crack and the measurement precision of the position.

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In our research, we focus on the maintenance and inspection management of cracks which accrued in reinforced concrete slab, proposed and developed the Robotics system for inspection by short range visual observation on the basis of the conventional inspection method. We suggested a robot that can photograph the cracks with less than 0.15 [mm] width from the ground. We have developed two crawler robots with camera attachment for inspection. One robot photograph a detailed image of the cracks, and another one photograph the entire image of the RC slab. Robot is operated by sequential control. We create a damage site map that showing the damaged position of the crack from the photographed images by image processing using an affine transformation. As a result, the error of the position of the crack of the damage site map was 1.6[%]. It was possible to improve the efficiency of inspection work with the robotics system

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When a serious accident occurs at a chemical plant, factory or power plant, early decontamination of a pollutant is important for lifesaving, damage suppression, early restoration and so on. A lot of robot systems have been developed or revalued for decontamination until the accident of the Fukushima 1^<st> nuclear power plant. These systems are valid for decontaminations and some of them have been operated in the Fukushima 1^<st> nuclear power plant actuary. They, however, are specialized for plane part such as wall, floor, roof and so on. Decontamination of infrastructures has been leaved until later because of difficulties due to complex shape. In this research, focusing on decontamination of infrastructures, especially on pipes in the factory, a decontamination robot system using water-jet as a washing mechanism is proposed. In this paper, a concept and total structure of the system is proposed. In addition to this, to improve a previous robot, a mobile mechanism using Mechanum wheel is proposed.

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In japan, about half-million bridges are present in the municipal roads. In 2023, 43% of them will be the age of more than 50 years. In small scale bridges, when the distance between the water surface and the slab bottom is small, there is that inspectors cannot be visually closer to the target site. Previously, these bridges are sometimes not been inspected in terms of the inspection cost and efficiency. However, since 2014, in order to be visually closer to the target sites have been mandatory, reduction of test cost has become a major issue. Accordingly, we have proposed an imaging apparatus which can enter the narrow space between the water surface and the slab bottom. By the vehicle with cameras moves over the float, it is possible to shoot a wide range of slab bottom. We made a prototype to confirm its basic performance. It is an apparatus that a vehicle with five cameras moves on the float of about the same size as the tatami. In a small scale bridge of the real, experiments were carried out to get the images of the slab bottom. As a result, it was possible to obtain resolution images necessary for general inspection.

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Recently, application of robots has been required in disaster sites. Rescue robots were applied to disaster sites and they had obtained various results for the Great East Japan Earthquake. However, as a disadvantage the available range is limited because remote control type robots become impossible maneuvers if communication is terminated, due to a fault used range. We consider that is necessary for robots to autonomous work with the ability of self-determine action in order to avoid these problems. Generally, GPS is used for autonomous mobile robots that are working in outdoor environment. However, localization accuracy is depended strongly on the type of a GPS receiver. Moreover, it remains problems by blocking of signal that localization possible environments is limited with blocked as tall buildings or trees. This paper, present a novel control method using GPS and 3-axis geomagnetic sensor for autonomous mobile robot used in outdoor environment. The experimentally obtained results show that accuracy of the autonomous moving is improved by correcting position and orientation data measured from features results.

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The passive dynamic control ("PDC") is a mechanical system control method based on an inherently safe design. It ensures safety of system by positively using a brake. For a two-link manipulator which used two antagonistic pneumatic artificial muscle actuators in a horizontal plane, the effectiveness of the PDC was shown. However, in a vertical plane, the balanced state is lost by movement of the controlled object, and the improved PDC was proposed where the PID control was used together with the PDC. Its effectiveness was examined through basic experiments. Here, the effectiveness of the improved PDC for lifting control of 2-link manipulator in a vertical plane is examined, where two arms are controlled simultaneously.

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Astronauts are using huge special machines in order to maintain physical function under the zero-gravity. This research aims to develop the wearable training device to do muscle training under the zero-gravity instead of them. First, we designed motor-unit system and its sensing device to control. Next, we developed Semi-Active Load Control Mechanism to use a PD feedback control method with this device at a constant force. We made an experiment to evaluate the control method, that the force point was moved by hand at a constant speed. But the output force had an unstable vibration component because of discontinuous law and human control. So we designed FIR digital filter and new control method to reduce unstable vibration. By using these methods, we showed the effectiveness through the evaluation experiment.

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Today in construction work, some workers have to do looking-upward works. Looking-upward work for many hours and many times make fatigue on their neck. In addition, the fatigue also affects the daily life as well as work. Therefore we develop neck-supporter for looking-upward work to reduce fatigue. In the conventional research, the fatigue on neck is reduces 40% by wearing neck-supporter. Current research issue is that assist effect is different from the physique of the neck-supporter's wearer. To solve this problem, we design 4 links statics model to assist their neck ideally considering wearer's physique. As a result of verification of position validity, this model was able to correctly estimate back of the head position. We simulated the assist ratio by using 3-pattern initial attitude degrees. The result was that initial attitude degrees greatly affect assist ratio. Future tasks are looking-upward work experiment to wear neck-supporter and compare the result of experiment to the simulation.

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Now substitute labor by the robot is necessary in order to compensate for the reduction in the workforce. However, there is a need for more simple teaching technique. Because, robot teaching has a large cost and has a need for knowledge related to teaching and programming. To solve this problem, teaching by showing technique has been proposed. In these methods, by expressing the motion trajectory of the demonstrator using the via-point, and performs the reconfiguration of the working trajectory. However, extraction condition of the via-points is not considered. Recent researches show achievement of task is related to the motion variance. This paper proposes a via-points extraction method using motion variance of demonstrator's movements and a trajectory generation method by imitation. Finally, the validity of the extracted via-points has been verified, using the proposed method in the peg transport task by experimental machine.

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We developed the grasping form variable type robot finger using nonlinear torque joint mechanism. This robot finger has an extension wire and a flexion wire. The posture of the finger is decided uniquely by the relation between extension torque which is generated by the nonlinear torque joint mechanism, flexing torque which is generated by tension given to a flexion wire, and additional extension torque which is generated by tension given to an extension wire. This robot finger can be switched adaptive grasp movement and pinching movement by adjusted the tension of the extension wire. In this paper, we derived the conditional expression of the torque balance for designing the robot finger. The validity of this expression and be able to switch the two behaviors were confirmed experimentally.

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JAMSTEC is now keeping a watchful eye on some global issues such as the seabed resources and energy, global warming, ocean earthquake and Tsunami. They are serious problems to us and will cause the greater damage to us in near future. In addition, they are intimately tied to the seabed condition and the seabed behavior. In order to work on these problems, effective tools to investigate the seabed and understand them should be prepared. So JAMSTEC is now developing various types of underwater vehicles for them. And also, various kinds of systems to apply to the underwater vehicles have been developing. Some of them are navigation systems, control systems and observation systems. They are important and essential technologies which defines the cruising performance and the observation performance. Especially, visualization systems are absolutely necessary as observation systems in order to understand the seabed environment. They are loaded onto the underwater vehicles which close to the seabed and cruise keeping a constant altitude according to their each characteristics and specifications. In fact, it could be argued that they dictate the cruise planning and the motion control of the underwater vehicle. This paper describes about the seabed investigation applying underwater vehicles including some fundamental technologies which are relevant to are relevant to are relevant to the seabed visualization.

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Compared with traditional submersibles, bio-mechanism based robotic fish has higher submerged maneuverability and propulsion efficiency. In order to maximize the thrust power of robot fish, a technique using dynamic meshes as well as User defined function (UDF) to control moving boundaries is established to simulate the circumference fluid of a swimming fish body, as well as a fish robot. The resistance of fluid and propulsion power is analyzed numerically under various conditions, and we try to clarify the main factors to influence the swim speed of the two models from their velocity and pressure fields.

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As part of the NEDO robot project, we are engaged in developing an underwater robot system, which investigates underwater infrastructure such as dams and river facilities. In this paper, we propose a surface boat system that can maintain its position on flowing water by changing its rudder angle. The surface boat is connected to a rope which is fixed at the river bank and the rudder angle is controlled using wireless technology to move the boat to the desired goal. Experiments are conducted in an indoor pool using a miniaturized boat and the results show the effectiveness of the proposed method.

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Japanese traditional boats going ahead by human power have high efficiency in comparison with the other human-powered boats. The reason why the Japanese traditional boat has high efficiency is to use lift as propulsive force. In this study, we have manufactured a small model of a Japanese traditional boat for experiment to examine the specification. Models of oar have been made by using a 3D printer. Each of models of oar is different from cross-sectional shape. The electrical power consumption and net propulsive force have been measured in the experiment. In addition, by using CFD analysis of water flow around each oar, lift, drag force and lift-to-drag ratio have been calculated. By comparing the experimental results and CFD results, it has been found that which cross-sectional shape of oar is suitable for the propulsion of Japanese traditional boats. This study will be useful to develop an underwater robot which applies the principles of the oar.

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We purposes of the mobile robot lightweight development, attention was paid to balloon that can lighter robot. The study was developed of the mechanism, and applications for guidance. Mechanism development, was design and fabrication center of gravity of moving mechanism. The balloon is mounted on a mechanism which was fabricated, and allow movement of such acrobatic somersault in situ. The development of the control system, which makes it possible to perform simple pose estimation by attaching a sensor yet made it possible to produced a new control board, and controls the attitude, of the propulsion mechanism. Development for guidance application, made it possible is performed the program development using the marker by using a monocular camera lightweight, to distinguish the marker.

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An extension mechanism with convex tapes has been developed for a compact mobile robot. Algorithm of posture control is implemented by using the data from an acceleration sensor. A basic experiment of the mechanism has been confirmed for the extension ability. Next, a high precision control and the strength analysis of the extension mechanism will be performed. And, the extension mechanism will be mounted on a mobile robot to verify the effectiveness.

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This paper deals with the paper transport mechanisms consists of two rubber layered rollers. The purpose of this paper is establishing a theory of paper transport velocity in the nip transport mechanism. First, a numerical analysis method of a contact problem between a rubber layered rollers using the result of two dimensional contact analyses was established. Next the effects of the normal load and paper tension on the strain of the rubber roller and paper and the velocity ratio of paper transport velocity to the tangential velocity of the rubber roller are characterized. Finally, the effectiveness of the proposed method was demonstrated by comparing the numerical results and experimental ones in case that the design parameter of nip transport mechanism was changed.

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Dew condensation from Heated Papers in Multifunction Peripherals (MFPs) is a chronic problem. The purpose of this study is the development of a simulation technology that calculate the in the non-steady advection diffusion equation of water vapor and estimate the dew condensation distribution in MFPs. The authors defined the water vapor flux expression for the observed moisture content transition rate of a heated paper, and considers the boundary conditions as the moving papers. Calculation results of the dew condensation distribution differences by air flow and initial moisture content rate variations were consistent with the experiment. This Simulation anables to esimate tde dew consistent for the design of MFPs without actual prototyping.

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In the transfer process of an electrophotographic image forming apparatus, the electrostatic force causes the paper jam, especially in a thin paper. Therefore it is necessary to understand paper deformation by generated electrostatic force. We are researching to understand the mechanisms of electrostatic force generated on a paper. We observe that the attraction on the thin paper is generated by electrostatic force. And the numerical simulation tool have been developed in order to analyze paper attraction by electrostatic force. Calculation of paper deformation by electrostatic force in each paper thickness is carried out with this numerical simulation. The simulation results show qualitatively agreement with the experimental results

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Paper shrinking after fusing process by moisture evaporation causes the degradation of print quality that is miss-registration of duplex printing in electrophotography. Though this phenomena has been recognized, the detail of the shrinking has not been measured. In this report, the paper shrinking is measured at 4-positions by an experimental apparatus. It shows the shrinkage difference between the front side and the back side of a sheet of paper. A calculation model to reveal this phenomena is proposed, which takes account of the laminar boundary layer on paper surfaces. The calculation result shows the tendency of the shrinking difference, though the shrinking at the front region of the sheet is larger than the experiment. It can be concluded that the laminar boundary layer is created on the paper surfaces after fusing process.

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In recent years, the photosynthesis microorganisms which produces the oil were found as the new biofuel. It can generate oxygen higher than plants, so it has expected as an oxygen supplier. It is usual that the aeration and impeller stirring are applied industrially as a culture mixing method for microorganisms, but in such flow systems, the shearing force promoting the mixing reaction is not uniform and the locally high shear region is occurred. So, there is concern that the cells of the photosynthesis microorganisms are destroyed. In this study, a cultivation experiment is performed using the Taylor Vortex Flow (TVF) which can be expected as loosing mixed stirring with low shearing flow. Then, the amount of alga multiplication and destruction by crushing the cells mechanically in homogenizer is observed in the experiment.

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In this study, we aim to measure the concentration distribution of the dispersed emulsion in the vegetable oil. It uses the ultrasound flow velocity distribution measuring machine for the measurement. Ultrasound we be achieved speed in places where there is an emulsion because the reflection at the interface. Emulsion is not be measured speed in a place that does not exist. By utilizing this to verify whether possible to measure the concentration distribution of the emulsion. It uses a Taylor-Couette Vortex Flow(TVF) in stirring method in the experiment. First of all consider the method of dispersing uniformly water in the TVF. Next verify the optimal conditions in measuring the emulsion. This time it alters the 1,2,4,8 MHz the fundamental frequency of the ultrasound waves to be irradiated. The results of the experiment, and disturb the flow by the baffle is placed in the water after it has caused the TVF only oil water was found to be substantially uniformly dispersed in the oil. In addition, to measure the emulsion has been found that it is desirable to use ultrasound 4 MHz.

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An impeller for liquid-phase agitations in chemical processes was designed based on a conventional disk turbine impeller with six flat blades which sucks liquid across the planes including the upper and lower edges of the blades. The altered impeller has a structure for the inflow entrance to be confined to a limited plane including the inner edges of the blades. We call this "closed impeller" and the prototype "open impeller". Liquid flow in the impeller rotational region of a baffled vessel with the closed impeller was examined for the flow path between the neighboring blades of the rotating impeller. Internal flow was compared between the closed and open impellers and modification was made for the structure of the former impeller. An impeller efficiency determined with the flow and power measurements demonstrated that an intention of such a structure was successful for energy transmission through the blades.

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Recently, the consumptions of the fossil fuel are rapidly increased because of increasing population and economic growth in developing country. As the results, the Global warming by increasing in carbon dioxide and lack of the fossil fuel are concerned. We must do developing the new fossil fuel such as peat or brown coal. However, the peat or brown-coal had a problem with very high water content. Therefore we developed the economic drying processes for using peat as energy source. We studied the comparing a squeeze method (compression-dewatering method) and thermal drying method. From the results, we found that the squeeze method is economic process better than thermal drying method.

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The Fukushima Daiichi Nuclear Power Plant Unit 5 lost all AC power at 15:40 when tsunami struck triggered by the Great East Japan Earthquake on March 11, 2011. After a 9 day struggle, cold shutdown was achieved. This paper focuses on the processes of the Unit 5 recovery in consideration of important events that took place in the field. In particular, the actions of on site personnel who responded to the accident have been reviewed in light of resilience engineering concepts and guidelines. A hypothesis of time-flow structure of Responding, which is one of the four cornerstones of resilience engineering, was developed based on previous researches. This hypothesis was verified through an analysis of the path to cold shutdown of the Unit 5. Finally, the necessity for new safety concept of "Safety-II", which aims not only to reduce risks but also to expand successes, was pointed out and lessons learned from the Fukushima accident spotlighted on the Unit 5 how to overcome emergency difficulties were presented.

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The Fukushima nuclear plant accident has been examined aiming at clarifying the factors influencing responding which is one of the four cornerstones of resilience engineering. Among the causal factors of responding, such as attitude, skill, health and environment, particular attention has been paid on the role of attitude. In addition, the case of Tokai Dai-ni nuclear plant, which was the success case despite tsunami attack, and the case of Fukushima Dai-ichi nuclear plant have been examined focusing on preparatory actions taken prior to the tsunami attack. Through the camparative exainations, attitudes of several kinds have been identified as key factors contributing to enhance organizational resilience. Moreover, the importance of safety-II concept proposed in conjunction with the methodology of resilience engineering has been clearly exemplified. As a whole, it can be concluded that the methodology of resilience engineering and the concept of safety-II are quite effective when utilized with the structured model.

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In reciprocating compressors, unexpected accidents have been reported under long-term operation. Although these machines are managed by monitoring and regular maintenance, it is difficult to predict a sudden accident or a damaged part far from preventing a fatal trouble in advance. The purpose of this study is to establish a new monitoring technique to detect the state of sliding parts, where it is known that some failure often occurs. In this paper, we examined the feasibility of estimation for the state of the sliding parts in a reciprocating compressor using both the vibration characteristics in the experiment for the small apparatus and in the eigenvalue analysis based on the mathematical model. To estimate the state of the sliding portion, each spring constant is identified solving an optimum problem with constraint. Moreover, we introduce an individual parameter identification method, where assuming that the initial value for each spring constant is nearly zero, parameter identification is carried out. As a result, it is found that we can estimate the position that has undergone changes in the characteristics of the sliding parts comparing each error function for the individual parameter identification.

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This study is about the inverse problem analysis using regression analysis. In this method, the regression coefficient is estimated as distribution. Thus probability of failure evaluation is possible. In addition, the Bayesian estimation is used. When the maintenance is considered from the result of damage evaluation, damage evaluation is not the whole, to estimate a part carefully. So, in this study, the weight function which changes arbitrarily the sampling ratio of the data for every damage size is introduced. The sampling ratio of study data is changed by changing the form of a weight function variously. When changing it, we considered the influence which the presumed accuracy in each damage has to a risk.

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Risk assessment is fundamental technique for safety of all fields. And hazard list is key for identify potential hazards in a product. The discussion in this paper is on consumer product safety. However, it is applicable to the safety at work. As today's markets are brimming with a variety of consumer products, it has been difficult to regulate all products. In particular, there is large risk of vulnerable consumers and imported products. Thus, when consumer product designers perform risk assessment, exhaustive identification of intended user and hazards is a necessity. In this study, integrated hazard list based of RAPEX (the Rapid Alert System for Non-Food Dangerous Products) which is operated in EU member states is developed. This list is added additional items of hazard from International Standards, e.g. ISO12100, ISO10377, and accident information which is published by NITE (National Institute of Technology and Evaluation) in Japan. The authors asked 10 students in our engineering department to identify hazards of home-use circular saw and blender by using the original hazard list in RAPEX and by using the developed hazard list. By comparisons of number of identified hazards by each list, the effectiveness of the developed list is cleared. Adding to this, the authors checked whether all causes of accidents shown in NITE database and SG Standards could be identified by the developed hazard list or not, and concluded the list is useful for designer of consumer product.

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In this paper, we investigate educational effect on delivery type experimental education of maintenance engineers. Experimental lecture time is about 6 hours. Experimental content is the principles of corrosion and corrosion protection. Instruments was used which was improved to the micro scale. Experimental lecture text was produced what can be easily understood only in presentation materials. In this lecture, engineer of three fields (ground, underground, floating facilities) participated. The total number of participants was 263 people. Expertise of its people were mechanical, electrical and civil engineering. It was people with a variety of experience to veterans from rookie. The results of questionnaire survey, understanding of basic knowledge of corrosion was increased to more than 95%. Micro-scaled experimental instruments is better to use a few people than one person. These instruments was found that the education effect is increased enough. Although experimental lecture were carried out 6 hours, participants did not go to sleep.

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Probabilistic risk assessment (PRA) is a technique for evaluating the safety of nuclear power plants. In particular, the level 1PRA has general versatility and has been utilized in various fields. In the level 1PRA, the identification of accident scenarios is very important. It is performed by top-down analysis or bottom-up analysis. In the previous study, the marine accident in Akashi Strait was analyzed by the bottom-up analysis method. However, the identification of accident scenarios required a more effective analysis to extract factors without slipping. So, in this study, we discuss accident scenario identification methods from both top-down and bottom-up analysis method. An example of the analysis of marine accidents was shown by these methods. The bottom-up analysis was referred to the previous study. As a top-down analysis method, the Master Logic Diagrams (MLD) was performed. By comparing the analysis result of MLD to the previous study, we discuss the effectivity of the identified accident scenario by both top-down analysis and bottom-up analysis.

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For preventing accident occurring at the contact area between overhead catenary system and pantograph, overhead catenary system must be carefully maintained, resulting in requiring heavy maintenance cost. The present on-board monitoring system for overhead contact lines mainly keeps watch on dynamic states of contact wire. However, its static states are extremely required for the efficient maintenance work of the overhead contact line. Therefore, the authors have been developing a method which estimates static height of contact wire by contact force and pantograph height. This paper describes the new method in detail and shows the verification results of on-track test.

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A high speed railway vehicle is greatly affected by track irregularity. Vertical vibration of a high speed railway vehicle makes worse the ride comfort of passengers. This paper aims at reducing such vibration, especially the 1^<st> mode bending vibration of carbody with the active suspension system. This system used the proposed method of designing a vibration control system. The controller was designed by applying liner matrix inequality (LMI). In addition, this paper investigates at the reduction of the actuator force than H-infinity control. The numerical simulation results show that the ride comfort of passengers is improved by the active suspension.

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Condition monitoring of railway tracks is essential in ensuring the safety of railways. In-service vehicles equipped with sensors and GPS systems can act as probes to detect and analyze real-time vehicle vibration. Such trains are known as "probe vehicles". Recently, a compact size on-board sensing device has been developed. This paper describes the track condition monitoring system using the compact size on-board sensing device and the diagnosis software. The diagnosis software provides a function to detect track irregularities using RMS of the car-body acceleration. It also provides a function to analyze in time-frequency domain using wavelet transform. Monitoring experience in a local railway line showed that the system is effective for practical use.

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This study proposes the track condition monitoring technique using car-body acceleration easily measured by an in-service vehicle for the sake of increase in safety of railway transportation. This paper demonstrates the possibility to estimate the track irregularities of conventional railway tracks using car-body acceleration only. In an inverse problem to estimate track irregularity from car-body acceleration, a Kalman filter was applied to solve the inverse problem. This estimation technique is utilized to estimate the track irregularity in longitudinal level (track geometry and 10m-chord versine). The Kalman filter became able to apply to inverse analysis by expressing track geometry in a random walk model, and having incorporated the model in an equation of state. The estimation technique can support a change of the vehicle velocity by selecting impulse response in the measurement equation for the vehicle velocity. Estimation results revealed that the proposed estimation technique is effective for track condition monitoring with acceptable accuracy for conventional railways.

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This paper proposes a method for classifying and evaluating conditions on catenary systems by applying the self-organizing algorithm. The proposed method is separated into two steps: (1) development of classification map and (2) evaluation of catenary condition. This paper focus only on the 1st step. The objective to develop the classification map of catenary systems is to make a diagnosis of catenary systems and detect their abnormalities or presages of them. In order to develop a classification map, contact force data obtained under various catenary conditions, which includes abnormal condition, are utilized via several signal processing processes (wavelet transform, cross-correlation coefficient calculation, statistic value calculation and so on). Abnormality detections are done based on the classification map so that detectable abnormality modes depend highly on the stored abnormality modes in the classification map. From that perspective, the map should be developed using contact force data obtained under various catenary conditions includeing many kinds of abnormal conditions one wants to detect in the diagnosis step. The 1st step therefore is done based on the simulation because it is not easy for the actual catenary system to be abnormal conditions to acquire the contact force data. By applying the proposed method in this paper, the conditions on catenary systems are well classified on the self-organizing map.

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An impulsive pressure wave (micro-pressure wave) emitted from a tunnel portal is one of the environmental problems in high-speed railways. The magnitude of the micro-pressure wave is approximately proportional to the maximum pressure gradient of the compression wavefront at the tunnel exit portal. Consequently, it is necessary to mitigate the pressure gradient of the compression wavefront for reducing the micro-pressure wave. In this study, field measurement in an actual slab-track tunnel was conducted for investigating the effect of ballast layers installed in the slab-track tunnel on the reduction of the micro-pressure wave. The results indicate that the ballast layers installed in the slab track tunnel mitigate the steepening of the compression wavefront and reduce the micro-pressure wave.

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The magnitude of an impulsive pressure wave (micro-pressure wave) emitted from a tunnel portal is approximately proportional to the pressure gradient of a compression wave at the tunnel exit portal. It is confirmed that ballast layers installed in a slab-track tunnel have effect on the reduction of the micro-pressure wave by a field measurement. In this study, method of a numerical simulation is investigated for estimating the effect of the ballast layers on the reduction of the micro-pressure wave. The results indicates that the effect of the ballast layers can be simulate by calibrating a parameter of a unsteady friction term.

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The coefficient of friction between the rails and the wheels is important in railway vehicle dynamics analysis. In general, the coefficient of friction is reduced by the water film between wheel and rail in the rain. The friction coefficient is known to be higher in the back side wheel, too. High speed railway vehicle such as SHINKANSEN are using this phenomenon, i.e., brake distribution of the front car is low, brake distribution of the behind cars are high. The monographic train with lightweight vehicle necessary to consider the influence of the friction coefficient carefully because the technique is not useful. In this study, the state measurement experiments including liquid film measurement around wheel and rail is performed using a scale model running test experimental appurtenances.

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The velocity of the flow over the roof of the train running in a tunnel is higher than that in an open section. While the flow velocity in the tunnel predicted by one-dimensional simulation is 1.2 times higher than the train running speed, the measured flow velocity in a tunnel is about 1.3 times higher than the train running speed. Therefore, three-dimensional incompressible Reynolds Averaged Navier-Stokes Simulation (RANS) of the flow over the roof of the train running in the tunnel was conducted in order to investigate the effects of the boundary layer developing along the train on the flow velocity. The surface roughness was added to the bottom of the train to simulate the equipment installed under the car body, and its effects on the flow over the roof were investigated. In addition, the simulation of the flow over the roof with the pantograph shields was carried out. The flow velocity over the roof with the pantograph shields was compared to that over the flat roof.

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Soil-vehicle interaction is one of the important factors for predicting trafficability of off-road vehicles. Tractive forces on the wheel surface to drive the vehicle can be estimated by soil deformation analysis around the contact area. Sand deformation and flow under a rolling and traveling wheel were observed by 2-dimensional PIV method from the side view through a transparent acrylic wall. The flow velocities of sand particles obtained on spatially allocated grids reveal that the fluctuations of sand flow make wave patterns on the sand surface after the wheel passed over. The finite element method was also conducted to simulate the traveling wheel experiment to discuss the possibility of the numerical simulation. The result of simulation qualitatively reproduced the experiment.

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This study focuses on autonomous driving using the map data that benefits reduction of calculation cost for autonomous driving system. This study utilizes the digital road map database used in car navigation systems, etc. as a map data. The digital road map database is the standard national database that is supplied by the Japan Digital Road Map Association and is supporting Japanese ITS infrastructure. This paper proposes a path planning algorithm from the departure point to the destination by using the digital road map database and a path tracking algorithm based on the preview driver model. The effectiveness of the proposed algorithm is verified by numerical simulation in driving scenario that simulates an urban area. The results of the simulations indicate that the proposed algorithm enables the vehicle to drive autonomously complying with the traffic laws such as left lane keeping and manners such as saving a space for oncoming right-turning vehicles when the host vehicle turns right. In addition, from the result of the comparison of driving trajectories with hand-drawn trajectories on the map by human subjects, it is confirmed that the vehicle trajectories by the proposed algorithm are appropriate.

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Many accidents are caused by human operation error. Above all, many fatal accidents occur by error of the steering operation. In addition, there are many problems of the steering operation in the low speed range driving. It is known from previous studies that drivers cannot detect accurate steering angle they turn by changing of grip position. Therefore, we developed the new steering system without changing of grip position. We made the experimental vehicle which is equipped with the new steering system realized by a steer-by-wire system. We compared the new steering system with the conventional steering wheel by actual vehicle experiment and evaluated the advantage of the proposal one.

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This study examines the driver assistance system informing the necessity of deceleration at a signalized intersection ahead during the red signal. The assistance system indicates the distance which the vehicle can forward by maintaining the present velocity until turning to the green signal using the signal information. If the indicated distance is longer than the distance to intersection from the vehicle, the system encourages driver the deceleration by blinking the indicated distance. The driving simulator experiments are conducted to evaluate the proposed assistance system. The assistance system avoids the unnecessary deceleration.

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To perform high-precision observation in recent space development, it is necessary to design a spacecraft with a highly precise shape. The highly precise shape design needs to estimate how the shape error is in ground tests. However the ground test validations tends to insufficient for highly precise spacecraft due to the difficulties of the estimations for the various type of shape errors, such as thermal deformation, a minute disturbance, deployment non-repeatability and so on. The numerical analysis is often used in such a case. The verification of the validity of the mathematics model is very important in the numerical analysis. One of the difficult part in the numerical analysis is modeling of friction, which gives a great influence on the structure accuracy estimations. This study is focusing on the deployment non-reproducibility caused mainly by frictional effects at joints. It is performed to construct a model in consideration of friction by using a finite element analysis software MSC. Marc. We verify the effect of the frictional force in the three-point bending test of the beam.

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This paper shows a study on the simulation of cantilevered beam vibration considering effects of fixture modeling. In the advanced spacecraft design, small vibration isolation is needed to meet highly precision requirement for structural positioning. To validate the small vibration isolation, the full-model ground based test is usually performed, which needs high cost. The numerical simulation can be effective for vibration designs although, for advanced spacecraft design, the highly precise numerical model has to be constructed. One of difficulties to build a highly precise numerical model is identify the vibration transmission of two members in the fastening parts. In this study, we focus on the fixture modeling in the vibration simulation. A cantilevered beam, which is clamped by a jig, is modeled. The contact analysis between the cantilevered beam and the jig is performed to evaluate the conditions in the fastening part. The vibration simulation is conducted to examine the effects of the fastening part modeling on the vibration characteristic.

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A spacecraft thermal design is performed to satisfy severe demands for allowable temperature and thermal deformations in the spacecraft. The key to the effective thermal design is to build accurate thermal mathematical model for the spacecraft, which can predict temperature variations of the spacecraft on orbit. One of the difficulties in building the accurate model is to identify the characteristics of the thermal contact resistance in joints. In this study, we experimentally study the influence of the contact shapes and the contact pressures in joints on contact thermal resistance of the combination region. We contact two members at each tips under contact loads. We set four different shape types and conduct thermal tests with various contact loads to examine the characteristics of the contact thermal resistance in the different contact conditions. The experimental results indicate that the contact thermal resistance tends to reduce in accordance with the increase of the contact load.

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A 100mm-size cube satellite, KSAT2, was developed by the Kagoshima Satellite Development Team. The KSAT2 was successfully launched in February 2014; its operation period was about 80 days. We were in charge of its thermal design. In the space, KSAT2 measured its battery temperature, and transmitted the data to the earth station. In this study, we calculated the battery temperatures of KSAT2 and compared them with the measured values. The calculations were conducted for the two cases for the attitude of the KSAT2; one is the attitude which will experience a higher temperature (Case 1) and the other one is that will experience a lower temperature (Case 2). The calculated results show that, in Case 1, the calculated temperatures are around 20 ℃ higher than the measured values. In Case 2, the calculated temperatures roughly follow the measured values. Therefore, actual attitude of KSAT2 is considered to have been closer to the Case 2.

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A solar power sail demonstrator IKAROS, which was launched in 2010, could accelerate and decelerate by receiving solar radiation pressure to its membrane surface in outer space. However, the membrane surface becomes uneven easily, because the membrane is very thin. The unevenness causes swirling motion, changing the spin rate and deterioration of the power conversion efficiency. In this study, effect of bridge structures for connecting divided sails on stress fields of sails was analyzed by using ABAQUS. It revealed the stress directions and compressive stress area. Inaddition, the bridges were modeled to piecewise linear springs to consider the changing of the natural length of the bridges. The analysis results revealed that the stress fields were extremely sensitive to the changing of the natural length.

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