Wear development between wheel/rail is closely related to crack initiation. Furthermore, there is a possibility that the worn profiles of wheel/rail influences the curving performance and the running stability. Therefore, predicting the wear development between wheel/rail is very important. In the previous research, the predicting model for worn profiles of rail with multibody dynamics was constructed. Moreover, some cases of wear experiment by use of the simplified test speciments has conducted to examine the wear development of wheel/rail. However, it has to be examined by experiment or analysis based on the wheel/rail profiles for predicting the worn profiles. In this research, the wear experiment with the discs which has actual wheel/rail profiles was conducted. Furthermore, the wear analysis method based on the wear experiment results was examined. As a result of the experiment and the analysis, the worn profiles of rail at the curved section was obtained. In addition, the analytical method with multibody dynamics for the prediction of the worn profile of rail was obtained.

To save labor and improve reliability of railway vehicle maintenance, we have been studying application of Artificial Intelligence (AI) technology to visual inspections of rolling stock equipment. This paper describes how we acquired appearance images for visual inspections, created training data and trained AI models. We built a practical AI development environment to find out what affects the judgment accuracy of AI models and how to improve accuracy through consistent creation and evaluation of AI models. Specifically, we worked on visual inspections of brake shoes for conventional trains and rubber tires for Maglev vehicle given importance of those parts. Our research established a procedure to develop highly precise AI models to distinguish conditions of railway vehicle underfloor equipment.

To predict the dynamic behavior of bogie frame vibration and stress under the operational condition in the design phase for railway vehicles, vehicle dynamics simulation is commonly used. This paper describes the modeling method for frequency characteristics of bogie suspension for vehicle dynamics simulation. The proposed method is based on the force-displacement hysteresis loop measured with vibration test and simulation model of bogie suspension to identify dynamic stiffness and damping coefficient of suspension model. As an example of bogie suspension, a single link assembly, which is used in traction device in railway vehicles, was modeled as suspension which had stiffness and damping coefficient that depend on frequency with this method. By comparing simulation and vibration test, it was confirmed that the simulation results of vibration and dynamic stress of a single link assembly with the proposed suspension model were good agreement with vibration test results.

The aim of this study is to understand the resistance forces acting on railway vehicles caused by sediment and snow. In order to investigate the relationship between railway vehicles and sediment and snow accumulation, a scale model experiment was conducted in which a flat plate simulating railway vehicle parts ran in a granular body that simulating sediment and snow. In scale model experiments, if some of the physical properties of sediment and snow, such as mass, density and viscosity, can be set in the granular materials used in the experiments (sand and powder with certain industrial properties), we believe that under the conditions under which these physical properties do not change, the resistance generated by these physical properties generated in scale model experiments can be interpreted by similarity according to scale. From the scale model experiments with flat plates and granular bodies, we investigated what elements of resistance forces are necessary for the elimination of granular bodies in scale model experiments. Based on the results, we propose a method for determining the resistance force acting on objects traveling in the granular body in a scale model experiment from the running speed, sediment height, and plate width of the flat plate.

Three-dimensional (3D) elastic vibrations that occur in railway vehicle carbodies can have negative impacts on ride quality, and efficient numerical analysis methods are required to study effective counter measure. The authors have proposed a method using a new vibration analysis model in which the railway vehicle carbody is modeled as a box-like structure composed of elastic plates, straight beams, and curved beams. This model can easily express complex 3D vibration shapes observed in actual carbody such as the interaction between the roof, floor, and side structures. This article reports the results of an improvement of this model and a series of studies of the effects of curveture and rigidity changes in the side structures on the natural modal characteristics of the elastic vibrations.

In SAE J3016 autonomous level 3 (conditional driving automation), safety and easiness of transition from autonomous to manual driving are very important. Vehicle standards and licensing systems for personal mobility vehicles are not currently established. It is, therefore, possible to introduce maneuver systems that differ from that of existing vehicles to new personal mobility vehicles with level 3 autonomous functions. In this study, driving experiment for an autonomous personal mobility vehicle is conducted using a driving simulator in which the transition from automatic to manual operation occurs with three types of maneuver systems. We investigate the influence of maneuver systems on the transition in the autonomous personal mobility vehicle to evaluate suitable maneuver systems for the transition.

Automated driving shuttles are hoped to provide convenient mobility services in rural areas. The social implementation of the automated driving vehicle must require prior discussion of the safety and comfort of passengers. Active pitch control, called APC, is one of the methods for passengers to prevent falling over when braking or accelerating. Previous papers proposed the control system designs and the control method to improve the transient response of APC. However, the subject experiments have not been conducted. This paper verifies the effectiveness of the APC in preventing falls and comfort by analyzing the results of subjective evaluation, EMG measurement and video analysis of subject experiments.

In recent years, the number of mobility vehicles apply some of automated driving technology has been an increase. Each type and mode mobility is progresses while using common technologies. In this paper, in anticipation of the combined operation of various types of mobility, an attempt was made to organize viewpoints on an automatic level for railroad, road, ship, and air vehicle.

In recent years, there has been a demand for the practical application of drones equipped with a fuel cell as a power source, which enables longer-distance flight. However, in order to operate a fuel cell drone, it is necessary to develop a protector that protects the high-pressure hydrogen tank from the impact of a crash. Carbon fiber is a material with a light mass. And this material has the characteristic that the energy absorption changes depending on the lamination and weaving method. Therefore, the authors focused on carbon fiber as a protector for hydrogen tanks. Then, in this research, protectors for hydrogen tanks with 6 different layers and weaves were manufactured. And collision tests of these protectors were performed. Based on results obtained in collision tests, energy absorption qualities of protectors were compared and evaluated.

This paper presents a new method to construct a nowcasting system for air turbulence at vertiport for safe takeoff and landing of UAM (=Urban Air Mobility). Since a vertiport is likely to be located on building rooftops, the effects of wake turbulence and downdrafts between structures may lead to serious accidents. A turbulence warning system at the vertiport would allow for the prior avoidance of hazards by shifting the timing of takeoffs and landings. Although direct observation by remote sensing devices and an advanced CFD analysis are expected to be useful for this problem, it is not easy to realize due to various uncertainties and physical constraints specific to complex urban spaces. In this study, we propose a technique to predict wind conditions and flight hazards specific to urban spaces using multi-point observation by distributed installation of low-cost small pressure sensor units.

The vertical rigidity of the suspension of freight vehicles is set to be more rigid according to heavy load conditions. However, safety should be improved by suppressing the roll motion while softening the vertical rigidity under light load conditions. Passenger cars use air springs to increase safety. However, freight trains do not use air springs. Therefore, a new anti-rolling device that does not use air springs was proposed. The proposed anti-rolling device uses lightweight carbon fiber reinforced plastic torsion bars. A scale model of the CFRP torsion-bar was built for freight cars and performance tests were carried out. FEM analysis was used to obtain the target shape of the CFRP torsion bar.