In order to reduce Shinkansen wayside noise at higher speeds, it is necessary to reduce not only pantograph noise but also noise from the lower part of cars. With the aim of absorbing noise from the lower part of the car through a process of multiple sound reflections between the car body and a noise barrier, we developed sound-absorbing panels for the lower part of the car bodies through acoustic tests using a full-scale cut car model and running tests using "FASTECH360S", a high-speed test train of JR-East. In order to assess which sound-absorption areas are more effective in reducing wayside noise coming from the lower part of the cars, we conducted running tests with the sound-absorbing and non-sound-absorbing panels in different layout configurations. As a result, we found that: 1) attaching sound-absorbing panels reduces wayside noise from FASTECH360S running at 320 km/h by approximately 0.9 dB at a point 25 meters from the track, 2) sound-absorbing panels installed to side skirts have the greatest noise reduction effect and 3) the sound-absorbing panels at the front and back ends of the bogie space and on the side beam contribute almost nothing to noise reduction.

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For in-wheel electric motor drive vehicles, a new vehicle dynamics control which is based on the tire force usage rate is proposed. The new controller adopts non-linear optimal control could manage the interference between direct yaw-moment control and the tire force usage rate. The new control is considered total longitudinal and transverse tire force. Therefore the controller can prevent tire force saturation near tire force limit during cornering. Simulations and test runs by the custom made four wheel drive in-wheel motor electric vehicle show that higher driving stability performance compared to the performance of the same vehicle without control.

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Energy-consuming devices are essential to modern life, but must be made more efficient to meet environmental conservation goals. One of the prime causes of energy loss is gravity. In this paper, we propose a framework to design potential fields for link mechanisms to minimize the amount of gravitational potential energy consumed, besides loss to friction and inertia. The framework allows design of customized potential fields such that any object or link mechanism can be moved along specific trajectories by simply adding a small auxiliary force that just overcomes the losses. We confirm this theory and the effects on mechanisms by kinematic analysis.

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In this research, the dynamic characteristics of bicycles are investigated focusing on small wheels. Multibody dynamics is used for the formulation of the bicycle model. The effects of the parameters of tire diameter and head angle are examined by focusing on a small wheel bicycle. The straight-ahead stability and upstanding stability are evaluated at each parameter. The results show the tendency of stability at each parameter and the influential parameter to the small wheel bicycle is found. The driving experiment using the small wheel bicycles with variable head angle is evaluated by the subjects. It is confirmed that varying head angle increases the stability of the small wheel bicycle. The results are corresponding with the simulation results and it is shown that the simulation captures the tendency of the stability and expresses the characteristic of the small wheel bicycle. Furthermore, the simulation using the effective parameters for small wheel bicycle was shown at the end. It showed the possibility of increase of the stability of a small wheel bicycle.

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In this paper, cooperative behavior of autonomous mobile robots against congestion is experimentally analyzed through multi-robot simulations. For this purpose, robots behavior regarding velocity is investigated. Two circular systems in which bottlenecks do not exist and exist are the research objects. In the simulation experiments, first off, a simple behavior model is applied to the robots. From the analysis results, behavioral features of the robots depending on two states, i.e., non-congestion and congestion, and presence or absence of bottlenecks are presented. These are criteria for evaluating the effectiveness of behavior models. After that, a proposed behavior model is applied to the robots and the effectiveness of cooperative behavior of the robots is evaluated on the basis of the criteria. Finally, it is shown that the proposed behavior model effectively solves jams or alleviates the influence in the congested systems regardless of bottlenecks.

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We propose a method for reducing the computational time of motion planning for stacker cranes. Most automated storage/retrieval systems (AS/RSs) are only equipped with one stacker crane. However, this is logistically challenging, and greater work efficiency in warehouses, such as those using two stacker cranes, is required. In this paper, a warehouse with two stacker cranes working simultaneously is proposed. Unlike warehouses with only one crane, trajectory planning in those with two cranes is very difficult. Since there are two cranes working together, a proper trajectory must be considered to avoid collision. However, verifying collisions is complicated and requires a considerable amount of computational time. As transport work in AS/RSs occurs randomly, motion planning cannot be conducted in advance. Planning an appropriate trajectory within a restricted duration would be a difficult task. We thereby address the current problem of motion planning requiring extensive calculation time. As a solution, we propose a “free-step” to simplify the procedure of collision verification and reduce the computational time. On the other hand, we proposed a method to reschedule the order of collision verification in order to find an appropriate trajectory in less time. By the proposed method, we reduce the calculation time to less than 1/300 of that achieved in former research.

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This research proposes a haptic velocity guidance assistance system for realizing eco-driving as well as enhancing traffic capacity by cooperating with ITS (Intelligent Transportation Systems). The proposed guidance system generates the desired accelerator pedal (abbreviated as pedal) stroke with respect to the desired velocity obtained from ITS considering vehicle dynamics, and provides the desired pedal stroke to the driver via a haptic pedal whose reaction force is controllable and guides the driver in order to trace the desired velocity in real time. The main purpose of this paper is to discuss the feasibility of the haptic velocity guidance. A haptic velocity guidance system for research is developed on the Driving Simulator of TUAT (DS), by attaching a low-inertia, low-friction motor to the pedal, which does not change the original characteristics of the original pedal when it is not operated, implementing an algorithm regarding the desired pedal stroke calculation and the reaction force controller. The haptic guidance maneuver is designed based on human pedal stepping experiments. A simple velocity profile with acceleration, deceleration and cruising is synthesized according to naturalistic driving for testing the proposed system. The experiment result of 9 drivers shows that the haptic guidance provides high accuracy and quick response in velocity tracking. These results prove that the haptic guidance is a promising velocity guidance method from the viewpoint of HMI (Human Machine Interface).

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Elderly drivers are increasing every year in Japan. However, physical depression caused by aging is also a cause of traffic accidents and they will all have to give up driving one day. The aim of this study is to clarify the effects of car dependency and the impact of having to stop driving among the elderly. And to propose alternative transportation options for elderly after having surrendered their driver's licenses. We carried out a questionnaire survey and a focus group interview. During this study, we sent 1338 questionnaires to people over 60 years old in regional cities that included areas with convenient access and inconvenient access to public transit. From our survey, we found that, over half of the elderly drive every day, the older people lower drive frequency. License holder of elderly with feelings of decreased motor skills awareness a decrease in driving ability. Moreover it is clarified that issue of alternative mobility are "mobility devices to maintain social and personal relationships" and "mobility devices as an extension of walking" and "use the existing public transport environment".

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Passive dynamic walking requiring little exertion is one way of realizing efficient bipedal locomotion. In this case, forces should be converted only to shape ideas for the bottom leg, which naturally alternates the vibration of the roll and yaw axes. To achieve our objectives, in this study we focus on a spinning top, and the change in the direction of movement about the rotation axis was defined as irregular motion. It was shown that this method of realizing motion axis conversion occurred during rotation. An initial angular velocity is generated on the center axis of the solid body's curved surface, and changed the motion into a backspin. First, it was confirmed that we can accurately describe a half ellipsoid as a twisted solid curved surface on its center axis. Next we changed the contact point. By adjusting the angular momentum, we also showed the method of momentum vector conversion through friction. We extracted the constraint condition, and a translational direction element of the angular momentum vector was synthesized. Finally, we showed a method for converting the irregular motion into translational motion, so that the irregular motion can realize a twist angle and an ellipsoid shape.

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