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Kim Y.,EcoTopia Science Institute | Oyabu T.,West Japan Railway Company | Obinata G.,EcoTopia Science Institute | Hase K.,Tokyo Metroplitan University
IEEE Transactions on Systems, Man, and Cybernetics Part A:Systems and Humans | Year: 2012

In this paper, we present some results from the study on the impedance characteristics of a human arm during the execution of vehicle steering control tasks by using a joystick-type steering device. We propose a new model of human-machine interaction where the damping coefficient of the interface device can be tuned to match the impedance characteristics of the human arm. To verify the proposed model, we developed a special experimental setup. We used a robot and force/torque sensors to simulate the joystick operation. We explored human-machine interactions when the operator uses only one hand to control the vehicle. The reaction forces of the joystick were simulated by a virtual impedance field tuned to match human arm impedance. In the tests, we simulate situations when the movement of the joystick in the forward-backward direction sets the speed of the vehicle while the lateral rotation of the same control stick changes the turning radius of the vehicle. The robot allowed us to simulate various impedance characteristics. With the tests, we investigated the operability of the simulated vehicle by tuning the viscosity coefficient of the joystick in order to match it with the stationary human arm impedance and time-varying human arm impedance. The test results allowed us to propose a new method to improve the operability of a joystick-type steering device, based on the online adaptive matching of the impedance characteristics of the human arm. The usefulness of the proposed method is confirmed through experiments. © 2011 IEEE. Source

Kumano H.,Shinshu University | Hirata T.,Shinshu University | Hagiwara Y.,West Japan Railway Company | Tamura F.,Shinshu University
International Journal of Refrigeration | Year: 2012

The effect of storage on flow and heat transfer characteristics of ice slurry was investigated experimentally. After ice slurry had been stored in the storage tank, variations in ice particle size were measured using a microscope, and diameter distribution and average diameter determined. The ice packing factor, Reynolds number and storage time were varied as experimental parameters. The pressure drop and heat transfer coefficient were measured when the ice slurry flowed in the horizontal tube. For laminar flow, the ratios of pipe friction and heat transfer coefficient decreased with storage time. For more than 12 h storage time, the ice slurry could not flow in the tube. The adhesion between ice particles seemed to cause a blockage in the tube. On the other hand, for turbulent flow, the pipe friction and ice slurry heat transfer coefficients were similar to that of the ethanol solution, and the storage effect was insignificant. © 2011 Elsevier Ltd and IIR. All rights reserved. Source

Yokoe T.,West Japan Railway Company
Nihon Kikai Gakkai Ronbunshu, C Hen/Transactions of the Japan Society of Mechanical Engineers, Part C | Year: 2010

Railway drivers are trained the measures about various troubles faced during driving, and they can usually operate appropriately in the training. However, they can't meet an actual trouble calmly when they face it, so that they can take another mistake. As a part to examine support plan to prevent such an effect, we carried out a survey for all train drivers in our company, for example about their experiences and feelings in trouble caused by their own mistake or not, besides measures how they will manage an inexperienced trouble, and supports what they want to demand when they lost calmness. Source

Fujino H.,West Japan Railway Company
Proceedings of the SICE Annual Conference | Year: 2012

The objective of this study is to examine why and how operators usually achieve a normal operational level. The author focuses on Threat and Error Management (TEM) in aviation as a key concept for finding an answer. Following this approach, the author conducted a participant observation of railway drivers and explored the above-stated question with reference to some of the behaviour he observed. The author uses a model to suggest that the daily routine by which operators achieve normal operation is guided by their own definitions of work and the negative emotions connected with those. It is further suggested that operators' definitions of work are regulated by their organisations' social environments and are intimately related to the satisfaction of the operators' needs for competence and relatedness. © 2012 SICE. Source

Mito Y.,West Japan Railway Company
Rail Human Factors: Supporting Reliability, Safety and Cost Reduction | Year: 2013

West Japan Railway Company (hereafter we) introduced risk assessment as the axis of basic safety program that was started in April, 2008. It was a first attempt for the railway business operator, and we have been committed to risk assessment for some years since then, setting up "Establishment of the System for No Fatal and Injury Passenger Accidents and No Major Worker Injuries" as the goal. Therefore, safety level has been steadily improved through clarification of potential risk factors in all workplaces and implementation of risk reduction measures. This paper provides our vision and methodology for the establishment of safety management system in accordance with risk management. © 2013 Taylor & Francis Group, London, UK. Source

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