Aging is becoming a serious problem in Japan. Physical load during a caring operation may not be tolerable for the elderly and very often it produces secondary lesions in care assistants. Practical power-assist devices are highly desired in the field of caring or welfare. A Pneumatic Artificial Rubber Muscle (PARM) is noticed as an actuator of an assist device because it is flexible and has a high mass-power rate. In this study, we have developed an assist device for caring that uses PARM to reduce a physical load. A two-link arm was designed to assist caring motions. The position controller using a disturbance observer was applied to a two-link arm to correspond to the difference of weight of members in need of caring. The disturbance observer is effective in terms of not only compensation for disturbance, but also nominalization of a controlled object. Robustness of the employed disturbance observer is realized by internal stabilization. A two-link arm was controlled by the position controller, however, improvement such as enlarging the rigidity in a perpendicular direction is necessary for it.

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A pneumatic system is used in a railway vehicle in a lot of elements such as the brake, suspension, and doors. However, the design of a pneumatic system for a railway vehicle was decided so far by experience, and evaluation regarding the unsteady characteristic of a pneumatic system had not yet been done. In a SHINKANSEN railway vehicle, the active suspension is used to improve the riding comfort at high-speed operation. However, examination of the unsteady characteristic of a fully active suspension is insufficient. In this study, we measured pressure and flow rate of the active suspension pneumatic system of a SHINKANSEN railway vehicle in real time, and verified the validity of that system design. To obtain knowledge for promotion of efficiency and cost reduction, the pneumatic system was modeled and simulated. The pressure pulsation of the pipe was simulated by changing the pipe diameter and the tank capacity.

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This paper proposes a novel fluid powered actuator sliding along a flexible tube. The actuator named Λ-drive is composed of a flat tube and a slider. In the slider, the tube is bent and then the buckling point occurs, which helps to cut off the fluid passage and to seal in order to provide the driving force to the slider without generating large friction. In this paper, after the conventional sliding actuators are compared, the design method of the proposed actuator for making stable drive possible, the classification of the driving mode, and the analysis of the output force are discussed. Moreover, the validity of the proposed analysis can be verified through the experiment of the linear and the spiral motion by the developed prototype. Finally, as one of the applications of the actuator, the active drive of the zipper is proposed and its feasibility is discussed.

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