Journal of Life Support Engineering
Online ISSN : 1884-5827
Print ISSN : 1341-9455
ISSN-L : 1341-9455
Volume 23, Issue 3
Displaying 1-4 of 4 articles from this issue
Research Papers
  • Toyokazu Takeuchi, Takahiro Wada, Masato Mukoubaru, Shunichi Doi
    2011 Volume 23 Issue 3 Pages 101-107
    Published: 2011
    Released on J-STAGE: February 14, 2013
    JOURNAL FREE ACCESS
    Myoelectric prosthetic hands improve ADL largely because the hand uses EMG signal induced by voluntary contraction of residual muscles of amputees for opening and closing the hand and the amputees can control its motion intuitively. On the other hand, it is difficult for the amputees to gain skills to use the prosthesis including precise EMG control ability required to control the prosthesis. In this paper, a new training system of Myoelectric prosthetic hand for upper limb amputees is developed using virtual reality technology in which amputee can train in the virtual environment. We hypothesize that efficacy of training depends on difficulty of given task. Thus, we propose a new training method that controls the success rate of given tasks by changing difficulty of the task in the virtual environment based on the trainee's skill level. The experimental results will show that the proposed method can control success rate of the given task by changing task difficulty according to the user's skill level. Further, it is shown that the success rate of the given task increases when the task difficulty is adjusted by the proposed training method.
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  • Yoshikazu Mori, Norikatsu Sakai, Kaoru Katsumura
    2011 Volume 23 Issue 3 Pages 108-115
    Published: 2011
    Released on J-STAGE: February 14, 2013
    JOURNAL FREE ACCESS
    A wheelchair with a lifting function is designed to assist a caregiver when transferring a wheelchair user not only indoors but also outdoors. The target user is typically a severely disabled person with disabled upper and lower limbs, and therefore needs the physical support when using a toilet or transferring from a bed to a wheelchair and so forth. Both the wheelchair and the lift are driven by their respective motors. The user can approach above the toilet stool or the bed from the rear because the large driving wheels are located in front of the body and the seat can be folded. This paper presents the concept design and the experimental results of a scale model wheelchair with the lifting function, which confirms the design effectiveness. In addition, the traveling, the lifting operation and how to fold are demonstrated using a full-sized prototype.
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  • Masafumi Oda, Toshiaki Hara
    2011 Volume 23 Issue 3 Pages 116-123
    Published: 2011
    Released on J-STAGE: February 14, 2013
    JOURNAL FREE ACCESS
    We have been developing a novel capacitance type force sensor that enables simultaneous measurement of a torque around the vertical axis as well as normal and two orthogonal shear forces on the skin surface. In our previous research, the prototype sensors were made and authenticated the potency. Prototype sensors are parallel plate type collocated a dielectric between two circuits. We have planned to use an approximated displacement-capacitance characteristic curve when we estimate an output force. Therefore, this paper reports about an ideal approximation of the curve and several applications, such as surgical robot and nursing-care system.
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Encouraging Prize form Barrier-Free System Development Foundation Awarded Research Papers
  • Yuka Maeda, Masaki Sekine, Toshiyo Tamura, Takuji Suzuki, Ken-ichi Kam ...
    2011 Volume 23 Issue 3 Pages 124-129
    Published: 2011
    Released on J-STAGE: February 14, 2013
    JOURNAL FREE ACCESS
    This study examined position dependency in photoplethysmography (PPG). For transmitted-light PPG, a sensor is usually attached on a fingertip and transmitted light is monitored. Although simple to use, a fingertip sensor and transmitted-light PPG cannot monitor vital signs during exercise and daily activities because the sensor attachment becomes disturbed. Reflected-light PPG can be applied to any part of the body. However, differences in cutaneous blood supply to different regions have been reported, and the accuracy of measurements can vary among neighboring sites. This position dependency can cause the pulse count to fail and necessitate sensor reattachment. The light source can also affect the characteristics of reflected-light PPG. To investigate position dependency in PPG, we compared the reflected light signals obtained from green and infrared PPG sensors at different sites. Eight young healthy subjects were recruited to participate in the study. Green and infrared PPG signals were collected simultaneously from three sites on the left arm of each participant. The correlations among adjoining green PPG signals were higher than those among adjoining infrared signals. Furthermore, the difference in the pulse interval was smaller among adjoining green PPG signals than among infrared signals. These results suggest that green-light PPG has less position dependency and thus may be more suitable for monitoring the pulse rate during daily activities.This study examined position dependency in photoplethysmography (PPG). For transmitted-light PPG, a sensor is usually attached on a fingertip and transmitted light is monitored. Although simple to use, a fingertip sensor and transmitted-light PPG cannot monitor vital signs during exercise and daily activities because the sensor attachment becomes disturbed. Reflected-light PPG can be applied to any part of the body. However, differences in cutaneous blood supply to different regions have been reported, and the accuracy of measurements can vary among neighboring sites. This position dependency can cause the pulse count to fail and necessitate sensor reattachment. The light source can also affect the characteristics of reflected-light PPG. To investigate position dependency in PPG, we compared the reflected light signals obtained from green and infrared PPG sensors at different sites. Eight young healthy subjects were recruited to participate in the study. Green and infrared PPG signals were collected simultaneously from three sites on the left arm of each participant. The correlations among adjoining green PPG signals were higher than those among adjoining infrared signals. Furthermore, the difference in the pulse interval was smaller among adjoining green PPG signals than among infrared signals. These results suggest that green-light PPG has less position dependency and thus may be more suitable for monitoring the pulse rate during daily activities.
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