[in Japanese]

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[in Japanese]

View full abstract

[in Japanese]

View full abstract

[in Japanese]

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[in Japanese]

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[in Japanese]

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The purpose of this study was to develop a method of transmission of information by using cutaneous sensation elicited by electrical stimulation. In this paper, we proposed to present dynamically cutaneous sensation patterns such as characters or graphic symbols that could be understood intuitively. First, a basic design of stimulation electrode was determined experimentally. Then, basic 16 presentation patterns were examined in pattern recognition experiments with neurologically intact subjects. As one of reasons of misrecognition, remaining sensation after electrical stimulation was considered. Therefore, inter stimulus interval (ISI) between two presentation patterns was determined experimentally. Based on results of the first recognition experiments and determined ISI, modified 14 patterns were examined in the recognition experiments. Correct recognition ratio was 70.7∼90% on 4 of 6 subjects. It was higher than or equal to that of previous research works, in which only 4 patterns were tested experimentally. In addition, the correct recognition ratio was also expected to be about 90 % in average if patterns including diagonal lines were removed as patterns used in the previous study. The method proposed in this paper was expected to be effective in recognition of many presentation patterns. Optimization of stimulating electrode and parameters of electrical stimulation for pattern presentation, and examination of pattern presentation for practical characters and graphic symbols would be required.

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Human-friendly electrically powered wheelchair (EPW) with good riding comfort becomes a real requirement of aging society. Many factors such as seating, stability, mechanical noise, and operability are related to the riding quality of EPW, and the body tilting for the acceleration and deceleration of EPW is one of important factors. Especially in the case of speed control by the joystick a sudden acceleration or deceleration is easily to be caused and the riding comfort becomes bad. In this study, an improvement on riding comfort has been tried by applying the state feedback control with state observer based on the modeling of EPW system including an operator. With a two dimensional model considering the swinging in forward and backward direction the swinging of operator is restrained and the riding comfort is improved. A sensory test on riding comfort for the handicapped and healthy subject was carried out, and the effectiveness of the control method was verified. Though the dispersion of every subject is obvious on the swing of trunk, it was confirmed that the riding comfort is improved since the swing becomes smaller.

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The rotational stability of cementless hip prostheses corresponds to their appropriate contour design. The appropriate contour design of a femoral stem is important for secure primary fixation. This paper addresses the issue of the fixation method of hip stems and their rotational stability. Specimens were four kinds of hip prostheses. The rotational displacement was measured and analyzed by applying a reproduced torsion moment. Different kinds of finite element models of four femoral stems were constructed for computer simulation. The measurements were accomplished by real stems used in clinical scene. Common conditions of analyses and measurements were: (i) a torsion load of 18.9 Nm was applied to the proximal femur as the intra-rotation; (ii) a stepping load of 1800 N was applied to the proximal tip of the stem; and (iii) rigid contact of the distal end of the model femur with the rigid base. As a result, it was found that the relative rotational displacement obtained by FEM was 0.21 mm in the Intra-Medullary Cruciate stem. For the VerSys stem, the relative rotational displacement was 0.10 mm. The relative rotational displacement of the PerFix SV stem was 0.67 mm. The relative rotational displacement of the Duetto SI stem was 0.03 mm. The relative rotational displacement obtained by laser displacement sensor was 0.37 mm in the Intra-Medullary Cruciate stem, 0.25 mm in the VerSys stem, 1.87 mm in the PerFix SV stem, and 0.17 mm in the Duetto SI stem. Judging from rotational displacement obtained by two approaches, three types of stem (Intra-Medullary Cruciate stem, VerSys stem, Duetto SI stem) provided rotational stability.

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In order to examine the degeneration in the walking ability of the aging people, this research tried to find out the reasons by testing free walking movements of the aged in an 8- year span. The examinees of the research were 9 aged men and women living in a nursing home. The research was done mainly by examining the first and the last testing data which measured knee extension strength, walking speed, step length, step rate and supporting time. Moreover, in order to examine the relationship between walking ability and daily life, an investigative interview about the examinees’ life-style was also done. The results showed that there was no obvious relationship between the change of maximum knee extension strength and the change of walking movements. The walking speed of more than half of the examinees increased. Both the step length and step rate contributed to this increase. Irrespective of an increase or decrease in walking speed, step rate, angular displacement of knee joint, single supporting time and double supporting time declined. It could say that the change in the walking movement and the improved results were in.uenced by the stair climbing, walking, and gate ball playing carried out in their nursing home.

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