MRブレーキによる足底高さ制御可能な歩行障碍者転倒防止用装具の検討

抄録

Fall causes decline of ADL (Activities of Daily Living) by broken bone or fear of falling, which leads to being bedridden or the condition of need for long-term care. Thus, fall prevention is important. At the same time, active walking training is also important in terms of escalating the action of daily life and improving the QOL (Quality of Life). Some people with walking disabilities have a relatively mild symptom, who have a possibility of falling while they can walk without being supported. From the above, we have studied gait training tool to achieve both fall prevention and respect good motion. In this study, we focused on insole, which affects the motion of center of gravity by changing the direction of the ground reaction force. Basically, fall happens when a resultant force of gravity and inertial force projected on the floor is outside of a base of support. Hence, controllable plantar height can prevent falling. We used MR (Magnetorheological) fluid brake for controllable plantar height device. MR fluid consists of micron-sized carbonyl iron particle and carrier fluid, whose yield shear stress can be varied by applying magnetic field. By applying to brake, friction force is generated against external force. We conducted the vibration test to evaluate the force characteristics. This result confirmed that friction force became dominant by applying an electrical current. Second, we conducted the constant load test to determine how much force MR fluid brake supports. With the application of a current of 1.0 A, MR fluid brake maintains its height up to a force of 200 N. In view of the place where MR fluid brake is installed, this withstand force is enough to support weight.