Operation of assistive apparatus through recognition of human behavior: Development and experimental evaluation of chair-typed assistive apparatus of nine-link mechanism with 1 degree of freedom

Because of deterioration of strength, range of joint motion, and balance ability, most care-dependent older adults require assistance to move from a seated position to a standing position. Although many sit-to-stand assisting apparatuses consisting of a seat, power transmission mechanism, and sensors have been developed, most of movements depend several actuators as the power transmission mechanism. This study aims to develop the chair-typed apparatus of nine-link mechanism with 1 degree of freedom at first, then to prove the possibility that the apparatus can be operated through the recognition of human behavior by one sensor. Here, the nine-link mechanism is divided into two mechanisms: the five link for raising the height; the four link for rotating. The mechanical part enables two input links for two mechanisms to be driven by one linear actuator simultaneously. The measurement with the infrared sensor enables the assistive apparatus to be operated automatically while patterns from measured data help the apparatus recognize what the user want to do: one is the sit-to-stand movement; the other is the stand-to-sit movement. It is discussed that the operating method through the human behavior is helpful for most older adults who are not familiar with the operation of machine.