2012 年 78 巻 789 号 p. 1899-1912
With a record-low birthrate and a rapidly-growing elderly population, Japan faces a severe demographic challenge, compounded by a chronic lack of nursing care staff. Among nursing care tasks, patient transfer is one of the most physically strenuous tasks. To free caregivers from such heavy physical work and to compensate for the lack of nursing care staff, we have developed two prototype robots, RIBA and RIBA-II, which were designed to come in direct contact with patients and conduct transfer tasks such as lifting and moving a patient from a bed or the floor to a wheelchair and back. This paper, focusing on RIBA-II, describes the motion design, handling method, safety measures, as well as the verification experiment conducted on healthy subjects. RIBA-II, who's whole body including the joints is covered with soft materials to realize a safe and easy contact with humans, has the ability to lift up a human up to 80kg with a certain safety factor from the floor and transfer him/her to a normal wheelchair with armrests. The robot is not an autonomous one but a robot operated by a caregiver to ensure safety. When conducting a transfer task, the caregiver handles the robot by stroking the rubber tactile sensors installed on the robot arms and, at the same time, confirms safety. The purpose of the robot is not only relieving caregivers from heavy physical works but also to replace the transfer task conducted by two caregivers by one robot and one caregiver. The feasibility has been demonstrated by the verification experiment as described in this paper.