Bathing care assistance with robot suit HAL

In the field of nursing care, caregivers have to bear a great burden due to assistive movements such as supporting of the care-receivers body, lifting them, moving them onto the wheel chair etc. In this paper, we focus on getting a care-receiver in and out of the bathtub, which is one of the most difficult movements for caregivers. Considering an important activity that puts a large burden on caregivers, lifting, there are many types of lifting devices available for transferring disabled people. Nevertheless it is difficult to use fixed equipment such as a mechanical lift with home care because it is expensive to rebuild the bathroom. The physical burden involved in assisting action in the field of nursing care can be greatly reduced by wearing the HAL (Hybrid Assistive Limb) full-body type. The objectives of this paper are to propose a new method of bathing care assistance using the robot suit HAL, to develop the upper half body of HAL, which reduces the physical burden on the wearer's upper limbs, and to show its effectiveness through an experiment. The study focused on reducing the trunk inclination angle, which is related to the physical load around the lumbar spine. The new method mainly uses the caregiver's upper limb to support the weight of the care-receiver. Therefore, we built a mechanism which locks the power unit of a HAL joint to assist the motor function of the wearer's upper limbs. To confirm the effectiveness of the proposed method, we demonstrated that the mechanisms of the power units kept the angles of the upper limbs steady while the wearer held a weight of 50(kg), and that the physical burden on the upper limb of the wearer was reduced. As a results of this experiment, we confirmed the effectiveness of the proposed method.