Development of a 4D hand gripping aid using a knitted shape memory alloy and evaluation of finger-bending angles in elderly women

As the global population ages, there is an increasing demand for physical assistive devices for the elderly. This study aimed to develop and evaluate a wearable gripping aid for elderly women to assist in their handgrip ability. We developed an actuator module for the hand-gripping aid using a 4D knitted shape memory alloy and attached to a flexible nylon glove. At baseline, we measured the bending angles of the knitted shape memory alloy and the subjects’ fingers while gripping. The bending angles of the gripping aid demonstrated similar hand mobility to those of elderly women in real life. We also found that SMA modules attached to a glove could implement the bending angle when gripping a ball derived from the index and middle fingers of elderly women. The finding could help to develop hand products that could be worn on the hand of the elderly by realizing the bending motion of each finger. The outcomes of this study suggest the practical potential of this wearable device as an effective hand-gripping aid for the elderly, based on a novel 4D material and ergonomic design approach.