An ultra-multijointed assistive robot finger

We propose a design for an ultra-multijointed assistive robot finger. Gripping necessitates the flexion and extension of a finger and is a basic function in daily life. Therefore, to enable people with hand paralysis to grip, it is necessary to assist their finger movement. To do so, we propose a novel ultra-multijointed assistive robot finger mechanism. This mechanism consists of many joints, wires, a finger frame, and a movement point. These joints enable the structure to adapt to the length and location of the wearer's finger and assist its bidirectional movement. The mechanism is moved by a linear power unit driven by a wire. Two assistive robot fingers are glued onto a glove to enable the user to stably grip everyday objects. We carry out four experiments to confirm the finger's range of motion, basic flexion and extension motions, flexion force of the fingertip, and grip performance for everyday objects. Experiments with five able-bodied participants show that the assistive robot finger does not limit the hand's range of motion. Furthermore, our assistive robot finger can assist finger movement. The force of the fingertip is more than 9.8 N, allowing everyday objects to be gripped successfully. Hence, the assistive robot finger developed in this study may have the potential to help those with hand paralysis grip everyday objects.