Development of a Dual Function Joint Modular Soft Actuator and its Evaluation using a Novel Dummy Finger Joint-Soft Actuator Complex Model

Soft actuators, made from soft materials, offer a safer alternative to rigid robots for use on hand rehabilitation devices. A current challenge is to ensure these actuators comply with human finger morphology. To gain better insights into actuator mechanics when worn on and interacting with human fingers, combining physical experiments with simulation approaches is necessary. However, no simulation has been implemented for finger-actuator interactions. This study proposes a new joint modular soft actuator designed to comply with a dummy finger joint. The new actuator has a dual function design for increasing axial elongation during bending, facilitating compliance with finger morphology. In addition, a novel FEM for the new actuator's interaction with the dummy finger joint (dummy joint-soft actuator complex) is developed and used with physical experiments for evaluating actuator performance. Results show that the new design increases the dummy joint's bending range while exerting smaller contact forces on the joint. Even when the joint is blocked at specific bending angles, the actuator remains compliant to finger morphology. This research is a significant advancement in soft actuator design for hand rehabilitation, emphasizing the interaction between human fingers and soft actuators.