Development and evaluation of fiber reinforced modular soft actuators and an individualized soft rehabilitation glove

In the research and development of soft rehabilitation gloves (SRGs), individualized support considering users' morphological and biomechanical characteristics is the next critical step toward use in rehabilitation practice. Compared with single-structure soft actuators for a whole finger, which require redesigning for each user, modular soft actuators enable the support for each joint by adjusting rigid connectors that are easier to fabricate. Several modular actuators have been developed, however, neither the effect of interaction between soft actuators and fingers nor the functionality of a hand under the support of an SRG has been appropriately evaluated. In this study, we proposed a new modular soft actuator that improved the support performance with enlarged chambers and fiber reinforcement. Moreover, we made an SRG with the proposed actuators and conducted an objective evaluation for the range of motion (ROM), torque, and response time of both actuators and the SRG with a dummy finger and hand. Furthermore, the Kapandji test, a clinical evaluation of the thumb's opposition, was performed to show the performance of the proposed actuators and the SRG. As a result, the new modular soft actuators showed better support performance, and the SRG can support multiple grasping profiles and enable the thumb's opposition. This work moves one step toward applying soft robotics to rehabilitation.