Abstract: A Multi-Degree-Of-Freedom (Multi-DOF) soft exoskeletal hand rehabilitation actuator was proposed to address the limitation of single-degree-of-freedom in existing soft exoskeletal hand rehabilitation devices. Serrated bellows chambers were strategically placed at three joints,and bidirectional square chambers were incorporated at the palm and finger joints to facilitate finger flexion-extension and adduction-abduction. The nonlinear relationship between the bending angle of the actuator chambers and input air pressure was established based on the segmented constant curvature assumption model. Finite element analysis investigated the impact of chamber wall thickness,length,spacing,and quantity on the actuator′s bending performance. A silicone molding process was employed for actuator fabrication,and an experimental platform was constructed for bending performance testing.Results demonstrate that at 60 kPa,the actuator achieves a 21.8° extension,and at 25 kPa,a 254.8° flexion,aligning with the natural range of human finger motion.

Key words: soft actuator, rehabilitation, multi-degree-of-freedom