Design, Modeling and Evaluation of Lattice Structure Pneumatic Actuators (LSPAs) for Soft Wrist Rehabilitation Robot

Soft robots have gained recognition as promising solutions in rehabilitation robotics due to their intrinsic flexibility and safety features. However, they often encounter challenges related to output efficiency and portability. This paper presents the design, modeling, and evaluation of an innovative wrist rehabilitation robot that employs two double-layer lattice structure pneumatic actuators (DLSPAs) to enhance efficiency. Key parameters of these DLSPAs are optimized through a mathematical model, with calibration experiments indicating that the discrepancy between actual and predicted values remains within 4% of the DLSPAs' maximum output force, thereby validating the model's accuracy. Furthermore, the DLSPAs achieve an end output force of 27.02 N, marking a 156% increase compared to single-layer lattice structure pneumatic actuators (SLSPAs) and underscoring the structural advantages of the design. To evaluate the clinical efficacy of the wrist rehabilitation robot, trials were conducted with 8 individuals post-stroke. Results demonstrate that, with robotic assistance, participants' lifting force reached 4.85 N and 5.11 N in dorsal extension and palmar flexion, respectively, with corresponding angular movements of 36.40${}^{\circ }$ and 38.36${}^{\circ }$. These findings suggest that the lattice-structured soft wrist rehabilitation robot offers substantial potential for effective assisted rehabilitation training.