Computational Modeling and Finite Element Analysis of Bio-Inspired Soft Pneumatic Actuators for Robotic Straightening

This study presents the design and analysis of a bioinspired soft pneumatic actuator (BSPA), using the finite element method (FEM), to ‎simulate the opening and closing movements of the human hand. The primary objective was to explore its potential application in assisting ‎stroke survivors during rehabilitation, specifically targeting the treatment of spastic-clenched fist deformities. Drawing inspiration from the ‎biomechanical motion and anatomical structure of the human hand, the actuator was engineered to actively extend while passively flexing, ‎mimicking natural hand movements. Key design parameters, including actuator width (16 mm), wall thickness (2 mm), actuation angles, and ‎chamber dimensions, were fine-tuned through iterative simulation to optimize the actuator’s mechanical response. The design process was ‎conducted using SolidWorks, with subsequent performance evaluation and simulation conducted in Abaqus CAE. Finite element analysis ‎allowed for a detailed examination of the actuator's behavior under different loading conditions, ensuring accurate predictions of its functionality. Simulation results indicated that the BSPA could extend to a 90° angle at a pressure of 110 kPa, demonstrating the potential to ‎mimic full hand extension. Additionally, block force tests showed that the actuator generated a total force reaction of 3N at 80 kPa, a level of ‎force sufficient to fully open the hand when integrated into a soft robotic glove. This force output was carefully evaluated to ensure it pro-‎vided sufficient assistance for stroke survivors experiencing muscle spasticity, without compromising safety or comfort. These findings ‎provide critical insights into the development of soft pneumatic actuators (SPAs) for medical and rehabilitative use, particularly for assisting ‎patients with hand mobility impairments. The study highlights the effectiveness of bioinspired designs in creating soft actuators that can ‎reproduce complex biomechanical movements. The results pave the way for further refinement and application of BSPAs in soft robotic ‎gloves for rehabilitation, offering a promising solution for improving the quality of life for stroke survivors by enhancing hand functionality ‎and motor recovery‎.