Stress and bending analysis of a soft pneumatic actuator considering different hyperelastic materials

Soft robotic is a branch of robotics which deals with the robots fabricated using soft materials. These robots are developed getting inspired from bio-living organisms and can mimic their behavior. For the actuation of soft robots various types of soft actuators have been developed such as pneumatic, hydraulic, electro-active, etc. Among these actuators, soft pneumatic actuators (SPAs) are the most commonly utilized soft actuators because of their larger output at low actuating pressure. Moreover, they are simpler in design and are cheaper to manufacture as compared to other soft actuators. Development of an analytical models for predicting the behavior of SPAs is challenging, because of nonlinear properties of the material. Finite element method (FEM) is an effective way to predict the behaviors of SPAs based on the different hyperelastic material models. In this work, a SPA is designed and analyzed considering three different hyperelastic materials namely, Dragon Skin 30, Elastosil M4601, and Smooth-Sil 950; which are identified from the existing literature. All the three actuators with three materials are actuated under similar loading and boundary conditions. The obtained FEM results for the three soft/hyperelastic materials are compared in terms of bending angle and stress distribution. It is found that, soft corrugated actuator developed with Dragon Skin 30 material generates maximum bending angle and is subjected to least stresses as compared to the other two materials.