Elasticity Versus Hyperelasticity Considerations in Quasistatic Modeling of a Soft Finger-Like Robotic Appendage for Real-Time Position and Force Estimation

Various methods based on hyperelastic assumptions have been developed to address the mathematical complexities of modelling motion and deformation of continuum manipulators. Here, we propose a quasi-static approach for 3D modelling and real-time simulation of a pneumatically actuated soft continuum robotic appendage to estimate the contact forces and the overall pose. Our model can incorporate external load at any arbitrary point on the body and deliver positional and force propagation information along the entire backbone. In line with the proposed model, the effectiveness of elasticity and hyperelasticity (neo-Hookean and Gent) assumptions are investigated and compared. Experiments are carried out with and without external load, and simulations are validated across a range of Young's moduli. Results show best conformity with Hook's model with about 6% average normalized error of position; and a mean absolute error of less than 0.08N for force applied at the tip and on the body; demonstrating high accuracy in estimating the position and the contact forces.