MODELING AND SIMULATION OF SOFT TISSUE FOR STUDYING ROBOT-TISSUE INTERACTION

This paper presents a simulator that integrates viscoelastic and nonlinear spring behavior within a mass-spring-damper framework, capturing complex tissue phenomena such as creep, stress relaxation, and strain-stiffening. The simulator leverages constitutive models to capture both elastic and time-dependent viscous effects. It further augments robust contact detection and employs implicit integration to maintain stability under large deformations. The simulator is validated using experimental data from controlled loading tests on lung tissues under various loading rates for robot-tissue interaction studies. Our results demonstrate that the simulator can be accurately calibrated to replicate measured force-displacement behavior and that real-time tuning of stiffness and damping coefficients is achievable. This work focuses specifically on simulating lung tissue mechanics. This application was selected for its relevance to the automation of pulmonary lavage—a medical procedure in which the mechanical properties of the lung tissue vary depending on the level of saline present. The proposed simulator is validated through comparison with experimental data, demonstrating its ability to reproduce soft-tissue interaction dynamics accurately.