A Multi-physics Model for Phase Change Actuation in Soft Robotics: Towards Untethered Soft Robots

This paper presents a multi-physics model for phase-change-driven actuation in soft robotics, focusing on untethered systems that autonomously generate pressure through liquid evaporation. The model integrates electrothermal, thermo-fluidic, and mechanical domains, coupling Peltier-based heating, vapor generation, and soft material deformation. By operating in a pre-boiling regime, the approach minimises thermal gradients, enhances responsiveness, and reduces energy consumption. The governing equations are integrated into a multiphysics model, providing an innovative tool for designing efficient, safe, and controllable actuators with applications in robotics, biomedical devices, and adaptive materials.