Modeling Soft Swimming Robots using Discrete Elastic Rod Method

Soft swimming robots are primarily composed of elastically deformable materials, which typically make up the robot’s body, limbs, and/or fins. Such robots can swim by moving their limbs, flapping their fins, or undulating their body in order to control thrust and direction. This chapter presents a technique to model these soft swimming robots using a computational framework based on the method of discrete elastic rods (DER). This approach to soft robot simulation draws inspiration from methods to simulate slender structures that are widely used in the computer graphics community. In this framework, the soft robot limbs or fins are treated as flexible rods that deflect in response to internal actuation and surface tractions from contacting bodies and the surrounding fluid. Here, we apply this model to the special case of a seastar-inspired robot composed of radiating limbs that produce motion through bending and hydrodynamic drag. We begin with an overview of the DER-based framework and then present simulation results for forward swimming and turning.