A Framework for Simulation of Magnetic Soft Robots using the Material Point Method

Simulation represents a key aspect in the development of robot systems. The ability to simulate behavior of real-world robots provides an environment where robot designs can be developed and control systems optimized. Due to the use of external magnetic fields for actuation, magnetic soft robots can be wirelessly controlled and are easily miniaturized. However, the relationship between magnetic soft materials and external sources of magnetic fields present significant complexities in modelling due to the relationship between material elasticity and magnetic wrench (forces and torques). In this work, we present a simulation framework for magnetic soft robots using the Material Point Method (MPM) which integrates hyper-elastic material models with the magnetic wrench induced under external fields. Compared to existing Finite Element Methods (FEM), the presented MPM based framework inherently models self-collision between areas of the model and can capture the effect of forces in non-homogeneous magnetic fields. We demonstrate the ability of the MPM framework to model the influence of magnetic wrench on magnetic soft robots, capture dynamic behavior of robots under time-varying magnetic fields, and provide an accurate representation of deformation when colliding with obstacles. We show the versatility of MPM framework by comparing simulations to a range of real-world magnetic soft robot designs previously presented in the literature.