Magnetic soft continuum robots with contact forces

Abstract

The emerging magnetic soft continuum robots (MSCRs) – a type of slender magnetoactive soft rods that can be steered remotely by magnetic fields – hold great potential in interventional treatments of cardiovascular diseases. While forming stable contact between the distal tips of MSCRs and targeted lesions is critical in many applications such as cardiac ablations, existing designs of MSCRs have not systematically considered their contact with the external environments. In this work, we present a set of designs and optimization of MSCRs that can apply forces in contact with the environments based on theoretical modeling and numerical analysis. We propose to design MSCRs with nonuniform magnetization and nonuniform rigidity patterns so that they can achieve high steerability in the confined anatomy and apply sufficient contact forces at the targeted lesions. We first adopt the theory of hard-magnetic elastica to describe the large deflection of the MSCR with contact forces at the distal tip. We then discretize the MSCR using the finite difference method and solve for the deformation and contact forces numerically. The developed finite difference method is validated by both analytical solutions and finite element simulations. We further adopt the genetic algorithm to achieve an optimized design of the MSCR that potentially has a high steerability and capability of applying forces. Offering a facile route to analyze and optimize MSCRs with contact forces, the present work may facilitate the design of MSCRs for applications in endovascular settings.