Enhancing Kinematic Performances of Soft Continuum Robots for Magnetic Actuation

TL;DR

This paper introduces a comprehensive framework for analyzing and optimizing the kinematic performance of soft continuum robots under magnetic actuation, combining equilibrium computation with spectral analysis of the configuration space.

Contribution

It develops a novel general formulation linking structural design, actuation inputs, and configuration space geometry, specifically applied to magnetic actuation scenarios.

Findings

Optimal magnet placement depends on actuation configuration.

Aligned magnetic moments enhance distal deformation.

Opposing moments favor proximal configurations.

Abstract

Soft continuum robots achieve complex deformation through elastic equilibrium, making their reachable motions governed jointly by structural design and actuation-induced mechanics. This work develops a general formulation that integrates equilibrium computation with kinematic performances by evaluating Riemannian Jacobian spectra on the equilibrium manifold shaped by internal/external loading. The resulting framework yields a global performance functional that directly links structural parameters, actuation inputs, and the induced configuration space geometry. We apply this general framework to magnetic actuation. Analytical characterization is obtained under weak uniform fields, revealing optimal placement and orientation of the embedded magnet with invariant scale properties. To address nonlinear deformation and spatially varying fields, a two-level optimization algorithm is developed that alternates between energy based equilibrium search and gradient based structural updates. Simulations and physical experiments across uniform field, dipole field, and multi-magnet configurations demonstrate consistent structural tendencies: aligned moments favor distal or mid-distal solutions through constructive torque amplification, whereas opposing moments compress optimal designs toward proximal regions due to intrinsic cancellation zones.