Energy-Based Kinematic Analysis on Magnetic Soft Continuum Robot With Asymmetric Magnetization

Abstract

Magnetically actuated soft continuum robots (MSCRs), which offer remote and wireless control via external magnetic fields along with high flexibility, have recently emerged as a promising technology for minimally invasive surgery (MIS). However, the magnetic actuation forces of MSCRs are generally limited, resulting in inherent workspace constraints. To overcome these limitations, various design strategies have been explored, including the development of an asymmetric magnetized soft continuum robot (AMSCR). Although AMSCRs have demonstrated a significantly larger workspace than conventional MSCRs, a quantitative relationship between the magnetization patterns of embedded magnetic particles and the resulting workspace has not yet been fully clarified. In this study, an energy-based kinematic analysis of AMSCR was conducted to address this issue. Specifically, the equilibrium posture of the AMSCR was determined by minimizing the total potential energy, considering different combinations of external magnetic field directions and internal magnetization patterns. Based on the resulting potential energy graph, the workspace of the AMSCR was quantitatively analyzed, and an optimal linear asymmetric magnetization pattern was identified. Furthermore, the proposed energy-based kinematic model was validated through finite element analysis (FEA) conducted using COMSOL Multiphysics, as well as through experiments performed on a fabricated AMSCR prototype. As a result, an optimal magnetization design method for linearly asymmetric AMSCRs was proposed and experimentally confirmed. The proposed approach is expected to be further applicable to the kinematic performance evaluation and design optimization of AMSCRs with various other magnetization patterns.