Design and simulation analysis of an octopus-inspired programmable magnetic soft robot.

Bioinspired soft robots leverage the efficient deformation mechanisms of living organisms to navigate complex environments. Magnetic actuation is a particularly promising modality for these designs due to its wireless control, rapid response, and biocompatibility. However, achieving sophisticated and controllable deformation remains a significant challenge. Inspired by the versatile deformation and stiffness-tuning capabilities of octopus tentacles, this study proposes a programmable magnetic soft robot (PMSR). The PMSR incorporates a truncated cone profile and an axisymmetric V-shaped notch structure to regulate its axial stiffness distribution, with internal magnetization profiles defined via programmable magnetization technology. A magnetic-mechanical coupling finite element model was established, incorporating mesh independence verification and literature benchmarking to systematically investigate deformation behavior of the PMSR under non-uniform magnetic fields derived by permanent magnet (PM). Simulation results demonstrate that adjusting the working distance and rotation angle of PM enables controllable bending. Extensive parametric studies elucidate the influence of notch geometry, magnetization patterns, material stiffness, and remanent magnetization on actuation performance. Furthermore, contact mechanics simulations in simplified vascular interventional scenarios show that the contact pressure between the PMSR tip and the vascular wall remains within a preliminary safe operational limit across various advancement distances and vessel curvatures. This work provides a robust analytical framework for the systematic design and performance prediction of bioinspired magnetically controlled soft robots.