Selective Geometric Modification for Independent Actuation of Multiple Soft Magnetic Manipulators

Soft Magnetic Manipulators (SMM) have the potential to improve current endoscopic procedures through extreme miniaturization and inherently safe tissue interaction. This relatively new field of soft robots is being extensively researched for various medical applications. However, utilization of two or more SMMs under stable control within the same workspace is challenging due to their exposure to similar or identical applied magnetic fields and field gradients. To improve stable independent control of SMMs in a shared workspce, we explore geometric varations to the SMM design, consisting of elastomeric double helices wrapped around a cylindrical core. The influence of geometrical properties on stiffness in two bending planes is investigated, as well as torsional stability across six tested designs. Experimentally acquired data on bending and twisting of proposed designs is compared to equivalent soft magnetic cylinders. Finally to demonstrate the capability of independent actuation, two selected designs are tested in multi-SMM parallel configurations, consisting of two and three parallel SMMs within the same workspace.