Selective separating and assembling motion control for delivery and retrieval of an untethered magnetic robot in human blood vessels

We developed an integrated magnetic robot (IMR) that can selectively separate and assemble tethered and untethered magnetic robots. The proposed IMR is composed of a flexible-legged untethered magnetic robot (FLUMR) and a delivery catheter. Assembled magnets (AMs) with zero net magnetic moment are placed at the distal tip of the catheter and the rear part of the FLUMR. A selective separating and assembling (SSA) mechanism was proposed that can control the separating and assembling motion by an external magnetic field (EMF) to generate relative rotational movements between the catheter and FLUMR by selectively producing the attractive and repulsive forces between AMs. Finally, the IMR was prototyped to verify the SSA mechanism, and the separation, mobility, drilling, and retrieval of the developed IMR using SSA mechanism was verified in in vitro experiments.