Magnetic propulsion performance of a compound spiral micro-robot applied in viscoelastic environment

In this paper, a novel robotic system in a viscoelastic intestine environment is described. It is about a magnetically actuated compound spiral robot (CoSbot), where an external master permanent magnet (MPM) is used to actively drive the robot, embedded with an internal slave permanent magnet. First, it has a compact structure with an integrated symmetric tile and two end caps. The integrated symmetric tile is comprised of four connected tiles with spiral ribs on the outside. This compound spiral outer structure could increase the hydrodynamic pressure, making the CoSbot suspend in the intestine with a non-contact posture. Second, since CoSbot is actuated by an external MPM, the robot can be further miniaturized without a loaded battery source, nor a complex actuation mechanism. Furthermore, an electromagnetic actuation system, to generate a rotational magnetic field controlling the stable motion velocity and axial force, is presented. Ex vivo contrast experiments have shown that CoSbot swims flexibly at a higher hydrodynamic pressure and suspended gesture.