Untethered Octopus-Inspired Millirobot Actuated By Regular Tetrahedron Arranged Magnetic Field

Flexible magnetic small-scale robots (overall dimensions smaller than 1cm) can use a patterned magnetization profile to noninvasively access a confined, enclosed liquid environment and therefore achieve applications in object manipulation or in minimally invasive procedures. Existing magnetic-controlled small-scale robots have shown wide usage for their high mobility and higher degrees of freedom than their rigid counterparts. Herein, an octopus-like soft robot is proposed for potential use in biomedical and engineering fields. First, a magnetic control system is established, which uses the minimum number of coils arranged by a regular tetrahedron structure. This system responds quickly and with high precision to propel a robot in 3D space utilizing the coupled field from multiple electromagnets in concert. An octopus-like robot with three legs is designed, which moves freely in the workspace without constraints. A time-asymmetric gradient magnetic field is applied, to ensure that the movement of the robot is more stable and controlled. At the same time, the movement of the tail improves the precision of the robot and makes control easier.