Three dimensional independent control of multiple magnetic microrobots

A major challenge for untethered micro-scale mobile robotics is the control of many agents in the same workspace for distributed operation. In this work, we present a new method to independently control multiple sub-mm microrobots in three dimensions (3D) using magnetic gradient based direct pulling as the 3D motion generation method. This is accomplished through the use of geometrically or magnetically distinct microrobots which assume different magnetization directions in a rotating magnetic field. Such diversity in design allows for different magnetic forces to be exerted on each, enabling path following with less than 370μm mean path deviation for a set of two microrobots of size 350μm and 1500μm. This addressability method could be used for the 3D control of a team of microrobots inside microfluidic channels or in the human body for localized therapy or diagnostics.