Equitranslational and axially rotational microrobot using electromagnetic actuation system

Recently, many researchers have focused on wireless microrobots as therapeutic agents for active drug delivery. Owing to their size limitation, they cannot be equipped with actuators/sensors, controllers and batteries. Therefore, external devices (magnetic field generator, position recognition devices, and control system) are used to realize the main functions (locomotion, sensing, and therapy) of biomedical microrobots and thus, to minimize their size. Especially, the small wireless microrobots, inserted into the human body, should have various steering, locomotive, and therapeutic functions for diagnosis and treatment. Generally, an external magnetic field is widely used for the locomotion of a wireless microrobot. However, microrobots using an external magnetic field cannot simultaneously realize equitranslational and axial rotational motions in the same microrobot system. In this paper, we developed an electromagnetic actuation (EMA) system and a spiral-shape microrobot and proposed its actuating algorithm. The developed wireless microrobot can show equitranslation and axial rotation in the same microrobot system. Finally, various experiments in a test-bed and in a blood vessel phantom validated that the developed microrobot can move to a target position by equitranslation and can penetrate a thrombus model by axial rotation.