Rotating Magnetic Miniature Swimming Robots With Multiple Flexible Flagella

Recent studies have been carried out for rotating single flexible flagellum: a possible propelling mechanism that has been adopted by several artificial microswimmers due to its relatively simple structure yet considerable propulsive force generation. In this paper, we introduce a miniature swimming robot design with multiple flexible artificial flagella that benefits from the increased number of flagella. The characteristic length of the robot body is less than 1 mm. Experimental characterization of swimming of the robot shows that swimming speed can be linearly improved solely by increasing the number of attached flagella, suggesting a new way for speed enhancement besides flagellum geometry optimization. In addition, a numerical model modified from the single, straight flexible flagellum case is further established to study propulsive force generation by nonstraight, flexible flagellum. A robot with multiple, sinusoidal flagella design is fabricated to demonstrate the capability of the proposed two-step photolithography-based microfabrication method to handle more complex flagella designs, which may enhance swimming performance.