Cooperative Control Strategy of Magnetic Microrobots in Bifurcated Microfluidic Channels

Magnetically actuated nanoparticle microrobots have great potential for biomedical applications, especially in blood vessels. However, they face a complex bifurcation environment, and magnetic control strategies targeting a single pathway limit the operational efficiency of the targeting task. In this letter, we propose a cooperative control strategy of magnetic microrobots in bifurcated microfluidic channels. A nanoparticle microrobot can be disassembled into two by a dynamic magnetic field. The microrobot with a length of 3 mm needs to set the rotation frequency of the magnetic field to about 1.7 Hz. The velocity of the microrobot in the microfluidic channel is inversely proportional to the angle of contact between it and the microfluidic wall. Take advantage of this velocity property, a cooperative control strategy based on environmental heterogeneity to control the horizontal distance difference between two sub-microrobots is proposed. The control strategy is experimentally verified in 2-D space with an error within 1 mm. The integrated tasks of disassembly, cooperative control and reassembly are completed. This letter also discusses how this strategy could be extended to 3-D and arbitrarily shaped microfluidic channels.