Design, Fabrication, and Characterization of a Helical Adaptive Multi-Material MicroRobot (HAMMR)

Adaptive locomotion is an advanced function of microrobots that can be achieved using smart materials. In this letter, a responsive hydrogel is utilized as a smart material and used to fabricate Helical Adaptive Multi-material MicroRobots (HAMMRs) with deformable tails to achieve adaptive locomotion capabilities. Moreover, a novel fabrication method is proposed to realize these types of helical microrobots with enhanced swimming performances by taking advantage of a strong magnetic head and deformable tail. The deformations of different tail designs and the fabricated microrobots are tested in different solvents. The swimming performances of the swimming microrobots are investigated experimentally under a rotating magnetic field and verified with theoretical calculations. The HAMMRs show significant deformations upon stimulation and changes in swimming performance which are in agreement with the scaled calculation result. Finally, the HAMMRs present an enhanced mobility with a highest published translational velocity for an adaptive swimming microrobot of 8.1 body length per second.