Magnetically-Actuated Micro-Scale Bristle-Bots

This work presents micro-scale bristle robots, with the size of 233 μm × 113 μm × 75 μm, having five bristles on the top and bottom sides of the robot body. The bristles are tilted 60° from the horizontal surface. The presented micro bristle-bots are fabricated using two-photon lithography direct laser write, followed by nickel (Ni) deposition as the magnetic material. A single electromagnet lying underneath the substrate is used to actuate the robots. The magnetic field applies a torque on the nickel layer of the robot body and, combined with the ON/OFF switching of the magnetic field, induces a rocking motion. This, in turn, modulates the friction forces at the bristle tips via stick-slip cycle, resulting in a net horizontal displacement. This work marks the smallest reported bristle-bot to date.