3-DOF untethered microrobot powered by a single laser beam based on differential thermal dynamics

The paper proposes a method of using laser as both a source of energy and means of control for untethered microrobots. Instead of using multiple laser spots to thermally control the motion of multiple robot actuators, the paper proposes to shape the power, frequency, and duty cycle of a single laser beam focused onto the whole body of the robot. It is shown through simulations that an appropriate selection of laser parameters along with a corresponding mechanical design can generate appropriate "stick and slip" motions resulting in 3-DOF (planar) operation for the microrobot with nonholonomic constraints. Based on the simulation results, we anticipate that the microrobot with a thickness of a few micrometers and a width of several hundred micrometers can achieve speeds in excess of a few mm/second, comparable with more conventional electrostatically and electromagnetically actuated microrobots. Initial experiments on chevron actuators confirm that pulsed laser can effectively drive stick-slip microrobots.