Ground Reaction Force Sensing in Milligram-Scale Legged Microrobots

This work uses compliant mechanism design to create a two-axis vision-based force sensor to measure 2-DOF ground reaction forces (GRFs) of legged 1 mg microrobots. The sensor was designed with a genetic algorithm to tailor the stiffness matrix. The design is printed using direct laser lithography and integrated into the "ground" of an experimental platform for magnetically actuated microrobots. The sensor deformation is observed visually as the robot steps on it, resolving sub-μN GRFs of microrobots for the first time.