Low-Mass and Low-Power Optical Flow Sensing and Control for Insect-Scale Flying Microrobots

Abstract

Past efforts in manufacturing, design, and fabrication have led to the realization of robotics at the insect-scale, including flapping-wing, flying microrobots at the scale of natural bees. Initial demonstrations were impressive from a mechanical and control engineering perspective, but rely on large motion tracking camera systems and external computers. This work describes some initial steps in transitioning from large external sensors and computation to prototypes that could potentially be integrated onboard. A system on chip (SOC) design for microrobotics applications consisting of an ARM Cortex-M0 with custom designed hardware accelerators for sensor interfaces, optical flow processing, control processing, and actuation output is emulated on a Field Programmable Gate Array (FPGA). The FPGA based microrobotics SOC is integrated with an insect-scale, flapping-wing, flying microrobot and at-scale sensors to verify the performance of each component. Towards onboard sensing, two at-scale optical flow based sensing strategies are presented. First, a 1D constrained optical flow based altitude control with an onboard optical flow camera is presented. Lastly, a combined Optical Flow and Inertial Measurement Unit (OF-IMU) sensor is fabricated at-scale and characterized for lateral position estimation.