Abstract-The design of autonomous robots involves the development of many complex, interdependent components, including the mechanical body and its associated actuators, sensors, and algorithms to handle sensor processing, control, and high-level task planning. For the design of a robotic bee (RoboBee) it is necessary to optimize across the design space for minimum weight and power consumption to increase flight time; however, the design space of a single component is large, the interconnectedness and tradeoffs across components must be considered, and interdisciplinary collaborations cause different component design timelines.In this work, we show how the development of a hardware in the loop (HWIL) system for a flapping wing microrobot can simplify and accelerate evaluation of a large number of design choices. Specifically, we explore the design space of the visual system including sensor hardware and associated optical flow processing. We demonstrate the utility of the HWIL system in exposing trends on system performance for optical flow algorithm, field of view, sensor resolution, and frame rate.