<title>Neuromorphic optical flow sensing for Nap-of-the-Earth flight</title>

Abstract

Nap-of-the-Earth (NOE) flight and the development of advanced Unmanned Air Vehicles (UAV) require further integration of environmental sensors and onboard processing equipment. Flying insects feature a panoramic eye which relies on Optical Flow for guidance and obstacle avoidance. Furthermore, flies bear remarkable neural fusing of visual, inertial, and aerodynamic senses. We describe the development of a miniature electrically-powered UAV featuring a neuromorphic electronic eye based on biological motion detection. The system is tethered within the laboratory on a custom-built whirling-arm test bed. The 20-photoreceptor onboard eye signals are processed by 19 custom Elementary Motion Detection (EMD) circuits which are derived from those of the fly. Visual, inertial, and tachymeter signals from the aircraft are scanned by a PC data acquisition board. Flight commands are output via the parallel port to a microcontroller interfacing with a standard radio-control model transmitter. Vision-based flight path trajectories and landings are simulated. This UAV project is at the intersection of neurobiology, robotics, and aerospace. Its purpose is to test biologically-inspired sensory-motor concepts within a challenging environment and to provide principles and technology to assist Micro Air Vehicles (MAV) indoors operations.