A Scalable, Economic Autonomous Flight Control and Guidance Package for UAVs

Abstract

As unmanned aerial vehicles (UAVs) rapidly evolve from remotely piloted vehicles (RPVs) to fully autonomous systems capable of performing aerial objectives and full missions without any assistance from a human operator, the need is emerging for a robust, economical, mission and flight control package which can be integrated to a variety of diversely capable airframes and platforms. At Cornell University, a flight control and mission guidance package has been rapidly developed to fulfill the requirements of operators wishing to adapt fixed-wing UAV and RPV platforms to an autonomous operational capability. Primary objectives for the project included low cost and versatility, in addition to the robustness and flexibility which allows the system to be easily and rapidly adapted to various airframes. The development package core consists of an embedded Crusoe i386 computer with PC 104 expansions, running Windows Embedded. Primary flight control operations rely on real-time feedback from solid-state attitude sensors, barometric airspeed and altitude sensors, and a digital magnetic compass. Navigation systems have been designed primarily to reference positioning information from the GPS satellite constellation. In addition, the flight and mission control package includes a real-time telemetry capability which may be adapted to operate on a number of suitable bandwidths. Telemetry allows operators to monitor the progress of preloaded missions while also providing the capability to update or alter mission parameters on the fly from a suitably configured ground-based interface. In addition to the computing and sensory elements, the core package includes appropriate power distribution for all on-board systems. The power supply is easily configured to allow for missions of varying duration, in addition to airframes with dissimilar power consumption or generation profiles. Primary system power is stored in the form of low-cost lithium polymer cells, and regulated through the package power supply. The development package has been designed to interface with servo-driven flight control surfaces, but flexibility allows for any number of interfaces which share compatibility with the system’s multiple I/O capabilities. These interfaces include serial (RS-485/RS-422/RS-232), parallel, USB, and Ethernet, in addition to the PC 104 Plus bus. Driving constraints for the development of this flight and mission control package were maintaining a robust and flexible system, while also keeping the package cost-effective. By utilizing robust, off the shelf hardware and system programming environments where appropriate, this project has quickly evolved to a prototype stage without sacrificing either cost or functionality. As currently configured, the core flight and mission control package can be rapidly adapted to any fixed-wing airframe. Minimal reliance on specialized hardware during the design stage ensured that critical parameters—such as controller constants—remained functions of software, and can be rapidly adapted as the package is moved between airframes. With a nominal package mass of 3kg and a prototype development cost of around $4,000 USD, the package stands to be easily adapted to a wide variety of existing airframe sizes while leaving room for ample mission capabilities, in addition to meeting overall expectations for economy and flexibility. 2nd AIAA Unmanned Unlimited Systems, Technologies, and Operations — Aerospac 15 18 September 2003, San Diego, California AIAA 2003-6505 Copyright © 2003 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved. Page 2 of 10 American Institute of Aeronautics and Astronautics INTRODUCTION As with many advanced unmanned systems, technologies and capabilities for unmanned aerial vehicles (UAVs) were primarily developed to serve the defense sector. Increasingly, however, these systems are experiencing a rollover into commercial and academic research areas such as survey work and aerial biology investigations. This transition has encouraged operators to seek a highly capable but affordable means of incorporating unmanned system capability into their operations, which cannot practically support the high overhead required of most defense-oriented systems. Further, as UAVs rapidly evolve from remotely piloted vehicles (RPVs) to fully autonomous systems capable of performing aerial objectives and full missions without any assistance from a human operator, the need is emerging for a robust, economical, mission and flight control package which can be integrated to a variety of diversely capable airframes and platforms.