Synopsis "Formation Flight Control for Aerial Refueling"
A controller is designed for an aircraft to autonomously fly formation during aerial refueling. Requirements for a refueling autopilot are stated. A six-degree-offreedom model is developed for an F-16 lead aircraft and a Learjet LJ-25 wing aircraft. Bare airframe stability of both aircraft is investigated, and stability augmentation is performed. A Matlab Simulink simulation is built to reproduce the sensor inputs that will be available to the wing aircraft in flight, including disturbances. Control frames are investigated to determine the optimum presentation of the error vector for control during the task of air refueling. Control laws are developed from the initial premise of proportional-plus-integral control on position error only, and made more complex until desired performance is achieved. Tanker flight profiles are designed for the lead aircraft, and simulations are accomplished to estimate controller performance. Stability and robustness are investigated through the addition of noise, turbulence, and time delays while exploring the capability limits during increasingly aggressive profiles. Modifications for flight test are described, and flight test results are reviewed from 7 formation flights of a USAF C-12 and a Learjet LJ-25 under fully autonomous control in an operationally representative refueling environment. Actual controller performance is analyzed and compared to predictions, and suggestions are made for future controllers.This work has been selected by scholars as being culturally important, and is part of the knowledge base of civilization as we know it. This work was reproduced from the original artifact, and remains as true to the original work as possible. Therefore, you will see the original copyright references, library stamps (as most of these works have been housed in our most important libraries around the world), and other notations in the work.This work is in the public domain in the United States of America, and possibly other nations. Within the United States, you may freely copy and distribute this work, as no entity (individual or corporate) has a copyright on the body of the work.As a reproduction of a historical artifact, this work may contain missing or blurred pages, poor pictures, errant marks, etc. Scholars believe, and we concur, that this work is important enough to be preserved, reproduced, and made generally available to the public. We appreciate your support of the preservation process, and thank you for being an important part of keeping this knowledge alive and relevant.
