Details

Vision-Based Control and Flight Optimization of a Rotorcraft UAV Vision-Based Control and Flight Optimization of a Rotorcraft UAV

by Hubbard, David Christian

Abstract (Summary)
A Rotorcraft UAV provides an ideal experimental platform for vision-based navigation. This thesis describes the flight tests of the US Army PALACE pro ject, which implements Moravec’s pseudo-normalized correlation tracking algorithm. The tracker uses the movement of the landing site in the camera, a laser range, and the aircraft attitude from an IMU to estimate the relative motion of the UAV. The position estimate functions as a GPS equivalent to enable the rotorcraft to maneuver without the aid of GPS. Flight tests were performed with obstacles and over concrete, asphalt, and grass in daylight conditions with a safe landing area determined by a separate method. The tracking algorithm and position estimation performance are compared to GPS. Accurate time synchronization of the inputs to the position estimation algorithm directly affect the closed-loop stability of the system, proportional with altitude. By identifying the frequency response of each input and adding filters to delay some of the inputs, the closed-loop system maintains stable flight above 18 m above ground, where the system was unstable without the additional filters.
Bibliographical Information:

Advisor:

School:Brigham Young University

School Location:USA - Utah

Source Type:Master's Thesis

Keywords:computer vision real time rotorcraft helicopter uav

ISBN:

Date of Publication:05/24/2007

© 2009 OpenThesis.org. All Rights Reserved.