A quadrotor is an omnidirectional unmanned air vehicle that is suitable for indoor flight because of its ability to hover and maneuver in confined spaces. The remote operation of this type of vehicle is difficult due to a lack of sensory perception; typically, the view from the onboard camera is the only information transmitted to the pilot. This thesis proposes using force feedback exerted by the command input device on the hand of the pilot to assist in avoiding collisions while navigating in indoor environments. Five candidate algorithms are presented for calculating the forces to be felt by the pilot based on the quadrotor's position and velocity in the indoor environment. The candidates include a parametric algorithm based on the dynamics of the quadrotor, two time-to-impact algorithms, and two algorithms that employ virtual springs between the quadrotor and obstacles. A method of incorporating the position of the command input device to improve the usability and effectiveness of the algorithms is also presented. A framework for simulating the quadrotor dynamics, indoor environment, and force feedback algorithms is described. In the simulation, the pilot commands a simulated quadrotor, using a commercial haptic interface, as it flies in an indoor environment. The pilot receives force feedback cues as the quadrotor navigates around obstacles. Two methods of control were used for the simulation. In the first method, displacements of the haptic interface correspond to velocity commands to the quadrotor. In the second method, displacements of the input correspond to desired roll and pitch commands. Two user study experiments, one for each control method, were performed to compare the force feedback algorithms in simulation. The results of the velocity control experiment suggest that higher force levels help to avoid collisions and that the time to impact algorithm results in fewer collisions than having no force, but is not significantly better than the other algorithms. The results of the angle control experiment suggest that the time to impact algorithm is clearly the best in terms of hits and hit length and has no disadvantages compared to the other algorithms. Finally, to demonstrate the force feedback algorithms and software in a real-world environment, the system was interfaced with a physical quadrotor. The quadrotor system is described and the results of the tests are presented.
| Identifer | oai:union.ndltd.org:BGMYU2/oai:scholarsarchive.byu.edu:etd-2923 |
| Date | 18 September 2009 |
| Creators | Brandt, Adam M. |
| Publisher | BYU ScholarsArchive |
| Source Sets | Brigham Young University |
| Detected Language | English |
| Type | text |
| Format | application/pdf |
| Source | Theses and Dissertations |
| Rights | http://lib.byu.edu/about/copyright/ |
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