Aggressive terrain following for motion-constrained vehicles in uncertain environments

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Abstract/Contents

Abstract
Scientific missions requiring underwater imagery or sample collection have often used highly maneuverable, remotely operated vehicles in order to operate close to the terrain. However, these vehicles come with limited operational range and high cost of operation. Long-range autonomous underwater vehicles (AUVs) can provide access to remote, potentially dangerous sites at a greatly reduced operational cost, but come with the added challenges of limited maneuverability and onboard computation. Recent advances in Terrain-Relative Navigation allow for high-precision map-relative localization. This in turn enables the use of prior map information for path planning purposes. This thesis presents a new approach for planning aggressive terrain-following trajectories that can provide improved imaging coverage while keeping the vehicle safe in an uncertain environment. Two methods are implemented for planning trajectories, incorporating constraints to both satisfy the dynamics of the vehicle and to maintain a safe minimum standoff distance in an uncertain environment. The first, using Model Predictive Control, allows for direct application of known vehicle dynamics, but does not provide real-time performance. The second, using geometric spline-based trajectories, must approximate the dynamics of the vehicle, but can provide trajectories to the vehicle in real time. This allows current measurements of the terrain to be combined with prior map information to provide the most up-to-date terrain information. This thesis also introduces a design tool utilizing the trajectory planning approach that can be used by vehicle designers to understand the terrain imaging capabilities of a particular vehicle configuration. Results of trajectories planned over regions of Monterey Bay are presented, and preliminary field trial results are shown for the vehicle tracking commanded trajectories. The design tool is demonstrated for challenging terrain in Monterey Bay evaluating the performance of the current vehicle and providing direction for the work required to perform imaging missions using the current vehicle.

Description

Type of resource text
Form electronic; electronic resource; remote
Extent 1 online resource.
Publication date 2016
Issuance monographic
Language English

Creators/Contributors

Associated with Houts, Sarah
Associated with Stanford University, Department of Aeronautics and Astronautics.
Primary advisor Rock, Stephen
Thesis advisor Rock, Stephen
Thesis advisor Kochenderfer, Mykel J, 1980-
Thesis advisor Schwager, Mac
Advisor Kochenderfer, Mykel J, 1980-
Advisor Schwager, Mac

Subjects

Genre Theses

Bibliographic information

Statement of responsibility Sarah Houts.
Note Submitted to the Department of Aeronautics and Astronautics.
Thesis Thesis (Ph.D.)--Stanford University, 2016.
Location electronic resource

Access conditions

Copyright
© 2016 by Sarah Emily Houts
License
This work is licensed under a Creative Commons Attribution Non Commercial 3.0 Unported license (CC BY-NC).

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