Six degree of freedom vehicle controller design for the operation of an unmanned underwater vehicle in a shallow water environment
Hajosy, Michael F.
MetadataShow full item record
Closed loop control of an unmanned underwater vehicle (UUV) in the dynamically difficult environment of shallow water requires explicit consideration of the highly coupled nature of the governing non-linear equations of motion. This coupling between an UUV's six degrees of freedom (6 DOF) is particularly important when attempting complex maneuvers such as coordinated turns (e.g. simultaneous dive and heading change) or vehicle hovering in such an environment. Given the parameter and modelling uncertainties endemic to these equations of motion, then a robust 6 DOF sliding controller employing six-element vector sliding surfaces provides a framework in which satisfactory UUV control can be achieved in shallow water. The vehicle equations of motion are developed and cast in a form that is amenable to non-linear sliding control design. A complete 6 DOF sliding controller with vector sliding surfaces is then formulated via a Lyapunov-like analysis. The sliding controller is then modified via a weighted least-squares approach to work with a particular UUV which has only 4 DOF control authority available. The modified controller is shown to work well for a variety of commanded UUV maneuvers in the presence of significant environmental disturbances and vehicle hydrodynamic parameter uncertainties via numerical simulation. Use of the signals generated by the controller are shown to be of utility in vehicle buoyancy control.
Submitted in partial fulfillment of the requirements for the degree of Ocean Engineer at the Massachusetts Institute of Technology and Woods Hole Oceanographic Institution September 1994
Showing items related by title, author, creator and subject.
Zhang, Yanwu (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2000-06)The thesis develops and demonstrates methods of classifying ocean processes using an underwater moving platform such as an Autonomous Underwater Vehicle (AUV). The "mingled spectrum principle" is established which concisely ...
Cooke, John G. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1989-09)The dynamics of an underwater vehicle are greatly influenced by the dynamics of the thrusters. Precise control, for example to perform repeatable survey or coordinated vehicle/manipulator control, should incorporate ...
Woodford, Thomas J. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1991-09)The oceanographic community is moving towards unmanned autonomous vehicles to gather data and monitor scientific sites. The mission duration of these vehicles is dependent primarily on the power consumption of the ...