Attitude control of an underwater vehicle subjected to waves
Willy, Christopher J.
MetadataShow full item record
This paper presents a method for estimating the spectra of water wave disturbances on five of the six axes of a stationary, slender body underwater vehicle in an inertia dominated wave force regime, both in head seas and in beam seas. Inertia dominated wave forces are typical of those encountered by a 21 inch diameter, torpedo shaped underwater vehicle operating in coastal waters and sea state 2. Strip theory is used to develop transfer function phase and magnitude between surface water waves and the slender body pitch, heave, and surge forces and moment for the vehicle in head seas, and for pitch, heave, yaw, and sway forces and moments in beam seas. Experiments are conducted which verify this method of transfer function calculation, and demonstrate the effects of vehicle forward motion in the head seas case. Using known sea spectra and linear time invariant systems theory allows for estimation of the water wave disturbance spectra for these forces and moments. Application of sliding control techniques are then developed for the underwater vehicle longitudinal plane equations of motion. Computer simulations are used to demonstrate the dependence of underwater vehicle depth control upon the pitch control, and adaptive pitch control is shown to provide good performance in the presence of substantial parametric uncertainty. Pitch disturbance rejection properties of variations of the sliding controller are investigated. Both single frequency and stochastic disturbances are used, and the stochastic disturbance is developed using the results of the earlier investigation.
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.
Benthuysen, Jessica A. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2010-06)In a stratified rotating fluid, frictionally driven circulations couple with the buoyancy field over sloping topography. Analytical and numerical methods are used to quantify the impact of this coupling on the vertical ...
Magde, Laura S. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 1997-03)The formation of new oceanic crust is the result of a complex geodynamic system in which mantle rises beneath spreading centers and undergoes decompression melting. The melt segregates from the matrix and is focused to ...
Griffith, David R. (Massachusetts Institute of Technology and Woods Hole Oceanographic Institution, 2013-09)Steroidal estrogens are potent endocrine disrupting chemicals that are naturally excreted by vertebrates (e.g., humans and fish) and can enter natural waters through the discharge of treated and raw sewage. Because ...