The work presented gives an energy-optimal solution to the guidance problem of an AUV. The presented guidance methods are for lower level control of AUV paths, facilitating existing global planning methods to be carried out comparatively more efficiently. The underlying concept is to use the energy of fluid flow fields the AUVs are navigating to extend the duration of missions. This allows gathering of comparatively more data with higher spatio-temporal resolution. The problem is formulated for a generalized two dimensional uniform flow field given a fixed final time and free end states. This allows the AUVs to navigate to certain spatial positions while maintaining the required temporal resolution of each segment of its mission. The simplistic way the problem is posed allows an analytical closed form solution of the Euler-Lagrange equations. Two dimensional thrust vectors are obtained as optimal control inputs. The control inputs are then incorporated into a feedback structure, allowing the particle to navigate in the presence of disturbance in the flow field. Further, the work also explores the influence of fluid-particle interaction on the control cost and behavior of the particle. The concept of changing the cost weights of the optimal cost formulation in situ has been introduced. Potential applications of the present concept are explored through an obstacle avoidance scenario. The optimal guidance methods are then adapted to non-uniform flow fields with quadratic and discontinuous spatial variation being the primary focus.
Doctor of Philosophy (Ph.D.)
College of Engineering and Computer Science
Mechanical and Aerospace Engineering
Length of Campus-only Access
Doctoral Dissertation (Campus-only Access)
De Zoysa Abeysiriwardena, Demuni Singith, "Energy-optimal Guidance of an AUV Under Flow Uncertainty and Fluid-Particle Interaction" (2018). Electronic Theses and Dissertations, 2004-2019. 6079.