Vehicle Control in Full Unsteady Flow Using Surface Measurements

Abstract

This dissertation is the first comprehensive attempt to address a new engineering problem: control of a vehicle maneuvering in a full unsteady flow field. The approach to the solution is focused in three main areas: modeling of a vehicle in full unsteady flow, control of a vehicle in full unsteady flow, and synthesizing the fluid loads for use in control of a vehicle maneuvering in a full unsteady flow field. To model a vehicle maneuvering in a full unsteady flow field this dissertation develops the Coupled Fluid Vehicle (CFV) model in which the fluid, which is a sum of a finite number of spatially dependent velocity fields whose contributions vary with time, is coupled to the vehicle rigid-body equations of motion. To control a vehicle maneuvering in a full unsteady flow field this dissertation develops the Fluid Compensation Control (FCC) strategy which gives the designer an opportunity to include the fluid states, in addition to the vehicle states, in the control law and an opportunity to balance reducing the fluid dynamic load through compensation and reducing the state error through regulation. To synthesize the fluid loads this dissertation has attempted to forward current work on the prediction of fluid loads from stagnation and separation point measurements using the Kutta principle, which says that the velocity around a vehicle is a smoothly varying function and that it is determined up to a multiplicative constant by its nodes (stagnation, separation, and reattachment points/lines), and by conducting an experiment to attempt to determine the correlation of the fluidic loads from the orientation and separation lines on a 3-dimensional bluff body.