Wind Estimation and Closed-loop Control of a Soaring Vehicle

Open Access
Author:
Bird, John Joseph
Graduate Program:
Aerospace Engineering
Degree:
Master of Science
Document Type:
Master Thesis
Date of Defense:
None
Committee Members:
  • Jacob Willem Langelaan, Thesis Advisor
Keywords:
  • soaring
  • uav
  • uas
  • drone
  • energy harvesting
  • bio-inspired
  • dynamic soaring
  • wind mapping
  • atmosphere
  • glider
Abstract:
Birds possess a remarkable ability to harvest energy from the atmosphere, allowing them to traverse vast regions foraging for food. From the thermalling flights of raptors and vultures to the astonishing flights of the albatross in the maritime wind shear, birds have shown that their soaring ability is diverse and adaptable, making such techniques of interest for improving performance of small uninhabited air vehicles. This thesis investigates techniques to map the wind field surrounding an aircraft and then to exploit that wind field for energy to sustain flight. Wind is accomplished through the use of the Kalman filter and its nonlinear variants applied to spline models and selected model functions. Both arbitrary two-dimensional updraft fields and vertical wind shears with anticipated forms are investigated through simulation and some flight experiments. Exploitation strategies and path following controllers to exploit wind maps are also investigated. A contour approach is used to exploit two-dimensional maps of convective updrafts, while a trajectory planning and selection system is used to exploit vertical shear of the horizontal wind. Path following controllers are developed to guide the aircraft on energy harvesting trajectories in both environments, and their suitability is investigated in simulation. The final result is a system that allows an aircraft with no knowledge of the wind field gather information, plan energy harvesting paths, follow the required trajectory, and update the trajectory as information is gathered. This system closes a loop around the energy harvesting problem. Batch and hardware in the loop simulation is used to establish the capability of the system.