Controlling swarms of micro-utility spacecraft.

摘要

Extending the operational lifetime and reliability of space systems requires many new on-orbit capabilities, including the ability to refuel, upgrade hardware, and detect and repair problems. The recognition of these needs and the vast foreseeable benefits of meeting them have sparked the development of multiple large-scale on-orbit servicing spacecraft programs, as well as a few small-scale technology demonstration platforms. The increased responsiveness and decreased cost of the latter provide the ability to prove certain crucial technologies more efficiently than their larger counterparts. Washington University's Bandit is one such vehicle currently in progress, designed to research the sensory, autonomy, and control problems of the multi-vehicle, close-proximity flight necessary to nearly all of the on-orbit servicing industry's ambitions.; This thesis addresses the multi-Bandit control problem, where success is defined by the attainment of stable and dynamically responsive swarm behavior while operating within the vehicle's highly limited actuation, computation, and state observation capabilities. To reach this end, a behavior-based potential function method is tailored for vehicles operating under such constraints. A stability analysis is derived that proves this controller will lead each inspector to its final desired equilibrium state within a calculable error bound, as is an analytical means to calculating control parameters. Specific potentials for inspection, docking, and collision avoidance are designed, and inspection and reconnaissance missions are simulated that prove the controller's general functionality, validate the derived analytical methods, and show favorable transient characteristics. They also reveal the aptitude of this behavioral method at adapting to changing mission requirements and unknown environmental dynamics. Future work will pursue further characterization of the robustness of the method, as well as explore the application of this controller and Bandit swarms to new on-orbit capabilities---such as assembly and asset protection tasks.