| This research concerns the implementation of fuel optimal propulsive control techniques on experimental space structures using constant force reaction control jets. Due to the nature of the solution to the fuel optimal control problem, which is the form of impulses, approximations in the form of finite duration pulses must be formulated and implemented so as to preserve near optimality. Nonlinearities can restrict the solution to the fuel optimal control problem to systems of relatively low order. Approximations utilizing low order solutions may be used to develop near fuel optimal controls for higher order systems. In this dissertation, four experimental studies are presented which address issues involved when applying fuel optimal control techniques to systems of low and high order. A near fuel optimal feedback control strategy for spacecraft vibration suppression is tested on an experimental structure possessing a significant number of flexible body modes. An exact solution to the fuel optimal control problem is implemented on a slewing hinged-free beam experiment which possesses both rigid and elastic body modes. Fuel optimal rigid-body control is applied in the numerical simulation of a spacecraft undergoing both single-pass and two-pass aerocapture and comparisons are made with competing optimal control approaches. An experimental structure exhibiting space-like dynamics is developed to verify fuel optimal techniques in propulsive actuation for rest-to-rest maneuvers. Four approaches are presented which include open-loop control of an out-of-plane maneuver, hybrid control of an in-plane maneuver, open-loop control of an in-plane maneuver, and augmented open-loop control of an in-plane maneuver. |
