Fixed gain attitude control laws are sensitive to modeling errors and actuator nonlinearities. Adaptive control can solve many of these challenges.
We present a retrospective cost-based adaptive spacecraft attitude controller designed using the system's impulse response as modeling information. The performance metric is based on rotation matrices and thus, the controller does not suffer from singularities or discontinuities present in vector attitude representations.
We demonstrate robustness to inertia and actuator scaling as well as actuator misalignment and nonlinearities, unknown disturbances, sensor noise and bias for thrusters and reaction wheels through numerical simulations.
We implement an averaged Markov parameter and decentralized control to address the problem of the singular input matrix of magnetic torquers. For control moment gyros, we develop a hybrid linearization and impulse response-based Markov parameter and present new guidelines to evaluate the feasibility of desired rest-to-rest maneuvers.
Finally, we address the problem of angular velocity-free attitude control of a flexible spacecraft with noncollocated sensors and actuators. We present a new approach to controlling harmonic nonminimum-phase systems using the step and impulse response of the linearized system. We demonstrate robustness to model uncertainty through system analysis and numerical simulations.PhDAerospace EngineeringUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/111607/1/gecruz_1.pd
