Trustable autonomous systems using adaptive control

A long standing problem in adaptive control is the derivation of robustness properties in the presence of unmodeled dynamics, a necessary and highly desirable property for designing adaptive flight control for systems with trustable autonomy. We provide a solution to this problem in this paper for linear time-invariant plants whose states are accessible for measurement. This is accomplished by using a Lipschitz continuous projection algorithm that allows the utilization of properties of a linear system when the adaptive parameter lies on the projection boundary. This in turn helps remove the restriction on plant initial conditions, as opposed to the currently existing proofs of semi-global stability. A direct implication of this result is the robustness of adaptive control systems to time-delays, and the guarantee that the underlying adaptive system will have a delay margin.