Direct Adaptive Augmentation of a Linear Controller for a Plant with Unmatched Uncertainties with an Application to Aircraft Fly-by-Wire Control

摘要

A method for direct adaptive fly-by-wire (FBW) flight control in a linear longitudinal dynamics model was developed and studied. Direct adaptive augmentation is used to recover baseline performance of a linear controller in the presence of unmatched uncertainties without an estimation loop. A method is proposed to determine how well the plant has to be known in order for the adaptive controller to maintain its theoretical foundation. This approach makes it possible to use linear quadratic regulator theory for tracking and a direct adaptive controller to compensate for plant uncertainties. A description of the new approach is presented, followed by an application example an simulation results. The results show that the adaptive controller was able to recover the baseline performance in the presence of unmatched uncertainties, as long as the uncertainties were inside predicted range. Recommendations are given for follow-on flight research and instrumentation.