Adaptive control of an aircraft with uncertain nonminimum-phase dynamics

This paper investigates four control architectures that use adaptive control to follow step, ramp, and harmonic roll-angle commands for a linearized aircraft model with an unknown transition from minimum-phase to nonminimum-phase (NMP) dynamics. In particular, we consider retrospective cost adaptive control (RCAC) with 1) a command-feedforward control architecture; 2) an output-feedback control architecture; 3) a centralized control architecture that uses both command feedforward and output feedback; and 4) a decentralized control architecture that uses both command feedforward and output feedback. For baseline tests, we assume that the location of the NMP zero is known. The goal of this work is to improve the transient response and rate of convergence. Numerical testing shows that RCAC with the decentralized control architecture using command feedforward and output feedback gives the fastest convergence. Furthermore, resetting controller coefficients at the start of the transition improves the transient response.