Application of stochastic robustness to aircraft control systems

Stochastic robustness, a simple numerical procedure for estimating the stability effects of parameter uncertainty in linear, time-invariant systems, is applied to a forward-swept-wing aircraft control system. Based on Monte Carlo evaluation of the system's closed-loop eigenvalues, this analysis approach introduces the probability of instability as a scalar stability robustness measure. The related stochastic root locus provides insight into modal variations of the closed-loop system. Three linear-quadratic optimal controllers are chosen to demonstrate the use of stochastic robustness to analyze and compare control designs. The example considers the stability robustness effects of uncertain actuator dynamics and higher order dynamics. Analysis of stochastic robustness is shown to provide a valuable tool for control system design.